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ELEMENTS 
 
 or 
 
 CHEMISTRY; 
 
 CONTAINING Tlin 
 
 °IIINCIPL£S OF THE SCIENCE, 
 
 EXPERIMENTAL AND THEORETICAL. 
 
 INTENDED AS A TEX I 
 
 AM' CO' 
 
 ILU/S'I R VTED WT v 
 
 - 
 
 1>Y VLONZO $RA"1 . \ 
 
 •ROFMiOR OF CUEMIstrv, natiual rm; ITOIt IN TBI 
 
 BROOKLYN NKW TOM. 
 
 FORTIETH EDITH 
 
 NEW YORK: 
 
 Published by mark h. nkwman & co., 
 
 no. n99 b a o 1 1) \\ i v 
 
tf& 
 
 V 
 
 %* % 
 
 >v 
 
 Entered according to Act of Congress, in the year 1840, 
 
 By Alonzo Gray, 
 In the Clerk's Office of the District Court of Massachusetts. 
 
 
 # 
 
/ / 
 
 PREFACE 
 
 $^l 
 
 *> 
 
 'X 
 
 In compJjflgntHe fii*st edition of this work, the author 
 attempted to prepare a text-book which should be well 
 fitted for elementary instruction. Most of the works on 
 chemistry appeared to him to be either too profound, on the 
 one hand, for those who were just commencing the study, or 
 too superficial, on the other, for those who wished to obtain 
 a scientific knowledge of the subject. ' 
 
 The design was to avoid these two extremes, and com- 
 bine the scientific with the popular and useful parts of the 
 subject. The rapid sale of the^first edition, and its intro- 
 duction into several colleges, have led to the -inference that 
 the attempt has not been_who%f pn%urees_sfulf The author 
 has therefore been 1ffify<J\d to revTse'and enlarge the work, 
 and put it into a I permanent form. A large amount of 
 matter, and numerous^engravings, have been added, for the 
 purpose of rendering the work better adapted to academies 
 and other schools.' 
 
 It is believed that greater success would attend the efforts 
 of teachers in this branch of science, if more attention were 
 given to the principles of chemistry, and less to its details. 
 The fundamental principles being thoroughly understood by 
 the student, he is prepared to attend to the details with 
 greater pleasure and success, as he will be able to connect 
 the effects with their appropriate causes. 
 
 Under the influence of this belief, the author has given a 
 greater prominence to the imponderable agents and the thir- 
 
PREFACE. 
 
 teen non-metallic substances, than to other parts of the work. 
 Most of the illustrations and experiments are introduced in 
 this part, so as to present and illustrate the philosophy of 
 chemical combinations, and the general nature of the com- 
 pounds thus formed ; in other words, the causes of chemical 
 changes and the mode of studying them. 
 
 By the introduction of numerous experiments and illus- 
 trations, the object has been to give to the work a prac- 
 tical character, so that the teacher, with a very simple 
 apparatus, and with limited means, may be able to give 
 numerous experimental illustrations to his classes. The im- 
 portance of studying chemistry experimentally, is admitted 
 by all ; and to aid teachers in constructing the more simple 
 forms of apparatus, many notes and drawings have been 
 added, and experiments described, which may easily be 
 performed by those who are not privileged with more costly 
 and extensive means of illustration. 
 
 In the arrangement of the imponderable agents, the phe- 
 nomena of common and voltaic electricity, electro-magnet- 
 ism, and magneto-electricity, are classed as effects of one 
 agent — electricity. 
 
 In the arrangement of the simple /-suj^tances, the logical 
 order has been adopted ; that is^fc^ch simple substance is 
 described, and then its combinations with those only which 
 have been previously describ&of so that only one substance 
 with which the pupil is unacquainted is presented at a time. 
 This classification a$p$a*rs to be the most convenient for 
 presenting the different compounds, and less liable than any 
 other to confuse the mind of the learner. This order, how- 
 ever, has been adopted only with the simple substances and 
 their binary compounds. 
 
 The salts occupy a separate chapter, in the arrangement 
 of which Turner's Chemistry has been made the basis. 
 Several new salts, and one entire family, — the silicates, — 
 have been added. 
 
PREFACE . 
 
 The chapter on Organic Chemistry has been entirely re- 
 written, and the whole very much enlarged, exhibiting the 
 new views contained in the works of Kane, Graham, and 
 Fownes — to which works, for further details, the student is 
 referred. <^ 
 
 The chapter on Analytical Chemistry ftas been consider- 
 ably enlarged ; but the methods of l^aaiysis have become so 
 accurate, the details so minute^ and the processes so com- 
 plicated, that those who_would obtain a full mastery of the 
 subject, must consuls Wt>rKs which treat particularly of 
 chemical analysis, ^sufficient only has been inserted to 
 give the pupil some idea of the nature of the processes, and 
 to enable him to test, if not actually to analyze, the sub- 
 stances which are mentioned. 
 
 The Glossary of chemical terms has been selected from 
 that prepared by Daniell, of LondoA and adapted to this 
 work. The table of con teqts<jtia> been much enlarged, and 
 a complete analysis of tfj^wOrk presented, in the form of 
 topics, which are^jnjended to be used instead of questions ; 
 the topics be^pg so arranged that, when the teacher sug- 
 gests one, the pupil may give a complete description of it. 
 This plan, it is believed, will prevent the evils incident to 
 direct questions, while it will secure all their advantages. 
 
 Chemical formulae have been extensively adopted. This 
 appears highly important, especially for those who intend 
 to become thorough students in the science. The notation, 
 (the use of symbolical language,) to express, in a condensed 
 form, complicated chemical changes, seems to be as useful 
 in chemistry as in algebra, and, although these symbols may 
 be unintelligible to the common reader, he who will thorough- 
 ly study them will find them the most efficient aid to a clear, 
 definite, and easy comprehension of the whole science. 
 
 In the description of the ponderable bodies, brevity has 
 
6 PREFACE. 
 
 been consulted, as far as was consistent with perspicuity 
 The illustrations and descriptions are much more extended 
 in the first two hundred pages than in other parts of the 
 work. The method of description which is employed in 
 natural history has been adopted, where the subject did 
 not require a more popular style. By this means, and by 
 using different kinds of type, a large amount of matter has 
 been condensed into a small compass, while, at the same 
 time, that which is more important to be studied is rendered 
 conspicuous. Many subjects of minor importance are only 
 alluded to, and reference frequently made to more extensive 
 works. 
 
 The sources from which most of the materials have been 
 drawn, are the works of Turner, Graham, Kane, and 
 Fownes. Other works have been consulted, and also many 
 original papers in the scientific journals of the day'; and it 
 is confidently believed, that in the recent revision of the 
 work no important discovery has been omitted. 
 
 a. a 
 
 Brooklyn Seminary, 
 January, 1848. 
 
fc>e 
 
 CONTENTS. 
 
 INTRODUCTION. 
 
 Page 
 Science defined — Physical and Natural science 21 
 
 Definition of matter — how many properties does it embrace ? 21 
 
 Division of Natural Science. 
 
 I. Natural Philosophy — method and object of. 21 
 
 ' II. Chemistry — method and object of 22 
 
 III. Natural History — method and object of 22 
 
 Plan of the Work. 
 
 Part I. Imponderable Agents — why so called 22 
 
 II. Chemical Affinity — definition of 23 
 
 III. Ponderable Bodies — chemical and natural substances. 24 
 Division of substances ; simple and compound bodies.... 24 
 Analysis and synthesis ; arrangement of chem. substances 24 
 
 PART FIRST. 
 
 CHAPTER I. — CALORIC. 
 
 The term heat how used — meaning of calorie 25 
 
 1. Sensible caloric defined. — 2. Insensible caloric do 25 
 
 Sect. 1. Sensible Caloric — Communication of. 
 
 The most important property of sensible caloric 26 
 
 I. Conduction — meaning and illustration of 26 
 
 Conducting power ; how does it differ in bodies ? 26 
 
 Different degrees of this power illustrated 27 
 
 1. Conducting power of solids ; illustrated by conductometer 27 
 
 Best and poorest conductors, metals, stones 27 
 
 Uses of conductors, benevolence of God illustrated 28 
 
 Ratio of the conducting power of solids 28 
 
 2. Conducting power of liquids ; how are liquids heated ? Ills 28 
 
 Heat applied at the top of liquids in a glass jar 29 
 
 3. Conducting power of gases ; how are they heated ? 29 
 
 II. Radiation — defined; radiant caloric, how projected ? 30 
 
 1 . Law of the intensity of heat at different distances 30 
 
 2. Degree of radiation, dependent upon what ? 30 
 
 Difference between bright, and dark or rough surfaces, Ills 30 
 
 Greater radiating power of rough surfaces/depends on what?. . 30 
 
8 . ^ CONTENTS. ^ 
 
 x .- V s * \ ■ ■ \ • , \\ 
 
 3. Rapidity of radiation dependent upon what ? 31 
 
 III. Disposition of Radiant Caloric — reflect., absorb., transmit. 31 
 
 1. Reflection of caloric ; law of reflection, angles of incidence and 
 
 reflection. Concave mirrors described 31 
 
 2. Absorption of caloric ; depends upon what ? 32 
 
 Best absorbers, reflectors, and radiators 32 
 
 Color of surface ; its effect upon the power of absorp., Ills 32 
 
 3. Transmission of caloric ; through air and gases, glass, etc 32 
 
 Opinions of Leslie, Brewster, De la Roche, and other chemists. 33 
 
 Radiant caloric modified by its connection with solar light 33 
 
 IV. Theories of Radiation — how many are worthy of notice ?. . 33 
 
 1 . Theory of Pictet, described 33 
 
 2. Theory of Prevost, do. grounds of preference 33 
 
 V. Application of the Theory of Prevost to the Expl. ofvaris Then 
 
 1. The phen. of the mirrors explained ; apparent radiation of cold. . 34 
 
 2. Formation of dew, process described and explained 34 
 
 Quantity of dew ; dep. upon what? grass, and polished surface.. 34 
 
 Why is there no dew in a cloudy night ?. 35 
 
 VI. Cooling of Bodies — different modes by which it is effected. 35 
 Velocity of cooling, defined; law of cooling, according to Newton. 35 
 
 VII. Prac. Application of the Laws of Conduct, and Radiant Caloric. 
 
 Best materials for windows ; double walls, doors, windows 35 
 
 Object of clothing ; kind best for different seasons of the year 36 
 
 Effects of Free Caloric. 
 
 I. General Law — Caloric expands all Bodies; Liquids, Solids, Gases. 
 
 1. Caloric expands solids ;. illustrated by what ? 36 
 
 2. Equal degrees of caloric expand some solids more than others.. . 36 
 Illustrated by pyrometer ; description of pyrometer 36 
 
 3. Effect of equal add'ns of caloric on the same solid at dif. temp's. 37 
 Expansion of brass and iron rods in the higher or lower temp's.. 37 
 
 4. Uniformity in the expansion of certain solids 37 
 
 II. Caloric expands Liquids more than Solids. 
 
 1. Illustrated by heating water in a glass tube, common thermom'r 38 
 
 2. Effect upon different liquids of equal degrees of caloric 38 
 
 3. Effect upon the same liquids of equal degrees at different temp's 38 
 Apparent exceptions to the general law that heat expands 38 
 
 III. Caloric expands Gases more than Solids or Liquids. 
 
 1. The expansion of air ; in glass ball, bladder 38 
 
 2 Law of the expansion of gases at all temperatures 39 
 
 Difference between gases, and solids or liquids 39 
 
 Theory of expansion ; caloric and cohesion, how related ?...... 39 
 
 IV. Apparent Exceptions to the General Law. 
 
 Water near the point of congelation ; Illustration 40 
 
 V. Force of Expansion when Water freezes. 
 
 Florentine Academicians ; experiments of Major Williams 40 
 
 Theory, or the cause of expansion when water freezes 40 
 
 VI. Advantages of this Excep. — wisdom and benevolen. of God 40 
 Process of freezing water ; effect if the contractions continued. . . . 41 
 Cast iron and antimony, how affected in cooling ? 41 
 
 VII. Practical Uses of the General Laic of Expansion and Contract. 
 
 Banding of wheels, steam-engine boilers, gallery at Paris 41 
 
 Winds ; depend upon what ? land and sea breezes 42 
 
 Thermometers ; by whom invented ? 42 
 
 1. Air thermometers ; plan of Sanctorius, illustrated 42 
 
CONTENTS. 
 
 9 
 
 Objections to air for the common purposes of a thermometer. . . . 43 
 
 2. Differential thermometer of Leslie ; mode of construction 43 
 
 Best substance for thermometers ; solids, liquids, or gases ? 43 
 
 3. Mercurial thermometer; construction and graduation ,... 44 
 
 Different scales; Fahrenheit's, Reaumur's, De Lisle's, Celsius's 45 
 
 4. Register thermometer; construction, object, and principle of... 45 
 Pyrometers ; derivation and meaning of the term 46 
 
 1. Pyrometer of Wedgwood ; founded upon what property 46 
 
 2. do. of Daniell ; construction of 46 
 
 3. Metallic thermometer of Brequet; construction, Illustrated 46 
 
 Amount of knowledge obtained by therm's and other instruments 47 
 
 Sect. 2. Insensible Caloric. ^ 
 
 Specific caloric ; meaning of, illustrated 47 
 
 Methods of determining specific heat of solids and liquids 48 
 
 Laic? of Specific Heat, I, 2, 3, 4, 5 48 
 
 Practical inference from the doctrine of specific heat 49 
 
 Effects of Insensible Caloric. 
 
 I. Liquefaction — states in which bodies exist 49 
 
 ] . Point of liquefaction ; fusion, congelation . 49 
 
 2. Caloric of fluidity ; Illustr., quantity in different substances. .. . 49 
 
 3. Freezing mixtures ; how produced ? salt and snow. 50 
 
 4. Limit to the decree of cold ; greatest cold by these processes.. . 51 
 
 5. Absolute amount of heat ; estimated by what means ? 52 
 
 II. Vaporization — defined, difference between gas and vapor. .. 52 
 Definition of volatile and fixed bodies ; liquids how vaporized.... . 52 
 
 Ebullition; 1. Boiling point defined ; is it fixed? 52 
 
 2. Circumstances which modify the boiling point of liquids 53 
 
 Pressure of the atmosphere ; variations of. 53 
 
 Barometer, construction and illustration of 53 
 
 1. Law of the boiling point as the pressure diminishes 53 
 
 Mercury frozen under the exhausted receiver of an air-pump. . 53 
 
 2. Law of the boiling point as the pressure increases 54 
 
 Marcet's digester ; construction of 55 
 
 Absorption of free caloric in ebullition, Illustration 55 
 
 Table of the latent heat of different vapors 56 
 
 Steam ; its formation and laws of expansive force 56 
 
 Sensible and insensible caloric of steam at all temperatures 57 
 
 Application of Steam to practical Purposes. 
 
 1 . Warming rooms ; water baths, dyeing vats. etc. 57 
 
 2. Steam engine ; invention of. principle illustrated 58 
 
 3. Steam generator of Mr. Perkins ; steam artillery 58 
 
 Distillation ; process illustrated and described 59 
 
 Evaporation — difference between it and ebullition 59 
 
 1. Evaporation of different liquids ; depends upon Avhat ? 59 
 
 2. Effect of increased and diminished pressure upon evaporation.. . 59 
 
 3. Extent of surface ; how does it affect the rapidity of evaporation 60 
 
 4. State of the atmosphere ; " " " " 60 
 
 5. Absorption of free Caloric by Evaporation ; cryophorus described 60 
 
 6. Cause of evaporation ; how have some accounted for it ? 61 
 
 7. Uses of evaporation ; cooling rooms, warm climates 61 
 
 Effect of perspiration explained ; fire kings, oven girls 61 
 
 Injurious effects of evaporation, miasma, fever and ague 62 
 
 1* 
 
10 CONTENTS, 
 
 Hi gre -tters; reduced to three principles. 62 
 
 cure's hygrometer ; depends upon what property ? 62 
 
 , Leslie's hygrometer; de;>ei>ds upon what property ? 62 
 
 ■; H ;•_ ■ r point, how determined 62 
 
 j&ppticati m - C . I : . ; Cm eric to die Erpl. .Ynt. Phen. 
 
 : rsses of thawing and freezing; Beet upon climate 63 
 
 : : of vaporization ; to modify the lie at of summer 64 
 
 :: of condensing vapors ; rain, source of the cold. 61 
 
 4 _r ::t of freezing water ; to modify the approach of winter. ... . 64 
 
 Why are the shores of a country warmer in winter, etc 64 
 
 Sect. 3. Sources of Caloric axd or Cold. 
 
 ; concentration of its rays, degree of heat 65 
 
 ; ical action ; combustion defined 65 
 
 3. Condensation ; ma tnerj . friction, percussion 65 
 
 4. Vital acik caloric produced in animals ? 66 
 
 Sources of cold, what? 65 
 
 Sect. 4. Nature of Caloric 
 
 Theory of Sir \V. Hersche] and Prof. Airy ; undulatory theory. . . . 65 
 
 Theory of .Newton; what snj position did he maker ' 63 
 
 CHAPTER II. — LIGHT. 
 
 1. Physical Properties of Light — belong to what science r 67 
 
 Velocity "of light ; disposition of it 7 67 
 
 H flection — the circumstances which govern it 67 
 
 III. Refraction — defined, refrangibilitv, Illustration 67 
 
 IV. I - _ ; — bow many kinds of rays? 63 
 
 1. Colorific rays ; mode of separating them ej prism, Illustration.. 63 
 
 Brewster, power 60 
 
 2. Calor .. : n p jsition, and degree of refrangibilitv 69 
 
 their position in the spectrum 69 
 
 1. Photographic drawing, IDs. 2 Daguerreotype described .. . 69 
 
 "' "._• : : . ~-:. : .., 7) 
 
 V. Mserpti n — Jr~~rd 70 
 
 1 Eflee : : fie :- : : a to absorb different colors 7 9 
 
 a colored? what produces the variety ? 7) 
 
 2. Efieel of chemical constitution upon the power of absorption . .. 70 
 
 I Effect of a I the rays ~) 
 
 VI. Igwitum ana] 1 : isstxwee — artificial light, of oil, lime. ... 71 
 
 VII. Phosphorescent* — defined 71 
 
 1. Solar phosphori ; snhstan ces i Reefed by the solar rays 7i 
 
 2. Phosphorescence from moderate heat ; lime 71 
 
 3. A nimal and vegetable phosphori 7 J 
 
 VUl. Photomei - - — and : s : : : f 72 
 
 Photometer of Leslie, of Count Kumford 73 
 
 Sources of light ; similar to those of caloric. 73 
 
 IX. Suture of Light — Newton's theory, undulatory theory .... 72 
 
 CHAPTER III. — ELECTRICITY. 
 
 EUetririty ; mode of producing H 73 
 
 Meaning of electrically excited, electrified, cause of it 73 
 
CONTENTS. 11 
 
 Sect. 1. Common Electricity. 
 
 1. Mode of exciting it ; friction upon resinous bodies 74 
 
 2. Friction upon vitreous substances ; effects of. 74 
 
 3. Bodies electrified with each kind ; how affected ? 74 
 
 Theories — 1 Theory of Franklin ; positive and negative states. ... 74 
 2. Theory of Du Fay ; vitreous and resinous, correspond to what 1 74 
 
 Inference from the last theory ; law of each fluid 75 
 
 Existence of the two fluids shown ; gold leaf electrometer 75 
 
 Non-conductors ; defined, conductors, do., insulators 75 
 
 Electrical machine described; Ills., direction of currents 76 
 
 Induction — defined and illustrated, several conductors 76 
 
 Theory of Induction — attraction and repulsion accounted for 77 
 
 Application of the Theory. 
 
 1. To the spark. 2. Stroke of lightning. 3. Leyden jar 77 
 
 4. Electrophorus ; described, illustrated, its use 78 
 
 Electrometers or Electroscopes — object of 78 
 
 Balance electrometer ; described, uses of 79 
 
 Laws of the Accumulation of the Electric Fluid, 
 
 1. Quantity of electricity on a conductor ; depends on what? 79 
 
 2. Mode of distribution ; on a sphere, ellipsoid, effect of points. ... 79 
 
 3. Tendency to escape from points due to what property ? 79 
 
 4. Law of attraction and repulsion between two electrified bodies. . 79 
 
 Sect. 2. Voltaic Electricity, or Galvanism. 
 
 History — discovery of Galvani, his theory 79 
 
 Discovery of Volta ; identity of galvanism, magnetism, etc 80 
 
 I . Simple Voltaic Circles — description of 89 
 
 Direction of the positive current; closed and broken circuit 80 
 
 Different modes of forming voltaic circles 81 
 
 Chemical action necessary to excite currents; form of battery 81 
 
 Calorimotor ; why so called ? 81 
 
 II. Compound Voltaic Circles — 1. Voltaic pile, described 81 
 
 2. Best form of the galvanic battery described 82 
 
 Size and number of plates; Hare's deilagrator other batteries... 83,84 
 
 Direction of the currents, relation of electricity to chem. affinity 84 
 
 Theories of Galvanism. 
 
 1. Theory of Volta. 2. Of Wollaston. 3. Of Davy 85 
 
 Lams of the Action of Voltaic Circles. 
 
 Difference between quantity and intensity 86 
 
 1 . Relation between the exciting liquid and the zinc 86 
 
 2. Tension and quantity of electricity in simple circles 86 
 
 3. Mode of measuring the energy of voltaic currents 86 
 
 Decomposing power; power of deflecting magnetic needle.... 87 
 
 4. Velocity of electricity through perfect conductors 87 
 
 Effects of Voltaic E' eel r' city or Galvanism. 
 
 I. Comparison of Common and Voltaic Electricity. 
 
 1. Action of voltaic electricity upon the gold leaf electrometer.... 87 
 
 2. Leyden jar charged by the battery ; conditions of 87 
 
 3. Velocity of common and voltaic electricity ; effects of 87 
 
 4. Tension of voltaic electricity ; striking distance 88 
 
 5. Effect of voltaic electricity upon the animal system 88 
 
 6. Deflection of magnetic needle and chemical decomposition . . . • 88 
 
12 CONTEXTS. 
 
 II. Power of Voltaic Currents to ignite ike Metals — Illustration 88 
 Theory; heating power of calorimotcr, and compound battery.... 88 
 
 III. Chemical Effects of Galvanism — history 89 
 
 1. First substance decomposed ; Illustration 89 
 
 Difference between substances as ascertained by galvanism. .. 99 
 
 2. Transfer of chemical substances ; Illustration 90 
 
 Theory of Faraday, of Davy ; electrodes, anode and cathode. . . 91 
 
 Electrolyzed, electrolyte, ions, anions, and cations 91 
 
 Results of Faraday's Investigations. 
 
 1. Decomposition by primary and secondary action 92 
 
 2. Compounds which are electrolytes 92 
 
 3. Simple substances for-m ions 92 
 
 4. Single ions indifferent to voltaic currents 92 
 
 5. Conditions for the decomposition of water 92 
 
 6. Substances which form electrodes 92 
 
 7. Conditions necessary to electro-chemical decomposition 92 
 
 8. Conduction of electric currents in cells of battery 93 
 
 9. Electro-chemical equivalents ; defined 93 
 
 Faraday's theory of electro-chemical decomposition 93 
 
 Magnetic Effects of Electricity or Electro-Magnetism. 
 
 History ; discovery of Oersted 94 
 
 I. Influence of Voltaic Currents upon the Magnetic Xccdle. 
 
 1,2, 3, 4, 5. Position of the needle in reference to voltaic currents 94 
 
 6. Plane in which a needle moves as related to voltaic currents. . . 95 
 
 7. Electro-dynamic action results from what ? 95 
 
 Galvanometers or Multipliers ; Illustration 95 
 
 Revolving Rectangle ; described 98 
 
 II. Influence of Voltaic Currents upon soft Iron and Steel. 
 
 1. Helix and stand ; description of 97 
 
 2. Kind of pole; dependent upon what? Illustration 98 
 
 3. Electro magnet ; what weight will it sustain ? 98 
 
 4. Magic circle ; description and illustration of 99 
 
 5. Vibrating magic circle ; description and illustration of 99 
 
 III. Volta- Electric Induction — Separable Helices, described... 101 
 
 IV. Magneto- Electric Induction — defined; Illustration 105 
 
 Magneto-Electric Machine described 105 
 
 V Theory of Electro-Magnetism and Magneto- Electricity 106 
 
 Application of the theory ; magnetism of the earth 106 
 
 VI. Thermo-Electricity — defined ; Illustration 103 
 
 VII. JYature of Electricity. 
 
 VIII. Use of Electricity— 1. Medicinal Effects 108 
 
 2. Application to the propelling of Machinery 109 
 
 3. Electro-Magnetic Telegraph ; principle and description 109 
 
 4. Electrography ; Electrotype, description of, theory 1 12 
 
 PART SECOND. 
 
 chsjmzcazi -aFrxmirsr. 
 
 Cause of chemical changes ; affinity defined 113 
 
 Varieties of Chemical Affinity. 
 
 Simple affinity, defined, elective affinity, double elective affinity . . . 114 
 
CONTENTS. 13 
 
 Circumstances which modify Affinity. 
 
 I. Cohesion — opposes chemical action, how destroyed ? 115 
 
 1. By pulverization ; Illustration 115 
 
 2. By solution ; solvents ; saturated solution 1 jg 
 
 Insolubility ; its effect on affinity ; Illustration 116 
 
 3. Fusion, defined, effect 117 
 
 II. Elasticity — its effect on affinity 117 
 
 1. Influence on decomposition , 117 
 
 2. Effect of a high temperature upon gaseous mixtures 117 
 
 III. Quantity of Matter — its effect upon affinity 117 
 
 I V . Gravity — specific gravity, effect 118 
 
 V. Imponderable Agents — effect of, upon affinity 118 
 
 Measure of affinity ; how is the force determined ? Illustration. ... 119 
 Effects of Affinity. 
 
 I. Change of Chemical Properties — Illustration 120 
 
 II. Change of Color — Illustration; dropping tube. • , 120 
 
 III. Change of Form — Illustration of 121 
 
 IV. Change of Temperature — Illustration , 121 
 
 V. Change of Specific Gravity — Illustration .1 21 
 
 Laws of Chemical Affinity. 
 
 I. Indefinite Proportions — defined ; how many cases ? 122 
 
 II. Definite Proportions by Weight — described . . . ,_j£? 122 
 
 1st law ; mode of expressing the ratio of combination 123 
 
 Standard of comparison ; equivalent, meaning of 123 
 
 Apparent variations of law ; Illustration 123 
 
 2nd law ; constitution of each substance fixed 124 
 
 Discovery of these laws, by whom, their use 124 
 
 III. Definite Proportions by Volume. 
 
 Compared with those by weight 125 
 
 Atomic Theory ; existence of atoms 126 
 
 Theory of definite proportions by weight ; Illustrated 126 
 
 Atomic weight ; absolute weight, magnitude and form of atoms. . . 126 
 
 Isomerism, defined, reconciled with definite proportions 127 
 
 Cause of chemical affinity ; electricity, second causes 127 
 
 PART THIRD, 
 
 PONDE1ABLS BODIES, 
 
 Specific gravity ; defined ; standard of comparison 129 
 
 1. Method of obtaining specific gravity of solids J 29 
 
 2. do of liquids; aerometer, Illustration. 3. Of gases.. ... . 130 
 
 Nomenclature — description of, history of, uses 130 
 
 1. Method of naming simple substances ; table of 131 
 
 2. Acid compounds receive what terminations, prefixes? etc 131 
 
 3. Binary compounds not acid ; prefixes and suffixes. 132 
 
 Metals and alloys; hydrates 133 
 
 4. Ternary compounds or salts ; terminations, etc 133 
 
 Notation, defined, symbols described, their use 134 
 
 Table of the symbols and equivalents of the thirteen non-metallic 
 
 elements, and the symbols of their compounds with each other 135 
 
 
14 CONTENTS 
 
 CHAPTER I. — CHEMICAL SUBSTANCES. 
 
 Class I. Non-Metallic Elements and their Primary 
 Compounds. 
 
 Sect. 1. Oxygen. 
 
 History of discovery ; natural history, process 136 
 
 Pneumatic cistern, description of, gasometers 137 
 
 Theory of process by manganese ; by chlorate of potassa 138 
 
 Physical and chemical properties ; Illustrated 139 
 
 Effects of combustion ; theory 140 
 
 Oxigenation and oxidation ; relation of oxygen to animals 141 
 
 Sect. 2. Chlorine. 
 
 Symb. Equiv. Sp. gr. ; history of discovery 141 
 
 Natural history ; 1. Process, theory. 2. Process, theory 142 
 
 Physical and chemical properties ; Illustrated ,. ...... . 143 
 
 Relations to water, to hydrogen ; bleaching effects 144 
 
 Relations to animals ; uses ; 1. Bleaching process, theory 144 
 
 2. Disinfecting^gency ; dissecting rooms ; diseases of skin 145 
 
 Hy-pochlorolkacid; Symb. Equiv. Sp. gr. process, properties . . 146 
 
 Chlorous, cldoricy and perchloric acids ; process, properties 147 
 
 Sect. 3. Iodine. 
 
 Symb. Equiv. Sp.gr.; history of discovery ; natural history .... 148 
 
 Process ; Physical and chemical properties, tests, uses 149 
 
 Iodic acid ; process, properties ; periodic, and chloriodic acids. .... 150 
 
 Sect. 4. Bromine. 
 
 Symb. Equiv. Sp. gr. ; history of discovery 151 
 
 Natural history ; process, physical and chem. properties illustrated 152 
 
 Bromic acid; properties, chloride of bromine ; bromide of iodine . . . 153 
 
 Sect. 5. Fluorine. 
 
 Symb. Equiv. ; natural history, properties as far as known 153 
 
 Sect. 6. Hydrogen. 
 
 Symb. Equiv. Sp. gr. ; history ; nat. history, processes 154 
 
 1." By heated iron ; Illustration - 155 
 
 2. By zinc and acidulated water; theory, impurities 155 
 
 Physical properties; soap bubbles, method of filling gas bags. . 156 
 
 Aerostation ; description of balloons 157 
 
 Chemical properties; illustrated, theory, relations to animals.. 157 
 
 Protoxide of hydrogen, water ; Symb. Equiv. Sp. gr., process 158 
 
 Physical and chem. properties illustrated, solvent properties 159 
 
 Composition, eudiometer described; compound blowpipe 160 
 
 Heat produced by blowpipe ; bin oxide of hydrogen, properties .... 161 
 
 Hydrochloric acid ; history, natural history, process, theory 162 
 
 Woulfe's Appa., physical and chemical properties, illustrated .... 163 
 
 Constitution ; uses and impurities 163 
 
 Hydriodic acid; Symb. Eq. Sp gr. ; process, properties, tests 164 
 
 Hydrobromic acid; Symb. Equiv. Sp. gr. ; properties 165 
 
 Hydrofluoric acid; history, process, theory, uses illustrated 165 
 
CONTENTS. 15 
 
 Sect. 7. Nitrogen. 
 
 Symb. Equiv. Sp. gr. history of discovery 166 
 
 Natural history; process, 1. By phosphorus 167 
 
 2. By sulphur and iron. 3. By muscle and nitric acid 167 
 
 Theory of process ; physical and chemical properties 167 
 
 Effect on combustion ; respiration, its nature 167 
 
 Common air ; physical properties, elasticity illustrated 168 
 
 Pressure of the air ; how discovered ? 168 
 
 Extent and composition of the atmosphere 169 
 
 Theory of the diffusion of gases of different sp. gr. ; Illustrated. 170 
 
 Impurities of the air ; eudiometry, uses of the air 171 
 
 Protoxide of nitrogen; history, process, theory of, properties 171 
 
 Respiration of; effect upon animals 172 
 
 Binoxide of nitrogen; history of discovery, process 172 
 
 Theory of process, properties, illustrated, affinity for water 173 
 
 Hyponilrous acid ; properties, nitrous acid, history 173 
 
 Processes, properties, respiration of. Nitric acid, history 174 
 
 Process, illustrated, impurities, properties 175 
 
 Chemical properties, illustrated, uses 1^6 
 
 Nitrohydrochloric acid, aqua regia; nitrohydrqfluoric acid 1/6 
 
 Quadrochloride of nitrogen ; process, properties 377 
 
 Tcriodide of nitrogen ; Symb. Equiv. properties -Ap. 177 
 
 Ammonia; history, process, theory of, properties, tests, uses 178 
 
 Sect. 8. Carbon. 
 
 Symb. Equiv. Sp. gr. ; nat. hist.; the diamond, where found, uses jgrj 
 
 Plumbago, anthracite, bituminous coal, peat, and lamp-black jgj 
 
 Charcoal ; 1. Process by slow combination of wood jg[ 
 
 2. By distillation of wood. 3. By hot sand Igg 
 
 Properties, hardness, theory of its absorbing properties Ig2 
 
 Clarifying agency, combustion of, durability of, infusibility, uses jg3 
 
 Carbonic oxide ; carbonic acir/,, history of discovery Ig3 
 
 Nat hist, process, theory of, relation to flame, to water. Ig5 
 
 Fermenting liquors, best test of carbonic acid, solidification of. . . . |gg 
 
 Relations to animals, choke-damp jg-y 
 
 Sources of carbonic acid, respiration explained jgg 
 
 | Ch oride, per chloride of carbon, Chloro- carbonic acid, chloral. . . . igq 
 
 Periodide and proliodide of, bromide of carbon, properties Ig9 
 
 Dicarburet of hydrogen ; history, process, properties, Illustration.. ]U() 
 
 defiant gas, or 2 carburet of hydrogen, Symb. Equiv. Sp. gr.. . . . 190 
 
 History, process, theory of, properties, Ills. ; action of chlorine. . . . 191 
 
 4 Carburet of H. etherine, 3 carburet, parrijjine, eupione, naphtha. . 192 
 
 Naphthaline, paranapthaline, idrialine, campkenr, and citrene 192 
 
 Gas lights ; history, process, portable gas, fire-damp 193 
 
 Efforts of Davy ; discovery of Wollaston 195 
 
 Effect of gauze' wire upon flame ; safety lamp, construction, etc. . . 195 
 
 Bicarburet of nitrogen or cyanogen, history, process, properties... 196 
 
 Cyanic, falminic, and cyanuric acids 196 
 
 Parncyinuric acid, chloride, bichloride, and bromide of cyanogen .. . '97 
 
 Hydrocyanic acid. Process, properties 197 
 
 Sect. 9. Sulphur. 
 
 Symb. Equiv. Sp. gr. ; nat. hist., process ; 111 us., sublimation. . -. . . 198 
 
 Properties, effect of heat, structure, impurities, uses 199 
 
 Hyposulphurous and sidpkurcwd arids, process, theory, crucibles. S00 
 
16 CONTENTS. 
 
 Hyposulphuric acid, process, properties ; sulphuric acid, process . . 202 
 
 Hydrous sulphuric acid, manufacture of, theory 202 
 
 Properties, affinity for water ; Illus. decomposition, tests 203 
 
 Uses ; dichloride, iodide, and bromide of sulphur 205 
 
 Hydrosulphuric acid, process, theory of 205 
 
 Properties, liquid form, tests, uses ; Illustration 20S 
 
 Production of sulphur; Illustration; hydrosulphurovs acid 207 
 
 Bisulphuret of carbon, or alcohol of sulphur, car bo sulphuric acid.. 207 
 
 Sulphuret and bisulphuret of cyanogen 203 
 
 Hydro sulphocyanic and cyanohydro sulphuric acids 208 
 
 Sect. 10. Phosphorus. 
 
 Symb. Equiv. Sp. gr. ; history, source 203 
 
 Process, properties, inflammability ; Illustrated 209 
 
 Theory of the heat and light, relation to animals 210 
 
 Oxide of phosphorus ; hypophosphorous acid 210 
 
 Phosphorous acid, process : phosphoric acids . 211 
 
 Phosphoric acid, process, properties ; pyro and vieta phosp. acids. . 211 
 
 Sesquichloride of phosphorus, Symb. Equiv., process, properties. . 212 
 
 Perchloride, protiodide, sesquiodide, and periodide of phosphorus . . 213 
 
 Protobromide, pe.rbromide, phosphuret of hydrogen, properties ..... 213 
 
 Perphosphuret <zf hydrogen, process, properties, inflammability of, 213 
 
 Jack o' the lantern ; sulphuret of phosphorus 2l4 
 
 Sect. 11. Boro>-. 
 
 Discovery ; process, property 215 
 
 Boracic acid; source, process, evaporating dishes 216 
 
 Terchloride of boron ; fuoboric acid, suphuret of boron 217 
 
 Sect. 12. Selen 
 
 ICM. 
 
 Discovery, oxide of, selenwus acid, properties 217 
 
 Selenic acid ; chloride and bromide of, hydroselenic acid 218 
 
 Sect. 13. Silicon. 
 Symb. Eq., discovery, properties, silicic acid, nat. history, process, 220 
 Chloride, bromide, and sulphuret of silicon, fluo silicic acid , . 221 
 
 CHAPTER II. 
 
 Class II. Metals, -with their Binary Compounds. 
 
 General properties of metals, metallic lustre 222 
 
 Sp. gr. of; malleability defined 222 
 
 1. Ductility, tenacity/ 2. Hardness. 3. Structure. 4. Fusibility 223 
 
 5. Volatility. 6. Affinity for other simple bodies 223 
 
 Combustibility ; number and date of discovery 224 
 
 Classification of the metals 227. 223 
 
 Order I. Metals ivhkh, hy Oxidation, yield Alkalies or Earth 
 Sect. 1. Metallic Bases of the Alkalies. 
 
 Potassium ; history of discovery 223 
 
 Process, properties, combustibility ; Illustration 229 
 
 Protoxide of potassium ; properties, hydrate of; Ills., tests 230 
 
 Potassa ; teroxide, iodide, bromide, fluoride, and chloride of. 230 
 
 Hyduret, nituret, suhmurets, phosphuret and seleniuret of. .»*.. 231 
 
CONTENTS. 17 
 
 Cyanuret, properties ; sulphocyanuret of 233 
 
 Sodium; Symb. Equiv. Sp. gr 233 
 
 Process, properties, affinity for oxygen, 233 
 
 Protoxide of soda, process ; sesquioxide, chloride of, origin, uses. 234 
 
 Iodide, bromide, fluoride, sulphuret, and cyanuret of 235 
 
 Chloride of soda, alloys of sodium and potassium 235 
 
 Lithium; protoxide of, or lithia, process, properties, fluoride of . . . . 236 
 
 Sect. 2. Metallic Bases of the Alkaline Earths. 
 
 Barium ; protoxide of, or baryta, how distinguished 237 
 
 Binoxide, chloride, iodide, bromide, fluoride, sulphuret 238 
 
 Cyanuret, sulphocyanuret, phosphuret of 239 
 
 Strontmm ; protoxide, strontia, peroxide and chloride of. 239 
 
 Iodide of, fluoride, protosulphuret 240 
 
 Calcium ; protoxide of, or lime, peroxide, chloride, uses; iodide.. 240 
 Bromide, fluoride, bisulphuret, phosphuret of, chloride of lime.... 241 
 
 Magnesium ; discovery, process, properties 242 
 
 Protoxide of, or magnesia, properties, uses 243 
 
 Chloride of, iodide, bromide, fluoride 243 
 
 Sect. 3. Metallic Bases of the Earths. 
 
 Aluminium; discovery, process, properties, sesquioxide of 244 
 
 Sesquichloride, sesquisulphuret, sesquiphosphuret 245 
 
 Glucinium; Symb. Equiv. Sp. gr. ; discovery, properties 246 
 
 Sesquioxide of, glucina, discovery, process, properties 246 
 
 Yttrium ; Symb. Equiv. ; process, properties 246 
 
 Thorium ; Symb. Equiv. ; process, properties, protoxide, do 247 
 
 Zirconium ; Symb. Equiv. ; discovery, process, properties 247 
 
 Order II, Metals the Oxides of which are neither Alkalies nor 
 
 Earths. 
 Sect. 1. Metals which decompose Water at a red Heat. 
 
 Manganese; history, process, properties, protoxide of, properties. . 248 
 
 Sesquioxide, peroxide, red oxide, varvicite, manganic acid , 249 
 
 Perchloride, perfluoride, protosulphuret, and cyanuret, alloys 250 
 
 Iron; Symb. Eq. Sp. gr. ; history, nat. history, process, properties 251 
 
 Protoxide of; process, properties, uses, 252 
 
 Peroxide of ; process, properties, etc. ; black oxide, source, tests. . 253 
 
 Protochloride ; perchloride, protiodide, properties 253 
 
 Periodide, protobromide, perfluoride, protosulphuret 251 
 
 Sesquisulphuret, magnetic iron pyrites, tetrasulphuret 254 
 
 Diphosphuret, perphosphuret, carburets, graphite, cast iron, steel. 255 
 
 Protocyanuret, protosulphocyanuret, sesquisulphocyanuret 255 
 
 r /inc; Symb. Eq. Sp. gr.; history, nat. history, process, properties. 256 
 Protoxide, hydrated oxide, chloride, iodide, bromide, fluoride, etc 257 
 Cadmium ; oxide, chloride, iodide, sulphuret, and phosphuret of257,258 
 
 Tin; process, properties, stream tin, tin foil$ protoxide of tin 259 
 
 Sesqui and binoxide, proto and bichloride, proto and biniodide of. . 259 
 Protosulphuret, sesquisulphuret, bisulphuret, and tersulphuret of. 260 
 Cobalt ; protoxide, zaffre-oxide, and peroxide of, sympathetic ink. 261 
 Protosulphuret, sesquisulphuret, bisulphuret, and subphosphuretof 263 
 
 Michel ; properties, protoxide, sesquioxide, and chloride of , 263 
 
 Protosulphuret, disulphuret subphosphuret, and cyanuret of. .... 264 
 
18 CONTENTS. 
 
 Sect. 2. Metals which do not decompose Water at any Tem- 
 perature, and the Oxides of which are not reduced to the 
 Metallic State by the sole Action of Heat. 
 
 Arsenic, and its compounds 264 — 268 
 
 Chromium and its compounds. Vanadium, ditto 268 — 270 
 
 Molybdenum, compounds of. Tungsten, ditto. Columbium and An- 
 timony ; . 271— 273 
 
 Antimony, compounds of. Uranium, Cerium, Bismuth. .... 274 — 276 
 
 Titanium, Tellurium. Copper and its compounds 277 — 280 
 
 Lead and its compounds ; Galena, alloys, etc 281 — 282 
 
 Sect. 3. Metals the Oxides of which are reduced to the Me- 
 tallic State by a red Heat. 
 
 Mercury and its compounds. Amalgams, Silver , ditto 283 — 287 
 
 Gold, compounds of, alloys, water-gilding 288 — 290 
 
 Platinum; palladium, rhodium, osmium, irridium 291 — 292 
 
 CHAPTER III. 
 
 Class III. — Salts or Secondary Compounds. 
 
 Sect. 1. Crystallization. 
 
 Crystal and crystalography defined 293 
 
 Planes, faces, edges, angles, primary and secondary forms of. 294 
 
 I. Prisms have six-sided or four-sided bases 284 
 
 (1.) Right Prisms. — 1. Hexahedron, or cube 294 
 
 2. 3. Right square and right rectangular prisms 294 
 
 4, 5. Right rhombic and right rhomboidal prisms 295 
 
 6. Regular hexagonal prism 295 
 
 (2.) Oblique Prisms. — 7. Rhombohedron. 8. Obi. rhombic prism . . 295 
 
 9. Oblique rectangular prism. 10. Oblique rhomboidal prism 295 
 
 II. Octohedrons. — 11. Regular octohedron. 12. Square octohedron 295 
 13. Rectangular oetohedrons. 14. Rhombic octohedrons 296 
 
 III. Dodecahedrons. — 15. Rhombic dodecahedron 296 
 
 Secondary forms ; cleavage defined, faces and direction of 296 
 
 Isomorphism, cry st allogenic attraction, water of crystallization 297 
 
 Sect. 2. Oxy-Salts. 
 
 General formula for the composition of the salts 302 
 
 1. Sulphates — of potassa, soda, Glauber's salts 303 
 
 Of lithia, ammonia, baryta, strontia, lime, gypsum 304 
 
 Of magnesia, alumina, manganese, protoxide of iron 305 
 
 Of protoxide of zinc, (white vitriol,) nickel, cobalt, chromium 306 
 
 Of copper, (blue vitriol.) mercury (turpeth mineral,) silver 307 
 
 Nitro-sulphuric acid, sulphate of soda, lime, potassa and magnesia. 308 
 
 Ammonia, soda, iron, chrome, and mangan, alums. 2. Sulphites .... 308 
 
 3. Nitrates — of potassa, (nitre beds,) of soda, ammonia 309 
 
 Of baryta ; pyrotechny, greeji-fire 310 
 
 Of strontia, (red-fire,) lime, magnesia, protoxide of copper 311 
 
 Nitrate and dinitrate of protoxide of lead, of mercury, of silver 31 2 
 
 Properties, illustration, lunar caustic, indelible ink 3l3 
 
 4. Nitrites. 5. Chlorates — of potassa, properties 314 
 
 Lucifer matches, chlorate of baryta, process, properties 315 
 
CONTENTS. 19 
 
 6. Perchlorates. 7. Chlorites. 8. Hypochlorites. 9. Iodates. 315 
 
 Iodate of potassa. 10. Bromales. 11. Phosphates 316 
 
 I. Phosphates — triphosph., diphosph., and phosphate of potassa.. 316 
 Of soda and ammonia, ammonia, lime, magnesia, amm. and mag. 317 
 Triphosphate of silver. — 2. Pyrophosphates 318 
 
 III. Mela phosphates — of soda, baryta, silver, etc 319 
 
 12. Arse/dates ; of soda, table of compounds 319 
 
 13. Arseiiites ; general properties, tests 320 
 
 14. Chromates ; of potassa, lead. 15. Borates; of soda, borax ... . 321 
 
 16. Carbonates ; of potassa, soda, ammonia 322 
 
 Of baryta, strontia, lime, magnesia 323 
 
 Of iron, copper, lead, white lead, mercury 324 
 
 17. Double Carbonates 326 
 
 18. Silicates; simple, bi, tri, and quadri silicates 327 
 
 Sect. 3. Order II. Hydro-Salts; acids of 328 
 
 Sect. 4. Order III. Sulphur-Salts; constitution of 330 
 
 Sect. 5. Order IV. Haloid-Salts ; constitution and descrip. of. . 333 
 
 CHAPTER IV.— ORGANIC CHEMISTRY. 
 
 Organic and inorganic compounds compared 335 
 
 Analysis of organic compounds 337 
 
 Theory of compound radicals ; substitutes, etc 340, 341 
 
 Theory of pyracids 342 
 
 Sect. 1. Amylaceous Substances. 
 
 Various kinds of starch 343 
 
 Gluten, gums, Arabic, etc .... 344 
 
 Lignin, xylodine 345 
 
 Eremacausis, sugar, cane and grape 346, 349 
 
 Saccharic acid, lactine, mucie acid 348 
 
 Manna, saccharic, and vinous fermentation 349 
 
 Acetous and viscous fermentation, theory of 350, 351 
 
 Sect. 2. Compound Radicals. 
 
 I. Alcohol, properties. Sulphuric ether 351, 352 
 
 Hydrochloric, hydrobromic, hydriodic ether 353 
 
 Mercaptan, nitric, hyponitrous and carbonic ethers 354 
 
 Boracic, silicic, oxalic, acetic, and formic ethers 355 
 
 Oenanthic and benzoic ethers, sulphovinic and phosphovinic acids. . 356 
 
 II. Aldehyde, acetous and acetic acids, vinegar 357 
 
 Acetates of potassa, of ammonia, and of lead 358 
 
 Acetates of copper, alumina, iron, zinc 359, 360 
 
 III. Kakodyle — alkarsine, alkargene 360, 361 
 
 Chloride, iodide, sulphuret, and cyanide of kakodyle 361 
 
 IV. Products of the dry distillation of wood: 
 
 Methylic ether, wood-spirit, chloride of methyle 362 
 
 Sulphate, nitrate, and oxalate, etc., of methyle 363, 364 
 
 V. Formic Acid — formates of potassa, ammonia, etc 364 
 
 Chloroform, bromoform. VI. Potato O'l, chloride of amyle 365 
 
 VII. Valerianic Acid. VIII. Bitter Almond Oil 366 
 
 Benzoic acid, chloride, iodide, etc., of benzoyle 367 
 
 Bonzole, benzoine, benzile 368 
 
 Amygdaline, amygdalic, and hippuric acids 368 
 
20 CONTENTS. 
 
 IX. Salicene, hydro-salicylic, salicylic acids, chloride of. 369. 370 
 
 X\ Oil of Cinnamon, cinnamic acid .' 371 
 
 XI. Oxide of Carbon, oxalic acid, oxalates, potassa, lime.. 371, 372 
 
 XII. Cyanogen, cyanic and fulminic acids, cyanite of amm. (urea) 373 
 
 Cyan uric and hydrocyanic (prussic) acids 379 
 
 Sulphocyonide and cyonate of potassium 375 
 
 Ferrocyonide of potassium, ditto of iron 376 
 
 XIII. Mellone, hydromellonic acid, mellonide of potassium, etc... 277 
 
 XIV. Uric Acid, '(lithic acid,) allontoin 378 
 
 Alloxan, alloxantin. murexide, murexan r 376 
 
 Sect. 3. Organic Acids, malic, citric, aconitic. tartaric 380 
 
 Tartrates of potassa and soda, antimony and potassa, tannic acid.. . 381 
 
 Acids, gallic, mellitic, lactic, uric, and croconic 382 
 
 Comenic, succinnic. oleic, crenic, apocrenic 383 
 
 Sect. 4. Vegetable Alkalies, morphia 384 
 
 Narcotina, cinchonia, quinia 385 
 
 Strychnia, emetia. nicotina, codeia, brucia, parilla. 386 
 
 Sect. 5. Oils and Fals. Fixed oils, glycerine 387 
 
 Stearine, stearic acid, margarine, margaric acid 388 
 
 Oleine. oleic acid, palm-oil, palmetic acid, olive and croton oils 389 
 
 Hogs lard, soaps, butter, butyrine, butyric and caporic acids . . 382, 390 
 
 Wax. 2. Volatile oils, spirits of turpentine 391 
 
 Camphor, resins, copal, lac, mastic, amber, balsams 392 
 
 Gum Resins, aloes, chaoutchouc, creosote 393 
 
 Sect. 6. Coloring Matters, lakes, blue dyes 394 
 
 Indigo, isatine, isatinic acid, chlorisatine, etc 395 
 
 Red, Dyes, cochineal, archil, erythrilin, litmus, madder . . . . '. 396 
 
 Yellow Dyes ; black dyes, logwood, Turkey reds 397 
 
 Sect. 7. Nutricious Substances, fibrine 397 
 
 Albumen, ligumine, proteine, gelatine, glycocoll 398, 399 
 
 Sect. 8. Complex Animal Substances, hematosin 399 
 
 Blood, animal heat, theory of 401 , 402 
 
 Saliva, gastric juice, bile, bilin, tannin 403 
 
 Chyle, milk, lymph, mucus, pus. sweat, urine 404 
 
 Urinary calculi, eggs, bones, teeth, shells 405 
 
 Horns, hair, skin, wool, silk, brain and nerves 406 
 
 Sect. 9. Growth and Nourishment of Plants and Animals 407 
 
 Germination, growth of plants, food of plants, source of carbon 408, 409 
 
 Humus, humic acid, etc., source of hydrogen 409 
 
 Source of nitrogen, nourishment of animals 410 
 
 Respiration, equilibrium of the vegetable and animal kingdoms 411 
 
 CHAPTER VI.— ANALYTICAL CHEMISTRY. 
 
 Sect. 1. Analysis of Mixed Gases 412 
 
 Sect. 2. Analysis of Minerals 413 
 
 Sect. 3. Analysis of Mineral Waters 414 
 
 Appendix ; Glossary ; General Index ; Index of Plates 420 
 
 NOTE. 
 
 F. and Fahr. for Fahrenheit's thermometer.— T. refers to Turner's Chemistry.— 
 VV. to Webster's Chemistry, 3rd Ed.— L. to Liebig.— B, toBerzelius.— Eq. and Equiv. 
 for Equivalent.— Svmb. for Symbol or formula. 
 
INTRODUCTION 
 
 / Science is classified knowledge. Physical or Natural 
 Science is the knowledge of the material world. The defi- 
 nition of matter embraces two properties, without which we 
 cannot even conceive of its existence. These properties are 
 extension, which includes length, breadth, and thickness, and 
 impenetrability , or the impossibility that any two portions of 
 matter should occupy the same space. There are other prop- 
 erties, which do not necessarily enter into our conception of 
 matter, but which universally belong to it, such as gravitation, 
 inertia, mobility, etc. 
 
 Natural Science consists of three great branches, which 
 are characterized chiefly by peculiar methods of investigation. 
 
 I. Natural Philosophy employs the method of general 
 physics ; that is, it observes, for example, the gravitation of a 
 stone let fall to the ground, and, neglecting the other proper- 
 ties of the stone, observes the same property in other bodies, 
 and generalizes the phenomena under a law. It is therefore 
 conversant with general laws, but not with all the general 
 laws, for its observation is restricted to the phenomena of 
 perceptible distance. By this we mean that it leaves to the 
 chemist all those phenomena which arise from the action of 
 the invisible atoms of matter upon each other, and attends 
 only to- those which belong to bodies of perceptible size. 
 With a few observations and experiments for data, it depends 
 for discovery upon calculation,\rfd its character is therefore 
 eminently mathematical. Its object f.s a knowledge of the 
 laws of motions and forces. 
 
22 INTRODUCTION. 
 
 II. Chemistry employs, in part, the method of general 
 physics, and, in part, the method of particular physics. By 
 the latter, we mean that its object is, in part, to describe 
 particular bodies or substances, by giving an account of the 
 various properties of each one, before calling the attention to 
 another. It invites our attention to the phenomena only of 
 imperceptible distance. With some aid from calculation and 
 observation, it depends for discovery chiefly upon experiment, 
 and has therefore been called Experimental Philosophy. Its 
 object is a knowledge of the constitution of substances and 
 of the phenomena attending a change of constitution. 
 
 III. Natural History employs the method of particular 
 physics, observes the phenomena of perceptible distance, and 
 depends for discovery chiefly upon observation, with some aid 
 from experiment aiid calculation. Its object is a knowledge 
 of natural objects. It embraces Zoology, or the study of 
 animals; Botany, or the study of plants ^Mineralogy, which 
 treats of minerals ; and Geology, which describes and accounts 
 for the condition of the crust of the earth. ) The physiology 
 of plants and animals is sometimes referred to Botany and 
 Zoology respectively, and .sometimes regarded as a fourth 
 distinct branch of Natural Science. 
 
 Plan of the Work. 
 
 I. The constitution and the changes of the constitution 
 of substances are intimately connected with the agency of 
 heat, light, electricity, and galvanism, of which the two last- 
 mentioned agents 'are supposed to be identical. Whether 
 these agents are themselves substances, or mere properties 
 of matter, is not certainly known. They have no appreciable 
 weight, and are therefore called imponderable agents. They 
 will form the subject of the First Part. 
 
 II. The Second Part will treat of chemical affinity. This 
 is the great agent to which all the phenomena of chemistry are 
 referred. It is distinguished from gravitation by exerting its 
 force between the particles of bodies, and from cohesion by 
 
INTRODUCTION, 23 
 
 acting only between particles of different kinds or in different 
 states of electricity.' For example, a block of marble is made 
 up of very small particles, each one of which is similar to the 
 whole; but each of these particles is composed of two others, 
 carbonic acid and lime, different from each other, and from 
 marble. When these particles of carbonic acid and lime are 
 brought into close proximity to each other, they assume dif- 
 ferent electrical states, and combine by the force of chemical 
 affinity, and form particles of marble. Cohesion then attaches 
 them to each other as fast as formed, and thus the block is 
 formed. Gravity acts upon it in the mass. The carbonic 
 acid and the lime are called the component particles. When 
 these combine, they form the integrant particles. Hence 
 Chemistry is defined to be that science the object of which is, 
 to examine the relations which affinity establishes between 
 bodies, ascertain with precision the nature and constitution of 
 the compounds it produces, and determine the laws by which 
 its action is regulated. 
 
 It is the object of Natural Philosophy to examine the sen- 
 sible motions and mutual relations of bodies in masses, con- 
 sequent upon gravity. 
 
 Chemistry investigates the constitution and qualities of 
 bodies as they stand related to chemical affinity. 
 
 III. The Third Part will comprise a description of sub- 
 stances, which will be arranged in two general divisions : The 
 first will embrace the elements and those compound sub- 
 stances which can be formed in the laboratory. These are 
 chemical substances. The second division will embrace 
 natural substances, or animal and vegetable compounds, 
 which have been formed by natural agencies. 
 
 Chemists divide substances into simple and compound. A 
 simple substance is one which never has been separated into 
 two kinds of matter, or which has never been decomposed. 
 There are about fifty-eight simple substances. A compound 
 body is one which is composed of two or more simple bodies, 
 of which there are many thousands. 
 
24 INTRODUCTION. 
 
 The composition of bodies is ascertained by two methods : 
 
 1. By separating the body into its simple elements, which 
 is called analysis ; and, 
 
 2. By causing the elements to combine and form the body, 
 which is called synthesis. 
 
 Chemical substances are arranged in three general di- 
 visions : 
 
 I. Non-metallic elements', and their primary compounds 
 with each other. 
 
 II. Metals, and their primary compounds. 
 
 III. Salts, or secondary compounds. 
 
 In the arrangement of the simple substances and their 
 primary compounds, the logical order is pursued; that is, 
 after describing one substance, the rest are described with the 
 compounds which they form with those previously described. 
 
 The Salts are divided into four orders : 
 
 J. Oxy-salts, or those salts the acid or base of which is an 
 oxidized substance. 
 
 II. Hydro-salts. This order includes no salt, the acid or 
 base of which does not contain hydrogen. 
 
 III. Sulphur-salts, or those salts, of which the electro- 
 positive or electro-negative ingredient is a sulphuret. 
 
 IV. Haloid-salts, including none, the electro-positive or 
 electro-negative ingredient of which is not haloidal, i, e,. 
 analogous in composition to sea salt. 
 
CHEMISTRY. 
 
 PART I. 
 
 IMPONDERABLE AGENTS. 
 
 CHAPTER I. — CALORIC. 
 
 The word heat has two meanings. It is the sensation which 
 we experience when we touch a hot body ; or it is the cause 
 of the sensation. In the first sense, it is an effect produced 
 only upon animals. In the second, it is the cause of a great 
 variety of effects in the mineral, vegetable, and animal king- 
 doms. The word caloric (Lat. calor) is used in the latter 
 sense. Where there can be no ambiguity, the word heat is 
 often retained in the same sense. Caloric exists in a free 
 or sensible, and in a latent or insensible state. 
 
 1. Sensible Caloric. In this state' caloric is capable of 
 producing the sensation of heat, and of expanding bodies. 
 It has sometimes been called the caloric of temperature. 
 Temperature expresses the power of exciting the sensation, 
 and is proportioned to the quantity of free caloric. A high 
 temperature is owing to a great quantity, and a low temper- 
 ature to a small quantity. 
 
 2. Insensible Caloric. In this condition, caloric produces 
 no sensation, but exists, often in great quantity, in substances, 
 without affecting their temperature, and appears to be com- 
 bined with them. 
 
 2 
 
26 Conduction of Caloric. 
 
 Sect. 1. Sensible Caloric. 
 
 Communication of Sensible Caloric, 
 1 ' .." ■ 
 
 T7*e wiosf important property of free caloric is its tendency 
 to an equilibrium; that is, a tendency to escape from hotter 
 
 to colder bodies, so as,t6 produce in all the same deo-iee 
 
 jf * *■ ° 
 
 of temperature, JHps communication takes place in two 
 
 ways — by conduction, and by radiation. 
 
 I. Conduction. By this is meant the passage of caloric 
 
 through a body, from particle to particle. 
 
 Experiment. Place bits of phosphorus along an iron rod, and apply 
 heat to one end of it ; the progress of the caloric will be indicated by 
 its igniting the phosphorus. 
 
 The property in the body, on which this transmission 
 depends, is called the conducting power. 
 
 If one end of an iron rod be held in the fire, the sensation 
 of heat will soon be experienced at the other extremity, in 
 consequence of the conduction of caloric from particle to 
 particle along the rod. If the rod be of glass, it will be 
 much longer before any heat is felt. Hence different sub- 
 stances conduct caloric with different degrees of facility. 
 
 If two bodies are in contact, caloric may be conducted 
 from one to the other. The more perfect the contact, other 
 things being equal, the more rapid the conduction. . This 
 is the reason why a heated body, when grasped firmly by the 
 hand, will burn it more severely than when held loosely. 
 
 1*he contact of two solids with each other, or of a solid 
 with a gas, is not so perfect as that of a solid with a liquid ; 
 and hence the communication is more rapid in the latter 
 case. When liquids are mixed with liquids, or gases with 
 gases, the contact is still more perfect, and the caloric is 
 more rapidly diffused through the whole. 
 
 From the two facts which have been mentioned, it follows 
 that the rapidity of conduction from a heated to a cold body 
 depends upon the conducting power of each substance, and 
 the closeness of contact. 
 
Conducting Power of Solids. 
 
 27 
 
 Exp. Plunge a heated iron into cold water, and again, equally heated, 
 into mercury. In the latter case, it will cool more rapidly ; for, while 
 the heat is conducted with equal facility in Both cases from the interior 
 to the surface, it is taken from the surface more rapidly by the mercury 
 than by the water. 
 
 Exp. Plunge into mercury two equal balls, one of iron and the othei 
 of marble, heated to the same temperature. The iron ball will cool the 
 more rapidly, because the caloric is more freely conducted from its in 
 terior to its surface. 
 
 Exp. Plunge the iron ball into mercury, and the marble into water. 
 The iron will cool more rapidly, for two reasons; the heat will come 
 to its surface more freely, and be taken off by the mercury more 
 rapidly, iron and mercury being each better conductors than marble 
 or water. 
 
 Of the different forms of matter, solids are better conduct- 
 ors of caloric than liquids, and liquids than gases. 
 
 1. Conducting Power of Solids. The power of solids to 
 conduct caloric varies greatly in different substances. 
 
 This fact "may be shown by Fig. 1. 
 
 the conductometer, (Fig. 1,) 
 which consists of a tin or ?ron 
 case, in which there may be 
 inserted small solid cylinders of 
 the same dimensions, but of 
 different materials. 
 
 Exp. Place upon one end of each, bits of phosphorus, and apply to 
 the other ends the same degree of heat by placing the case over boiling 
 water. The caloric will be conducted along from one extremity of 
 each to the other, and those substances which conduct most rapidly will 
 first ignite the phosphorus. 
 
 According to the experiments of M. Despretz, if the con- 
 ducting power of 
 
 Gold be represented by 1000 
 ' Silver will be . . . 973 
 
 Copper 898.2 
 
 Platinum ..... 381 
 
 Iron 374.3 
 
 Zinc ...... 363 
 
 Metals generally are the best conductors of caloric, while 
 furs and porous substances are the poorest conductors. 
 The conducting power of stones is next to that of the 
 »ls, and crystalline stones are better conductors than those 
 y 
 
 Tin . . 
 
 303.9 
 
 Lead . . 
 
 179.6 
 
 Marble . 
 
 . 23.6 
 
 Porcelain 
 
 . 12.2 
 
 Fine clay 
 
 . 11.4 
 
28 Caloric— -'Conducting Power of Liquids. 
 
 The earths are very bad conductors of caloric. E: 
 glass, baked wood and charcoal, are still poorer; while silk, 
 hair, feathers and down, have a less conducting power than 
 any other class of solids. 
 
 Among the latte re, the less its conducting 
 
 power. Hence the utility of fine wool and furs in the win 
 prevent the escape of caloric from the body : while, in the sum- 
 mer, we select those substances for our clothing which have a 
 coarser fibre. In this we see the benevolence of God in furnish- 
 ing those animals which inhabit the colder regions of the 
 with finer clothing than those which inhabit warm climates. 
 The fur of animals is also finer in winter than in summer. 
 
 Snow and ice are poor conductors ; and hence, bv a wise 
 const:- 3 earth in winter is rarely frozen :: any :: .. 
 
 siderable depth. The ice and snow keep it warm by pre- 
 al heat from escaping. 
 
 The conducting powers of solids are generall^n the ratio 
 of their densities, Thus if a piece of metal be reHtred more 
 dense by hammering, there will be an incre 
 ducting power, and if its density be less, there will be a cor- 
 responding diminution of this power. 
 
 2. Conducting Power of Liquids. In liquids the conduct- 
 ing power is much less than in solids. So Feeble is 
 some, among whom is Count Rumford, have denied its ex- 
 istence. But, notwithstanding the slight conducting power 
 of liquids, heat can be diffused through them much more 
 rapidly than through solids. '_ effected by a motion 
 
 among the particles, which brinr- 
 contact with the heated surface. 
 
 If, for example, heat is applied to the 
 bottom of a vessel of vval 
 pj^!ples of water which are in contact 
 the bottom, are soon heated, and con- 
 tly expanded and made lighter, so 
 hey are forced to rise, in order tc 
 He to the heavier cold particles, which 
 '"" to the bottom. The latter, in turn, are 
 eated, and give place to others ; and thus 
 the process continues until two currents 
 are established, the one of heated part;: 
 rising to the surface, and the other of colder part: 
 o the bottom, In this way all the water is soon 
 
Conducting Poicer of Gases. 
 
 29 
 
 direct contact with the bottom.* A little powdered amber or 
 gum copal, put into the water, will indicate the direction 
 of the currents. 
 
 But if heat be applied to the top of "the ves- 
 sel, the water at the bottom will remain cold, 
 while that at the top is boiling. 
 
 Exp. Suspend in a tin cup a hot cannon ball on the 
 top of a jar of water, (Fig. 3,) at the bottom of wlrich is 
 a piece of ice. The water will boil rapidly at the top, 
 while the ice remains unmelted. But if the ice is 
 placed upon the top, and heat applied to the bottom, 
 the ice will all be melted before the water can be 
 made to boil. 
 
 , Exp. Or, burn ether (Fig. 4) on the top of a glass 
 funnel filled with water, into which, an air thermome- 
 ter is cemented. The thermometer will be but slightly 
 • affected. A ring of tin should be placed on the top of 
 the water, within half an inch of the sides of the fun- 
 nel. The ether, poured within this ring, will burn, 
 without the risk of breaking the glass. 
 
 It has, however, been shown that liquids do 
 conduct heat, independently of any intestine J^\ J3^ 
 motion. But the power is very slight. 
 
 3. Conducting Poiuer of Gases. Gases and vapors conduct 
 heat very slightly, if at all. Liquids and gases are heated 
 by a process called (convection J The particles move easily 
 upon each other, and are brought into direct contact with the 
 heated surface, and convey away the heat. 
 
 II. Radiation. If a'^eated body be suspended in the air, 
 its caloric will be diffused both by the currents of air, which 
 circulate to and from its surface, {convection,) and by the 
 conducting power of the air. But if the hand be placed be- 
 neath the heated body, a sensation of heat will be perceived, 
 which is not due to either of these causes, but to the direct 
 passage of the rays through the air. 
 
 For if a heated body be suspended in a vacuum, entirely 
 removed from conducting substances, it will rapidly cool 
 
 * A Florence flask, or a glass tube, may be used for this experiment, 
 and the water heated by a common tin lamp filled with alcohol. • • 
 
30 
 
 Radiation of Caloric 
 
 down to the same temperature with surrounding bodies 
 Caloric, which is thus thrown off from heated bodies in all 
 directions, like rays of'light from the sun, is called radiant 
 caloric. 
 
 1. If a thermometer be placed at the distance of two 
 inches from a heated body, it will be affected but one fourth 
 as much as at the distance of one inch ; if it be placed at the 
 distance of three inches, one ninth as much ; if at four inches, 
 one sixteenth as much ; at five inches, one twenty-fifth, etc. 
 
 QHence, in consequence of a radiation in all directions, the 
 intensity of the heat is in the inverse ratio of the square of 
 the distance.) The intensity of light and the force of gravi- 
 tation follow the same law. 
 
 2. The degree of radiation, and consequently the intensity 
 of radiant heat, are greatly modified by the kind of surface. 
 
 {Bright, polished surfaces dp not radiate so rapidly as those 
 which are dark and roughj 
 
 Fig. 5. 
 
 Exp. Take a square 
 tin cu p, a, (Fig. 5,) one 
 side of which is bright, 
 another rough, a third 
 painted black, and the 
 fourth painted white. 
 Fill it with hot water, 
 ana bring an air ther- 
 mometer, c, near each 
 side. The rough and 
 black surfaces will 
 radiate more rapidly 
 than those which are ^ 
 white and polished. 
 
 If the rays of caloric are brought to a focus by the mirror b, the dif- 
 ferent degrees of caloric from the several surfaces will be much more 
 evident.* 
 
 The greater radiating power of rough surfaces is supposed 
 to be due to the great number of radiating points; or perhaps 
 
 * The late experiments of MeJJoni do not seem to confirm this -view. 
 By using a cup of marble, whose external surfaces were differently 
 prepared, the first polished, the second smooth but tarnished, the third 
 streaked in one direction, and the fourth in two, crossing each other at 
 right angles, and filling the vessel with hot water, each of the sides 
 projected the same quantity of radiant caloric. — Edin. Philos. Jour 
 XJCVL 299. 
 
Reflection of Caloric. 
 
 31 
 
 it may ISaowing to the greater amount of surface exposed 
 within a given space. . 
 
 3. The rapidity of radiation also depends upon the differ- 
 ence between the temperature of the radiating body and that 
 of the surrounding bodies. Hence, with a given temperature 
 of the latter, the higher the temperature of the radiating body, 
 the more rapid the radiation. 
 
 III. Disposition of radiant Caloric. Radiant caloric passes 
 in right lines through a vacuum, through air and gases, with- 
 out any apparent obstruction ; but when it falls upon solid or 
 liquid substances, it is disposed of in three ways : > 1. It re- 
 bounds from the surface, or is reflected. 2. It enters into the 
 substance, or is absorbed, 3. It passes through the body, or 
 is transmitted. 
 
 1. Reflection of Caloric. When radiant caloric falls upon 
 bright, polished surfaces, it is mostly reflected in lines, which 
 form angles with a perpendicular to the reflecting surface, 
 equal to the angles formed by the same perpendicular, and 
 the lines in which the rays went to the surface. 
 
 Thus, let BAG (Fig. 6) be a smooth 'sur- Fig. 6. 
 
 face, S the incident ray, P the perpendicular ^ j 
 
 to the surface, and R the reflected ray. The 
 angle RAP is equal to the angle PAS. The 
 
 angle PAS is called the angle of incidence, A.V.- p 
 
 and PAR the angle of reflection. Light fol- 
 lows the same law. If a concave surface be 
 used, the rays of caloric will be reflected and jj| 
 brought to a focus. This may be shown by 
 ivvio metallic mirrors, as in Fig. 7. a and b 
 
 Fig 
 
32 Absorption of Caloric. 
 
 are two reflectors of polished metal, (brass or tin,) 12 inches 
 in diameter, and segments of a sphere of 9 inches radius. 
 Place them at any convenient distance apart, from 6 to 12 
 feet. If a heated ball of iron be placed in the focus of a, and 
 an air thermometer in that of 6, the caloric will first radiate 
 to the surface of a, and then be reflected in parallel lines to 
 the surface of b, whence the rays will be reflected to the focus 
 in which the bulb of the thermometer is placed, and will 
 cause the liquid to descend, showing an increase of tempera- 
 ture. If phosphorus be placed in the focus, it will be ignited. 
 If snow be substituted for the heated ball, the thermometer 
 will show, by the rise of the liquid, a diminution of tempera- 
 ture. As bright, polished surfaces reflect most of the calorific 
 rays which fall upon them, we can see the reason why they 
 are not easily heated. 
 
 2. Absorption of Caloric. When radiant caloric falls upon 
 rough, opaque substances, it is mostly absorbed ; that is, it 
 passes directly into the substance, and renders it hot : some 
 of the rays are also reflected. 
 
 The power of absorption, as well as of radiation and re- 
 flection, depends mostly upon the surface. \ Those surfaces 
 which reflect most, radiate and absorb least, and those which 
 radiate and absorb most, reflect least. The power of absorp- 
 tion and that of radiation are equal ; and as each increases, 
 the power of reflection diminishes. 
 
 The* color of the surface also affects the power of absorp- 
 tion. Dr. Stark has shown that black surfaces, other things 
 being equal, absorb the most; dark green next to black; 
 scarlet next: and white the least of all colors.* 
 
 Exp. This fact may be shown by placing strips of cloth of different 
 colors upon snow, exposed to the sun's rays; the black will be found 
 to sink into the snow to the greatest, arid the white to the least, depth, 
 because the black absorbs the rays which melt the snow, and the white 
 reflects them. Hence the advantage of painting rooms white, or of 
 whitewashing them : the rays of caloric are thus kept passing from 
 side to side, without being absorbed and conducted away. 
 
 3. Transmission of Caloric. When radiant caloric falls 
 upon the surface of transparent solid or liquid bodies, it 
 passes through them in a slight degree. 
 
 It passes easily through air and other gaseous substances, 
 without sensibly affecting them; but glass and crystalline 
 
 * Recent experiments seem to disprove this doctrine; a black surface is . 
 Tougher. 
 
Theories of Radiation. 33 
 
 substances intercept most of the rays. Prof. Leslie contends 
 that glass does not permit the rays to pass directly through it, 
 but absorbs them at one surface, and transmits them to the 
 other by conduction, from which they are again radiated. 
 This opinion is supported by Dr. Brewster by an argument 
 drawn from his optical researches. But the experiments of 
 De la Roche lead to a different conclusion — that the calorific 
 rays do pass through glass, although slowly. This opinion is 
 supported by other chemists. 
 
 The radiant caloric which is associated with solar light 
 passes readily through glass and other transparent bodies. 
 The caloric, in this case, seems to be modified by its con- 
 nection with light, and may be collected into a focus with the 
 light, as in the case of a burning-glass. Caloric, thus asso- 
 ciated, suffers refraction in passing from one medium to 
 another, and in general is subject to the same laws with light. 
 
 IV. Theories of Radiation. Of the various theories to 
 account for radiation,* only two seem worthy of notice. 
 
 1. The theory of Pictet supposes that a hot body will 
 radiate caloric to surrounding colder bodies, until the equi- 
 librium is restored, and then cease. 
 
 2. The theory of Prevost supposes that all bodies, what- 
 ever be their temperature, are constantly giving out and 
 receiving radiant caloric. When a body is giving out more 
 rays than it is receiving, it is cooling. When it gives and 
 receives an equal number, its temperature remains stationary, 
 and is in equilibrium with surrounding bodies. When it 
 receives more rays than it gives off, its temperature is in- 
 creasing. On- this theory, all bodies — the polar ice, as well 
 ■ as the burning sands of the tropics — are constantly radiating 
 
 and absorbing caloric. 
 
 Although most of the phenomena of radiation may be 
 explained on both theories, preference is generally given to 
 that of Prevost. The ground of this preference is found in 
 the close analogy between the laws of light and heat. It is 
 we I k lown that luminous bodies continually exchange rays. 
 A feeble light sends rays to one of greater intensity, and the 
 quantity of rays emitted by each does not seem to be affected 
 2* 
 
34 Application of the Theory of Prevosi. 
 
 by the vicinity of other luminous bodies. In like manner all 
 bodies are supposed continually to exchange rays of caloric. 
 
 V. Application of the Thtory of Prcvost to the Explana* 
 tion of various Phenomena, 
 
 1. In the experiments with the mirrors, if the ball in the 
 focus of one mirror is of the same temperature with the 
 thermometer in that of the other, and with surrounding 
 objects, the thermometer will remain stationary, because it 
 receives from the ball the same quantity of rays which it 
 sends to it; but if the temperature of the ball be raised above 
 that of the surrounding objects, the thermometer will receive 
 more rays than it imparts, and will consequently show an 
 increase of temperature. If ice be substituted for the ball, 
 the thermometer will show a diminution of temperature, be* 
 cause it gives out more rays than it receives. 
 
 When ice is placed in the focus of a mirror, there is cm 
 apparent radiation of cold. But on this theory it is easily 
 explained, and is what might be expected previous to experi- 
 ment.* Cold is a negative term, merely expressing the 
 absence, in a greater or \ ess decree, of caloric. 
 
 5 3 O ' 
 
 2. The formation of dew depends upon radiation, and is 
 satisfactorily accounted for by this theory. The earth, during 
 the day, becomes heated by absorbing the sun's rays, and the 
 moisture is driven off into the air. During the night, it radi- 
 ates more caloric than it receives, and becomes colder than 
 the surrounding atmosphere. Successive strata of air charged 
 with moisture, come in contact with the earth, and the 
 moisture is condensed in the form of dew. 
 
 The quantity of dew wili therefore depend upon the radi- 
 ating power of the surface, and the quantity of moisture in 
 the air ; the more rapid the radiation, the more dew will be 
 formed There is more dew upon grass and leaves than 
 upon stones ; and the thermometer will sink 15° or 20° lower, 
 when placed upon grass, than when suspended in the air, or 
 laid on polished surfaces. In India, ice is formed by ex- 
 posing water in pans in a clear night, when the temperature 
 
 * See Turner, 6th edition, p. 13, note 
 
Cooling of Bodies. 35 
 
 of the air is never down to the freezing point. But why is 
 there, no dew in a cloudy night? Because the clouds reflect 
 back the radiant caloric to the earth, which therefore cannot 
 become cooler than the air. In a clear night, there is no 
 such interchange of rays, and the caloric passes off into the 
 regions of space.* 
 
 VI. Cooling of Bodies. The cooling of a hot body is 
 effected in two ways, already noticed. When surrounded by 
 solid bodies in contact with it, the heat is carried off by 
 conduction, and the velocity of cooling will depend upon the 
 conducting power. When the heated body is immersed in 
 liquids, the same is true to some extent, although much de- 
 pends upon the mobility of the particles. But when sur- 
 rounded by gases, the cooling takes place by means of con- 
 duction and radiation, and in a vacuum, by radiation alone. 
 
 Velocity of cooling means the number of degrees lost in a 
 given time. Law of cooling refers to the relation which the 
 velocities of equal successive periods bear to one, another. 
 The higher the temperature, other things being equal, the 
 greater the velocity. If a body heated to 1000° lose 100° 
 during the first second, Newton inferred that it would lose 
 T \ of the remainder, or 90°, during the next second, 81° the 
 next, 72.9° the next, and 65.6° the next. These numbers 
 form a geometrical series, whose ratio is 1.111 : and, though 
 the law is not universal, it holds true, when the temperature 
 is but a little elevated above the air. 
 
 VII. Practiced Application of the Laws of Conducted and 
 Radiant Caloric. The material for windows should be a bad 
 conductor of heat, as well as transparent ; hence glass is best 
 adapted to the purpose. Glass also admits solar heat, while 
 it prevents the escape of artificial heat. Double walls, doors, 
 and windows, add to the warmth of buildings, because they 
 confine between them a stratum of air, which, when not in 
 motion, is a good non-conductor. Snow, furs, woollens, etc., 
 are better non-conductors, because they enclose air. Stoves 
 which are rough radiate more heat than those which are 
 
 * The quantity of dew seems to depend also upon the difference be- 
 tween the temperature of the atmosphere and that of the earth. 
 
36 Effects of Free Caloric. 
 
 polished. As the temperature of the human body usu&ilj 
 exceeds that of the atmosphere, the object of clothing in 
 cold weather is to retain the natural warmth ; and hence it 
 is made of good non-conductors. In hot weather, clothing 
 should conduct off the heat more freely. Also, under a hot 
 sun, a black dress is more uncomfortable than one of light 
 color. Many articles employed in the common uses of life 
 are selected with reference to their conducting and radiating 
 properties, as materials for furnaces, culinary apparatus, etc, 
 
 Effects of Free Caloric. 
 
 The phenomena which may be ascribed to caloric as an 
 agent, and which may therefore be classified as its effects, 
 are numerous : some of these effects will now be enumerated. 
 
 The most remarkable property of caloric, as we have seen, 
 is the repulsion, which exists among its particles, by which 
 it tends to an equilibrium, or to bring all substances to the 
 same degree of temperature. This property enables it to 
 penetrate all bodies, and, by its accumulation, to separate the 
 integrant molecules from each other. It thus acts in oppo- 
 sition to cohesive attraction ; hence it may be stated as a 
 general law, that 
 
 I. Caloric expands all bodies; liquids more than solids, 
 and gases more than either. 
 
 1. Caloric expands solids. This may be shown by fitting 
 an iron cylinder to en aperture, so that it will just slide 
 through; heat it, and it will be too large to pass throucrh. 
 
 2. Equal degrees of caloric expand some solids more than 
 others. This may be shown by an instrument called a 
 pyrometer, or fire measurer. 
 
 Fig. 8 represents this instrument. It is furnished with 
 several rods, as iron, brass, copper, lead, and glass. 
 
 BB, posts standing in A, and secured from spreading apar* 
 by the two bars CC. G, a thumbscrew, passing through the 
 post B, and entering one end of the rod D, holds it against 
 a lever at the other end ; as the rod is heated, it expands and 
 presses against the lever, which raises E, at the end of which 
 is a cord passing up, over the hub of the index, and down 
 
Expansion of Solids. 
 
 37 
 
 again to the balance rod F; E is raised by the expansion of 
 the rod D ; F falls, drawing the cord, and giving motion to the 
 hand. 
 
 Fig. 8. 
 
 The following substances, when heated from 32° to 212° 
 Fahr., are elongated as follows : 
 
 Flint glass, .... t2"Vf °f ' ts length, 
 
 Iron » ¥"b 
 
 Co PPer, Trix 
 
 Brass > irih- 
 
 l\pad i " 
 
 - L,edU > TbT 
 
 3. Equal increments, or additions of caloric, at different 
 temperatures, do not expand the same solid equally. 
 
 That is, the expansion of a brass or iron rod will be much 
 greater between 500° and 600°, than between 100° and 200°, 
 or than between 200° and 300°. The higher the tempera- 
 ture, the greater the expansion, with equal additions of 
 caloric. This results from the fact that the power of cohe- 
 sion is constantly diminished, the farther the integrant parti- 
 cles are removed from each other by heat. 
 
 4. The expansion of some solids is more uniform than 
 others, with equal additions of caloric. The expansions of 
 the more .infusible solids are uniform within certain limits 
 From 32° to 122°, their expansion is equal to that between 
 
38 
 
 Expansion of Liquids. 
 
 122° and 212°. But above 212°, the higher the temperature, 
 the greater the expansion, for equal additions of caloric. 
 II. Caloric expands liquids more than solids. 
 
 1. This fact may be illustrated by heating a Fig. 9. 
 column of water in a glass tube, and an iron rod 
 of the same dimensions, by a spirit lamp ; the water 
 will rise in the tube, while the iron will scarcely be 
 affected. The reason is, that the cohesive at- 
 traction in liquids is nearly destroyed. 
 
 Exp. Plunge a common thermometer into a jar of hot 
 water, (Fig. 9.) The bulb of the thermometer will be ex- 
 panded, and its capacity increased, but the mercury will 
 be more expanded, and will rise in the tube. 
 
 2. Equal increments of caloric ex- 
 pand some liquids more than others. 
 This may be illustrated by partially 
 filling several glass tubes furnished 
 with bulbs with different liquids, and 
 placing them in hot water; as the 
 liquids expand, they will rise to dif- 
 ferent heights in the tubes, as shown 
 in Fig. 10. 
 
 3. Equal additions of caloric, at different temperatures, 
 do not expand the same liquids equally. The same law holds 
 here as in the case of solids — the higher the temperature, the 
 greater the expansion for equal amounts of heat; and those 
 liquids also which expand the least are more uniform within 
 certain limits. Apparent exceptions to the general lav/ are 
 found in the case of some liquids, near the point of con- 
 gelation. Water expands by a diminution of temperature, 
 and contracts by an addition of caloric, between the freezing 
 point and 40° Fahr. 
 
 III. Caloric expands gases more than 
 solids or liquids. 
 
 1. The expansion of air may be shown by 
 simply inverting a glass tube terminated by a 
 bull), and partly filled with water, (Fig. 11,) 
 in a vessel of the same liquid : on heating the 
 bulb, the air will expand, and expel the liquid 
 from the tube ; or by holding a bladder partly 
 
Expansion of Gases. 39 
 
 filled with air near the fire, the air will soon expand, fill the 
 bladder, and even burst it.* 
 
 2. All gases, at any temperature, are expanded equally 
 by equal additions of caloric. In this respect, gases differ 
 from solids and liquids. If, therefore, we can ascertain the 
 expansion of one gas for a given number of degrees, we rnay 
 know that of all others. The law of the expansion of air 
 has been determined by Gay Lussac, who found that a given 
 quantity of dry air dilates to T |^ of the volume it occupied 
 at 32°, for the addition of each degree of Fahr. 
 
 Theory of Expansion. This has been already noticed. In 
 the case of solids, the integrant particles are held together 
 by cohesive attraction, but the caloric, being self-repellent, 
 has the effect to overcome this force, and to separate the 
 particles from each other. f In case of liquids, cohesive at- 
 traction is much more feeble ; it will therefore require less 
 power to separate the particles, and hence they are more 
 expansible than solids. Gases are still less under the influ- 
 ence of cohesion, and hence are more expansible. In fact, 
 the form which matter assumes seems to depend upon the 
 relative force of caloric and cohesion. In solids, cohesion 
 preponderates ; in gases, caloric ; but in perfect liquids, these 
 forces are in equilibrium, (the caloric being in a combined, 
 and not a sensible state.) 
 
 IV. Apparent Exceptions. Allusion was made to water 
 and somf other substances as apparent exceptions to the 
 general law that heat expands and cold contracts all bodies. 
 Water continues to contract, until it arrives at 39°, and then 
 begins to expand until congelation takes place. 
 
 * So great is the tendency of air and other gases to expand, that, if 
 a given portion be confined in a bladder, or in a very thin glass of a 
 square form, and put under the exhausted receiver of an air pump, the 
 same efFect will be produced as when heat is applied ; the particles of 
 gases seem to be wholly free from the influence of cohesive attraction, 
 and expand by their own caloric when the pressure is removed. 
 
 t On the supposition that caloric is material, the efFect is easily ac 
 counted for; but though its particles repel each other, they must have 
 a strong attraction for matter, or they could not be introduced into it 
 Caloric, therefore, is the antagonist force to cohesive attraction, but 
 possesses a powerful attraction for matter, peculiar to itself. 
 
40 The Force of Expansion. 
 
 Exp. Take a glass lobe, with a bnlb at one end. fill it with warm 
 water, and place it in a mixture of salt and snow. The water in the 
 tube will sink until it arrives at 39°, and then begin to rise until it 
 arrives at 32°. The water, in becoming ice, will increase in bulk ^, 
 and ice, in melting, will diminish in bulk J ff ; hence, if the specific 
 gravity of water is 10, ice will be 9. The maximum density of water 
 is a: >:- : 7iir. 
 
 V. The force of expansion, when water freezes, is 
 great. The Florentine academicians burst a hollow brass 
 globe, whose cavity was only one inch in diameter, by freez- 
 ing the water contained in it. This most have required a 
 force equal to OT.T^O pounds. Major T .Villiams, in 1784-5, 
 performed similar experiments at Quebec, by bursting bombs, 
 which also illustrated the amazing force of water in the 
 
 of congelation. 
 
 In consequence of this expansive force, glass md earthen 
 Tessels are broken, by suffering water to freeze within them ; 
 water pipes are burst; pavements are thrown up, and de- 
 stroyed, and walls, especially in moist grounds, thrown 
 down. 
 
 Theory. The cause of this expansion is supposed to be 
 due to crystallization. The particles, at 39°, seem to be 
 endowed with a kind of polarity, and attract the edges of 
 each other : and, at 32" , they are arranged in ranks and files, 
 which cross at angles of 60° and 120°, as may be seen when 
 water is freezing in a saucer. This new arrangement of the 
 particles is supposed to increase the bulk ; but, whether this 
 hypothesis be correct or not, it seems best to explain the 
 
 VI. Advantage of this Exception. The wisdom and be- 
 nevolence of God are strikingly exhibited in this arrange- 
 ment. Otherwise, all our rivers, and lakes, and the ocean 
 itself, in cold climates, would become solid masses of ice ! 
 
 When a body of water is freezing, there are two currents 
 
 * This hypothesis relieves us from the necessity of supposing a real 
 exception to the laws of nature. The effect is due to the operation of 
 another law, (crystallization.) to which the law of expar - 
 place. For, after the crystallization is completed, the us-ual law pre- 
 vails, and ice contracts, with the further reduction o8" tempers. - , 
 sure* are thus produced, in extreme - .-, by the contraction 
 
 of ice on ponds. 
 
Uses of the Law of Expansion. 41 
 
 established, as in the case of boiling water. The surface 
 gives off its caloric to the air, and the particles become heavy, 
 and sink down. This forces the warm particles below to 
 rise. But at 39° these currents arc arrested, because the 
 colder particles begin to expand, and remain at the top. As 
 soon as they are frozen, a covering of ice prevents, in a great 
 measure, the escape of caloric from beneath, and the process 
 of freezing is greatly retarded. But, if the contraction ex- 
 tended to the freezing point, the colder particles would con- 
 tinue to fall to the bottom, until the whole should be brought 
 to that point, and then suddenly freeze; or, if they should 
 freeze upon the surface, the ice would continue to sink down 
 until the whole should become a solid mass. 
 
 Hence, in cold climates, the rivers and lakes would be 
 converted into solid ice, and all their inhabitants would be 
 destroyed ! But, by this simple and beautiful arrangement, 
 the ice is retained upon the surface, and confines sufficient 
 stores of caloric to preserve the inhabitants of the waters, and 
 render the coldest climates habitable by man. 
 
 Water is not the only liquid which expands under the 
 reduction of temperature; as the same effect has been ob- 
 served in a few others, which assume a highly crystalline 
 structure, on becoming solid. Hence the exactness with 
 which cast iron fills the mould, and the use of antimony in 
 casting types. Mercury is a remarkable instance of the re- 
 verse; for, when it freezes, it suffers a very great contrac- 
 tion. 
 
 VII. Practical Uses of the general Law of Expansion and 
 Contraction. All kinds of machinery are, of course, affected 
 by this law. It must be strictly regarded in the construction 
 of delicate time-pieces. Great use is made of it in the band- 
 ing of wheels ; the iron is heated, and fitted to the dimen- 
 sions, and then suddenly cooled, so that, by its contraction, 
 it presses with great force, and becomes immovably fixed. 
 In riveting together iron plates for steam engine boilers, it is 
 necessary to produce as close a joint as possible. This is 
 effected by using the rivets red-hot; the contraction, which 
 the rivet undergoes in cooling, draws the plates together 
 with a force which is only limited by the tenacity of the 
 metal of which the rivet itself is made. 
 
 M. Moiard, a few years since, at Paris, availed himself of this 
 
42 * TJtermometers. 
 
 principle, to restore to their perpendicular direction two opposite walls 
 of a gallery, which had been pressed outward by incumbent weight 
 Through holes in the walls, several strong iron bars weie introduced, 
 so as to cross the apartment, with the ends projecting; upon which 
 strong iron plates were screwed. The bars were then heated, and, 
 while hot, the plates were screwed up. On cooling, the bars con- 
 tracted, and drew the walls together. By repeating this process several 
 times, they were restored to their original position. Balloons were 
 first sent up filled with air which had been expanded by heat. 
 
 Winds. The phenomena of winds depend upon the expan- 
 sion of the air by the heat of the sun. Tn this way the trade 
 winds are produced. Land and sea breezes depend upon radi- 
 ation and expansion. During the day, the earth is more 
 heated than the water, and the air is more expanded, and 
 rises up. This will produce currents of cold air from the 
 water to the land, called sea breezes. During the night, the 
 earth radiates caloric more rapidly than the water, the air be- 
 comes cooler, and currents pass from the land to the water. 
 These are called land breezes. Winds are also produced in 
 those deserts which become greatly heated during the day. 
 
 Thermometers. But one of the most ingenious and useful 
 applications of this law is to be found in the thermome- 
 ter. Its invention is generally ascribed to Sanctorius, who 
 flourished in the seventeenth century. Some ascribe it to 
 Cornelius Drebel, and others to Galileo. 
 
 1. Air Thermometers. The substance employed 
 by Sanctorius was atmospheric air, by the expan- Fig. 12. 
 sion and contraction of which he was enabled to 
 measure variations of temperature. His plan was 
 very simple. The instrument consists of a glass 
 tube, (Fig. 12,) open at one end, with a ball blown 
 at the other ; enough of some colored liquid is 
 poured in to fill half the tube, which is then in- 
 verted in a vessel of the same liquid. The air in 
 the bulb, by its expansion, causes the water in the 
 tube to sink, and, by its contraction, the pressure of 
 the atmosphere causes it to rise. By adapting a ^J 
 scale to the tube, the instrument is fitted for use.* 
 
 On one account, air is the best substance for a thermometer, 
 
 * This instrument is easily constructed by heating a glass tube in 
 the fire, and blowing a bulb upon the end} then insert the open end in 
 some colored liquid. 
 
Differential Thermometer. 
 
 43 
 
 Fig. 13- 
 
 because its expansions and contractions are equal, with equal 
 additions of caloric. But there are two objections to the use 
 of this instrument ; — it can be depended upon only when the 
 barometer stands at a fixed point ; variations of atmospheric 
 pressure materially affect the rise or fall of the liquid. The 
 expansion of gases, also, with slight degrees of caloric, is so 
 great, that the length of the tube for measuring high or low 
 temperatures would render the instrument inconvenient in 
 practice. 
 
 2. Differential Thermometer. Sir J. Leslie, in 1804, con- 
 structed a thermometer, in which air is used, which is not 
 affected by atmospheric pressure. 
 
 It consists of two glass balls, (Fig. 13,) 
 joined together by a glass tube, bent twice 
 at right angles. The balls contain air, but 
 the tube is nearly filled with sulphuric acid, 
 colored with carmine. To one leg of this 
 tube is applied a scale. It is evident that no 
 effect will be produced upon the liquid, if 
 both balls are heated alike, because the air 
 in both will suffer equal expansion; but the 
 slightest difference between the temperature 
 of the two balls, will instantly be indicated by 
 the rise or fall of the liquid in the tube. 
 Hence its only use is to detect slight variations of tempera- 
 ture between two substances, or of two contiguous spots in 
 the same atmosphere, in very delicate experiments, where 
 caloric is reflected, or refracted to a focus. It is hence called 
 the Differential Thermometer. 
 
 A much more delicate instrument of this kind has been 
 constructed by Dr. Howard, of Baltimore, in which the vapor 
 of ether, or alcohol, in vacuo, is used instead of air. 
 
 But if air expands too much, and is affected by pressure, so 
 as to be unfitted for the common purposes of measuring the 
 degrees of temperature, solid substances, on the other hand, 
 expand too little. 
 
 The substance most convenient is a liquid, and the object 
 iB^to find some liquid whose dilations are nearly equal with 
 equal additions of caloric, and whose boiling and freezing 
 
44 Mercurial Thermometer. 
 
 points are removed at the greatest distance from each other 
 Alcohol and ether would answer this purpose very well in 
 one respect, — they resist congelation to a very low tempera- 
 ture, but boil much sooner than water. Mercury seems to be 
 the only substance which will answer the necessary condi- 
 tions. 
 
 3. Mercurial Thermometer. This instrument "Fig. 14. 
 (Fig. 14) is constructed in the following manner : 
 A tube is selected with a small bore, of uniform 
 diameter, and a small ball is blown at one end. 
 The air is then mostly expelled from the bulb, by 
 holding it in a spirit lamp, and the end of the tube 
 quickly inverted in a cup of clear, dry mercury. 
 As the bulb cools, the atmosphere forces the mer- 
 cury into the bulb, which fills it two thirds full ; 
 the bulb is again heated, and the mercury rises up, 
 nearly rilling the tube, and expelling the air. It is 
 again inverted over mercury, when the bulb and 
 one third of the tube are filled ; it is then heated 
 until it boils, and fills the tube to the top. A fine flame is 
 then darted from a blowpipe* upon the open extremity of 
 the tube, so as to fuse the glass, and close the aperture 
 before the mercury recedes. It is then said to be hermeti- 
 cally sealed, and the space abandoned at the upper extremity 
 of the tube, as it cools, is a vacuum. 
 
 Graduation. This is effected by ascertaining two fixed points ; and, 
 as water always freezes at the same temperature, and also boils at the 
 same temperature, when the barometer stands at the same height, we 
 have only to immerse the bulb and a part of the stem in melting snow, 
 or water containing ice, and mark the point to which the mercury 
 sinks. This is the freezing point. To fix the boiling point, distilled 
 water should be used, and the barometer should stand at 30 inches. 
 A small quantity of the water, not more than one inch in depth, and 
 contained in a deep metallic vessel, is made to boil briskly, and the 
 point to which the mercury rises, is marked ; this is the boiling point 
 These two points being fixed, the interval is variously divided into 
 equal parts. 
 
 * Fig. 15 represents the most common forms 
 of the blowpipe. It consists of a brass or copper 
 tube, tapering nearly to a point, through the small 
 end of which the air is forced, either by placing 
 the large end in the mouth, or by adapting to it a 
 oair of bellows. 
 
Register Thermometer. 
 
 45 
 
 Newton first suggested a scale, in which 
 the zero was placed at the freezing point, 
 and the interval divided into 40 parts, or 
 degrees. In Fahrenheit's thermometer, 
 which is generally used in this country and 
 in England, the zero is placed at 32° below 
 the freezing point, and the interval between 
 the freezing and the boiling points is divided 
 into 180 parts, so that the boiling point of 
 water is 212°. Fahrenheit fixed his zero 
 by immersing the thermometer in a mixture 
 of snow and salt. Reaumur's scale places 
 the freezing point, at zero, and the boiling at 
 80°. De Lisle placed the boiling point at 
 zero, and the freezing at 159° below; this 
 is used in Russia. But the most convenient 
 scale is- that of Celsius, in which the freez- 
 ing point is at zero, and the boiling at 100°, 
 called the Centigrade thermometer ; this is 
 used in France. The different scales are 
 seen in Fig. 16. 
 
 The scale is either marked on the tube 
 by a diamond, or on ivory or paper, and at- 
 tached to the tube. The degrees above the 
 boiling and below the freezing points occupy 
 equal spaces with those between these points. 
 The temperature expressed by one scale can 
 be reduced to that of another, by knowing 
 the relation which exists between their de- 
 grees. The lower part of the scale, in labo- 
 ratory thermometers, (Fig. 14,) turns up by 
 a hinge, so that the bulb can be immersed 
 in corrosive liquids. 
 
 4. Register Thermometer. 
 This instrument consists of 
 two thermometer tubes, (Fig. 
 17,) bent at right angles, and 
 retaining a horizontal position. 
 One tube contains alcohol, and 
 the other mercury. A small piece of black enamel is placed 
 in the tubes on the surface of each liquid. As the alcohol 
 contracts by exposure to cold, the enamel follows j* ♦««•*•*»- 
 
 
 
 Fig, 
 
 16. 
 
 
 
 4) 
 
 o 
 
 :: 
 
 0} 
 0> 
 
 
 
 210-1 
 
 ZOj-1 
 SSO-j 
 180- 1 
 
 .70:: 
 
 -z 
 50-1 
 
 =L„ 
 
 
 - „ 
 
 
 
 
 
 :-(6- 
 
 
 
 l=- 
 
 ~ 
 
 
 
 - 
 
 
 
 
 = •30 
 
 
 IW- 
 
 
 
 - 
 
 
 
 
 
 = -80 
 
 -- 
 
 iau_: 
 
 
 
 \ — 
 
 ~JK1: 
 
 :-40=: 
 
 
 
 - 
 
 : 
 
 
 
 --70 
 
 _: 
 
 
 
 
 - 
 
 
 : so-- 
 
 
 
 = - 
 
 
 
 
 ml 
 
 .20 - 
 
 jo-1 
 no- 1 
 
 .CO- '- 
 5C ■ 
 80-1 
 
 70-j 
 
 50- \ 
 
 
 bG : 
 
 
 
 
 
 
 , Vv . 
 
 
 
 -4&- 
 
 
 : 70-; 
 
 
 
 
 
 
 _< ":- : 
 
 
 
 - 
 
 
 -80-1 
 
 
 
 -- 
 
 ._■_ 
 
 
 
 zzW 
 
 — \ 
 
 ^ir: 
 
 
 
 r-3cT 
 
 —-'- 
 
 IC-3-- 
 
 
 
 - 
 
 
 
 
 
 -- 
 
 . 
 
 I2'0 : : 
 
 
 
 
 — \ 
 
 
 
 z-zo 
 
 
 
 
 
 
 
 
 Z' 
 
 
 
 
 
 :c-: 
 
 •ic-l 
 
 z-W- 
 
 J o- : 
 i. 
 
 l-" : ': 
 
 
 
 1_ 
 
 
 
 
 E — 
 
 
 
 
 
 
 
 
 \— 
 
 
 
 
 
 ,,. - 
 
 
 
 
 
 
 
 
 110 
 
 
 no- 1 
 
 
 
 \A-\ 
 
 
 i 
 
 - < 
 
 -— 1 - 
 
 
 
46 
 
 Pyrometers of Wedgwood and Daniell. 
 
 the bulb ; but when it expands, the enamel remains stationary, 
 and suffers the liquid to pass by it. When the mercury con- 
 tracts, the enamel does not follow it; but when the mercury 
 expunds, it is forced along. Consequently, it remains at the 
 highest temperature. The enamel, in the tube of alcohol, 
 will indicate the lowest, and that in the tube of mercury the 
 highest,- temperature during any given time. 
 
 For measuring temperatures below 39° F., the freezing 
 point of mercury, alcohol, or ether, must be employed ; for 
 temperatures above 662°, no liquid can be used, as they are 
 all either decomposed, or dissipated in vapors. For very high 
 temperatures, therefore, some of the more infusible solids 
 are used. The instruments for this purpose are called 
 
 Pyrometers. This term is derived from two Greek words, 
 signifying measurer of fire. 
 
 1 1. Pyrometer of Wcdgicood. This is founded on the 
 property which clay possesses of contracting when strongly 
 heated, without expanding when cooled ; but the indications 
 of this instrument cannot be relied on, and it is seldom used. 
 
 2. Pyrometer of Danidl. This instrument, the best now 
 in use, consists of a bar of platinum enclosed in a case 1\ 
 inches in depth, made of black lead : one end of the bar is 
 fixed ; the other is made to move an index, as it is heated. 
 This, however, is not perfectly accurate, owing to the greater 
 expansion of the platinum, in high temperatures, with equal 
 degrees of heat. Generally, these instruments depend upon 
 the elongation of a metallic bar by heat ; and one of the best 
 for illustration is described on page 37. 
 
 3. On the same principle is the 
 Metallic Thermometer of Brequet, 
 (Fig. 18,) for temperatures between 
 the freezing and boiling points of 
 water. It consists of a slip of silver 
 and one of platinum, united face to 
 face with solder, and coiled into a 
 spiral, d, one end of which, c, is 
 fixed, while the other is connected 
 with an index, e, which moves over 
 a circular, graduated plate, f, f. 
 Thi> index is found to move over 
 equal spaces with equal additions of 
 caloric ; and so sensible is it to slight 
 
 Fig. 18. 
 
Insensible Caloric. 47 
 
 rariations, that when enclosed in a large receiver, which 
 was rapidly exhausted by an air pump, it indicated a reduc- 
 tion of temperature from 66° to 25° = 41°, while a sensible 
 mercurial thermometer fell only 36°. 
 
 It will be readily seen that thermometers do not give us 
 the absolute, but only the relative quantity of caloric con- 
 tained in bodies. The true zero, or that point where abso- 
 lutely no caloric exists, is unknown. Some have conjectured 
 that it is 1200° or 1400° below the freezing point of water. 
 But it is mere conjecture ; nor is it known, on the other hand, 
 how high a temperature might result from an accumulation 
 of heat. Neither limit is known. The thermometers and 
 other instruments measure only a few degrees, in the middle 
 of a scale, whose extremities are indefinitely extended. 
 
 Sect. 2. Insensible Caloric. • ■ 
 
 Every one sees that a quart of water contains double the 
 quantity of caloric which is contained in a pint of the same 
 liquid, when the temperature of both is the same. This is 
 called insensible caloric, because it does not affect the ther- 
 mometer. 
 
 Specific Caloric. But different quantities of caloric are 
 required to raise equal weights of different substances to the 
 same temperature ; and, conversely, different quantities a^p 
 given out by them in cooling equally. Suppose, for example, 
 that, on adding a given quantity of heat to a pound of water 
 at 50°, the temperature will become G0°, — the addition of the 
 same quantity to a pound of sperm oil at 50°, will raise the 
 temperature to 70°, while a pound of powdered glass will be 
 raised from 50° to 100° by the same quantity of caloric. 
 The temperature is increased 10°, 20°, and 50°, in these dif- 
 ferent substances; i. e., if the required temperature to which 
 they shall be raised be given, the oil will require but half as 
 much heat as the water, and the glass only one fifth as much. 
 Specific heat the relative quantity of caloric requisite to 
 raise the temperature of sjzb stances equally; i. e., taking 
 water for a standard at 1 , the specific heat of sperm oil will 
 be 1 5 (J; and of powdered glass y 2 ^.* 
 
 * The phrase capacity for caloric was formerly used, and was in- 
 
48 Methods of determining Specific Heat. 
 
 In these experiments, a portion of caloric disappears. 
 This portion has been called latent or combined caloric, 
 in reference to the theory mentioned in the note below 
 The phrase insensible heat is preferred, as not involving any 
 theory. 
 
 Methods of determining Specific Heat. Various methods 
 have been employed to ascertain the specific heat of sub- 
 stances. The most convenient method is to mix with the 
 substances, all being at the same temperature, a given quantity 
 of some liquid, as water, at some other given temperature, 
 and observe the relative effects. Thus, as in the example 
 given, a pound of water at 80° may be added to a pound of 
 the same at 50°, and the resulting temperature will be the 
 mean, 65° ; another pound of water at 80° to a pound of oil 
 at 50°, and the resulting temperature will be 70° ; i. e., the 
 oil will gain 20° while the water loses but 10° ; and again, a 
 pound of water at 80° to a pound of glass at 50°, and the 
 temperature of the mixture will be 75°, the glass gaining 25° 
 by 5° loss of the water. Other and more difficult experi- 
 ments are necessary to ascertain the specific heat of gases 
 and of solid bodies. 
 
 Laws of Specific Heat. The principal laws of specific 
 heat are the following : — 
 
 1. At the same temperature, and, in the case of gases, 
 with the same pressure, the specific heat of each body is 
 .constant. 
 
 2. The higher the temperature, and, in the case of gases, 
 the less the pressure, the greater the specific heat of the same 
 body. 
 
 This is supposed to be owing to expansion. In gases, the 
 specific heat varies with the density and elasticity ; the greater 
 the density, the less the specific caloric ; and the greater the 
 elasticity, the greater the specific caloric. 
 
 .3. A change of form is accompanied by a change of spe- 
 cific caloric. The specific heat of a body, as it passes from 
 a solid to a liquid state, is increased. It is also supposed to 
 
 tended to convey the idea, that a portion of the heat enters fato and is 
 combined with substances in a latent state ; but this is hypothetical, 
 and the pUtaje specific hgat is preferred, as involving mejely a fact, 
 
Effects of Insensible Caloric. 49 
 
 be increased by a change of the body from a liquid slate to 
 th.it of a gas or vapor. 
 
 4. As each substance has a specific heat peculiar to itself, 
 it follows that a change of constitution is accompanied by a 
 change of specific heat. 
 
 5. A change of specific heat is generally accompanied by 
 a change of temperature. Thus the expansion of a gas, 
 which increases its specific heat, diminishes its temperature 
 
 As a practical inference from the doctrine of specific heat, 
 it may be remarked, that much less fuel will be necessary to 
 heat some substances than others. 
 
 Effects of Insensible Caloric. 
 
 These are liquefaction and vaporization.* 
 
 I. Liquefaction. All bodies exist in one of three states, 
 solid, liquid, or gaseous, and their forms seem to depend, as 
 we have seen, (page 39,) upon the relative forces of cohe- 
 sion and caloric. Hence, by the increase and diminution 
 of either of these forces, we can cause the body to assume 
 either of these states. If a solid be sufficiently heated, it will 
 become liquid, and then gaseous. So general is this fact, 
 that it may be stated as a law. 
 
 1. Point of Liquefaction. The temperature at which . 
 liquefaction takes place, is called the melting point, or point 
 effusion, as that at which liquids solidify is termed the point 
 of congelation. These points are identical ; but there is a 
 very great difference in substances as to the degree of heat 
 which is required to fuse them. Each substance has a fixed 
 point of fusion and of congelation. 
 
 2. Caloric of Fluidity. If a pound of ice, which is at 
 32°, be melted in a pound of water at 172°, the temperature 
 of the whole will not be at the mean of 102°, but at 32°, 
 showing that 140° have been taken into a latent state, by the 
 liquefaction of the ice. Generally, liquefaction is accom- 
 
 * Classed as effects of insensible caloric, because the free caloric 
 passes into an insensible state, which is essential to the process. 
 3 
 
50 Caloric. — Freezing Mixtures. 
 
 panied by the conversion of free into insensible heat. The 
 heat which thus disappears seems essential to the process of 
 liquefaction, and is called the caloric of fluidity. - Its quantity 
 varies in different substances, as in the following table : — 
 
 Ice . . . 140° Fahr. Beeswax . 175° Fahr. 
 Sulphur . 143.68° « Zinc . . 490° 
 
 Spermaceti 145° « Tin . . 500° 
 
 Lead . . 162° " Bismuth . 550° 
 
 Irvine. 
 When the process is reversed, in congelation, this insensi- 
 ble caloric is thrown out in a free state. Thus the freezing 
 of water produces heat. 
 
 3. Freezing Mixtures. Liquefaction may be produced 
 without the addition of heat, and hence the caloric of fluidity 
 will be obtained, in part, from the temperature of the sub- 
 stances melted, but chiefly from the surrounding bodies ; a 
 great degree of cold is thus often produced. On trhis princi- 
 ple various freezing mixtures are contrived. The most com- 
 mon method of producing cold is, to mix together equal 
 quantities of fine salt and fresh fallen snow, or pounded ice. 
 The salt melts the snow by its affinity for water, and the 
 water dissolves the salt, so that both are liquefied. The degree 
 of cold produced is 32° below the freezing point of water, 
 or at zero. This led Fahrenheit to commence his scale at 
 that point. Any other substance, which has a strong affinity 
 fjgr water, may be substituted for salt The crystallized 
 chloride of calcium is the best, because it produces the most 
 rapid liquefaction. The following table, constructed by Mr. 
 Walker, contains the proportions of several substances to 
 produce different degrees of cold. 
 
 MIXTURES. b/^Sghj, Thermometer sinks ^f^ 
 
 Sea-salt 1 ) to - - 5° 
 
 Snow 2 J * " * 
 
 Sea-salt . ... . . 2\ 
 
 Muriate of ammonia . 1 / . . . to — 12° 
 
 Snow 5 ) 
 
 Sea-salt 5 \ 
 
 Nitrate of ammonia . 5> . . . to — 25° 
 
 Snow 12 ) 
 
 Muted sulphuric acid 2 J from + 3a o ^^ 55deg 
 
Freezing Mixtures. 
 
 51 
 
 Concentrated muriatic acid 5 ) frQm , 3^ tQ _ 2r 59 ^ 
 
 Snow 8 J ' ° 
 
 Concentrated nitrons acid 4 1 from + 32 o to _ 
 Snow 7 J ' 
 
 — 40 c 
 
 30° 62 
 
 72 
 
 51° 83 
 
 Chloride of calcium . O ) c , or , , 
 Snow 4 |from + 32 to- 
 
 Snow P °' aSSa ' ' : ' 3 from +32° to- 
 
 Freezing may also be effected by the rapid solution of 
 salts. The following table exhibits the proportions, taken 
 from Walker's essay in the Phil. Trans. 1795. The salts 
 must be finely powdered and dry. 
 
 MIXTURES. 
 
 Muriate of ammonia 
 Nitrate of potassa 
 Water .... 
 Nitrate of ammonia 
 Water .... 
 Nitrate of ammonia 
 Carbonate of soda 
 Water .... 
 Sulphate of soda . 
 Diluted nitrous acid 
 Sulphate of soda . 
 Nitrate of ammonia 
 Diluted nitrous acid 
 Phosphate of soda 
 Diluted nitrous acid 
 Phosphate of soda 
 Nitrate, of ammonia 
 Diluted nitrous acid 
 Sulphate of soda . 
 Muriatic acid . 
 Sulphate of soda . 
 Diluted sulphuric acid 
 
 Parts 
 by Weight. 
 
 Thermometer falls 
 
 Deg. of Cold 
 produced. 
 
 5 > from + 50° to + 10° 40 deg. 
 16) 
 
 j J from + 50° to + 4° 46 
 1 >from + 50°to — 7° 57 
 |*| from + 50 c 
 
 to — 3° 53 
 
 from + 50° to — 14° 
 
 4 } from + 50° to — 12° 
 
 9) 
 
 6 > from + 50° to — 21° 
 4) 
 
 ®1 from + 50° to 
 
 64 
 
 62 
 
 71 
 
 0° 50 
 
 4} from + 50° to + 3° 47 
 
 In order to the greatest effect, the substances should be 
 cooled in a freezing mixture before they are united. 
 
 4. The degree of cold produced by these artificial pro- 
 cesses, is limited. The greater the difference between the 
 temperature of the air and that of the mixture, the more 
 rapidly will the air communicate caloric to it; and this soon 
 
52 Vaporization — Ebullition. 
 
 puts a limit to the degree of cold. According to Mr. Walker 
 the greatest cold did not exceed 100° below the zero of 
 Fahrenheit. But a more intense cold is produced by evapo< 
 ration. 
 
 5. No process, however, will deprive a body of all its 
 caloric. Dr. Irvine has attempted to infer the absolute 
 amount from the specific caloric of bodies ; thus ice contains 
 T \j- less specific caloric than water ; and, as this T \y is equal to 
 140°, it is inferred, that water contains ten times the amount, 
 or 1400° of caloric ; but the estimates made by different 
 chemists vary from 900° to 8000°, which shows that but little 
 confidence can be put in their calculations. 
 
 II. Vaporization. By vaporization is meant the conver- 
 sion of liquid and solid substances into vapor. It is generally 
 supposed that, if sufficient caloric be applied, all substances 
 are susceptible of this change. 
 % A gas differs from a vapor in the circumstance that it is 
 not so easily condensed into a liquid^ it retains its state at 
 ordinary temperatures and pressures. " The only difference 
 between gases and vapors is the relative forces with which 
 they resist condensation." — T. 
 
 Some substances yield vapor readily, and are called vola- 
 tile. Others sustain the strongest heat of furnaces, without 
 volatilizing, and are hence said to be fixed in the fire. This 
 difference seems to depend on the relative forces of cohesion 
 and caloric. Liquids are more easily vaporized than solids ; 
 and solids, with a lew exceptions, like camphor, assume the 
 .liquid state before they are converted into vapor. 
 
 Liquids may be vaporized in two ways: 1. by ebullition ; 
 2. by evaporation. In the first case, there is a rapid produc- 
 tion of vapor, causing commotion in the liquid; and in the 
 second, the process is conducted silently, the vapor impercep- 
 tibly passing off from the surface of the liquid. 
 
 Ebullition. 
 
 1. Boiling Point. The temperature at which a liquid is 
 
 converted by ebullition into a vapor, is called its boiling 
 
 point. This point varies greatly in different liquids under the 
 
 same circumstances, and in the same liquid under different 
 
Ebullition. 53 
 
 degrees of pressure. But each liquid has a fixed boiling point, 
 when all the circumstances are the same. 
 
 2. The chief circumstance which modifies the boiling 
 point of the same liquid, is the pressure of the atmosphere. 
 A column of air, extending to the top of the atmosphere, 
 presses upon every square inch of surface with a force equal 
 to 15 lbs. This is sufficient to sustain a column of mercury 
 3D inches, or a column of water 34 feet. But the pressure 
 varies at different times on the surface of the earth ; and as 
 we ascend high mountains, the pressure diminishes rapidly. 
 The instrument by which this variation is measured is called 
 the 
 
 Barometer, the principle of which may be illustrated by 
 filling a glass tube, open at one end, and about 33 inches long, 
 with mercury, and inverting the open end in a cup of the 
 same liquid. (See Fig. 19.) The pressure of the atmos- 
 phere on the surface will sustain the mercury in the tube to 
 the height of from 27 to 31 inches. 
 
 When the barometer stands at 39 inches, ether boils at 
 96°, alcohol at 176°, water at 212°, and mercury at 662°, F. 
 If the barometer stand at 28 inches, all these substances will 
 boil at a lower temperature, and if it rise to 31 inches, the 
 boiling points will be raised. Hence the two following laws : 
 
 1. As the pressure on the surface of liquids diminishes, 
 their boiling temperatures diminish. Thus water heated to 
 72°, and placed under the receiver of an air pump, will boil, 
 on exhausting the air, if the temperature be preserved. 
 
 Ether will boil violently, under an exhausted re- Fig. 19. 
 ceiver, at the common temperature of the atmos- 
 phere. 
 
 Exp. 1. Fill the barometer tube a with mercury, (Fig. 19,) 
 and invert it in a cup c of the same liquid ; then introduce a 
 small quantity of ether. As soon as it reaches the vacuum 
 r. it boils rapidly, and the vapor forces the mercury down the 
 tube. 
 
 Exp. 2. The pulse glass (Fig. 20) 
 acts on the same principle. It is con- 
 structed by blowing a bulb b on the end 
 of a glass tube, in which a small open- 
 ing is made, and through this a similar 
 
 Fig. 20. 
 
54 Influence of Pressure upon the Boiling Point. 
 
 bulb a is blown on the other end. Some spirits of vrine are now in. 
 troduced, and heated in the closed bulb a until the vapor escapes from 
 the aperture in b, when it is hermetically sealed. The heat of the hand 
 upon either bulb is sufficient to cause violent ebullition. 
 
 Ether boils in vacuo at — 44°, alcohol at 36', and water 
 at T'2 : . and liquids generally boil at temperatures 140 = less in 
 vacuo than at the common pressure. 
 
 It is owing to this fact, that intense cold can be produced 
 by boiling ether in vacuo. Water, and even mercury, under 
 favorable circumstances, may be frozen. To render the 
 experiment successful, there should be sulphuric acid in 
 the receiver to absorb the vapor of ether, which, by its 
 pressure, would otherwise soon prevent the ether from 
 boiling. 
 
 2. As the pressure on the surface of liquids increases, their 
 boiling temperatures increase. "When water is heated to the 
 temperature of 212°, its force upon each square inch is equal 
 to 15 lbs. As this is equal to the pressure of the atmosphere, 
 it will, at this temperature, escape in vapor: hence it cannot 
 be heated in the open air above this point. But if the pres- 
 sure be increased sufficiently, it may be heated to any extent, 
 without exhibiting the phenomena of ebullition. 
 
 rig. 2i. 
 
 Exp. Boil water in a Florence flask, (Fig. 21,) and cork 
 )t tiorht : the ebullition will instantly cease, because the 
 steam formed will press upon its surface ; but by pouring on 
 cold water, and condensing the steam, it will boil violently; 
 pour on warm water, and it will stop boiling. This is a 
 convenient mode of illustrating both of the above laws : as 
 the pressure is increased by the formation of steam, the 
 boiling point is raised, while it is lowered by condensing 
 the vapor and diminishing the pressure. This is called the 
 culinary paradox. 
 
 But, in order to exhibit the influence of pressure upon the 
 boiling point, we must employ a strong metallic boiler, called 
 a digester, which consists simply of a strong boiler furnished 
 with stop-cocks and valves, and an apparatus to ascertain the 
 temperature and pressure. Water confined in this boiler 
 may be heated to a very high temperature without boiling:; 
 but the steam which will be formed will endanger the boiler, 
 before we can ascertain its greatest expansive force or pres- 
 sure upon the liquid. 
 
Marcel's Digester. 
 
 65 
 
 For experiments on the pressure of Fig. 22. 
 
 steam, Marcet's digester (Fig. 22) is 
 well adapted : a is a strong brass globe, 
 into which a portion of mercury is poured, 
 and then half filled with water ; b a ba- 
 rometer tube passing through a steam- 
 tight collar to the bottom of the olobe : c 
 is a thermometer graduated to 400° or 
 500° ; d a stop-cock ; e a spirit lamp ; * 
 and/' a brass stand, upon which the whole 
 is supported. Upon the stop-cock d a 
 steam gun may be screwed. When heat 
 is applied, the pressure is measured by 
 the height to which the mercury rises in 
 the tube b, and the temperature is ascer- 
 tained at the same time by the thermome- 
 ter c On the application of heat, as 
 soon as the water boils, the thermometer 
 will stand at 212°, and the pressure, of 
 course, will be equal to one atmosphere, 
 or 15 lbs. to the square inch. As the 
 temperature increases to 217°, the jtres- 
 sure will elevate the mercury 5 inches, 
 and at 242° about 30 inches, each degree of temperature 
 raising the mercury about one inch. 
 
 Absorption of Free Caloric in Ebullition. When water is 
 converted into steam, a great quantity of sensible heat is 
 taken up into a latent state ; which, on condensation, again 
 appears in a free state. 
 
 If, for example, steam at 212° sufficient to form one pint 
 
 M 
 
 * The spirit lamp is very useful for pro- 
 ducing heat in the laboratory. It consists 
 of a small glass lamp a, (Fig. 23,) the wick 
 of which passes through a metallic collar c; 
 b is an extinguisher, to prevent the wick 
 from absorbing water when not in use. It is 
 filled with alcohol, which burns in the same 
 manner as oil, but does not yield any smoke. 
 A common glass or tin lamp will answer a 
 very good purpose, using alcohol instead 
 of oil. 
 
 Fig. 23. 
 
56 Steam 
 
 of water, be condensed in ten pints of water at 117°, the 
 temperature of the whole will be 212°; the ten pints will be 
 elevated 95° : this is equivalent to raising the temperature of 
 one pint 950°. The latent heat of steam is, therefore, 950° ; 
 other substances are subject to the same law. Hence it may 
 be stated generally, that, in ebullition, heat is taken into a 
 latent state, and given out on condensation. 
 
 The latent heat of different vapors is various, as may be 
 seen in the following table : — 
 
 Latent Heat. 
 
 Vapor of water at its boiling point . . . 967° 
 
 Alcohol 442 
 
 Ether ' 302.379 
 
 Petroleum . 177.87 
 
 Oil of turpentine 177.87 
 
 Nitric acid 531.99 
 
 Liquid ammonia 837.28 
 
 Vinegar . 875 
 
 Steam is formed, ordinarily, by ebullition. At the moment 
 when water takes the state of vapor, in the open air, it has an 
 expansive force equal Jto one atmosphere, or 15 lbs. on the 
 sq. inch. If, then, it be disconnected from water, its laws of 
 expansion and contraction, at all temperatures above 212°, 
 are the same as all gaseous bodies. Equal increments of 
 caloric expand it equally, and its expansion is in the ratio Gf 
 the heating power ; for every degree of Fahrenheit's ther- 
 mometer, it expands ¥ ^ of what its volume would be at 32°, 
 if it did not condense. It may be heated, like any gas, until 
 it is red hot, if the vessel is sufficiently strong. But steam 
 is usually formed in the boiler where water is present, and, as 
 the temperature increases, fresh portions of steam are con- 
 stantly added to that which is already formed, so that its 
 expansive force increases in a much more rapid ratio. 
 
 According to the experiments of Dulong and Arago, if we 
 take atmospheric pressure for unity, we shall find the pres- 
 sure of steam at 233.96°, equal to 1£ atfhospheres. 
 
 250.52 equal to 2 atmospheres, or 301bs. to the sq. inch. 
 
 275.18 " 3 " 45 
 
 320.36 "6 " 90 " " 
 
Uses of Steam. 57 
 
 374 equal to 12 atmospheres, or ISOlbs. to the sq. inch. 
 435.56 " 24 " 360 
 
 486.59 "40 « 600 
 
 510.60 " 50 « 750 
 
 When steam, at a high temperature, is condensed in cold 
 water, a loud, crackling noise is heard, which is due to the 
 collapse of the water, a vacuum being formed by the sudden 
 condensation of the steam. 
 
 Exp. Let a jet of steam rush from the digester through a pipe into 
 cold water. 
 
 When liquids are converted into vapor, under high pres- 
 sure, the vapor is very dense. If, then, it is allowed to escape 
 from the orifice of the boiler, the hand may be held at a short 
 distance without being burned, though the temperature of the 
 steam, before it escapes, is several hundred degrees. 
 
 This is due to its expansion, and the consequent absorption 
 of its sensible caloric. When water is converted into steam 
 at 212°, it absorbs 950° of caloric. If now it be condensed 
 to 32°, it will give out 950° of latent, and 180° of sensible 
 caloric -x: 1130°. Now, if we take the same weight of steam, 
 at a higher temperature, 250°, and condense it to 32°, it will 
 give out 912° of ^sensible, and 218° of sensible caloric = 
 1130°; hence the sum of the sensible and insensible caloric 
 contained in equal weights of steam, is exactly the same at all 
 temperatures — 1130°. 
 
 The absorption of caloric seems to perform a similar office 
 in vaporization and liquefaction, being essential both to the 
 formation of vapors and of liquids. 
 
 Application of Steam to practical Purposes. 
 
 I. It is used for warming rooms. For this purpose it is 
 conveyed in pipes, and continues to heat the room until its 
 caloric is nearly exhausted. It is then condensed to water, 
 and gives out its latent caloric. 
 
 Every cubic foot of steam in the boiler will heat 200 
 feet of space to 70° or 80°; and each square foot of steam 
 pipe will warm 200 cubic feet of space. 
 
 It is used for heating water-baths and dyeing-vats; for 
 3* 
 
5S Caloric. — Steam Engine. 
 
 bleaching cloth; for producing a vacuum by its condensa- 
 tion; for various culinary purposes; also, for drying various 
 substances, such as muslins, calicoes, gun-powder, etc. 
 
 2. But its most important application is to the propelling 
 of machinery : the instrument employed for this purpose is the 
 steam engine; the invention of which is due to Capt. Saverv. 
 
 The principle of his invention may be illus- ri = - 2 j^ 
 
 trated by a tube, with a ball blown at one end, 
 (Fig. "24); fill this with water, and invert it in 
 the same liquid, apply heat to the bulb, and, 
 d as the water is at 21*2°, steam will be 
 formed, and force the water out ; but. as soon as 
 the steam comes in contact with the cold water 
 in the vessel, it is suddenly condensed; a 
 vacuum is formed, and the atmosphere forces 
 the water with great violence up the tube, so 
 as to fill the bulb. If a piston be fitred to 
 the tube, it will constitute the instrument devised by Dr. 
 Wollaston, except that the steam in his apparatus is con- 
 densed by putting the bulb into cold water. T 
 phere presses the piston down, while it is raised by ca 
 
 the water in the bulb to boil. 
 
 • • - 
 The moving power of the steam engine is the same as in 
 
 -;>aratus, but the ste :ed in a separate ves- 
 
 sel called the condenser : this constitutes the improvement of 
 Watt, by which means, the temperature of the cylinder is 
 
 below 212° Fahr. 
 
 3. The steam generator of Mr. Perkins sustains a pres- 
 sure of 500, 1000, and even ioOOlbs. on the square inch. 
 The steam is then so hot as to set fire to tow, and even ignite 
 the generator at its orifice. At this very high temperature, 
 it is about half as heavy as water. It is a remarkable fact, 
 that, at such pressures, the steam will not rush through a 
 small aperture, through which it will rush with great violence, 
 and a roaring noise, when the temperature and pressure are 
 diminished. .Mr. Perkins thinks that 400 atmospheres, or 
 
 ■ the square inch, is the maximum of pressure ; 
 i. e., that under this pressure, water will remain liquid at any 
 temperature, even at a white heat. Tl^e boiler of the gener- 
 ator is small, and not more than a gallon of water is used at 
 a time. 
 
Evaporation. 
 
 59 
 
 Steam Artillery. Mr. Perkins has succeeded in applying this amaz- 
 ing force to the propelling of cannon balls. He states that sixty 41b. 
 balls can be discharged in a minute, with the accuracy of a rifle 
 musket, and to a proportional distance. A musket may also be made 
 to throw from one hundred to a thousand balls per minute. It is great- 
 ly to be hoped that his experiments will prove successful ; for, if such 
 engines of death could be brought into the field of battle, few nations 
 would be willing to settle their disputes in that way. Few would fight 
 in the prospect of certain death. 
 
 Distillation. This process is 
 conducted by converting liquids 
 into vapor, which passes into a 
 long, metallic tube, or worm, sur- 
 rounded by cold water. The va- 
 por is condensed, and the liquor 
 runs off at the opposite extremity 
 of the tube. Fig. 25 represents 
 this apparatus ; a a copper boiler, 
 b its head, connected with the 
 worm, which is coiled in the refrigerator d. The vessel d is 
 filled with cold water to condense the vapor in the worm as 
 it passes through it. 
 
 Evaporation. 
 The only difference between evaporation and ebullition is, 
 that the one takes place quietly, and the other with the ap- 
 pearance of boiling. Evaporation takes place at all temper- 
 atures, but ebullition at fixed temperatures. The former 
 takes place, not only in all liquids, but in many solids, as 
 camphor ; the latter is confined to liquids. 
 
 1. Evaporation is much more rapid in some liquids than in 
 others, and it is always found that those liquids whose boiling 
 points are lowest evaporate with the greatest rapidity. 
 
 Thus alcohol, which boils at a lower temperature than 
 water, evaporates also more freely, and ether, whose point 
 of ebullition is yet lower than that of alcohol, evaporates 
 with still greater rapidity. Also, if the temperature of the 
 liquid be raised or lowered, the evaporation will be more or 
 less rapid. 
 
 2. Increase of pressure checks evaporation, and diminution 
 of pressure promotes it ; thus water will evaporate much more 
 rapidly in a vacuum. 
 
60 Caloric. — Uses of Evaporation. 
 
 This is precisely what we should expect from the fact 
 just mentioned, that evaporation is most rapid in liquids 
 whose boiling point is lowest; for the diminution of pressure 
 lowers the boiling point. From the three facts which have 
 been mentioned, it may be inferred that evaporation is more 
 rapid as the distance between the boiling point and the tem- 
 perature of the substance diminishes. 
 
 The other circumstances that influence the process of 
 evaporation are, 
 
 3. Extent of Surface. As evaporation goes on from the 
 surface, it is evident that, the greater the extent of surface, 
 the more rapid the evaporation. 
 
 4. State of the Atmosphere. If the atmosphere be already 
 saturated with moisture, evaporation will be checked ; or, if 
 the air remain still, it will soon become saturated, and the 
 evaporation is promoted by the motion of the air. 
 
 5. Absorption of Free Caloric by Evaporation. If a dish 
 ofwater.be placed in the exhausted receiver of an air pump, 
 and another, of sulphuric acid, to absorb the vapor of the 
 water, the water will evaporate so rapidly, as to be frozen by 
 the absorption of its sensible caloric* Hence the effect of 
 evaporation is to produce cold ; because the sensible caloric 
 passes into an insensible state. 
 
 Exp. This may be further illustrated by filling a small glass tube 
 with water, and surrounding it with cotton wool. If the cotton wool 
 be soaked with ether, and a current of air, from a common bellows, be 
 directed upon it, the v/ater, in the course of a few moments, will congeal. 
 
 Exp. A very satisfactory experiment 
 is performed with the cryophorus, an in- Fig. 26» 
 
 strument invented oy Dr. Wollaston. , % 
 
 It consists of two glass balls, (Fig. 26.) %/js^t P_\ 
 
 connected by a glass tube. Both balls fe§S|r ^P? 
 
 are free from air ; but one of them con- a^L 
 
 tains a portion of distilled water. When 
 
 the other ball is placed in a freezing mixture, so as to condense the 
 
 watery vapor as fast as it formed, the evaporation is so rapid from the 
 
 * The most intense cold which has been produced is the effect ot 
 evaporation If a large quantity of carbonic acid gas be condensed 
 into a liquid by pressure, and suffered to escape through a small aper- 
 ture, it will congeal by its own expansion ; the solid acid thus formed 
 will evaporate so rapidly in a vacuum, as to produce the cold of — 13(>° 
 Fahr. At this temperature, the strongest alcohol becomes viscid, and 
 common alcohol becomes frozen. 
 
Uses of Evaporation. 61 
 
 surface of the water in the other ball, as to freeze it in two or three 
 minutes. 
 
 6. Cause of Evaporation. The cause of evaporation is, 
 doubtless, the same as that of ebullition — caloric; although 
 some have attempted to account for it on the supposition of 
 an affinity between the air and the evaporated liquid ; but 
 evaporation in a vacuum is fatal to this hypothesis. 
 
 7. Uses of Evaporation. It is well fitted for cooling 
 apartments. All that is necessary for this purpose, is to 
 sprinkle the floor with water. 
 
 It moderates the heat of warm climates ; hence places near 
 large bodies of water are cooler in the summer than those 
 more remote, and the greater the heat from the sun's rays, 
 the more rapid the evaporation, and of course the greater 
 quantity of sensible caloric goes into an insensible state. 
 
 Evaporation not only takes place from the surface of water, 
 but from the surface of the earth, and from plants and ani- 
 mals,: hence it tends to defend the animal, as well as the 
 vegetable system, from external heat. When an animal is 
 exposed to external heat, perspiration commences over the 
 whole surface, and the liquid, in passing to a vapor, absorbs 
 the sensible caloric. On this principle fire-kings subject 
 themselves to a high temperature, with but little inconve- 
 nience. The oven girls of Germany, also, often expose them- 
 selves to a temperature of from 250° to 280°, and one girl 
 breathed five minutes in an atmosphere of 325°. In these 
 cases, water boils rapidly, and beef-steak is cooked in a 
 few minutes. If, however, the air be moist, or the body be 
 varnished, so as to prevent perspiration, the heat cannot be 
 sustained for a moment. The heat produced by violent 
 exercise is carried off in the same manner. 
 
 But the vital principle, doubtless, has much to do in forti- 
 fying the system against the extremes of heat and cold; for, 
 although men may be subjected to a range of temperature 
 of more than 400°, — from 350° above to 75° or 80° below 
 zero, — the temperature of their bodies does not vary five 
 
62 
 
 Caloric. — Hygrometers. 
 
 degrees, but remains stationary at 98° and 100°, during all 
 the varieties of external temperature. 
 
 Evaporation often fills the air with deadly miasma. The 
 fever and ague is supposed to be produced in this way. Con- 
 siderable effect is also produced upon the bulk of gases, and 
 it becomes a point of great interest to ascertain the amount, 
 especially when delicate experiments are to be performed. 
 
 The atmosphere, of course, always contains a portion of 
 watery vapor. At the freezing point it contains T \^ of its 
 volume, and the higher the temperature, the more vapor is 
 it capable of sustaining. The instruments for measuring the 
 amount of vapor in the air, and other gases, are called 
 
 Hygrometers. These vary in form, but may all be reduced 
 to three principles. 
 
 1. The first is founded on the property of some substances 
 to elongate when placed in a moist atmosphere, and to con- 
 tract when dry. The human hair possesses this property in 
 an eminent degree, and is the substance employed by Saus- 
 sure. 
 
 2. The second kind of hygrometer depends on the rapidity 
 of evaporation, the temperature and pressure being the same; 
 the more vapor there is in the air, the slower will the process 
 go forward. Leslie's hygrometer is constructed on this prin- 
 ciple. 
 
 3. The third kind depends on the fact that, if a cold body 
 b3 introduced into moist air, the mois- 
 ture will condense on it ; as is some- ' 
 times seen on the surface of glass and 
 earthen vessels filled with cold water, 
 and is an indication of rain. The tem- 
 perature at which the moisture is con- 
 densed is called the dew point. On 
 this principle the hygrometer of Prof. 
 Daniel! is constructed, and is the best 
 instrument now in use. 
 
 Thus, a b (Fig. 27) are two balls of 
 glass, connect-d by a tube. The ball 
 b is made of black glass, and contains 
 a little ether, into which the bulb cf a 
 small thermometer is immersed. The 
 
 Fig. 37t 
 
Explanation of Natural Phenomena. 63 
 
 air is driven out of both bulbs, so that they contain nothing 
 but ether and its vapor. On the standard c there is a ther- 
 mometer to measure the temperature of the air. 
 
 Exp. Moisten a with ether, and the cold produced by its evaporation 
 will condense the vapor of ether which rises up in b, and will cause a re- 
 duction of its temperature. At the moment the dew begins to form on the 
 glass 6, the difference of temperature between b and c will show the dew 
 point, and thus we ascertain the quantity of moisture in the atmosphere at 
 that time. 
 
 It will be seen that the dew point will vary with the quan- 
 tity of water in the atmosphere. The difference between the 
 temperature of the air arid the dew point will be greatest 
 when the air is very dry, and least when it is very moist. 
 
 A more simple apparatus has been invented by Mr. Jones 
 of London, which is said to give tolerably accurate results. 
 It consists of a delicate Mercurial Thermometer, the bulb of 
 which is about three quarters covered with muslin. Ether 
 is placed on the muslin to produce cold, and the dew is de- 
 posited on the uncovered portion of the bulb. The tempe- 
 rature at which the dew begins to form, is indicated by the 
 height of the mercury in the tube, as in an ordinary ther- 
 mometer. 
 
 The quantity of moisture in the atmosphere, as indicated 
 by either of the above instruments, is dependent on the tem- 
 perature and pressure ; hence the dew point will vary with 
 the height to which we ascend. It is on this principle that 
 air on the surface of the earth when k is carried up over high 
 mountains, deposits a portion of water in the form of clouds, 
 which are so often seen resting on the high summits. On 
 this principle also rain is often produced by the rising up of 
 currents of air. The air expands as the pressure is dimin- 
 ished, grows colder, and its moisture is precipitated. 
 
 Application of the Laws of Insensible Caloric to the Explana 
 Hon of Natural Phenomena. 
 
 1. We have seen that, when solids are converted into li- 
 quids, they absorb large quantities of caloric. Hence the 
 process of thawing, contrary to the common belief, is a 
 freezing process. Ice, in becoming water, absorbs 140° of 
 sensible caloric ; hence countries surrounded by water are 
 
64 Explanation of Natural Phenomena. 
 
 cooler in the spring than those where less ice is formed dur. 
 ing the winter. 
 
 2. Liquids, in passing to vapors, absorb sensible caloric. 
 In the vaporization of water, nearly 1000° of caloric are ab- 
 sorbed. It is therefore a much more powerful cooling pro- 
 cess than the liquefaction of ice; hence the heat of warm 
 countries is greatly reduced by the constant formation of 
 vapor. This is the reason why the transition from the cold 
 of winter to "the heat of summer is not sudden, but gradual ; 
 the ice and the water cannot obtain caloric in sufficient 
 quantities to convert them into vapor. 
 
 3. When vapors and gases become liquids, they give out 
 large quantities of caloric; hence it is usually warmer after 
 a rain, a large quantity of caloric being evolved by the con- 
 densation of the vapor in the atmosphere. If, however, the 
 earth is dry and hot, the heat converts the water into vapor, 
 and renders the air cooler. 
 
 4. Liquids, in becoming solids, give out caloric; hence 
 the process of freezing is a heating process. To prevent 
 some substances from freezing, we have only to place them 
 near those which congeal at a higher temperature ; thus 
 water placed in a cellar will prevent vegetables from freezing, 
 because they require a lower temperature than water to 
 freeze them ; before they reach the point of congelation, the 
 freezing of the water renders its insensible caloric sensible, 
 and prevents them from attaining it. 
 
 By the process of converting water into ice, — a process 
 constantly going forward when the thermometer stands at 
 32° Fahr., — large quantities of caloric are thrown off into the 
 atmosphere ; hence the shores of a country are warmer in 
 the winter than the interior; hence, too, the approach of the 
 cold season is gradual, — the greatest degree of cold rarely 
 occurs till after the winter solstice, twentieth of December. 
 Were these laws suspended, September and March would 
 be of equal temperatures. June would be the warmest, and 
 December the coldest month in the year. 
 
 \ 
 
Caloric. — Sources cf Caloric. 65 
 
 Sect. 3. Sources op Caloric. 
 
 The principal sources of caloric are, 
 
 1. The sun. 
 
 2. Chemical action, including electricity, galvanism, and 
 combustion. 
 
 3. Condensation by mechanical action, including percus- 
 sion and friction. 
 
 4. Vital action. 
 
 1. Sun. The heat produced by the sun varies with the 
 kind and color of the surface, according to principles already 
 noticed. The temperature produced by their direct action is 
 seldom more than 120° ; but, when the rays are concentrated 
 by means of convex lenses, or concave mirrors, a very intense 
 heat is produced. Lenses have been constructed concen- 
 trating sufficient heat to melt some of the most refractory 
 metals ; but the most intense heat, at any considerable dis- 
 tance, is produced by several concave mirrors, which reflect 
 the rays to one focus. Metals and minerals have thus been 
 melted at the distance of 40 feet, and wood ignited at the 
 distance of 120 feet from the mirrors. 
 
 2. Chemical Action. Caloric is often produced by chem 
 ical and electrical action. A very great heat occurs in the 
 phenomena of combustion, which may be defined to be the 
 disengagement of light and heat in substances by chemical 
 action. But the most intense heat is produced by voltaic or 
 electrical action. 
 
 3. Condensation. It has been already stated that sub- 
 stances develop caloric by diminution of their bulk, as when 
 gases pass to liquids and to solids. A fire is often kindled 
 by rubbing pieces of dry wood against each other; heavy 
 machinery, if not properly oiled, often ignites wood ; axle- 
 trees of carriages are burned off; the sides of vessels are set 
 on fire by the descent of the cable. The friction in these 
 cases condenses the parts, and the caloric is developed. So, 
 
66 Nature of Caloric. 
 
 when iron is struck with a hammer several times, it becomes 
 hot. Fire is also struck from steel with any hard substance, 
 like flint. This is denominated percussion. 
 
 4. Vital Action. The caloric developed by vital action 
 has been shown to be due to the combination of the oxygen 
 of the air, with the carbon and hydrogen of the worn-out 
 tissues of the body. It is a process of slow combustion. 
 
 Sources of Cold. The sources of cold are, liquefaction, 
 vaporization, and rarefaction. 
 
 Sect. 4. Nature of Caloric. 
 
 On this subject there are two theories. Sir H. Davy and 
 some others considered caloric as a property of matter ; and 
 Sir William Herschel and Prof. Airy have attempted to ex- 
 plain its nature by supposing that there exists a subtile ether, 
 which pervades all space and all matter, and that caloric is 
 the effect of vibrations made in this fluid, somewhat similar 
 to the vibrations of the air which produce the sensation of 
 sound. This theory is called the undulatory theory, and is 
 most favorably received by chemists. 
 
 Sir Isaac Newton supposed that caloric was a subtile, ma- 
 terial fluid. If caloric is material, it is matter under very 
 peculiar circumstances. So far as we can determine, it pos- 
 sesses few, if any, of the common properties of matter; its 
 particles are self-repellent, opposed to cohesive attraction. 
 If it is material, its particles must be exceedingly small, as 
 they penetrate all other substances, however dense. They 
 must also be influenced by gravity ; but no quantity of them, 
 however great, possess the least appreciable weight. It pos- 
 sesses neither extension nor impenetrability ; but if it is mat- 
 ter, it must have these properties. 
 
 
Physical Properties of Light — Refraction. 67 
 
 CHAPTER II. 
 
 LIGHT. 
 
 The physical properties of light belong to the science of 
 Optics, a branch of Natural Philosophy. But light has also 
 chemical properties, which come within the province of 
 Chemistry. 
 
 I. Physical Properties of Light. Light is emitted from 
 every visible point of a luminous object, and is equally dis- 
 tributed on all sides, if not interrupted, diverging like radii 
 drawn from the centre to the circumference of a sphere. It 
 travels at the rate of 192,000 miles in a second, requiring 
 about eight minutes to pass from the sun to our earth. Its 
 velocity is so great, that the light emitted in the firing of a 
 cannon, or a sky-rocket, will be seen by different spectators 
 at the saipe instant, whatever may be their respective dis- 
 tances from it ; the time required for light to travel one 
 hundred or one thousand miles being inappreciable by our 
 senses. When light falls upon any body, it is either reflected, 
 transmitted and refracted, or absorbed. 
 
 II.. Reflection. The reflection of light is influenced by 
 the same circumstances as that of caloric, and follows the 
 same laws; the angles of incidence and reflection are equal. 
 (Fig. 6, page 31.) It is owing to the reflection of light that 
 we are able to see the various objects in nature, an image 
 of the object being formed by the reflected rays upon the 
 retina of the eye. 
 
 III. Refraction. When a ray passes from a rarer to a 
 denser medium, as from air into water, it is refracted towards 
 a perpendicular to the refracting surface : this property is 
 called refrangibility. 
 
 Thus (Fig. 28), I is the ray before it reaches the refract- 
 ing surface 3. Instead of passing directly through to a, it 
 is bent towards the perpendicular, to the surface p t and pro- 
 
68 
 
 Decomposition of Light. 
 
 Fig, 
 Id 
 
 28. 
 
 h 
 
 
 X "\ 
 
 
 r a 1 
 
 ceeds to r. But in passing from a denser 
 to a rarer medium, it is refracted from 
 a perpendicular to the refracting sur- 
 face. Thus, in passing from r, it is re- 
 fracted at the surface towards I, instead 
 of proceeding to d. Hence a stick 
 partly in water appears bent. Objects 
 viewed through some substances, as Ice- 
 land spar, appear double in consequence of a double re- 
 fraction. 
 
 IV. Decomposition of Light. Solar and stellar light con- 
 tain three kinds of rays : — 
 
 1. Colorific, or rays of color. 
 
 2. Calorific, or rays of heat. 
 
 3. Chemical rays, or those which produce chemical 
 effects. 
 
 1. Colorific Rays. These may be separated into seven 
 primary colors : red, orange, yellow, green, blue, indigo, and 
 violet. 
 
 Fig. 29. 
 
 C 
 
 The instrument by which this separation is effected is a 
 triangular prism (Fig. 29) of glass, ice, or any transparent 
 substance. A beam of light r is admitted into a dark room, 
 and, passing obliquely through two sides of the prism p, is 
 refracted by both. The different colors are separated, be- 
 cause some are refracted more than others ; and, instead of a 
 white spot after the beam passes through the prism, as at 8, 
 there appears a long, colored surface c, called the solar spec- 
 trum. 
 
 Dr. Wollaston supposes that there are but four colors, viz. : 
 red, green, blue, and violet, occupying spaces in the propor- 
 tion of 16, 23, 36, 28. 
 
Calorific Rays — Daguerreotype. 69 
 
 According to Sir D. Brewster, there are but three colors, 
 red, yellow, and blue, a mixture of which produces the others. 
 
 The prismatic colors differ in their illuminating 'power. 
 This is greatest in the yellow and green, and diminishes each 
 way to the violet and red. 
 
 2. Calorific Rays. The calorific rays exist in the greatest 
 intensity in, and near the red rays, and diminish rapidly 
 towards the violet; the greatest heat is sometimes entirely 
 without the red rays ; this, however, depends upon the kind 
 of substances used to separate the rays; in some cases, it is 
 quite on the verge of the orange. The refrangibility, then, 
 of the calorific rays is much less than that of the colorific. 
 This is shown also by the fact that, when the solar rays are 
 concentrated by a convex lens, the focus of heat is farther 
 from the lens than that of light. 
 
 3. Chemical Rays. On the side of the spectrum, a little 
 beyond the violet, are invisible rays, which have a peculiar 
 effect upon chemical changes. They are most powerful on 
 the verge of the violet, and diminish towards the red. 
 
 1. Photographic drawing depends upon the injluencc of 
 these rays. 
 
 Exp. Cover one side of a plate of glass with beeswax, colored with 
 lamp-black, and draw a picture on it by removing the wax with a sharp 
 point. If then a solution of salt in water be spread on a piece of white 
 paper, and the nitrate of silver in solution poured upon it, the chloride 
 of silver will be formed. Place the paper then over the glass, and the 
 sun's rays passing through, where the wax is removed, will form a 
 picture upon the paper, by changing the chloride black wherever they 
 strike it. 
 
 Exp. Soak a piece of white paper in a saturated solution of bichromate 
 of potassa, dry it rapidly, and put it in a dark room. Place over it 
 prints, dried plants, etc., and expose it to the sun; the objects will be 
 represented yellow on an orange ground. To fix the drawing, wash it 
 carefully, to dissolve the salt which has not been acted upon by the 
 light. The object will then appear white on an orange ground. 
 
 If sulphate of indigo be used with the bichromate of 
 potassa, it will give to the object and to the paper different 
 shades of green. 
 
 2. Daguerreotype. A method of fixing the images of ob- 
 jects on metal has lately been devised by Daguerre 
 
70 Magnetic Rays. 
 
 Exp. Expose a plate of silvered copper, well cleaned with dilute 
 nitric acid, to the vapor of iodine ; an extremely thin coat of iodide of 
 silver will be formed. Place the plate in the Camera Obsc-.ru for eight 
 or ten minutes, in such a position that the light may come from tiie 
 object, and an image of it be formed on the plate; then expose it, at an 
 angle of 48°, to the vapor of mercury ; heat it to 167° Fahr., and the 
 images will appear. The plate should then be exposed to the action of 
 hyposulphite of soda, and washed in a large quantity of distilled 
 water* 
 
 Magnetic Rays. Dr. Morrichini, of Rome, discovered 
 that the more refrangible rays possessed the property of 
 rendering iron magnetic; Mrs. Somerville confirmed this 
 statement by magnetizing a sewing needle with less than 
 two hours' exposure to the violet rays; but others vhave not 
 been so successful, and it is questionable whether these rays 
 possess this property. 
 
 V. Absorption. The rays of light are separated by ab- 
 sorption. When light falls upon a substance, more or less 
 of it disappears like sensible caloric. 
 
 1. The different colors are absorbed variously by different 
 surfaces. This is the cause of the great variety of colors ; 
 for, when all the rays are absorbed except the red, and these 
 only reflected, the body is red. Thus, in colored bodies, only 
 a part of the rays can be reflected ; and to the admixture of 
 the different colors in the reflected portion, is owing all the 
 beautiful variety of color. 
 
 2. The absorption of light varies with the chemical consti- 
 tution ; hence, by the action of chemical agents upon each 
 other, every variety of color can be produced at pleasure. 
 
 Exp. Into a little chloride of calcium, in solution, pour a few drops 
 of sulphuric acid ; a white solid will be formed. 
 
 Exp. Into a dilute solution of persulphate of iron pour the tincture 
 of gall ; fine black ink will be formed. 
 
 Exp. Into an infusion of purple cabbage put a drop or two of sul- 
 phuric acid ; a beautiful red will be produced. 
 
 Exp. Nitrate of mercury and infusion of gall will form an orange 
 color. 
 
 Exp. Nitrate of lead and hydriodic acid, yellow. 
 
 Exp. Vegetable infusion and an alkali, green. 
 
 Exp. Aquae ammonia and sulphate of copper, blue. 
 
 Exp. Ferro-cyanuret of potassa and sulphate of iron, indigo. 
 
 Exp. Red and indigo, mixed, form violet. 
 
 3. When all the rays are absorbed, so that none can be 
 reflected, the body is black ; for the same reason, everything 
 
 * See Jour. Franklin Inst. XXIV. 207. 
 
Li gin . — Ignition — Phosphorescence. 7 1. 
 
 is black in total darkness. If none of the rays are absorbed, 
 and all are reflected, the body is white.* 
 
 VI. Ignition and Incandescence. The phenomena of 
 ignition and incandescence include all kinds of artificial 
 light, which is obtained by the combinations of inflammable 
 matter, or the heating of non-combustible bodies. Solids 
 begin to emit light in the dark at 700°, and in the light at 
 1000° F. Gases require a higher temperature; flame is in- 
 candescent gas. The color of the rays depends upon the 
 kind of substances and the degree of heat: the white light 
 of oil, candles, etc., when transmitted through a prism, has 
 but three primary colors — red, yellow and green. The 
 dazzling light emitted by lime intensely heated, gives -the 
 prismatic colors almost as bright as the solar spectrum. 
 Different substances assume different colors when intensely 
 heated. Chemical rays exist very feebly in most artificial 
 light, but in the intense light of lime, under the compound 
 blowpipe, they are more easily detected. 
 
 VII. Phosphorescence. There are many substances in 
 nature which possess the property of shining in the darlc, 
 without the emission of caloric. These are said to be phos- 
 phorescent, and are known by the term phosphori, (although 
 there is no phosphorus connected with the phenomena.) 
 
 1. Sola7- Phosphori. Many bodies acquire this property on exposure 
 to the solar rays for a few hours. Such, for example, is Canton's phos- 
 phorus, a composition made by mixing three parts of calcined oyster 
 shells with one of the flowers of sulphur, and exposing the mixture 
 for an hour to a strong heat in a covered crucible. Chloride of cal- 
 cium (Homberg's phosphorus) possesses the same property ; also, 
 nitrate of lime, (Baldwin's phosphorus,) and a variety of other sub- 
 stances, such as carbonate of baryta, strontia and lime, the diamond, 
 fluor-spar or chlorophane, apatite, boracic acid, etc. Scarcely any 
 phosphori act unless they have been exposed to light. 
 
 When phosphorescence ceases, it can be restored by a 
 second exposure to the light, or by passing electric dis- 
 charges through the substance. 
 
 2. Phosphorescence from Moderate Heat. Chlorophane 
 and several mineral substances require to be heated before 
 
 * Colors have an important influence on the absorption %nd disen- 
 gagement of odorous matters. White bodies are the leasrafosorbent 
 and dark the most so. 
 
72 Photometers. 
 
 they phosphoresce. Lime is a remarkable instance ; when 
 heated, it gives out a dazzling white light, too intense to 
 look upon without injury to the eyes. Light is also emitted 
 during the crystallization of many salts, as the sulphate of 
 potassa and fluoride of sodium. 
 
 Exp. Put three drachms of the vitreous arsenous acid into a matrass, 
 with an ounce and a half of hydrochloric acid, and half an ounce of 
 water; boil the mixture for ten minutes, and then suffer it to cool 
 slowly. When crystallization commences, each little crystal will be 
 attended by a spark ; on sudden agitation, great numbers of crystals 
 shoot up, accompanied with an equal number of sparks ; if larger 
 quantities are taken, and the vessel shaken at the right moment, the 
 emission of light is so powerful as to illuminate a dark room. 
 
 3. Animal and Vegetable Phosphori. Some animal and 
 vegetable substances emit light at common temperatures, 
 without exposure to the sun's rays. This property is re- 
 markable in some fish, as the mackerel ; the light makes its 
 appearance just before putrefaction commences, and ceases 
 when it is completely established. Some species of decayed 
 wood possess this property in a remarkable degree. 
 
 VIII. Photometers. It is sometimes desirable to measure 
 the intensity of light, emitted from different objects, and an 
 instrument has been invented for this purpose, called the 
 Photometer, or light measurer. The principal one employed 
 for this purpose is that of Leslie. 
 
 It consists of a very delicate and small differential ther- 
 mometer, one bulb of which is made of black glass, and the 
 whole is enclosed in a small glass tube. The white ball 
 transmits all the light and heat, and is of course unaffected ; 
 the black ball absorbs all the rays, and heats the air within, 
 so as to cause the liquid to rise. Its action of course depends 
 upon the heat produced by the absorption of light. 
 
 Some objections to this instrument have been stated by 
 Turner. 
 
 Count Rumford's Photometer determines the comparative 
 strength of lights, by a comparison of the shadows of bodies. 
 
 Sources of Light. These are similar to those of caloric — 
 the sun, stars, chemical action, mechanical action, and caloric. 
 
 IX. Nature of Light. Light and caloric have been re- 
 garded by some as identical. Newton supposed that light 
 
Electricity. 73 
 
 was a material, subtile fluid, which emanated from luminous 
 bodies in all directions in right lines, and produced the sen- 
 sation of vision, by falling upon the retina of the eye; this 
 is termed the Newtonian theory. But Descartes, Huygens, 
 and Euler, proposed a different theory, which has been lately 
 revived by Sir John Herschel and Prof. Airy. This theory 
 supposes that light is produced by vibrations in an elastic 
 medium, which pervades all space, and that vision is the 
 effect of these vibrations, meeting the retina, in the same 
 manner as pulsations of air impress the nerve of hearing, 
 and produce the sensation of sound. At present, the 
 strongest evidence is in favor of this theory, which has 
 received the name of the undulatory theory. (See Sir J. 
 Herschel's article on Light in the Encyclopedia Metropol- 
 itana.) Either of the above theories answers the purpose of 
 classifying the facts, and it is not material which is adopted 
 
 CHAPTER III. 
 
 ELECTRICITY. 
 
 The word electricity is derived from the Greek name for 
 amber,* a substance which possessed the property of at- 
 tracting light bodies when rubbed. 
 
 1. If a piece of sealing-wax, or a glass rod, be rubbed with a 
 dry woollen or silk cloth, each becomes capable of attracting 
 and repelling light substances. In this state each is said 
 to be electrified, or electrically excited. When friction is 
 applied to many other substances, they exhibit similar phe- 
 nomena. The cause of-this attraction and repulsion is as- 
 cribed to an agent called electricity, and when it is excited 
 by friction, it is designated by the title of common elec- 
 tricity. 
 
 2. If a plate of copper and a plate of zinc, having copper 
 wires soldered to each, be immersed in acidulated water, 
 and the ends of the wires brought into contact, they will 
 
 * HX$XTQOV. 
 
74 Common Electricity. 
 
 exhibit similar phenomena of attraction and repulsion. When 
 electricity is excited in this way, there is always a chemical 
 action between the metal and the liquid, and it is called 
 Galvanism, in honor of Galvani, who made the discovery; 
 also Voltaic electricity, from Volta, who first demonstrated 
 its existence as independent of the animal system. 
 
 Sect. .1. Common or Frictional Electricity. 
 
 Common electricity is generally excited by the friction of 
 one substance upon another. 
 
 1. If a piece of sealing wax, or any resinous substance, be 
 rubbed with a silk cloth, and a pith ball, suspended by a 
 thread, be brought near it, the ball will be at first attracted, 
 and then repelled. 
 
 2. If a rod of glass, or other vitreous substance, be rubbed 
 in a similar manner, and brought near the ball, it will attract 
 it, while the sealing-wax will repel it. - 
 
 3. If two balls be each electrified by the sealing-wax, or 
 by the glass, they will repel each other ; but if one is electri- 
 fied by the wax, and the other by the glass, they will attract 
 each other ; hence, when friction is applied to resinous and 
 vitreous bodies, opposite effects are produced. The state 
 induced by friction upon the glass, was called by Dr. Frank- 
 lin positive, and that induced upon the wax negative, and the 
 substances were said to be positively or negatively electrified. 
 
 Theories. 1. Franklin supposed that electricity pervaded 
 matter generally, and that friction tended to bring it upon 
 the surface of bodies, or drive it from them ; that it was in 
 its nature self-repellent, but possessed a powerful attraction 
 for common matter; when a body was electrified positively^ 
 it had more than its share of electricity ; when it was electri^ 
 fied negatively, it had less than its natural portion, 
 
 2. Du Fay supposed that there were two fluids : the one de- 
 veloped by the friction of the glass he called vitreous, which 
 answers to the positive electricity of Franklin, and the other, 
 developed by the friction of the wax, he called resinous, which 
 corresponds with the negative electricity of Franklin. Each 
 
A 
 
 Electricity. «- Gold Leaf Electrometer 75 
 
 fluid repels itself, and attracts the other. It follows from 
 this theory, that substances electrified by the same fluid repel, 
 and those electrified iy the opposite fluids attract, each other, 
 and friction only tends to separate them. 
 
 The existence of the two fluids may be shown Fig. 30. 
 by the. Gold Leaf Electrometer,* (Fig. 30,) which ma 
 
 consists of two strips of gold leaf suspended by a X T 
 brass cap and wire, in a glass cylinder. When 
 electrified with either kind of electricity, the leaves 
 diverge. 
 
 But if, when the leaves diverge with negative 
 electricity, a substance excited positively be brought 
 near, the leaves will collapse. s£SSii 
 
 Exp. Bring excited sealing-wax in contact with the brass knob a, 
 the leaves will diverge with negative electricity. Place now, excited 
 glass upon the knob, and the leaves will come together, because the 
 positive fluid restores the equilibrium. . If pith balls be suspended by a 
 wire or thread, similar effects may be produced. 
 
 Some substances, such as glass and resin, retain the elec- 
 tricity upon their surfaces when excited, and are hence called 
 non-conductors of electricity. 
 
 Other substances, as the metals, do not retain electricity 
 upon their surfaces, unless they are surrounded by rton-con- 
 ductors, but convey it away, or oppose no barriers to the 
 union of the two fluids; such bodies are called conductors of 
 electricity. The metals are all conductors; dry air, glass, 
 sulphur, and resins, are non-conductors ; water, damp wood, 
 moist air, alcohol, and some oils, are imperfect conductors. 
 The non-conductors are called insulators. 
 
 Some substances exhibit signs of electricity when heated, 
 such as tourmalin, topaz, diamond, beryl. 
 
 Electrical Machine. The instrument by which the phe- 
 nomena of common electricity may be best exhibited, is the 
 electrical machine^ (Fig. 31,) which consists of a cylinder, or 
 ^late of glass G, revolving on an axis, and subjected to the 
 friction of a rubber R of leather or silk, Upon which is spread 
 a thin coat of amalgam, composed of tin and mercury, 
 
 * HXsxtquv and utroor, a measurer of electricity. 
 
 t In the absence of an electrical machine, many experiments may be 
 performed with a rod of glass, or sealing-wax, two inches in diameter, 
 and rubbed with a silk handkerchief 
 
insulated by a glass pillar, and communicating with the ground 
 by a brass chain, C. Attached to the machine is a cylindrical" 
 netallic conductor, P, which is also insulated by a glass pillar. 
 When the machine is in operation, vitreous electricity 
 lows from the rubber and glass, by means of fine points, to 
 he prime conductor, P, and resinous electricity passes in an 
 >pposite direction. If the hand be placed upon the con- 
 luctor, currents of electricity will pass in opposite directions, 
 :he vitreous passing into the body from P, and the resinous 
 down the chain C to the ground. But if the hand be held 
 at a little distance from the conductor, a spark will dart 
 through the air, and cause a prickling sensation, accompanied 
 by a slight report, with light and heat. The sound is pro- 
 duced by the collapse of the air, as the fluid forces a passage 
 through it; and the light and heat are supposed to result from 
 the sudden condensation of the air, as in the fire syringe. 
 
 Induction. If an insulated body be brought near the prime 
 conductor, it will manifest signs of electricity opposite to 
 that of the conductor, on the side nearest the conductor, and 
 similar to the conductor on the other side, while the centre 
 of the body will be neutral. The electricity, in this case, is 
 induced by the presence of the electrified conductor ; and 
 
I 
 
 Electricity. — Induction — Theory. 77 
 
 the process is called induction. Several insulated conductors 
 placed contiguous, will exhibit the same phenomena if a 
 communication be made between the last and the ground. 
 
 Thus, (Fig. 32,) Fig. 32. 
 
 let A represent the 12 3 4- 5 
 
 positive conductor k A K J 
 
 of an electric ma- |y °M_ i |M| q_ 
 
 chine, b and c in- ^QE-* c - 
 sulated conductors, 
 
 with a chain pass- _ 
 
 ing to the ground. 
 
 The conductor b will be electrified by induction, as will be 
 indicated by the attached balls. Thus 1, being positive, will 
 attract the balls 2, which are rendered negative by induction. 
 The balls 3 are also rendered positive, 4 negative, and 5 
 positive, while the centres b c will remain neutral. 
 
 Theory. The phenomena of induction has led to the 
 true theory of attraction and repulsion. The reason why an 
 excited body attracts another is, that it induces in it an 
 opposite electrical state. Induction is therefore an essential 
 function, both in the development and continuance of elec- 
 trical currents, and consists in a polarized state of the 
 particles, or positive and negative points, induced by the 
 presence of an electrified body. 
 
 Application of the Theory. According to this theory, an 
 excited body attracts light substances, because it induces in 
 them an opposite state of electricity. 
 
 1. On moving the hand towards the prime conductor, it is 
 electrified negatively by induction ; when a spark is received, 
 the equilibrium is restored. 
 
 2. When a cloud, positively or negatively electrified, 
 passes over a tower, or a tree, it induces an opposite state in 
 them, and a stroke of lightning follows in consequence of the 
 attraction between the two accumulated fluids ; hence the 
 utility of lightning-rods to form a communication between 
 the clouds and the ground. 
 
 3. The action of the Ley den Jar is due to induction. It 
 consists of a glass jar, lined on the inner and outer surfaces, 
 save a few inches near the mouth, with tin foil. Through the 
 stopper, made of dry wood or sealing-wax, a brass rod com- 
 
Electrometers. 
 
 rounicates with the inner surface. When positive electricity 
 is applied to the inside, it drives off the same fluid on the 
 outer surface, and induces the negative fluid. These fluids 
 exert a strong mutual attraction upon each other, through 
 the glass, and enable both to accumulate in larger quantities 
 than they would do on separate conductors. When a com- 
 munication is made between the inner and outer surfaces, 
 the equilibrium is suddenly restored, accompanied by a 
 sharp report. When several jars are connected by their 
 outer surfaces, and also by their inner surfaces, they consti- 
 tute an electrical battery. 
 
 4. The action of the Electropliorus 
 (bearer of electricity) (Fig. 33) de- 
 pends upon the same principle. It may 
 be constructed by pouring melted resin 
 into the cover of a firkin, taking care, 
 when it cools, to render the surface even. 
 Adapt to this a circular piece of board 
 covered with tin foil, and fix a glass rod 
 in the centre for a handle. This instru- 
 ment may be used instead of the machine for charging Ley- 
 den Jars. 
 
 Electrometers, or Electroscopes. These are instruments for 
 detecting the presence of electricity, as in the Gold Leaf 
 Electrometer, (page 74,) or for determining the degree of its 
 tension, or attracting and repelling power. For this last 
 purpose, the Balance Electrometer is used. 
 
 Thus A (Fig. 34) is a Leyden jar, which may be con* 
 
Laws of the Accumulation of the Electric Fluid. 79 
 
 nected with the prime conductor of an electric machine ; B, 
 a brass ball connected with D, E ; C, another ball, with a 
 chain, G, connecting it with the table or the outside of the jar; 
 D, a brass rod balanced at the centre, and insulated by the glass 
 post H ; E is a ring which may be placed at any distance 
 from F, bringing the ball in contact with B. If, now, the jar 
 be positively electrified, the ball on the end of E will be re- 
 pelled, C will be electrified negatively by induction, and 
 there will be a powerful attraction between C and the ball 
 on the end of D, which will bring them together, and the 
 equilibrium will be restored. The force of attraction will be 
 measured by the distance between the balls and the weight 
 applied at E. With a powerful electrical battery, successive 
 vibrations may be produced in the beam, and a bright spark 
 and loud report produced at each contact of the balls. 
 
 Laws of the Accumulation of the Electric Fluid. 
 
 1. Free electricity is always accumulated upon the surface 
 of an insulated conductor, and does not penetrate its sub- 
 stance ; hence the quantity does not depend upon the quantity 
 of matter in the conductor, but upon the extent of surface. 
 
 2. The mode in which electricity is distributed over the 
 surface of conductors, depends upon their form. On a sphere, 
 it forms a uniform stratum. On an ellipsoid, the stratum is 
 thickest on the extremities of the longer axis, and, as these 
 extremities approach to the form of points, the accumulation 
 increases till the tension becomes so great, that it flows off 
 into the atmosphere ; hence electricity cannot be retained on 
 a conductor which has points attached to it. 
 
 3. This tendency to escape is due to the repulsion of its 
 particles. 
 
 4. Coulomb proved by his Torsion Electrometer, that the 
 repulsion of two bodies similarly electrified, and the attraction 
 of two oppositely electrified, varies inversely, as the square 
 of the distance between them. 
 
 Sect. 2. Voltaic Electricity, or Galvanism. 
 
 History. In the year 1791, Galvani, an Italian Professor 
 of Anatomy at Bologna, discovered that if a silver probe were 
 made to touch the crural nerve of a recently killed frog, and 
 a strip of zinc the muscle, violent contractions would be pro- 
 duced at each contact of the two metals — the same effect aa 
 
80 Simple Voltaic Circles. 
 
 is produced by an electric spark. Hence he concluded that 
 the phenomena were due to electricity, generated by the 
 animal system. Some years after, Prof. Volta, of Pavia, dis- 
 covered that the animal system was not necessary to the de- 
 velopment of this kind of electricity, which he proved by the 
 construction of a pile of insulated plates, of different metals, 
 called the Voltaic pile. This discovery has given to this form 
 of exciting electricity the epithet voltaic. 
 
 But the identity of the agent concerned in galvanism, and 
 of that in the common electrical machine, is now a matter of 
 demonstration. Magnetism has been supposed to be due to 
 the same agent, and also chemical affinity. But it is more 
 in accordance with all the phenomena to suppose that those 
 agents are not identical, but, in many respects, distinct forces. 
 " Galvanism," according to Dr. Hare, " is light, heat, and 
 electricity, combined." 
 
 I. Simple Voltaic Circles, E.rp. Place a piece of zinc 
 upon the tongue, and a piece of silver under it : whenever the 
 projecting edges of these metals are brought into contact, a 
 peculiar sensation will be perceived, and, if the plates are 
 large enough, a flash of light. This effect is not due to elec- 
 tricity generated by the animal system, but to that developed 
 in the metals; for if the same plates. 
 or larger plates, be placed in water, 
 (Fig. 35,) and the connection made, 
 electricity will be excited; feeble in- 
 deed, but in sufficient quantities to be 
 detected by a proper apparatus. If, 
 however, a few drops of sulphuric or 
 nitric acid be added to the water, and 
 the ends of the plates C and Z brought 
 into contact directly, or by means of wires soldered to the 
 plates, bubbles of hydrogen gas will rise from the surf ice of 
 the copper plate C, and electricity will be developed in larger - 
 quantities. The currents will continue to circulate from one 
 plate to the other, as long as the wires are kept in contact, 
 but will cease when they are separated. This is a case of a 
 ■^le voltaic circle. The direction of the positive current 
 is indicated by the position of the arrows. When the wires 
 are in contact, the circuit is said to be closed, and a current 
 of positive electricity flows through the water from the zinc 
 plate Z to the copper C, and from the copper along the con- 
 
Compound Voltaic Circles. 81 
 
 ducting wires to the zinc. A current of negative electricity, 
 on the theory of two fluids, passes in an opposite direction. 
 When the wires are separated, the circuit is said to be broken 
 
 The contact may be made above the water, or in it, or the 
 plates may touch each other throughout, or be soldered to- 
 gether ; in either case electricity will be excited; but if one 
 plate is out of the liquid, no currents can be produced. 
 
 A simple voltaic circle may be formed of one metal and 
 two liquids, provided a stronger chemical action is induced on 
 one side of the plate, than on the other. Simple voltaic cir- 
 cles may also be formed of various materials; but, generally, 
 they consist of one perfect and two imperfect conductors 
 of electricity, or of two perfect and one imperfect conductors. 
 
 Metals and prepared charcoal are perfect, water and 
 aqueous solutions imperfect conductors. But, whatever be 
 the construction, chemical action seems absolutely necessary 
 to the development of voltaic currents. 
 
 The most common and convenient form 
 of the simple battery, is that of two cyl- 
 inders of copper, C, (Fig. 36,) the one 
 within the other, separated about one 
 inch, with a bottom soldered on, so as to 
 contain the exciting liquid, a, between 
 them, and a cylinder of zinc, Z, placed 
 between the two cylinders of copper, and insulated by ivory 
 handles The two plates are furnished with wires, terminated* 
 by the cups b 6, which contain a globule of mercury. The 
 connection is made by means of wires dipped into the mercury 
 in the cups. Or, the copper and zinc may be coiled around 
 each other, so that each surface of zinc may be opposed to 
 one of copper, but separated from it by a small interval. 
 By thus exposing a large surface of zinc to a similar sur- 
 face of copper, Dr. Hare was enabled to melt the most 
 refractory metals, and from this circumstance gave it the 
 name of Calorimotor. 
 
 II. Compound Voltaic Circles. Compound circles consist 
 of a series of simple circles, for the purpose of increasing 
 the intensity of voltaic currents. The first combination of 
 this kind was made by Volta, and is called the voltaic pile. 
 
 4* 
 
82 
 
 Compound Voltaic Circles. 
 
 1. This pile consists of zinc and copper plates, Fig. 37. 
 (Fig. 37,) placed alternately one above another, 
 with strips of woollen cloth moistened with salt 
 water between each pair. By connecting the top 
 and bottom plates, currents of electricity will be 
 set in motion. 
 
 2. But other forms of voltaic circles are now 
 in use. The most convenient is that invented 
 by Wollaston. It consists of any convenient 
 number of zinc and copper plates, so arranged, 
 
 that each zinc plate is surrounded by two of copper. 
 
 A (Fig. 38) is a trough to contain the exciting liquid ; B 
 a case passing around the plates, and connected by chains to 
 the windlass C, by means of which the plates can be lowered 
 into the liquid, or raised to any position required.* EE are 
 small hand-vices attached to the poles. The zinc plates are 
 confined in copper cases, insulated by wood at each end. 
 The copper cases are separated |- of an inch, by pasteboard, 
 which, with the wood, is saturated by oil and wax. The 
 connection between the zinc and copper plates is made by 
 strips of copper soldered to the zinc of one pair, and to the 
 copper of the adjacent pair; by this construction, the power 
 of the battery is increased nearly one half. 
 
 Fig. 38. 
 
 As each zinc plate is connected to the adjacent copper 
 plate, the currents are urged along from one to the other, in 
 opposite directions, till they meet at the poles. 
 
 The size and number of plates may be varied at pleasure. 
 The largest battery ever constructed is that of Mr. Children, 
 
 * In some batteries, the plates are stationary, and the trough is raised 
 and lowered. This is the most convenient construction, especially in 
 large batteries. 
 
Grove's Battery, 
 
 83 
 
 the plates of which were 6 ft. long and 2 ft. 8 inches broad. 
 The most convenient size is 4 inches by 6. A battery con- 
 taining 209 or 309 plates, and thrown into vigorous action, is 
 nearly as powerful as one much larger.*" The battery of 
 Dr. Hare is called a Dejiagrator, from its surprising power 
 of burning the metals. 
 
 The direction of the currents in this apparatus is the same 
 as in the simple circles : positive electricity passes from the 
 zinc through the liquid to the copper plates, and is given off 
 at the copper pole of the battery, while negative electricity 
 takes the opposite direction, and appears at the zinc or 
 negative pole. 
 
 During the action of the battery, all the hydrogen evolved 
 in the process is given off at the surface of the copper, and 
 the weight of the hydrogen during any given time, and that 
 of the zinc dissolved, will be as 1 to S^.'S, which is the ratio 
 of their chemical equivalents. This shows the close con- 
 nection between electricity, thus excited, and chemical 
 affinity. 
 
 Fig. 39. 
 
 2. Grove's Battery. — One of the most powerful as well as 
 economical batteries now in use is the one constructed by 
 Prof. Grove. It consists of a series of platinum and amal- 
 gamated zinc plates arranged in the following manner. The 
 zinc plates are cast in the form of hollow cylinders, a, a, 
 
 * In experimenting with the battery, the plates should not be im- 
 mersed in the liquid but a few minutes at a time; by raising and lower- 
 ing them for each experiment, their vigorous action will be kept up much 
 longer; or the troughs may be so constructed, that, by a partial revolu- 
 tion, the exciting liquid may be withdrawn from the plates, or thrown 
 upon them at pleasure. . 
 
84 Galvanic Batteries. 
 
 (Fig. 39.) with a projection, b, b, about two inches in length, 
 to the end of which strips of platinum foil are soldered. 
 Within the zinc cylinders small earthen cups are placed. 
 These are then put in half-pint glass tumblers ff; the zinc 
 in one tumbler and the platinum foil, attached to its end, in 
 the earthen cup of the next plate. The zinc is the negative, 
 and the platinum the positive pole or electrode. 
 
 To charge the battery, sulphuric acid, diluted with 5 or 6 
 parts water, is put into the tumblers to act upon the zinc, and 
 fuming nitrous acid into the earthen cups in contact with the 
 platinum foil. 
 
 When the poles are united, positive electricity is generated 
 in the zinc plate at the negative end of the battery, and passes, 
 with the hydrogen of the decomposed water, into the porous 
 cup, to the platinum plate, as indicated by the arrows. The 
 nitrous acid is decomposed by the current, the hydrogen 
 unites with its oxygen, and the binoxide of nitrogen escapes 
 into the air. The current then passes to the zinc plate, 
 thence from zinc to platinum, through the conducting fluids, 
 to the platinum or positive pole. The negative current 
 passes in the opposite direction, commencing at the positive 
 plate and passing to the negative pole. 20 or 25 cups will 
 produce effects fully equal to one hundred or more of zinc 
 and copper plates. The intensity of the action may be kept 
 up for a very long time ; hence such batteries are called 
 Sustaining Batteries. 
 
 Smee's Battery is, however, the most simple, and the most 
 easily managed of any which have yet been noticed. It con- 
 sists of silver and amalgamated zinc plates, (Fig. 40.)* 
 
 The silver plate is covered with platinum, in fine division 
 called platinum black, and is placed between two zinc plates, 
 b b (Fig. 40) and secured by a clamp. The battery is then 
 charged by placing it in a half-pint tumbler containing di- 
 luted sulphuric acid. The action commences whenever the 
 poles s % are in contact, and ceases when they are separated. 
 This battery is remarkable for affording a constant -current 
 of electricity for days and weeks together ; hence its use in 
 electro-metallurgy. It is distinguished for the quantity of elec. 
 tricity it is capable of generating, but is surpassed by most 
 others for intensity of action. By increasing the number of 
 * Manufactured bj B. Pi^o & Son, N. Y, 
 
Theories of Galvanism. 
 
 Fig. 40. 
 
 85 
 
 plates, however, sufficient power is generated for most ex- 
 periments. For experiments in electro-magnetism, it is far 
 preferable to any other. Instead of the silver plate, one of 
 lead covered with silver, and then with platinum black, is 
 said to work better than a thin plate of silver. 
 
 Theories of Galvanism. 
 
 On this subject there are three theories: 1. The first 
 originated with Volta, who conceived that electric currents 
 are set in motion, and kept up, solely by contact of the dif- 
 ferent metals. He regarded the interposed solution merely 
 as a conductor to convey the electricity from one point to 
 another. 
 
 2. The second theory was proposed by Dr. Wollaston, 
 who supposed that chemical action was the sole cause of 
 exciting and continuing the voltaic currents ; and the fact 
 that no sensible effects are produced by a combination of 
 conductors, which do not act chemically upon each other, is 
 the strongest proof of its truth r'even in the voltaic pile, the 
 energy of the action depends upon the oxidation of the zinc. 
 
»t Lams of the Actum of Voltaic Circles. 
 
 The third theory was suggested by Sir H. Davy, and is 
 intermediate between the two preceding. He supposed that 
 the electric equilibrium was disturbed by contact of the 
 
 me:ilf. zzi :if rr: ::: zzr:^z:s z^~z :; :j ; V; "::';•.: ,~ :::.';:. 
 
 T^r -.ie:-.-; ::' ^":Li=::-z :> n : ™ -rnrrifv rr_-.'::i:ci 
 
 Z.-\\ : :_-" :V: J:: . : ;-" F;.~- \': C'Zii, 
 
 Electricians distinguish between quantity and intensity in 
 Galvanism, as in ordinary electricity. 
 
 Q ..:.-:::;. ri:"r:s ::■ :>.r it.;-;:: :■: ;':; r!ri::: :■.::: :c: :n 
 motion ; tension, or intensity, to the energy or effort with 
 which a current is impelled. Common etectricir 
 tension; voltaic, great quantity, — and this is the principal 
 
 1. In the broken circuit, there is a strain to establish an 
 electric current, because without this, oxidation cannot take 
 place. There exists between the exciting fluid and the zinc, 
 a desire, as it were, for chemical action, which cannot be 
 
 zr.-r.i-:-: iz:z, :; :!: = zz '■'-"-- '.'.zzzz. i _::: := :;::.:: ::: :~.e 
 escape and circulation of electricity. This strain or I 
 := "fi:. i ::::: .ir is : r if: . -.7 ::~^: :'.ir r:::::.r_r ~ . :. : 
 and the zinc is great. Currents of high tension are urged 
 
 " • - - " - - :ZZ? 
 
 they more readily overcome obstacles to the: i 
 
 ■ - - 
 
 tension ; but if the plates- are large, a great quantity of 
 
 The condition which causes a high tension is an extended 
 
 L-T":! ::ziz::::. z zz z~.r --'zz'.- line : :' —jiizh s.:::—-: r 
 
 - 
 
 cirri:::- E..: :':.: : : \z: : .v :z :l::s :" ; r -:■;--:• ': ::: ■; 
 :":;. il-fi vir"~ :: ; '■'■ : '■ := ::-:;ri5r_ : ;-" :'..: :" :r :■? —;.:::. rich 
 
 -i=5-r-= ••l:r_z :!:: ".:: :: i :: i.r.r : : Fir iiij :f t:::\v e-pil 
 :: : i: --'_-.-. :1"_ : :. : -:5 :1c: :.:r.. . -; : :' :!:- :■='.'.- :z ■■':.. :'.z the 
 
 3. The energy of voltaic currents is measure 
 their power of deflecting a magnetic needle 
 ekemiad tkcosrpositio*. The deflection of the needle depends 
 
Electricity. — Effects of Galvanism. 87 
 
 upon quantity ; hence a single pair of plates will deflect the 
 needle more than a number of small ones combined ; but de- 
 composition depends upon quantity and intensity together. 
 The decomposing power of the battery, however, does not 
 increase in the ratio of the number of plates, but as the 
 square root of the number, so that, when the number varies 
 as 1 to 4, the decomposing power is as 1 to 2. 
 
 The deflecting power of a single pair of plates varies in- 
 versely as the square root of the distance between them. 
 Thus, if a plate of zinc be placed at one, four, and nine 
 inches from a plate of copper, the deflecting powers will be 
 in the ratio of 3, 2, 1. 
 
 4. The velocity of common electricity through perfect con- 
 ductors, is surpassed only by that of light, being, according to 
 Wheatstone's Experiments, about 118,000 miles per second. 
 From some experiments, it is infered that the velocity of 
 voltaic electricity is somewhat less. Hence this agent has 
 been employed to communicate intelligence from one place 
 to another. The Electro-Magnetic Telegraph, by which this 
 is effected, depends upon the velocity of electricity and its 
 power to impart magnetism to soft iron. 
 
 Effects of Galvanism. 
 
 I. The effects of common and voltaic electricity have many 
 points of resemblance. 
 
 1. If a zinc and copper plate be immersed in dilute nitric 
 acid, and the wire attached to the zinc plate be made to 
 touch a gold leaf electrometer, the leaves will diverge with 
 negative electricity, and if the wire of the copper plate be 
 applied, it will indicate positive electricity. This effect is 
 much greater when a battery of several pairs of plates is 
 employed. It appears to be due to the disturbed equilibrium 
 in the zinc plate; the chemical relation of which to the acid 
 renders the metal positive, at the expense of the attached wire, 
 while the copper plate, induced by the contiguous zinc, be- 
 comes negative, at the expense of its wire, which becomes 
 positive. 
 
 2. A Lryden jar may be charged from either wire of an 
 unbroken circuit, provided a large quantity of electricity be 
 developed, connected with high tension. This effect depends 
 upon the number of plates and the energy of the action. 
 
 3. Voltaic, like common electricity, passes through the 
 
88 Effects of Galvanism. 
 
 air, and other non-conductors, in the form of sparks, accom- 
 panied with a report, and the development of light and heat. 
 Hence it will inflame gunpowder, phosphorus, hydrogen and 
 oxygen, and other inflammable substances. 
 
 4. Its tension, however, is so feeble, compared with com- 
 mon electricity, that it has, according to Mr. Children, a very 
 small striking distance; i. e., the space of air through which 
 the spark will pass is comparatively small. With a battery 
 of 1250 pairs of four-inch plates, he found the striking dis- 
 tance to be ¥ \y of an inch. If the air be rarefied, the distance 
 will be increased, and diminished by condensation. 
 
 5. The effect of voltaic electricity upon the animal sys- 
 tem is similar to that of common electricity. 
 
 6. Both kinds also deflect the magnetic needle, and pro- 
 duce chemical decomposition. 
 
 II. One of the most surprising effects of voltaic currents 
 
 is their power of igniting the metals. 
 
 Exp. Attach to each pole of the battery strips of metallic leaves, 
 and bring them in contact ; the metals will burn with the most vivid 
 scintillations. (See Fig. 38.) 
 
 The color of the light varies in different metals. Gold 
 leaf burns with a white light, tinged with blue, and yields 
 a dark brown oxide. Silver emits an emerald-green light, 
 of great brilliancy ; copper, a bluish-white light, with red 
 sparks; lead, a beautiful purple ; and zinc, a brilliant white 
 light, tinged with blue and red. If the communication be 
 made with charcoal points, (that from the box-wood is the 
 best,) the light is equal, if not superior, in intensity, to that 
 emitted during the combustion of phosphorus in oxygen gas, 
 and the heat is sufficient, it is said, to partially fuse the car- 
 bon, a substance which is fusible by no other means of pro- 
 ducing heat.* 
 
 Theory. The heating power seems to be due, for the 
 most part, to the quantity of electricity developed ; hence, for 
 melting wires, a calorimotor is preferable to a compound bat- 
 tery. The heat is supposed to arise from the difficulty with 
 which the electric currents pass along the conductors ; but 
 
 
 * On examining the points after they have bepn subjected to the 
 action of a powerful battery, one will present a conical appearance, like 
 the head of a pin, the other a corresponding cavity. The carbon thus 
 transposed has been supposed to be partially melted; but probablv it is 
 nothing but earthy matter in the carbon. 
 
Chemical Effects of Galvanism. 89 
 
 as the substances are good conductors, the effect will take 
 place only when the quantity of electricity transmitted, is out 
 of proportion to the extent of surface over which it has 
 to pass. 
 
 As heat and light are produced in vacuo, under water, or 
 in gases which do not contain combustible matter, these phe- 
 nomena cannot be attributed to combustion, but to the pro- 
 duction of light and heat by the electric fluid itself. The 
 effects of common electricity from the electric machine, 
 and in the case of lightning, are so similar to those above 
 described, that there can be no doubt of the identity of the 
 agents concerned in their production. 
 
 III. Chemical Effects of Galvanism. The phenomena 
 which accompany chemical combinations are similar to those 
 produced by voltaic electricity. But the agency of voltaic 
 currents to effect the decomposition of chemical compounds 
 is a most important and useful discovery, which was first made 
 by Carlisle and Nicholson. 
 
 1. The first substance decomposed by the gal- 
 vanic battery was water. The water for decom- 
 position is put into a small vessel, a, (Fig. 41.) 
 The tubes h o, after being filled with water, are 
 inverted in the vessel, passing through holes in the 
 stopper; n and p are platinum wires passing 
 through the sides of the vessel into the o^en ends 
 of the tubes. When the poles of the battery are 
 connected with the wires, the positive with p, and 
 the negative with n, hydrogen gas is disengaged 
 at the negative, and oxygen at the positive wire. 
 The two gases will rise up in the tubes in small bubbles, and 
 displace the water. By measuring the gases, it will be found 
 that there will be exactly two measures of hydrogen in the 
 tube h to one of oxygen in the tube o. If the gases are col- 
 lected in the same tube and exploded in the eudiometer, they 
 will entirely disappear, and water will again be formed. By 
 this means, the composition of water, both by analysis and 
 synthesis, is accurately ascertained. 
 
 This important discovery led to similar trials upon other 
 substances. Other compounds, such as acids, salts, and alka» 
 
90 
 
 Chemical Effects of Galvanism. 
 
 lies, were subjected to the agency of galvanism, and all were 
 decomposed — one of their elements appearing at the positive, 
 the other at the negative pole. In these decompositions, it 
 was found that the same kind of body always went to the 
 same pole. The metals, inflammable substances in general, 
 alkalies, earths, and the oxides of the common metals, were 
 uniformly found at the negative wire, while oxygen, chlorine, 
 and the acids, were found at the positive pole. This led to 
 a division of substances into Electro-positive, and Electro- 
 negative — a distinction,however, which is not found, by later 
 experiments, to accord with facts. 
 
 2. The transfer of chemical substances from one vessel to 
 another was noticed by Sir H. Davy. This transfer may be 
 shown by two wine-glasses, (Fig. 42.) 
 
 Put a solution of sulphate of soda into one, 
 n, and distilled water into the other, p ; then 
 connect them with moistened amianthus or 
 cotton thread. If, now, the negative pole of 
 the battery is connected with n, and the pos- 
 itive with p, the acid will pass over into the cup p containing 
 the distilled water — if the poles are reversed, the alkali will 
 pass over into this cup. If, instead of distilled water, infusion 
 of purple cabbage be used, the presence of the acid will be 
 detected by the red color which it will give to the infusion, 
 and that of the alkali by its changing the infusion to green.* 
 
 But the effect in this experiment, and in those where three 
 vessels are used, (the middle one of which, although contain- 
 ing a very delicate test of the presence of an acid or of an 
 alkali, will suffer them to pass through it without detection,) 
 can be accounted for on the principle that a part of the salt 
 passes over into the cup by capillary attraction; as it has 
 
 * A very simple apparatus for showing the changes of 
 color when salts in solution are subjected to galvanic 
 action, is shown in Fig. 43, which consists of a glass tube, 
 bent in the form of the letter U. Fill both legs with a 
 neutral salt colored with the infusion of purple cabbage ; 
 on immersing the poles p and n, the color may be trans- 
 ferred from o°ne leg to the other as often as the poles are 
 Changed. 
 
Chemical Effects of Galvanism. 91 
 
 been proved by Faraday that decomposition never takes 
 place unless the electric fluid actually passes through the sub- 
 stance. 
 
 It was in pursuing these researches that Davy made his 
 great discovery of the decomposition of the alkalies and 
 earths, which, until that time, had been considered simple 
 bodies. 
 
 Theory. The theory of decomposition, proposed by Davy, 
 was this : He conceived that the poles of the battery were 
 centres of attraction to one element of the compound, and of 
 repulsion to the other ; hence, when the two poles were im- 
 mersed in water, the oxygen of the water was attracted by 
 the positive, and repelled by the negative pole, while the hy- 
 drogen was repelled by the positive and attracted by the neg- 
 ative pole. The elements, thus acted upon by four forces, 
 were separated, and made to appear at their respective poles. 
 
 But this theory does not account for all the phenomena. 
 If it were true, we should expect decomposition to be effected 
 by one pole alone, as it exerts the attractive and repellent 
 influence ; but this is never the case. 
 
 Mr. Faraday has lately revised this part of the subject, and 
 not only added much that is new, but shown that many prin- 
 ciples, especially the above theory, are erroneous. 
 
 He contends that the poles have no attractive or repulsive 
 tendency, but simply afford a path for the voltaic currents 
 to enter the liquid. Instead of poles, he calls them elec- 
 trodes* which means the way or door for electric currents, 
 and may be air, water, metal, or any other substance capable 
 of conducting the currents to and from the substance to be 
 decomposed. The point where the positive current enters 
 the liquid, he calls the anode,i and that where it quits it, the 
 cathode, f 
 
 When a compound is decomposed by galvanism, it is said 
 to be electrolyzed,§ and substances capable of decomposition 
 are called electrolytes; the elements of an electrolyte are 
 
 ¥ From y/Lsy.TQov and o<5oc, a way. 
 
 t From «ra, upwards, and 6dos, the way in which the sun risei 
 
 t From xara, downicards, the way in which the sun sets, 
 
 § From ijiUxTfov and Xvw, to unloose or set free. 
 
92 Results of Faraday's Investigations. 
 
 called ions* Anions are the ions which appear at the anode 
 cations, those that appear at the cathode. The anions are 
 the electro-negative substances, such as oxygen, chlorine, 
 acids, etc. ; the cations, the electro-positive, such as hydro- 
 gen, alkalies, metals, etc. 
 
 The following are the principal results of Faraday's inves- 
 tigations : — 
 
 1. All compounds, contrary to what has been hitherto 
 supposed, are not electrolytes; that is, are not directly de- 
 composable by the voltaic currents. But many bodies may 
 be decomposed by secondary action. Thus water is directly 
 decomposed by an electric current ; but nitric acid is decom- 
 posed by secondary action — the decomposition of the water 
 contained in it, aids the decomposition of the acid. Very 
 numerous secondary actions are produced in this way, because 
 the disunited elements, separated by direct action, are pre- 
 sented in their nascent form, which is peculiarly favorable to 
 chemical action. 
 
 2. Most of the salts or secondary compound^ are resolva- 
 ble into acid and oxide ; but in the binary compounds, such 
 as acids and oxides, the ratio of combination has an influence 
 which has been hitherto overlooked. No two elements ap- 
 pear capable of forming more than one electrolyte. The 
 proto-chloride of tin is readily decomposed, but the by-chlo- 
 ride is not. Hence substances which consist of a single 
 equivalent of one element, and two or more of another, are 
 not electrolytes, that is, are not decomposed directly by 
 electricity. 
 
 3. Most of the simple substances are ions, that is, capable 
 of forming compounds decomposable by galvanism. 
 
 4. A single ion, by itself, has no tendency to pass to either 
 of the electrodes, that is, it is indifferent to the voltaic cur- 
 rents. 
 
 5. There is no such thing as a transfer of the ions, in the 
 sense supposed by Davy. In order that the elements of water 
 should appear at the two electrodes, there must be a row of 
 particles between them. 
 
 6. The air, or the surface of water, may constitute an elec- 
 trode, as well as metals. 
 
 7. Electro-chemical decomposition cannot occur unless a 
 current of electricity actually passes through the compound , 
 
 * From tov, goings neuter participle of the verb to go. 
 
Theory of Electro-Chemical Decomposition. 93 
 
 that is, the compound must be a conductor of electricity 
 On this principle many substances, by change of state, resist 
 decomposition. Water is easily decomposed, but ice is not ; 
 many solid substances, also, are not electrolytes, because they 
 are not conductors. Chemical compounds differ in the elec- 
 trical force required for their decomposition ; some require 
 but a feeble current, others a powerful one. 
 
 8. The conduction of the electric currents in the cells of a 
 battery depends upon decomposition. If the zinc or the cop- 
 per be attacked chemically by a substance which is simple, or 
 a non-conductor, no currents can be set in motion. 
 
 9. Electro-chemical decomposition is perfectly definite ; 
 that is, in the voltaic circle 32.3 parts of zinc are dissolved 
 during the evolution of one part of hydrogen. This is in the 
 ratio of their chemical equivalents. The same is true of all 
 electrolytes. Hence Mr. Faraday has given to the quantities 
 of electricity, requisite to effect the decomposition of various 
 substances, the name of electro-chemical equivalents. This is 
 a new and important discovery, and illustrates the close 
 connection between chemical affinity and electricity. Hence, 
 in order to estimate the quantity of electricity circulating in 
 a voltaic apparatus, it is only necessary to collect the gae 
 evolved from the acidulated water during any given time. 
 
 Theory of Eleciro-Chemical Decomposition. We have al- 
 ready noticed the theory of Davy, which supposes that all 
 substances are in one of two states of electricity, and that the 
 poles have an attractive and repulsive force ; but Mr. Faraday 
 has shown that this theory cannot be tfue. All substances 
 are indifferent when by themselves, but assume one of the 
 two states when brought in contact. Only one substance is 
 always negative — oxygen ; and but one always posi- 
 tive — potassium : between these extremes, they may be made 
 to assume either positive or negative states. To account for 
 the decomposition of water, we must conceive of a line of 
 particles between the two electrodes, along which the current, 
 passes. When a particle of oxygen is evolved at the positive 
 electrode, its hydrogen is not transferred at once to the op- 
 posite electrode, but unites with the oxygen of the contiguous 
 particle of water, on the side towards which the positive 
 current is moving ; then it passes to the next, and so on, until 
 
94 Magnetic Effects of Electricity. 
 
 it arrives at the pole. A similar row of particles of oxygen 
 start from the negative electrode at the same moment, and 
 combine successively with the particles of hydrogen as they 
 pass them on their way to the positive pole or electrode.* It 
 is supposed that other compounds are decomposed by a 
 similar process. 
 
 Magnetic Effects of Electricity, or Electro-Magnetism. — 
 History. It had been noticed for a long time that, when a 
 ship, for example, was struck with lightning, the magnetic 
 needle often had its poles destroyed or reversed, and that the 
 iron often became magnetic. This led to the supposition, 
 that electricity might be employed to communicate the mag- 
 netic properties to iron or steel ; but no results of importance 
 were obtained until the winter of 1819, when Prof. Oersted, 
 of Copenhagen, made his famous discovery, which forms the 
 basis of a new and very important branch of science. 
 
 I. Influence of Voltaic Currents upon the Magnetic Nee- 
 dle. The discovery made by Oersted was, that the me- 
 tallic wire, or any part of a closed voltaic circle, causes a 
 magnetic needle, when brought near it, to deviate from its 
 natural position, and assume positions depending upon the 
 relative position of the needle and the wire. 
 
 Thus, suppose a magnetic needle freely suspended with its 
 poles pointing north and south. (See fig. 41:) 
 
 1. If, now, a positive current pass from north to south in 
 the same plane with the needle, but a little above it, the north 
 pole will turn to the east, and the south pole to the west. 
 
 2. If the current pass under the needle, the north pole 
 moves west, and the south east. 
 
 3. If the current pass on the west side of the needle, and 
 in the same horizontal plane, the magnet will have a tendency 
 to move in a vertical direction, the north pole being elevated, 
 and the south depressed. 
 
 4. If the current pass on the east side, the north pole is 
 depressed, and the south elevated. 
 
 5. If the current flow from south to north, the needle will 
 move in opposite directions. 
 
 * The quantity of electricity sufficient to decompose a single grain 
 of water would be equal to a powerful flash of lightning. 
 
Magnetic Effects of Electricity. 95 
 
 The deflection is rarely 45°, in consequence of the mag- 
 netism of the earth ; but if that force is counteracted, as it 
 may be, by suspending two magnets near each other, of equal 
 power, with their poles reversed, the declination will be 90° ; 
 hence the tendency of a magnetic needle is to stand at right 
 angles to an electric current. 
 
 6. If the wire be placed in a plane, perpendicular to the 
 one in which the magnet moves, and the positive current 
 ascends or descends to the centre of the needle, no action 
 will take place; but if it be moved towards the north or south 
 poles, they will be attracted or repelled. Hence the plane in 
 ichich a needle moves is always perpendicular to that in which 
 the voltaic currents circulate. 
 
 7. The phenomena of Electro-Dynamic action result 
 wholly from electricity in motion, and depend upon quan- 
 tity alone ; hence a simple circle of large plates is best fitted 
 for exhibiting it.* 
 
 From the above facts it will be seen, that the magnetic 
 needle may be employed, not only to ascertain the existence 
 and direction of voltaic currents, but also to measure their 
 force. The instruments used for these purposes are called 
 
 Galvanometers or Multipliers. As it is proved by expert 
 ment that every part of a wire in a closed circuit exerts an 
 equal force upon the poles of a needle, if we can increase 
 the number of points, the combined force will be greatly 
 increased. This can be done by coiling the wire into the 
 / brm of a circle or rectangle; each coil will exert its own 
 force, independent of its neighbor, and the united force will 
 depend upon the num- 
 ber of coils. Thus (Fig. Fig. 44. 
 44) NP are the two ends |L ^ 
 
 of a copper wire bent in ]fjf X\r 
 
 the form of a rectangle, ^ — n 
 
 in the centre of which, B ll 7 ^ ft s|A 
 
 and in a plane perpendic- 
 ular to the plane of the 
 wire, is placed a mag- 
 netic needle. A gradu- 
 ated circular plate meas- 
 
 * The simple battery, Fig. 36, p. 81, is best fitted for experiments on 
 this subject The exciting liquid should be a solution of sulphate of 
 copper. 
 
l» 
 
 96 
 
 Electro-Magnetism, or 
 
 ures the degree of decimation, which indicates the quantity 
 of electricity circulating along the wires. It will be seen, 
 -M;hat if the positive current pass above the needle from north 
 to south, that is, from P to a, and then pass around the south 
 pole from A to B, there will be double the effect produced. 
 By increasing the number of coils, the deflection of the 
 needle will be much greater. This constitutes the Electro- 
 Magnetic Multiplier of Schweigger. 
 
 If the directive power of the needle be destroyed, or if the 
 currents are sufficiently powerful, the needle will stand at 
 right angles to the direction of the currents. Then, if, at the 
 moment it has attained this point, the currents be sent in an 
 opposite direction, it will perform a revolution. Thus, by 
 changing the direction of the currents, a needle may be made 
 to revolve rapidly. 
 
 If the magnet is fixed, and the rectangle suspended ^ee to 
 move, it will exhibit the same phenomena while the voltaic 
 currents are passing around it. 
 
 Fig. 45. 
 
Magnetic Effects of Electricity. 97 
 
 The Revolving Rectangle is constructed on this principle. 
 MM (Fig. 45) is a permanent horse-shoe magnet; C, a rec- 
 tangular coil of copper wire, connected at each end to an 
 axis, by which means it may be made to revolve; ZP are two 
 cups ; to form a connection with the poles of a battery ; the 
 wires 66 are connected with the cups, and press on opposite 
 sides of the cylindrical metallic pole-changer, which revolves 
 between them. The pole-changer consists of two pieces of 
 silver, with a small space between them; one of these pieces 
 is connected with one end of the wire of the rectangle, and 
 the other piece with the other end ; a is an arch of brass to 
 support the rectangle and the wires. If the two cups be 
 connected with the battery, P with, the positive, and Z with 
 the negative pole, the positive current will pass along the 
 wire 6 next to N, and from the wire to one side of the pole- 
 changer, and thence several times around the rectangle to 
 the wire 6 next to S. 
 
 When the positive current is passing from P around this 
 rectangle, one side is impelled towards one pole of the maguet, 
 and the other towards the other pole. When the sides arrive 
 in the plane of the poles, the force still continues to act, and 
 they are forced by, and complete half a revolution, standing 
 again at right angles to the poles of the magnet, the point at 
 which they commenced their revolution : at this point the 
 pole-changer sends the currents in opposite directions, and 
 the revolution is continued. Reverse the current, by chang- 
 ing the battery wires, and the rectangle will revolve in an 
 opposite direction. 
 
 II. TJie influence of voltaic currents on soft iron and steel 
 was noticed by Da*y and Arago about the same time. If an 
 iron or steel needle be suspended in the galvanometer instead 
 of the common needle, at right angles to the conducting 
 wires, permanent magnetism will be communicated to the 
 steel, and the iron will become powerfully magnetic, as long 
 as the currents circulate, but will lose this property when 
 the circuit is broken. Davy succeeded in producing a similar 
 effect by a discharge from a common electric battery. 
 
 1. This effect can be exhibited in the most satisfactory 
 manner by coiling an insulated copper wire in the form of 
 a helix, d, (Fig. 46,) and connecting the two ends of the wire 
 66 with the cups CZ, into which the poles of a battery may 
 
98 
 
 Elec tro-Magn cti sm . 
 
 be inserted. Bars of soft iron or 
 steel, placed in the coil, will become 
 magnetized the instant the voltaic cur- 
 rents circulate around the coil. If 
 the positive current flows from Z 
 around the helix, n will be the north 
 pole, and s the south pole. If it flow 
 from C, the poles will be reversed. 
 
 2. If a bar of soft iron (Fig. 47) 
 be wound with copper wire from c to 
 a in one direction, and from a to d in 
 an opposite direction, and currents of 
 electricity passed around the bar, by 
 connecting the wires b e 
 
 with a voltaic battery, the r Jk 
 
 bar will have three poles ; c 
 and d will be similar poles, 
 and a an opposite pole com- 
 mon to the other two, as 
 may be shown by bringing a 
 magnetic needle near each. 
 By changing the direction 
 of the battery currents, the 
 poles are reversed : hence 
 the kind of pole depends upon 
 direction of the voltaic currents. 
 
 3. Although soft iron does not re- 
 tain its magnetism, yet its magnetic 
 properties, while the voltaic currents 
 are passing around it, are truly sur- 
 prising. 
 
 If a soft iron cylinder, two inches in 
 diameter, and bent in the form of a 
 horse-shoe magnet D, (Fig. 48,) be 
 wound with copper wire, and the ends 
 BC connected with the battery, it will 
 be converted into a powerful magnet. 
 On applying the armature A, it will 
 sustain several hundred pounds. Mag- 
 nets of this description may be made 
 to sustain from 200 to 2000 lbs. It 
 will be seen that the principle is the 
 same as in the helix; and, as in the mul- 
 
 Fig. 47. 
 
 th 
 
Magic Circle. 
 
 99 
 
 tiplier, by increasing the number of coils, the magnet becomes 
 more powerful, but the force does not increase directly as the 
 number of coils; for each additional coil is farther from the 
 axis of the iron bar, and the power it exerts is inversely as 
 the square of the distance from the axis. 
 
 4. The 3Iagic Circle, with two iron ar- 
 matures, acts also on the same principle. 
 
 r (Fig. 49) is a coil of insulated copper 
 wire; ab the two ends which may be con- 
 nected with the battery. When the wires 
 b a are connected with the battery, and the 
 two armatures are brought into contact, one 
 of them passing through the ring, they adhere 
 to each other very strongly, and, although 
 they weigh less than f lb., they will sustain a weight of 56 lbs. 
 without separation. The voltaic currents not only communi- 
 cate magnetism to the iron and steel placed in the ring, but 
 the helix itself becomes magnetic while transmitting the cur- 
 rents, as is proved by its attracting iron filings. These and 
 other facts, developed by voltaic currents, seem to prove the 
 identity of the magnetic and electric fluids. 
 
 5. Vibrating Magic Circle. MM (Fig. 50) is an electro- 
 magnet, which may be used instead of a permanent magnet, 
 c, a coil of coarse wire suspended from the post S ; one end of 
 the wire a dips into the cup e, which is connected with the post 
 S, and which also communicates withp; the other end of the 
 wire d is connected with the other cup, which is insulated 
 from the post S, 
 
 and into which Fi S» 50. 
 
 also one of the 
 poles of the 
 battery may be 
 immersed; con- 
 nect the other 
 pole of the bat- 
 tery with p, and 
 a current of 
 electricity 
 pass along 
 post S to 
 cup e; as 
 wire a dips into 
 it, the current 
 
100 
 
 Pages 's Revolving Magnet. 
 
 will pass down the wire b around the coil c, and then up the 
 wire d to the other cup; as the currents circulate, the coil 
 will be attracted to the pole of the magnet M; this will lift a, 
 and break the circuit, and the coil will fall back beside the 
 post S ; a will again be immersed in e, and the coil be again 
 attracted upon M. Thus vibrations are produced as long as 
 the currents of electricity circulate. 
 
 6. Page's Revolving Magnet and Bell Engine. — By using 
 an electro-magnet in connection with a permanent steel mag- 
 net, or another electro-magnet, and reversing the currents by 
 a pole changer, very rapid revolutions may be produced. 
 The following is Page's revolving magnet, with a bell at- 
 tached to mark the rapiditv of the revolutions. 
 
 Thus, N S (Fig. 51.)* repre- 
 sents the north and south poles of a 
 permanent horse-shoe magnet. A 
 is a bundle of coarse iron wire, 
 wound with copper wire, constitu- 
 ting an electro-magnet, which is 
 fitted to an axle S. By means of a 
 pole changer, connected with the 
 axle below the electro-magnet, the 
 battery current may be made to pass 
 in opposite directions as the magnet 
 revolves upon its axle. By this 
 means the polarity of the electro- 
 magnet can be constantly changed. 
 Suppose it stand at right angles to 
 the permanent magnet, and is ren- 
 dered magnetic by a current of 
 electricity, its south pole will be at- 
 tracted to the north pole of the steel 
 magnet, and its north pole to the fSgjsiTT^j^r^--' ~ 
 south pole of the steel magnet. As Jfe^-^j; 
 it turns \ of a revolution, the pole ^4 =- " 
 changer sends the current in the op- 
 posite direction, and changes its poles; mutual repulsion now 
 takes place, because similar poles are near each other, and it 
 moves another quarter of a revolution by repulsion, and then 
 another quarter by attraction of opposite polarities. The mo- 
 ment it has completed 1 a half revolution, the poles are changed, 
 
 * Davis's Manual of Magnetism, p. 114, fig. 7"2. 
 
Volta- Electric Induction. 101 
 
 and it continues to revolve. To the axle is attached an endless 
 screw, which acts upon a toothed wheel with a projecting pin 
 for the purpose of raising the hammer of the bell at each 
 revolution. If the wheel has 100 teeth, the magnet must re- 
 volve 100 times to produce one revolution of the wheel, which 
 is indicated by a stroke of the hammer against the bell. The 
 velocity of the rotating magnet may be determined by no- 
 ting the numbpr of strokes in a minute, or in any given 
 time. It has often made 100 revolutions in a second, or 6000 
 in a minute ; and for each revolution of the magnet, its poles 
 are changed twice or 12000 times a minute. For this effect 
 the current must pass through some 20 feet of wire, and con- 
 vert the inclosed bundle of iron wire into a magnet, twice at 
 each revolution. Some idea may thus be formed of the 
 rapidity with which this agent moves through conducting 
 substances. On the above principles, and others yet to be 
 developed, a variety of machines have been constructed. 
 Many of them are beautifully figured and described in 
 Davis's Manual of Magnetism. 
 
 III. Volta- Electric Induction. The fact that an electri- 
 cally-excited body induced electricity in other bodies brought 
 near it, (page 76,) led Faraday to inquire whether electricity 
 in motion would not have the same efFect. This fact he soon 
 established. 
 
 If a copper wire be wound in the form of a helix, and the 
 ends connected with a battery, and then another wire be 
 wound around this, but insulated from it, and the ends con- 
 nected with a galvanometer, currents of electricity will be 
 induced in the insulated wire, as often as the battery current 
 is broken. All the effects of galvanism may be produced by 
 the insulated wire. 
 
 The phenomena of Volta- Electric Induction may be ex- 
 hibited in the most satisfactory manner by the 
 
 Separable Helices, (Fig. 52,) an apparatus very well fitted 
 for illustration, for producing sparks, and imparting shocks 
 of almost any degree of intensity. 
 
 b (i-^ig. 52) is a hollow coil of coarse wire fixed upon a 
 stand, Z ; one end of the wire is connected with the cup, and 
 
102 
 
 Volta-Electric Induction. 
 
 Fig. 5 2. 
 
 
 the other with the steal break-piece* which is fixed to the 
 stand, by the side of the coil ; a is a coil of fine wire, which 
 may be placed over the coil b ; d is a bundle of wires, which 
 may be slipped into the copper case c, and placed in the cen- 
 tre of the coil b. 
 
 Fig. 53 represents this apparatus entire. The following 
 are the principal facts which it is fitted to exhibit : — 
 
 Exp. 1. Connect one pole of the battery with the cup on the left of c. 
 (Fig. 52.) and move the other pole along the break-piece: vivid spark 
 will be produced at each interruption. 
 
 Exp. 2. Remove from the wires d the copper case c. and insert theiu 
 gradually in t_ie coil b while the currents are circulating, and the sparks 
 on the break-piece will increase in brilliancy until the wires reach the 
 bottom, when the greatest effect will be pro 
 
 Exp. 3. Place the coil a upon b. and let the currents circulate as before. 
 If the handles t f. (Fig. 53} which communicate with the extremities of 
 the wire forming the coil a, be held in the hands, powerful shocks will be 
 felt as the wire conveying the battery current passes across the bre: .:• 
 As the outer is insulated from the inner coil, the shocks do not proceed 
 from the battery current, but from currents induced in the wire of the 
 outer helix. Currents thus induced produce all the phenomena of the 
 battery currents. 
 
 * A breal: may consist of air. or any non-conductor. J with 
 
 a conductor, thai, when the w irr conveying the • 
 the conductor to the non-conductor, the circuit may be broken : and it is 
 
 only at the moment of interrupting the battery current in the inner that 
 electricity is induced in the outer coil. 
 
Volta- Electric Induction. 
 
 103 
 
 Fig. 53. 
 
 Exp. 4 A single wire* will increase the power of the shocks, and by 
 increasing the number of wires, the sparks will increase in brillianey, and 
 the shocks will become more and more powerful. 
 
 Exp. 5. If the copper case be placed upon the wires, the effect will be 
 the same as when no wires are used. 
 
 The battery current which passes around the inner coil of 
 wire is called the primary, and tiie induced current the 
 secondary current. It is not necessary to this effect that one 
 of the coils should surround the other, but may be placed 
 
 * Fine wires answer abetter purpose than a solid bar; if however, the 
 bar be slit length wise down to the axis, the effect will be nearly equal to 
 the wires, and if the copper case be sawed open lengthwise, it will not 
 destroy the effect of the wires. 
 
Ij34 Volia-Elcctric Induction. 
 
 above it in the form of a flat spinal. Thus, let A (Fig. 54) 
 (Davis's Manual, p. 149, Fig. 97) be a coil of copper ribbon, 
 having the two ends connected with a battery. Let B be a 
 second coil placed just above it, with its ends connected with 
 the ends of a third coil C. Over this place a fourth coil W, 
 with handles attached by wires to each extremity as above. 
 
 Exp. 1. By passing the battery current through A, secondary currents 
 will be induced in B, one, when the circuit is completed, passing in a di- 
 rection opposite to the battery current, called the initial, and one, "when 
 the battery current is broken, circulating in the same direction, and called 
 the terminal current. 
 
 Exp. 2. When C is connected with B, as in Fig. 54, the secondary cur- 
 rent passes also through C, and will produce a tertiary current in W, and 
 if VV be a coil of fine wire, strong shocks are ft-lt, by clasping the hnndles. 
 A ribbon will give a quantity current, but its intensity will be slight com- 
 pared with the fine wire coil. 
 
 Tertiary currents are also induced both when the battery 
 circuit is closed and when it is broken, and. the initial and 
 terminal tertiaries flow in directions opposite to the corres- 
 ponding secondaries. Tertiary currents are capable of pro- 
 ducing currents of a fourth order, and these latter currents 
 of a fifth order, and so on, as high at least as the seventh 
 order. 
 
 The directions of these currents, produced by the initial 
 and terminal battery currents, are represented by the sign +, 
 when they flow in the same direction, and — , when in an 
 opposite direction. 
 
 - At the beginning- At the ending. 
 
 Thus, Primary current, -f- -f- 
 
 Secondary current, — • -4- 
 
 Tertiary current, -f- — 
 
 Quaternary current, — -f- 
 
 It will be seen that these induced currents must react upon 
 each other, and diminish their effect, by inducing currents in 
 an opposite direction. In this way also, induced currents 
 act against the battery current, i nd this feet presents a 
 serious difficulty in using this agent for moving machinery. 
 
 There is a striking analogy between factional and'' voltaic 
 
Magnetico- Electric Induction. 
 
 105 
 
 electricity, in the fact that both kinds induce electricity in 
 bodies which are in their vicinity ; but there is also a marked 
 difference in the circumstance that the presence of a body 
 electrified by stactical electricity, throws surrounding bodies 
 into an excited state which is constant, while the currents in- 
 duced by voltaic electricity are produced only at the moment 
 that the battery currents commence and cease to flow. If 
 the battery current is constant, no secondary currents will be 
 induced after the first wave is excited. Hence the rapid suc- 
 cession of shocks from the outer coil, when the battery cur- 
 rent is rapidly broken and closed. 
 
 IV. Magneto-Electric Induction. The power of the 
 magnet to induce electricity greatly exceeds that of vol- 
 taic currents. 
 
 Fig. 55. 
 
 il!llii!iii!!liiiiilii!»l!Ss!l!Mllitii!!ii:i!iiL_ 
 
 The apparatus best fitted to exhibit this effect is the Mag- 
 neto-Electric Machine, (Fig.' 55.) which consists of a perma- 
 nent horse-shoe magnet, SN, supported by pillars upon the 
 stand Z, and an armature, g, wound with copper wire, and 
 made to revolve upon an axis, c, near the poles of the magnet, 
 by means of the wheel h; one end of the wire is soldered to 
 the axis, by which means it is connected with a break-piece, 
 against which the wire c presses; the other end of the wire 
 
 * Fine wires answer a better purpose than a solid bar ; if, however 
 the bar be slit lengthwise down to the axis, the effect will be nearly 
 equal *.o the wires, and if the copper case be sawed open lengthwise, 
 it will not destroy the effect of the wires, 
 5* 
 
106 Theory of Electro-Magnetism, etc, 
 
 is soldered to a silver ferule, a, insulated from the axis, against 
 which the wire 6 presses; the wires c b communicate with 
 the cup into which the wire p is inserted ; the wire n is cun-» 
 nected with the axis by means of the post on the right of b ; 
 p and n therefore represent the two ends of the wire which 
 surrounds the armature. When the armature is set in motion 
 by the multiply ing-wheel h, its magnetic state is continually 
 changing. When the two extremities of the armature are 
 midway between the poles of the magnet, the armature is 
 neutral. As they advance towards the poles, they acquire a 
 gradually-increasing polarity, until they are opposite the poles, 
 and gradually diminish, as they pass the poles, until they are 
 midway again between the poles, when the armature becomes 
 neutral, as before. By this revolution, a current of elec- 
 tricity will be induced in the wire which surrounds the arma- 
 ture, and will pass from the break-piece to the ferule, by 
 means of the wire e b, which connects them; excepting, 
 when the end of the wire e is passing across the break-piece, 
 yien there will be induced in the wire which surrounds the 
 armature a secondary current, which passes by sparks at each 
 point of interruption, or at the wires p n, if they are brought 
 nearly into contact. By pressing the hands, previously moist- 
 ened, upon the handles connected withjp n, powerful shocks 
 will be felt at each interruption. Deflagrations may also be 
 produced, and decompositions effected, and generally the 
 electricity thus induced produces effects precisely similar to 
 those from the voltaic battery. The phenomena of elec- 
 tricity, thus produced, are sometimes called Magneto-Elec- 
 tricity.* 
 
 V. Theory of Electro-Magnetism and Magneto-Electricity . 
 In order to understand the theory of M. Ampere, by which 
 the phenomena of electro-magnetism and magneto-electricity 
 may be best explained, it is only necessary to keep in view 
 the following principle, which lies at the basis of the theory * 
 
 When two positive or two negative currents are passing in 
 the same direction, and parallel, they attract, and when pass- 
 ing in opposite directions, they repel each other. 
 
 * The best apparatus for experiments upon electrn-magnetism and 
 magneto-electricity, is manufactured by Daniel Davis, Jr. No. 11, 
 Cornhill, Boston,." 
 
Theory of Electro-Magnetism, etc. 107 
 
 If, now, we suppose that all magnetic bodies, and the earth 
 itself among the number, derive their magnetic properties 
 from currents of electricity circulating, in reference to their 
 axis, in one uniform direction of revolution, we can account 
 for all the phenomena of Magnetism, Electro-Magnetism, and 
 Magneto-Electricity. 
 
 Fig. 56. 
 
 To make this view clear. Suppose that 
 around the cylinder of Lteel, (Fig. 56,) at right |j^ 
 angles to the axis, currents of positive electricity * 
 are constantly circulating in a direction opposite 
 to that in which the sun moves. The cylinder 
 will be a magnet, n the north pole, and S the 
 south pole, and, if it be poised upon a pivot, it 
 will differ in nothing but in form from a mag- 
 netic needle. 
 
 Application of the Theory. 1. The reason 
 tnat the needle turns to the east when the 
 positive current passes above it from north to 
 south is, that the currents in the magnet, and those in the 
 wire, move in different directions. The needle is repelled, 
 and turns so that the currents may coincide. 
 
 2. When the positive current passes under the needle, it 
 moves to the west, because then also the two positive currents 
 coincide. 
 
 3. When it passes on either side in the same horizontal 
 plane, it tends to a vertical motion, for the same reason as 
 above ; but if the positive current passes from south to north, 
 the phenomena are all reversed. 
 
 4. When it passes around the poles in a vertical plane, in 
 the same direction in which the sun appears to move, the 
 needle will perform one half a revolution, because the cur- 
 rents move in opposite directions, and the needle revolves so 
 that the currents in it may coincide with those in the con- 
 ducting wire. 
 
 5. Bars of steel and soft iron become magnetic when 
 placed in the helix around which currents of electricity 
 circulate, because similar currents are induced in them. 
 
108 Thermo-Electricity. 
 
 6. If we suppose positive currents of electricity to be 
 passing around the earth in the same direction in which the 
 sun appears to move, they would convert it into a magnet, 
 the north pole of the earth corresponding to the south pole of 
 the magnetic needle : hence, if soft iron or steel bars are placed 
 in a north and south direction, they will become magnets by 
 induction, the positive currents passing from west to east, 
 because then they would coincide with the same currents in 
 the earth which pass from east to west; hence the reason 
 that a magnetic needle stands north and south, is, that the 
 currents of electricity circulating around the earth, and those 
 circulating in the needle, will coincide only when the needle 
 takes that direction, 
 
 VI. Tiiermo-EIcciricity. Thermo-electric phenomena re- 
 sult from currents of electricity excited in metals by heat. 
 The existence of these current was first demonstrated in 
 18:21 by Seebeck. 
 
 If a magnet be suspended in a rectangle formed of a bar 
 of antimony or bismuth, having its extremities connected 
 with copper wires, and heat applied to one end of the bar, 
 the needle will be deflected in one direction, and in an 
 opposite direction when heat is applied to the other <md 
 Similar effects are produced when either end is cooled below 
 the natural temperature. Other metals,' treated in the same 
 manner, exhibit similar phenomena, but bismuth and an- 
 timony are the best. Prof. Gumming has shown that a 
 rotary motion may be produced by placing platinum and 
 silver wires, soldered together in a circular form, upon a 
 magnet, and applying heat. 
 
 VII. Nature of Electricity '. Some suppose that there is 
 no transfer of any tiling in what are called electric currents, 
 but a process of induction passing progressively along among 
 the molecules of a conductor. Others ascribe them to waves 
 of vibrating matter, just as the phenomena of light and 
 caloric are explained, by the undulatorv theory. 
 
 VIII. Uses of Electricity. 1. Both voltaic and common 
 electricity have been employed in medicine ; in some cases, 
 with highly beneficial effects. It acts powerfully upon the 
 
Electro-Magnetic Telegraph. 
 
 109 
 
 nervous system, and has been the means of restoring sen- 
 sation to parts of the body which had become paralytic ; 
 so powerfully does it act upon the vital energies, that persons 
 who have been deprived of life, either by some accident, or 
 by design, have been resuscitated by its agency. Its influ- 
 ence is constant and universal in the animal, vegetable, and 
 mineral kingdoms. 
 
 2. Attempts have been made to employ voltaic electricity 
 as a motive power in the arts, to supersede the use of 
 steam ; but all attempts hitherto have been unsuccessful. Suf- 
 ficient power has been generated to turn a small lathe ; and it 
 is to be hoped that an apparatus will yet be constructed to 
 render available the great force which this agent is capable 
 of exerting. This force depends upon the property of the 
 voltaic currents to communicate magnetism to soft iron, 
 thus producing a powerful attraction, and the property of the 
 iron to change its poles, and consequently its attracting and 
 repelling power as currents circulate in different directions. 
 (See Fig. 42.) 
 
 3. Electro-Magnetic Telegraph. A most beautiful and 
 highly useful application of voltaic electricity has lately- 
 been made, for the purpose of communicating intelligence 
 from one place to another. The instrument is called the 
 Electro-Magnetic Telegraph. The one invented by Prof. 
 S. F. B. Morse appears to have been the most successful. 
 It consists of an electro-magnet, m, (Fig. 57.) an armature 
 connected with a lever balanced upon d, and having near the 
 
 Fig. 57. 
 
110 Electro-Magnetic Telegraph. 
 
 end of its longer arm, a steel point or pens, which may be 
 made to press against the roller. The paper passes around 
 this roller, «.nd is moved along by the clock-work c. When 
 the circuit is closed, the electro-magnet is magnetized and 
 attracts the armature upon its poles. This brings the pen in 
 contact with the paper pp, and produces a dot or line according 
 to the time the current circulates. Thus, suppose the bat- 
 tery at Washington and the telegraph in New York, with 
 wires w w extending from the magnet to the battery. The op- 
 erator in Washington, by closing the circuit, magnetizes the 
 electro-magnet in New York, and brings the pen against the 
 paper, and by breaking and closing the circuit, he can form 
 a series of characters consisting of dots and dashes, which 
 are the symbols of letters or words ; thus information is com- 
 municated with the rapidity of lightning. If is found that 
 one wire is sufficient for the effect, if opposite poles at the two 
 extremities are connected with a plate buried in the ground. 
 It is found also, that several telegraphs, on the same wire, 
 may be worked along the line, or at the two extremities of 
 it. A bell b is usually attached, which is to notify the opera- 
 tor at the station that intelligence is expected; at the same 
 time also the clock-work is set in motion. 
 
 The following is Morse's Telegraphic alphabet, with the 
 letters which the characters represent. 
 
 Alphabet. Numerals. 
 B P ™ 2 
 
 D R--- 4 
 
 E - S 5 
 
 F T 6 
 
 j __ X ~- 
 
 L Z 
 
 M & - 
 
 N 
 
Electro-Magnetic Telegraph. Ill 
 
 3 1 e c t r o * M a 
 
 * _____ 
 g net i c Tel 
 
 eg r a p h i 
 
 n v ented b 
 
 y P ro fess 
 
 o r M o rsein 
 
 18 3 2 
 
 House's Lightning Printing Press. Mr. House has invent- 
 ed a very ingenious Telegraph, which he has designated 
 by the above name, in which type are used to print the com- 
 mon letters on strips of paper. It is a very beautiful in- 
 vention. 
 
 In the practical operation of the Electro-Telegraph, there 
 are many influences which tend to obstruct it in its action — 
 
 1. The wires are liable to be severed either by design or 
 accident, and some time must elapse before they can be 
 mended. 
 
 2. The influence of thunder storms upon the wires, by in- 
 duction will cause a flow of electricity, and put the machine 
 into operation at a distant station. 
 
 3. Lightning sometimes strikes the wires and either melts 
 them off or travels to the different stations, affecting the ope- 
 rators with very powerful shocks. 
 
 4. A difference of temperature at the two extremities of a 
 long wire, will often produce currents of electricity in the 
 wires, which obstruct the regular communications. 
 
 Jn these and some other ways, communications are liable 
 "To be interrupted ; but notwithstanding these obstacles, it has 
 proved eminently successful. Most of the principal cities in 
 the United States are already connected by telegraphic lines, 
 and the time cannot be far distant when not only every por- 
 tion of this country, but the extremes of every continent of 
 the earth, will be closely united bv means of this truly won- 
 derful and useful invention. 
 
112 
 
 Electricity. — Electrography. 
 
 4. Electrography. A still more recent application of 
 voltaic electricity has been made to the " production oi 
 perfect metallic casts or copies of medals, copperplates, and 
 other works of art." The discovery appears to have been 
 made about the same time, by Prof. Jacobi, of St. Petersburg, 
 and Mr. Spencer, of Liverpool. The instrument by which 
 this effect is produced is the 
 
 Electrotype; and the eifect depends upon the decomposition 
 of some metallic salt, by which the metal is precipitated upon 
 the object to be copied, either forming a mould for the cast, 
 or raising lines which maybe used for making - impressions 
 on paper or other materials.* 
 
 Fig. 58 represents one form of the 
 electrotype, and the mode of taking 
 impressions. A is a glass vessel, in 
 which a division is made by casting 
 across it plaster of Paris, (earthen 
 ware, a bladder, or any porous mem- - 
 brane, as thick pasteboard, will answer 
 the same purpose.) Into one of the 
 partitions is put a saturated solution 
 of sulphate of copper, and into the 
 other acidulated water. The object 
 
 C to be copied is soldered to one end of a wire, d, and a 
 piece of zinc, Z, to the other end ; the object is then immersed 
 in the cupreous solution, and the zinc into the acidulated 
 water. The deposit of metallic copper then commences 
 upon the object c, copying, with the most scrupulous exact- 
 ness, every line, and even the shades of polish. In about 
 two or three days, a complete mould may be obtained. 
 The copper mould is separated from the matrix by gentle 
 heat. 
 
 Theory. The metallic salt and the water are both decomposed. The 
 sulphate of copper is resolved into sulphuric acid and oxide of copper, 
 the water into oxygen and hydrogen. The acid and oxygen go to the 
 zinc, and the hydrogen and the oxide of copper to the copper pole, the 
 hydrogen unites with the oxygen of the oxide of copper, and the me- 
 tallic copper is deposited upon the metal or object to be copied. 
 
 * For a description of this process, see Davis's Manual oi" Maonetism, 
 p. 199, Seq. 
 
x PART I 1 
 
 CHEMICAL AFFINITY 
 
 In all those phenomena, which appropriately come under 
 the observation of the chemist, chemical affinity is the great 
 cause to which they are referred. Other agents, as light, 
 heat, electricity, cohesion, etc., modify its action, and some 
 knowledge of them is therefore an essential preparation for 
 the study of this, — the great subject of chemistry. The de- 
 tails, to which we shall attend in the examination of particu- 
 lar substances, are, almost exclusively, but the effects of this 
 principle. The student, therefore, should be familiar with 
 the circumstances which modify its action, its varieties or 
 different modes of operation, its effects, and especially the 
 laws in accordance with which these effects are produced. 
 
 Chemical Affinity is an attraction, which acts only at in- 
 sensible distances, bettoeen particles of different kinds, and 
 forms a new substance* Cohesion is distinguished from it, 
 by acting only between particles of the same kind, as well as 
 by being governed by different laws. 
 
 Varieties of Chemical Affinity. 
 
 Although this power is the same in all cases, it will facili- 
 tate the progress of the student to distinguish some of tlte 
 
 * A late writer (Griffin, Chemical Recreations) maintains that there 
 is no such thing as chemical affinity, because we know merely that 
 bod. ps combine. We might as well deny that any force or power ex- 
 ists because we see only its effects. From the fact that bodies do com- 
 bine, we infer that some power causes them to combine, although 
 indeed, we know nothing of it, except in its effects. 
 
114 Varieties of Chemical Affinity. 
 
 different cases in which it operates. Between many sub- 
 stances it does not exist at all, as is seen in mixing oil and 
 water. The most simple case is the direct union of two sub- 
 stances, as when oxygen gas and iron unite, and form iron 
 rust. This is called Simple Affinity. The combination of 
 alcohol with camphor is another example. 
 
 Exp. But if water be added to this solution of camphor, the alcohol 
 will combine with the water, and desert the camphor, which again ap- 
 pears free, or is technically said to be precipitated. As the alcohol 
 appears to choose the water in preference to camphor, such cases are 
 called examples of single elective affinity* 
 
 The following are examples of the same kind : — 
 Exp. Into a solution of sulphate of copper (blue vitriol) immerse a 
 clean iron wire ; the sulphuric acid (oil of vitriol) will elect the iron, 
 and the copper will be precipitated, forming a metallic coating upon 
 the wire. 
 
 Exp. Into a solution of protonitrate of mercury put a sheet of cop- 
 per, or cents, well cleaned with dilute sulphuric acid ; the nitric acid 
 will elect the copper, and the metallic mercury will be precipitated, 
 and form a covering over the cents, which will give them the appear- 
 ance of silver. 
 
 But, in other cases, two compounds mutually decompose 
 
 each other, and form two new compounds. 
 
 Exp. Thus, if carbonate of ammonia and hydrochlorate of lime be 
 mingled, each will be decomposed. The former consisting of carbonic 
 acid and ammonia, and the latter of hydrochloric acid and lime, the 
 carbonic acid will unite with the lime, and the hydrochloric acid with 
 the ammonia, forming carbonate of lime, and hydrochlorate of ammo- 
 nia. This change may be very easily understood from the annexed 
 formula, in which the symbols are used.t 
 
 C + Am. 
 
 C abandons Am. and goes to Ca; at the 
 
 same time HC1 abandons Ca, and goes to Am. ; 
 
 and the results are C -f Ca. and HC1 -f- Am. 
 
 HC1 + Ca. 
 
 _ 
 
 * Elective affinity is the basis of chemical science ; for if each sub- 
 stance attracted every other with the same force, when combination 
 had once been effected, the decomposition of many, if not of most 
 substances, would be impossible ; hence there would be but few 
 changes in matter which would come under the investigation of the 
 chemist. 
 
 t C= Carbonic acid, and Am. = Ammonia; HC1 = Hydrochloric 
 acid, and Ca. = Lime. 
 
Operation of Chemical Affinity. 115 
 
 Exp. To a solution of alum (sulphate of alumina and potassa) add 
 a solution of acetate of lead. Sulphate of lead and acetate of alumina 
 are formed by a double decomposition. The sulphate of lead will be 
 precipitated, and the acetate of alumina will remain in solution. 
 
 Exp. ISitrate of ammonia and sulphate of soda will mutually decom- 
 pose each other. In all cases of double decomposition, the alkali in one 
 of the compounds will just neutralize the acid in the other, so that, if 
 any delicate test of an acid or an alkali (as vegetable infusion) be 
 placed in the mixture, no effect will be produced upon it; hence, as 
 the quantities of acid and of alkali, in all neutral salts, are just suffi- 
 cient to saturate each other when double decomposition takes place, 
 these quantities are called equivalents. 
 
 Such cases are examples of double elective affinity* Cases 
 are more numerous, however, in which the changes are much 
 more complicated ; but they may all be referred to the three 
 modes stated above. 
 
 Circumstances which modify the Operation . of Chemical 
 Affinity. 
 
 That one substance has a stronger affinity for some than 
 for others, cannot be doubted. But combination and decom- 
 position do not always depend upon the relative force of af- 
 finity alone. Several circumstances modify the operation 
 of this power. These are, cohesion, elasticity, quantity of 
 matter, gravity, and the imponderable agents. ^ 
 
 I. Cohesion. In order that substances should combine 
 with each other, it is necessary that their particles should be 
 in contact. But cohesion holds together the particles of each 
 substance, so that they cannot be freely intermingled. Co- 
 hesion must, therefore, be destroyed to facilitate chemical 
 action. This may be effected in three ways : — 
 
 1. By reducing the substance to powder. 
 
 Exp. Take two pieces of crystallized nitrate of copper ; roll one of 
 them up in tin foil ; grind the other to powder, and wrap it in a piece 
 of the same metal; drop a little water upon both as they are rolled 
 up. In a few minutes, that which is pulverized will combine with 
 the metal, and burst into a flame, while the other will not be affected. 
 
 Exp. Take two equal portions of chalk, and pulverize one ; pour 
 
 * Single and double elective affinity are the same in principle. The 
 only difference is, that, in the one case, a compound is decomposed by 
 a third substance, and but two affinities are in operation, while, in the 
 other, two compounds mutually decompose each other, and four affin- 
 ities are brought into action. 
 
116 Operation of Chemical Affinity. 
 
 dilute sulphuric acid on each, and the action will be rapid in the case 
 of the pulverized chalk, but moderate in the other case. In this ex- 
 periment, one of the substances is in solution ; and usually it will be 
 found insufficient to pulverize both substances, and resort must be haa 
 to the second method. 
 
 2. By dissolving the body in some liquid. 
 
 Exp. Mix together tartaric acid and carbonate of soda; no action 
 will follow; pour on water, and they will be dissolved, and a violent 
 action ensue. 
 
 Solution is effected when a solid is put into a liquid, and 
 entirely disappears, leaving the liquor clear. The body 
 which thus disappears is said to be soluble ; the liquid is 
 called a solvent, and the compound liquor a solution. Water 
 is the principal solvent; alcohol, ether, oils, alkalies, and 
 acids, are also employed. When water, or any solvent, has 
 dissolved as much of any substance as it can, it is said to be 
 saturated, and the solution is called a saturated solution. 
 
 Solution should not be confounded with diffusion, which 
 is merely a mechanical mixture. 
 
 Essp. This distinction may be seen by mixing magnesia in water. 
 The particles of magnesia are suspended at first in the water, rendering 
 it turbid, and they would soon subside to the bottom ; but if nitric acid be 
 added, the magnesia will be dissolved, and the water will become clear. 
 
 Most substances are more soluble in hot than in cold 
 water; as a hot saturated solution cools, the water will not 
 therefore be able to hold in solution all of the substance 
 which had been dissolved, and it appears again in a solid 
 state. The power of cohesion has the ascendency over the 
 affinity of the liquid for the solid, and forms the latter into 
 crystals. Hence the phenomena of crystallization are owing 
 to the ascendency of cohesion over affinity. 
 
 By evaporation, also, the solid may be recovered from so- 
 lution. In either case, the crystallization is often confused, 
 especially when the process is rapid. 
 
 Insolubility has been found to exert a remarkable influence 
 on affinity, in the case of an alkali with two acids, or an acid 
 with two alkalies, one of which will form with the alkali a 
 soluble, and the other an insoluble compound. The one 
 which is insoluble is always formed in preference to the solu- 
 ble compound. 
 
 Exp. Thus, if nitric and snlphuric acids and barvta be 1 brown to- 
 gether in water, sulphate of baryta, which is insoluble, will be formed 
 in preference to nitrate of baryta, which is soluble. 
 
 It is obvious that, while the solution of one of the substances 
 
Operation of Chemical Affinity. 117 
 
 is usually necessary, the solution of both will further facilitate 
 the action. 
 
 3. By heat. — Fusion is the reduction of a solid to a liquid 
 state by caloric, and facilitates chemical action by enabling 
 the particles to intermingle, and come within the sphere of 
 each other's affinity. In liquids a slight degree of cohesion 
 remains, and hence heat is applied to them with advantage. 
 A hot liquid will act more powerfully upon most solids than 
 the same liquid when cold. 
 
 L- II. Elasticity. Cohesion, as we have seen, opposes 
 ichemical action by keeping the particles out of the sphere 
 of each other's influence. Elasticity, or the gaseous state, 
 is still more unfavorable to the operation of affinity, because 
 the particles are removed too far from each other to be at- 
 tracted ; hence most gases, though possessing a strong attrac- 
 tion for each other, will not combine unless they are in the 
 nascent state, that is, when in the act of assuming the gase- 
 ous form. 
 
 In this way elasticity not only prevents chemical union, 
 but it favors decomposition. 
 
 1. When two highly-elastic gases combine, forming a 
 liquid or solid, the compound will be decomposed by a very 
 slight cause : the chloride of nitrogen is a familiar example. 
 It is an oily liquid, composed of two gases. A slight eleva- 
 tion of temperature will cause instant decomposition, even 
 with explosive violence. Generally all compounds which 
 contain a volatile principle are easily decomposed by a high 
 temperature. Hence caloric sometimes favors chemical action 
 by destroying cohesion, while at others it prevents it, and 
 favors decomposition by promoting elasticity. 
 
 2. There are some gases, however, which readily combine 
 at a high temperature, as in the case of gaseous explosive 
 mixtures. Oxygen and hydrogen gases require the heat of 
 flame to effect their union. The caloric, in such cases, ac- 
 cording to Berthollet, expands the gases in immediate con- 
 tact with the flame, which acts as a violent condensing force 
 to contiguous portions, and brings them within the sphere of 
 each other's attraction. The same explanation is applied to 
 the combination of gases effected by passing electric shocks 
 llnough them. 
 
 III. Quantity of Matter. Oxygen combines with lead in 
 
118 Operation of CJicmical Affinity. 
 
 three proportions, forming three ■■ distinct compounds. The 
 peroxide, or that which has the greatest quantity of oxygen, 
 is easily decomposed by heat ; the second compound, in 
 which there is less oxygen, requires a higher temperature to 
 effect decomposition; and the third, which has the least oxy 
 gen, will sustain the heat of our furnaces without yielding up 
 its oxygen. Hence, generally, when one substance combines 
 with another in several proportions, the affinity is stronger in 
 the case of the less than of the greater portions* 
 
 On this principle, also, when a salt is dissolved in water, 
 the first portions are dissolved more rapidly than the last, and 
 the force of affinity diminishes up to the point of saturation, 
 when it is overcome by the cohesion of the solid. 
 
 This principle led Berthollet to account for all chemical 
 changes without the aid of affinity, the existence of which he 
 was disposed to deny ; but M. Dulong has found that the 
 principle of Berthollet is not in accordance with the results 
 of experiment. 
 
 ' IV. Gravity. The influence of gravity on chemical action 
 is seen when substances of different specific gravities com- 
 bine ; as, when two liquids are put together, the heavier 
 liquid will sink to the bottom ; or, when salt is dissolved in 
 water, the salt will remain at the bottom, and prevent the 
 particles of water from coming into contact with those of 
 the salt, 
 
 V. Imponderable Agents. The influence of caloric over 
 chemical phenomena has already been alluded to. It favors 
 chemical action in the case of solids, by destroying cohesion, 
 and opposes chemical action in the case of gases, by increas- 
 ing their elasticity. The influence of light has already been 
 noticed. Common electricity is often employed for the com- 
 bination of gases, and galvanism for decompositions ; but the 
 same effects may be produced by either. 
 
 * In consequence of the influence of quantity of matter over chem- 
 ical changes, the chemist generally employs more of one substance 
 than is necessary to effect the decomposition of another. 
 
Measure and Effects of Chemical Affinity. 119 
 
 Measure of Affinity. 
 
 Since some substances have a stronger affinity than others, 
 attempts have been made to measure its different degrees of 
 force. It was once supposed that its relative strength could 
 be ascertained by the order of decomposition, as may be ex- 
 plained from the following table: — 
 
 Sulphuric Jlcid. 
 Baryta, Lime, 
 
 Strontia, Ammonia, 
 
 Potassa, Magnesia. 
 
 Soda, 
 
 If to the sulphuric acid, united with the magnesia, forming 
 the sulphate of magnesia, ammonia be added, the acid will 
 leave the magnesia, and elect the ammonia, forming the sul- 
 phate of ammonia. If to this, lime be added, the acid will 
 desert the ammonia, and unite with the lime ; this again will 
 be decomposed by the soda, and so on to baryta. Hence 
 sulphuric acid has the strongest affinity for the baryta, and 
 the force is in the order in which the several substances are 
 arranged. 
 
 Exp. This order may be shown experimentally thus: To a filtered solu- 
 tion of nitrate of silver add metallic mercury; the silver will be precip- 
 itated, and the nitric acid will combine with mercury, forming the nitrate 
 of mercury. Immerse in this a piece of clean sheet lead; the mercury 
 will now be precipitated, and the lead will remain in solution. 
 
 Suspend in this a strip of clean copper; the lead will be thrown down, 
 and the nitrate of copper will remain in solution. 
 
 In this place a sheet of bright iron, and in a short time the iron will 
 displace the copper, forming a solution of nitrate of iron. 
 
 To this present a piece of zinc ; the iron will be separated, and the 
 zinc will combine with the acid. 
 
 Add liquid ammonia ; the zinc will be separated, and nitrate of ammo 
 nia remain in solution. 
 
 To this pour lime water; the ammonia will be liberated in the form 
 of a gas. and nitrate of lime remain in solution. 
 
 Add to this oxalic acid, and the oxalate of lime will be thrown down, 
 while a mixture of water and nitric acid remains. 
 
 Hence the practical chemist, when he wishes to decom- 
 pose any compound, is enabled to decide upon the substance 
 which will produce that effect. 
 
 But the circumstances which modify the action of chemical 
 affinity are so numerous, that the order of decomposition is 
 not, in every case, the measure of affinity. To determine the 
 
120 Effects of Chemical Affinity. 
 
 relative force of affinity in doubtful cases, ^observe the ten- 
 dency of several substances to unite with the same, under 
 the same circumstances ; and then notice the apparent facility 
 of decomposition, when these compounds are exposed to the 
 same decomposing agent. 
 
 Effects of Affinity. 
 
 The changes which accompany the action of affinity are 
 changes of chemical properties — of color, form, temperature, 
 and specific gravity. 
 
 I. Change of Chemical Properties. It is one of the most 
 remarkable facts in chemistry, that, when two bodies combine 
 chemically, the compound is generally possessed of properties 
 entirely different from those of the components. 
 
 Exp. 1. Pour sulphuric acid upon magnesia, and the compound will 
 be Epsom salts, entirely unlike either. 
 
 Exp. 2. Burn oxygen and hydrogen gases, and water will be 
 formed, which is wholly different from either of its constituents. 
 
 There are some cases in which affinity produces com- 
 pounds without much change of properties, as in the case 
 of solution ; but the force of affinity in such cases is very 
 feeble. 
 
 Exp. Salt dissolved in water, and camphor in alcohol, are instances. 
 
 II. Change of color is often the effect of affinity. 
 
 Exp. 1. To the chloride of calcium add nitrate of silver, both in 
 solution ; a white precipitate will be formed, which is the chloride of 
 silver. (See page 69.) 
 
 Exp. 2. To a solution of nitrate of lead add a few drops of hydriodic 
 acid, and a beautiful yellow pigment will be formed. 
 
 Exp. 3. Into an infusion of purple cabbage pour a few drops of any 
 alkali, and the color will become green ; add an acid gradually, drop 
 by drop,* and the purple color will be restored ; add a few drops more 
 
 * For this and sim- 
 ilar puTposes,the drop- 
 ping tube a (Fig. 59) 
 may be used. It is a 
 glass tube, with a bulb, 
 as a, with a small ap- 
 erture at the smaller 
 end, through which any liquid may be drawn up into the bulb by pla- 
 cing the mouth upon the larger end. Having partially filled the bulb, 
 {dace the thumb over this end, and, by admitting the air slowly, the 
 iquid will drop out at the smaller end. 
 
Effects of Chemical Affinity. 
 
 121 
 
 of acid, and it will become red. By the gradual addition of the alkali, 
 the effects may now be reversed. 
 
 III. Change of form frequently accompanies chemical 
 combination. 
 
 Exp. 1. Take oxygen and hydrogen gases, and explode them; they 
 will form a liquid — water. Hence chemical affinity converts gases into 
 liquids. 
 
 E.rp. 2. If the two gases, Fig. 60. 
 
 ammonia and the hydrochlo- 
 ric acid, be brought together 
 in their nascent state, i. e., 
 at the moment of their for- 
 mation, they will produce 
 the solid hydrochlorate of 
 ammonia. Hence chemical 
 affinity converts gases into 
 solids. The two gases may 
 be formed by putting hy- 
 drochlorate of ammonia and 
 
 lime in one retort, (Fig. 60,) and liquid hydrochloric acid in the other, 
 and applying heat ; as the gases meet in the glass receiver b, they will 
 combine and form a white solid. 
 
 Exp. 3. Take chloride of calcium in solution, and pour in sulphuric 
 acid ; a solid precipitate — the sulphate of lime — will be thrown down 
 Hence affinity converts liquids into solids. 
 
 Exp. 4. Into a solution of pearlash or saleratus pour sulphuric 
 acid, and a portion of the liquid is converted into the form of a gas, 
 which escapes with effervescence. 
 
 Exp. Add one part of fuming nitric acid to two of alcohol ; both liquids 
 will be converted into ammonia, and pass off in gas. Hence affinity 
 converts liquids into gases. 
 
 Exp. 5. Mix two solids, the nitrate of ammonia and sulphate of 
 soda? on rubbing them in a mortar, they will become liquid. Hence 
 chemical affinity converts solids into liquids. 
 
 E.rp. 6. Explode gunpowder; it will be wholly converted into gas 
 Hence chemical affinity converts solids into gases. 
 
 IV. Change of Temperature. The heat arising from the 
 
 combustion of fuel, is owing to chemical action. 
 
 Exp. Wet a piece of paper with spirits of turpentine and sulphuric 
 acid, and then throw on a tew grains of chlorate of potassa; the paper 
 will instantly be in flames. 
 
 V. Change of Specific Gravity. In changes of gases into 
 liquids or solids, or of the latter into the former, there is, of 
 course, a great change of density. But where there is no 
 
 : change of form, there is usually more or less of this change. 
 
 Exp. Mix 100 measures of strong sulphuric acid with 100 of water, 
 and the mixture will be less than 200 measures. 
 6 
 
122 Laws of Chemical Affinity, 
 
 Laws of Chemical Affinity. 
 
 The laws which regulate the action of affinity, constitute 
 the most important part of the whole subject ; for they are the 
 foundation of modern chemistry. As they are expressed 
 mathematically, they have consequently imparted to it a high 
 degree of accuracy, and greatly elevated its rank as a science. 
 Most substances have been found to combine in clef nit e pr o- 
 portions, and with such the laws of affinity are chiefly con- 
 cerned ; but there are numerous cases of apparently indefinite 
 proportions, which first demand a separate consideration. 
 
 I. Indefinite Proportions. Of these there are two cases, 
 
 in the first of which, any quantity of one substance may be 
 
 combined with any quantity of another. Thus a drop of 
 
 alcohol will combine with a quart of water, or a drop of water 
 
 with a quart of alcohol. 
 
 Exp. Take a large glass vessel, and fill it nearly full of water ; color 
 it purple with the infusion of red cabbage; a drop of sulphuric acid will 
 change it red, or a drop of alkali will give it a green color, which shows 
 that both the acid and the alkali must combine with the whole of the 
 water. 
 
 In the second case, the proportions are indefinite within 
 
 certain limits. Thus with 2 J lbs. of water, a pound or any 
 
 less quantity of common salt will combine, but if a larger 
 
 quantity of salt be employed, all the excess above a pound 
 
 will remain undissolved. The limit to the process is the 
 
 point of saturation. (See page 108.) 
 
 The most common instances of indefinite proportions are 
 solutions where the proportions are indefinite below the point 
 of saturation. Instances of unlimited indefinite proportions 
 are less numerous. It is important to observe, in these cases, 
 that the force of affinity is usually feeble, and the change of 
 properties slight. Thus, in the common liquors, the properties 
 of the alcohol are slightly modified by its combination with 
 water ; and in solutions there is also little change. 
 
 II. Definite Proportions by JVcight. In the most numerous 
 and interesting cases of chemical combination, a certain 
 portion of one substance unites with one, two, three, or 
 
Laws of Chemical Affinity. 123 
 
 more t mes a given weight of another. These cases are 
 usually characterized by a greater energy of combination, 
 and a much greater change of properties than those which 
 have been described. The great law of definite proportions 
 by weight may be thus stated : — <■ 
 
 1. The proportions in which substances combine may be 
 expressed by fixed numbers, or by the multiples of these num- 
 bers. The following table is an illustration : — 
 
 Water is composed of Hydrogen 1 part -f- Oxygen 8 parts. 
 
 Binoxide of Hydrogen " 
 
 H 
 
 1 
 
 " 
 
 + 
 
 < 16 
 
 Protoxide of Nitrogen " 
 
 Nitrogen 
 
 14 
 
 u 
 
 + 
 
 < 8 
 
 Binoxide " 
 
 U 
 
 14 
 
 11 
 
 + 
 
 < :e 
 
 Hyponi irons acid " 
 
 a 
 
 14 
 
 a 
 
 + 
 
 ' 24 
 
 Nitrous acid " 
 
 a 
 
 14 
 
 " 
 
 + 
 
 ' 32 
 
 Nitric acid " 
 
 a 
 
 14 
 
 " 
 
 + . 
 
 1 40 
 
 A comparison of all the cases shows that hydrogen enters 
 into combination in less quantity relatively than any other 
 substance. It is therefore taken for a standard of comparison, 
 and in the above table appears as unity. The lowest ratio 
 in which oxygen combines with other substances is eight 
 times that of hydrogen. The lowest combining ratio of nitro- 
 gen is fourteen. If any simple substance does not combine 
 with hydrogen, its lowest combining ratio may be ascertained 
 from its combination with any other substance, whose ratio 
 has been de^r mined. Thus from the above tabic the com- 
 bining ratio of nitrogen is seen in its compounds with oxy- 
 gen, whose ratio was ascertained in its compounds with 
 hydrogen. The lowest combining ratio is also called an 
 equivalent, ox proportional. (See page 107.) 
 
 Inspection of the above table will show, that while eight is 
 the lowest combining ratio of oxygen, it combines also in the 
 ratio of 16, 24, 32, and 40 parts; that is, two, three, four, 
 and five times the lowest ratio, agreeable to the above-men- 
 tioned law. 
 
 There are some cases in which substances do not unite 
 with one equivalent of one to one, two, or more equivalents 
 of another, but apparently of one to one and a half. Such 
 an irregularity conforms to the general law, on the supposi- 
 
124 Laios cf Chemical Affinity. 
 
 tion that two of the former unite with three of the latter. In 
 some cases, also, two equivalents of one substance unite with 
 five of another. 
 
 The law of definite proportions by weight may bo thus 
 illustrated algebraically : — If x and y be the equivalents of 
 any two substances, their compounds must be x-\-y, x-f-2 y, 
 z-\-3 y, x-f-4y, etc. ; sometimes we shall have 2 x-\-S y, 
 and rarely 2 x-{-5 y. 
 
 It is evident from the above that the equivalent of any 
 compound is the sum of the equivalents of its constituents, 
 each being multiplied by the number of times it enters into 
 the combination. Thus, in the above table, the equivalent of 
 water is l-j-8:z=9, of nitric acid, 14 + 49 = 54, etc. 
 
 2. The' second law of definite proportions is the follow- 
 ing : — 
 
 Every substance has its constitution invariable. Thus 
 nitric acid is always composed of one equivalent of nitrogen 
 and five of oxygen. No other substances, and no other 
 number of equivalents of these, by combination can form 
 nitric acid. 
 
 The same is true of every substance whose elements com- 
 bine in definite proportions. The least change of these de- 
 terminate quantities will either form an entirely different sub- 
 stance, or a portion of that substance which is ji excess will 
 remain uncombined ; hence whatever be the circumstances 
 under which chemical substances are formed, whether formed 
 ages ago by the hand of nature, or quite recently by the 
 agency of the chemist, their composition is always inva- 
 riable. 
 
 The merit of establishing this law is due to Wenzel, a 
 Saxon chemist, who published his views in 1777. But Dr. 
 Dalton, an eminent English chemist, discovered the first law, 
 and deduced from the scattered facts a theory of chemical 
 unioh, embracing the whole science, and first published in 
 1803. Drs. Wollaston, Thompson, and other chemists, fol- 
 lowed out these views. But to no one, in this department, is 
 science so much indebted as to Berzelius 
 
Laics of Chemical Affinity. 125 
 
 The application of these laws, in the arts, is of immense 
 importance. In the manufacture of compounds, they teach 
 precisely what proportions of the ingredients should be used. 
 If these are expensive, an excess of one would be a seri- 
 ous loss. 
 
 III. Definite Proportions by Volume. The principal law 
 
 of definite proportions by volume is precisely similar to that 
 
 of definite proportions by weight, the parts being determined 
 
 by measure, as in the former case by weight. This law holds 
 
 true only in the case of gases and vapors. It is supposed 
 
 that substances which have not yet been made to assume 
 
 the form of a gas or vapor, would conform to this law, if 
 
 they should assume such form. The law may be illustrated 
 
 by the following table: — 
 
 100 vols, carbonic acid gas combine with 100 of ammoniacal gas. 
 " « " " 200 " 
 
 " fiuoboric " " 100 " 
 
 " " « " 200 " 
 
 But there are two laws of definite proportions by volume, 
 which do not hold true to the same extent in definite propor- 
 tions by weight. The first is, that a simple ratio of one to 
 two, one to three, &,c, exists between the volumes of differ- 
 ent constituents in the same compound. This may be seen 
 in the above table. 
 
 The second law is, that, in combination, gases and vapors 
 are condensed by a portion, which is in a simple ratio to the 
 volume of one of the constituents. 
 
 The laws of definite proportion by weight and by volume 
 are not inconsistent with each other, for the specific gravity 
 always bears such a relation to the combining ratio by volume 
 as to establish their harmony. Thus hydrogen and oxygen 
 combine in the ratio of two of the former to one of the latter 
 by volume, and of one to eight by weight. But as oxygen is 
 sixteen times heavier than hydrogen, one Volume of it is eight 
 times as heavy as two of the latter. In other words, the 
 compound ratio of the specific gravity and of the equiva- 
 lents by volume, is equal to the ratio of the equivalents by 
 weight. 
 
126 The Atomic Theory. 
 
 Atomic Theory. 
 
 Existence of Atoms. The atomic theory supposes matte! 
 to be composed of minute, indivisible" a|pms. Hypotheti 
 cally, matter is infinitely divisible, that is, to Almighty power; 
 but in fact it is not infinitely divided. Sir Isaac Newton re- 
 garded it as probable, "that the primitive particles; being 
 solids, are incomparably harder than any porous bodies com- 
 pounded of them, even so very hard as never to wear, or 
 break in pieces: no ordinary power beiug able to divide what 
 God himself made one in the first creation." 
 
 Tlieory of definite Proportions by Weight. When sub- 
 stances combine in their lowest equivalents, they unite atom 
 to atom, (Fig. 61 ;) 
 in higher proportions, 
 one atom of one to 
 two, three, or more 
 atoms of the other. ■ 
 
 This theory exactly accounts for the facts of definite propor- 
 tions; for if in one compound we have one atom of A 
 joined to one of B, and in another one of A joined to 
 two of B, through the whole mass, the sum total of B in the 
 latter case will be exactly twice as much as in the former 
 case. 
 
 Atomic Weight. If in a compound of one grain of hydr 
 gen with eight of oxygen there be an equal number of atoms 
 of each, an atom of the latter will be eight times as heavy as 
 an atom of the former. In this way we know the relative 
 weights of the atoms of all substances, whose equivalents are 
 known. As the numbers are the same, the terms are often 
 interchanged. 
 
 The absolute iceight and magnitude of atoms cannot be 
 determined. Dr. Thompson calculates that a cubic inch of 
 lead contains more than 8S3,49'2,000,000 atoms. 
 
 The shape of atoms is matter of hypothesis. They are 
 generally supposed to be spheroidal. 
 
Isomerism. — Cause of Chemical Affinity. 127 
 
 Isomerism. 
 
 It was formerly supposed that when two elements combine 
 in the same ratio^ they must always give rise to the same 
 compound; but it lias of late been discovered that this is not 
 always the case. Thus there are 3 compounds of oxygen 
 and phosphorus, whose composition is identical, each being 
 composed of 31.4 parts by weight of phosphorus, and 40 
 parts by weight of oxygen ; and yet these substances differ in 
 their properties- The same is true of the two cyanic acids. 
 Berzelius has applied to such compounds, as a class, the 
 general term isomeric, from two Greek words,* which ex- 
 presses an equality in the ingredients; and to distinguish the 
 isomeric bodies from each other the terms jparaf and tneta 
 are prefixed. 
 
 To reconcile the phenomena of isomerism with the theories 
 of chemical combination, we have only to suppose that the 
 same elements may combine in different ways, so as to give 
 rise to compounds essentially distinct; for example, we may 
 suppose that the 2 atoms of phosphorus and the 5 atoms of 
 oxygen, which form 3 isomeric bodies, may be grouped dif- 
 ferently; thus, 2 atoms of oxygen may first unite with the 
 
 2 of phosphorus, and this compound unite with the other 
 
 3 atoms of oxygen, or 4 of oxygen may unite with 1 of 
 phosphorus, and 1 of oxygen with 1 of phosphorus : these two 
 compounds may then combine, and form a different sub- 
 stance from the first, although both contain the same number 
 of atoms of each element. It is evident that these groups 
 may be varied still further; hence the kind of substance may 
 depend upon the order in which the atoms are united. In a 
 few cases, the equivalents of isomeric bodies differ : olefiant 
 gas and etherine are an example. The equivalent of olefiant 
 gas is 14.24* and that of etherine 23.48, or exactly double. 
 
 Cause of Chemical Affinity. 
 
 The cause of affinity has been supposed to be electricity. It 
 appears that when two substances combine, they are in oppo- 
 site states of electricity. It is believed to accord best with the 
 
 * loog, equal, and peQag, part. t Ilaqa, near to. 
 
128 Cause of Chemical Affinity. 
 
 simplicity every where observed in the laws of nature to 
 ascribe the phenomena of electricity, galvanism, magnetism, 
 and chemical affinity, to one and the same agent. By such a 
 generalization we seem to be progressing in the chain of 
 causation nearer to the great and ultimate cause, the agency 
 of God. But such a view, in the present state of science 
 cannot be maintained ; and, although these agents have many 
 points of resemblance, they differ in too many respects to be 
 regarded as identical. In fact, we should be under the 
 necessity of believing that a force might modify, increase, 
 diminish, counteract, and overcome, itself. Some suppose 
 that what we call the agents and laws of nature, have no 
 real existence as distinct powers. They deny the agency 
 of second causes, and ascribe every operation of nature to 
 the immediate power of God. Others suppose that there are 
 real agents or causes dependent upon God, but possessed of 
 power in themselves, to act as second causes, or subordinate 
 agents, in the various phenomena of matter. Whichever 
 view we take, we must, in the end, refer the ultimate cause 
 to the impulse of the divine will ; although, for the mere 
 purposes of scientific classification, something, perhaps, is 
 gained by the introduction of second causes. 
 
PART III 
 
 PONDERABLE BODIES 
 
 Specific Gravity means the relative weight of different 
 substances, compared with some standard. In the case of 
 solids and liquids, the weight of the body is compared with 
 water as unity ; i. e., if a given quantity of water by measure 
 be weighed,* and that weight represented by 1, the weight 
 of an equal quantity by measure of any other substance is 
 compared with it. In the case of gases, air is taken for the 
 standard of comparison, or for unity, and an equal quantity 
 of any other gas is weighed, and compared with it. 
 
 There are several methods of ascertaining the specific 
 
 gravities of bodies. 
 
 Fig. 62. 
 
 1. One of the best, if the body is a 
 solid, is to weigh it in the air, and then 
 in water, in a manner represented, in 
 Fig. 62. If the body weighs 10D grains 
 in the air, and 63 grains in water, then, 
 to ascertain its specific gravity, institute 
 the following proportion: As 100 — 6'), 
 or 43 : 103 : : 1 : 2.5; hence the sp. gr. 
 of the body is 2.5, or two and a half 
 times as heavy as water. If the solid is 
 lighter than water, suspend to it a body 
 heavier than water, whose specific gravity 
 is known, and then weigh it as in the first instance. 
 
 2. To ascertain the specific gravity of liquids, the Areom- 
 ct r is a convenient instrument. It consists of a tube, 
 
 A cubic foot of distilled water weighs 62.5 lbs. 
 6* 
 
130 Nomenclature, 
 
 a, (Fig. 63,) graduated with numbers, upon the end 
 of which are two bails, the lower filled with mer- 
 cury. If the instrument sink in distilled water to 
 1, it will sink below that mark in liquids which 
 are lighter than water, and will remain above it 
 n those which are heavier. The specific gravity 
 of each liquid is thus ascertained by the numbers 
 on the scale. 
 
 . The specific gravity of liquids is also ascertained 
 by the use of a small bottle containing just 1000 
 grains of water ; by filling it with any other liquid, its weight 
 will express directly its specific gravity. 
 
 3. The specific gravity of gases is more difficult : a given 
 portion of air is carefully weighed in a thin glass flask ; the 
 air is then exhausted, and the flask weighed; the difference 
 gives the weight of the air ; this is taken for unity, and the 
 weight of an equal quantity of any other gas is compared 
 with it ; thus, 100 cubic inches of dry air, at 60° F. and 
 30 in. barometer, weigh 31.0117 grains; 100 cubic inches of 
 oxygen weigh 34.109 grains. Now, to ascertain the sp. gr. 
 of oxygen, institute the following proportion : — 
 
 As 31.0117 : 34.109 : : 1, the sp. gr. of air, to 1.1025, 
 the sp. gr. of oxygen. The sp. gr. of any other gas may be 
 found in the same way. 
 
 Nomenclature. 
 
 The study of particular substances has been greatly facili- 
 tated by the introduction of the nomenclature. By the use of 
 systematic names, expressive of the constitution of substances, 
 the recollection of the name will call to mind the const'itu* 
 tion ; while, on the other hand, if there be any difficulty in 
 remembering names, the constitution will at once show what 
 the/name must be. Hence, although compounds are very 
 numerous, the student can have no difficulty in remembering 
 their names and constitution, for the one necessarily suggests 
 the other. 
 
 The present nomenclature was introduced in 1787 by the 
 French chemists. It resulted from the labors of Lavoisier, 
 Berthollet, Guyton-Morveau, and Fourcroy. Since that time, 
 it has undergone but a few slight changes. The former no- 
 
Nomenclature. 
 
 131 
 
 menciature, if such the entire want of system could be 
 called, was barbarous in the extreme ; fanciful names were 
 introduced, and often many such were attached to the same 
 substance. 
 
 1. Simple Substances. The names of such elementary sub- 
 stances as had long been known, remain unaltered, as of 
 gold, iron, etc. Those which have been discovered within 
 the period of modern chemistry, have received names ex- 
 pressive of some obvious property; thus the name oxygen 
 signifies a generator of acids; iodine, violet-colored, from 
 the beautiful color of its vapor ; chlorine, green, from the 
 color of the gas. The following are the names of the simple 
 substances, with their symbols annexed: — - 
 
 Oxygen, O. 
 
 Chlorine, .CI. 
 
 Iodine, I. 
 
 Bromine, Br. 
 
 Fluorine, F. 
 
 Hydrogen, H. 
 
 Nitrogen, N. 
 
 Carbon, C. 
 
 Sulphur, S. 
 
 Phosphorus, P. 
 
 Boron, B. 
 
 Silicon, Si. 
 
 Selenium, Se. 
 
 Potassium, (Kalium,) K. 
 
 Sodium, (Natrium ,) , Na. 
 
 Lithium, L. 
 
 Barium, Ba. 
 
 Strontium, Sr. 
 
 Calcium, Ca.- 
 
 Magnesium, .Mg. 
 
 Aluminium, Al. 
 
 Glucinum, G. 
 
 Yttrium, Y. 
 
 > Thorium, Th. 
 
 Zirconium, Zr. 
 
 Manganese, Mn. 
 
 Iron, (Ferrum,) Fe 
 
 Zinc, 
 
 Cadmiu m, ......... . Cd. 
 
 Tin, (Stannum,) Sn. 
 
 Cobalt, Co. 
 
 Nickel, Ni. 
 
 - Arsenic, As. 
 
 Chromium, Cr. 
 
 Vanadium, V. 
 
 Molybdenum, Mo. 
 
 Tungsten, (Wolfram,) W. 
 
 Columbium, (Tantalum,) Ta. 
 
 -Antimony, (Stibium,) Sb. 
 
 Uranium, U. 
 
 Cerium, Ce. 
 
 Bismuth, Bi. 
 
 Titanium, Ti. 
 
 Tellurium, Te. 
 
 Copper, (Cuprum.) ...Cu. 
 
 Lead, (Plumbum,) Pb. 
 
 Mercury, (Hydrargyrum,) . . . .Hg. 
 
 Silver, (Argentum,) Ag. 
 
 Gold, (Aurum,) Au, 
 
 Platinum, .. PL 
 
 Palladium, Pd 
 
 Rhodium, R, 
 
 Osmium, Os 
 
 Iridium, Ir 
 
 Latanium. La 
 
 Zn. 
 
 2. Acid Compounds. The names of acid compounds have a 
 peculiar construction. ' All the acids formed by combination 
 of oxygen with other substances, including a great majority 
 of the whole number, take the name of the other substance, 
 (wjuch is called the base,) changing its termination. If there 
 
132 Nomenclature. 
 
 be two oxygen acids formed with the same substance, the 
 stronger, which contains more oxygen, takes the termination 
 te, and the weaker,_g&u>. In the case of more numerous 
 tcid compounds, the prefix hi/go, signifies inferiority, as in 
 the following of oxygen with sulphur, beginning with the 
 stronger, and proceeding to the weaker : — 
 
 Sulphuric acid, Sulphurous acid, 
 
 Hyposulphuric acid, Hyposulpburous acid. 
 
 Sometimes the prefix j3o* is used to indicate an additional, 
 but indefinite quantity of oxygen. Thus perchloric acid 
 contains more oxygen than cn 7 oric acid. 
 
 Acids which do not contain oxygen receive names which 
 are compounded of the names of their constituents, the first 
 enunciated terminating in o, and the last in ic ; as, chloro- 
 carbonic acid. Often the first is shortened : as, fluo-boric, ra- 
 il of fluro-boric : this is the case with the hydrogen acids ; 
 as, hydrochloric acid, hydrosulphuric acid. 
 3. Binary Compounds icliicli art ds. In such com- 
 
 pounds, the names are composed of the names of their con- 
 stituents. In the compounds of oxygen, chlorine, iodine, 
 bromine, and fluorine, with other substances, they are first 
 \::ated, and receive the termination ide ; as, oxide of iron, 
 chloride of iron, iodide of mercury, bromide of carbon, 
 fluoride of zinc. In their compounds with each other, the 
 order of enunciation is not essential, although it is com- 
 monly that in which they are above mentioned; thus we 
 may say, chloride of bromine, or bromide of chlorine : but the 
 r;- is more common. 
 
 pounds of the other non-metallic substances with each 
 other and with the metals, receive names of similar construc- 
 tion, except that the termination urd takes the place of ide ; 
 as, carburet of iron, bicarburet of hydrogen, sulphuret of 
 arsenic. 
 
 In many cases, one substance unites with another in 
 several proportions, and the compounds are designated by 
 numeral prefixes — proto the first, hi (formerly dcuto was used) 
 Xbl 7- c ,co~ r third, nuadrn the fourth, etc.. and pz> 
 
 * The e is onutisrd by some cheaah ride, 
 
 
Nomenclature. 133 
 
 highest degree, but indefinite; scsqui signifies one and a half. 
 If, however, the last enunciated substance, or base, be in two 
 or more proportions, the dividing prefixes di, tri, etc., are 
 used ; subsequi indicates one and a half of the base. 
 
 The following table exhibits all the cases of the use of 
 numeral prefixes : 
 
 Triphosphuret of copper =1 equiv. phosphorus and 3 equiv. copper. 
 
 Dinoxide of copper =-1 " oxygen and 2 " copper. 
 
 Subses iUiphosphuret of copper =1 " phosphorus and ]| " copper. 
 
 Protoxide of copper =1 " oxygen and 1 " copper. 
 
 Sesquioxide of manganese = 1| " oxygen audi " manganese. 
 
 Binoxide of manganese = 2 " oxygen and 1 " manganese. 
 
 Teriodide of nitrogen =3 " Iodine and! " nitrogen. 
 
 Quadrochloride of nitrogen =4 " chlorine and 1 " nitrogen. 
 Peroxide of iron = iron oxidated in the highest degree. 
 
 Many metals, whose names terminate in um, merely change 
 ium or um into a to indicate the state of protoxide. Thus 
 potassa = protoxide of potassium, lithia =s protoxide of lithi- 
 um, etc. The protoxide of calcium has long been known by 
 the name of lime. 
 
 Alloys, or compounds of metals with each other, not being 
 yet reduced to the laws of definite proportions, have no sys- 
 tematic names. 
 
 Some binary compounds, whose combinations are analo- 
 gous to those of simple substances, receive simple names, 
 which in composition receive the termination arct, and follow 
 the rules above given. These are ammonia and cyanogen. 
 Another binary compound, water, forms compounds which 
 are called hydrates ; as, hydrate of lime. 
 
 4 Ternary Compounds, or Salts. These are foamed by the 
 combination of acids with other binary compounds, which 
 are called, in reference to them, bases- The name of a salt 
 is composed of the names of the acid and base. If the name 
 of the acid have a termination ic, it is changed into ate ; ous 
 is changed into ite. Numeral prefixes are used according 
 to the rules which have been given, as in the following ex- 
 amples : — 
 
 Di nitrate of the protoxide of lead =■ 1 eq. nitric acid and 2 eq. protoxide of lead. 
 Protmiitratr of mercury ='1 " " and I " " of mercury. 
 
 ?e^|'ii-!ii|>lia'e of p tassa =1^" sulphuric acid & 1 " potassa. 
 
 Bis 1. h;i!' of peroxide of mercury = 2 " " and 1 " perox. of mercury 
 
 Tersulphate of alumina =3 " audi " alumina. 
 
1S4 Notation. 
 
 As the acids never unite with the metals directly, but gen- 
 erally with their oxides, and sometimes other compounds, in 
 the case of the oxides, the name is abbreviated : thus, by 
 protonitrate of mercury is always understood protonitrate of 
 the protoxide of mercury. Also, the prefix proto is often 
 understood, and we say, nitrate of mercury. 
 
 There are many ternary compounds, little known, how- 
 ever, except to the chemist, called sulphur salts, and haloid 
 salts, whose nomenclature follows the rules of binary com- 
 pounds which are not acid. 
 
 Notation. 
 
 Notwithstanding the great advantages of the chemical no- 
 menclature, a much greater help is given to the student in 
 the notation. By this, as in algebra, long and intricate pro- 
 cesses are exhibited to the eye at a glance, and the relations 
 of the constituents in complicated compounds easily compre- 
 hended. Each element is represented by a symbol consisting 
 of its initial, or, in the case of two or more which have the 
 same initial, of the initial and one of the following letters, 
 as on page 123, where the symbols of all the elementary 
 substances are given. In the case of potassium, sodium, 
 tin, iron, and several others, the symbols are derived from 
 the Latin names. 
 
 The symbols of compounds are composed of the symbols 
 of their constituents, algebraically connected; as, Fe-j-Cl, 
 chloride of iron. In binary compounds, the sign -j- is often 
 omitted. Coefficients are used to show the number of equiv- 
 alents ; as, N -J-4C1, quadrochloride of nitrogen ; or, if several 
 symbols are written together without the sign -j-, an index is 
 substituted for the coefficient, because the coefficient multi- 
 plies all which come between it and the next sign. Thus 
 the symbol of the substance last mentioned may be written 
 NCI 4 . Some Chemists place the index thus NCL. 
 
 Cyanogen, ammonia, and water, although compounds, have 
 simple symbols, like the elements ; thus we have Cy, Am, and 
 Aq, (Aqua,) instead of NC 2 , H 3 N, and HO. 
 
Notation 135 
 
 The symbols of oxygen and sulphur are abbreviated. The 
 
 symbols for the compounds of oxygen are written thus: — 
 
 ! N for N+50, N for N + 40, N for N + 30, etc., each dot 
 
 indicating an equivalent of oxygen. A comma is used in the 
 
 same manner for the compounds of sulphur; thus, P for PS 
 
 I In place of the coefficient 2, a dash is often drawn through or 
 
 j beneath the symbol. This i3 very convenient in the case of 
 
 ! half equivalents ; as, Mn, signifying 2Mn-[-30, that is, Mn-|- 
 
 | HO, scsquioxide of manganese. In compounds of compli- 
 
 ! cated constitution, it is often necessary to multiply several 
 
 j terms by one number, or to connect them as a whole to 
 
 j another term. This is done, as in algebra, by the use of 
 
 j vincula or parentheses; thus (K-f-2S)-|- Aq, shows that Aq 
 is combined with K-J-2S, as with one substance; but if the 
 parentheses were omitted, thus, K-f-2S-|-Aq, the symbol 
 would indicate a combination of three distinct substances, 
 each one with the other. Also in 2(K-}-2S), the first coeffi- 
 cient belongs to what is within the parentheses as to one 
 substance. 
 
 If the student will, for practice, explain the constitution and 
 give the names of the compounds in the annexed table, he will 
 become familiar with the rules of nomenclature and notation. 
 
 The following table contains the names, equivalents, and 
 symbols of the thirteen non-metallic elements, and the sym- 
 bols of their compounds with each other, in the order in 
 which they are described in this work : — 
 
 Oxygen, equiv. 8; symbol, O. 
 
 CI, CI -f O, CI -f 40, CI + 50, CI + 70. 
 
 I, I-f-50, 1 + 70, 3C1+I. 
 
 Br, Br + 50 or BrO 5 . 
 
 F. 
 
 H. H+0 or H, H + 20 or H, H + Cl, 
 
 "4-1, H + Br, H + For HF. 
 
 Chlorine, 
 
 a 
 
 35.42 
 
 Iodine, 
 
 a 
 
 126.3 
 
 Bromine, 
 
 a 
 
 78 
 
 Fluorine, 
 
 u 
 
 18.68 
 
 Hydrogen, 
 
 u 
 
 1 
 
 Nitrogen, 
 
 u 
 
 14.15 
 
 
 or N, NO 3 or N, NC1<, Nl 3 , NH 3 . 
 
136 
 
 Chemical Substances. — Oxygen, 
 
 fC,< 
 J CI, 
 1 cm 
 
 c, C, C-fCl, C 4 CP, C 2 Cl, CCl 3 , C-f. 
 
 n„^» Q „„- cio. J ^h CH 2 , C 2 H 2 , CH 4 , C 6 H 3 , C fi H% C 10 H 4 
 
 Carbon, equiv.6.12; sym.<| C ^ H6? ^^ fr Cy ^ c \ 30 o H \ CyC1 
 
 LCyCl 2 , HCyS 2 , CyS 2 : H 2 CyS 2 . 
 S, SO 2 , SO 3 , SO*, SOS S 2 C1, SCI, HS, 
 HS 2 , CS 2 . 
 
 Sulphur, " 16.1 
 
 Phosphorus/ 
 Boron, ° 
 
 Silicon, 
 
 15.7 
 10.9 
 
 Selenium, « 39.6 
 
 22.5 
 
 P, P 2 0, P 3 0, P 2 3 , P 2 5 , P 2 C1 3 , P 2 C1 5 , PI, 
 
 P 2 P, PBr, P 2 Br 3 , H 3 P 2 . 
 
 B, B + 30, B -f 3C1, B + 3F. 
 
 Se, Se + O or Se, Se -f 20 or Se, Se -f- 30 
 
 or Se. 
 
 Si, Si-fO, SiCl, SiBr, SiS, SiF. 
 
 CHAPTER I. 
 
 CHEMICAL SUBSTANCES. 
 
 These substances will be arranged in three classes : 1st,- 
 non-metallic elements, and their primary compounds, with 
 each other ; 2d, metals, with their primary compounds ; and 
 3d, secondary compounds, or salts. 
 
 Class I. Non-metallic Elements and their Primary Com' 
 pounds with each other. 
 
 Sect. 1. Oxygen. 
 
 Equiv. 
 
 C by vol. 50. 
 
 I ' ; wgt. 
 
 sp.gr.^i; 
 
 1024 
 
 Air 
 Hyd. 
 
 Symb. O 
 
 History. Oxygen was discovered by Dr. Priestley, of Eng- 
 land, August, 1774, by exposing the red oxide of mercury to! 
 the solar focus. It. was also discovered by Scheele, a Swe- 
 dish chemist, in 1775, and the same year by Lavoisier, of Paris, 
 neither being acquainted with the discovery by the others. 
 The honor of the discovery, as is usual in such cases, is as- 
 cribed to Priestley, who called it dcphlogisticated air ; Scheele 
 gave it the name of empyreal air ; Condorcet, vital air ; anc 
 Lavoisier, oxygen. This latter name was suggested from th< 
 belief that it was the only acidifying principle in nature. I 
 
 
Pneumatic Ciste: 
 
 137 
 
 is derived from two Greek words,* signifying a generator of 
 acids. It has since been found, however, that, although 
 present in most acids, it is not the only substance capable 
 of forming acid compounds. But, as a great majority of acids 
 are oxygen acids, the name is not inappropriate. 
 
 Natural History. Oxygen is the most abundant substance 
 known. It forms £ of the atmosphere, § part of water. By 
 far the greater part of the solid crust of the earth is composed 
 of oxydized substances, and it will not be far from the truth, 
 if we estimate oxygen to constitute f of all the matter with 
 which we are acquainted. f 
 
 Processes. Oxygen can easily be obtained from the oxides 
 of metals, and from some of the salts. The oxides of man- 
 ganese and of lead, and the chlorate of potassa, are most 
 commonly used. The separation is effected by exposing 
 these substances to a red heat, in an iron retort, connected 
 by a pipe with the pneumatic cistern. 
 
 For the collection of gases which are not absorbed by 
 water, the 
 
 Fig. 64. 
 
 Pneumatic Cistern is 
 generally employed. It 
 consists of an oblong 
 box, C, (Fig. 64,) made 
 water-tight ; b b, two 
 shelves to support re- 
 ceivers, as r ; w, a well 
 filled with water, across 
 which a board is placed, 
 also to support receiv- 
 ers, with small holes to 
 let the gas through as it 
 
 comes from the retort, which is placed over the side of the 
 box. The shelves b b may be made for gasometers, or gas- 
 holders ; and in that case they" are boxes open at the bottom 
 of the cistern, with stop-cocks passing through one corner in 
 the top of each. These are made air-tight by a lining of 
 sheet lead. When they are filled with water, the gas is in- 
 troduced, by means of a lead pipe, through an aperture in the 
 
 * 'Otuc and ysrruui. 
 
 t If we suppose the sun and planets, with the stellary systems, to be 
 composed of matter similar to our earth, the quantity of oxygen which 
 actually exists must be immeasurably great. 
 
138 Oxygen. 
 
 side of each, near the bottom; as it rises up, it displaces the 
 water; I is a lamp-stand and retort,* as it is connected with 
 the cistern.f 
 
 Theory. To understand the theory of the process by man- 
 ganese, it is necessary to notice the composition of its three 
 oxides. 
 
 Manganese. Oxygen. 
 
 Protoxide, 27.7 or 1 equiv. -f- 8 or 1 equiv. = 35.7 
 
 Sesquioxide, 27.7 " -f- 12 or 1£ " =39.7 
 
 Peroxide, 27.7 " -f 16 or 2 " =43.7 
 
 The oxygen may be separated from the binoxide in two 
 ways : — 
 
 1. By simply exposing it to a red heat. In this case, the 
 binoxide parts with \ equiv. of oxygen, and is converted into 
 sesquioxide. 1 oz. of manganese will yield 128 cubic inches 
 of oxygen. 
 
 2. By putting it, in fine powder, into a glass flask, with an 
 equal weight of concentrated sulphuric acid, and heating the 
 mixture by a spirit lamp, the manganese parts with one equiv. 
 of oxygen, and the sulphate of the protoxide of manganese 
 remains. About twice the quantity of gas is obtained by 
 this process, 1 oz. yielding 256 cubic inches of gas. But the 
 former method is most convenient in practice. 
 
 For these processes, the manganese should be previously 
 ascertained to be free from carbonate of lime, which yields 
 carbonic acid gas on being heated. J Oxygen obtained in 
 this way is not quite pure, but is sufficiently good for all pur- 
 poses of experiment. 
 
 The gas obtained from chlorate of potassa is much purer, 
 
 but more expensive. 
 
 It may be easily obtained by subjecting the salt to a dull 
 red heat in a green or white glass flask, made without lead, 
 
 * Retorts are either plain, as in Fig. Fig. 65. 
 
 58, or tubulated, as Fig. 65. A Florence 
 flask will answer a good purpose, if a lead 
 tube is fitted to it. "See Fig. 66. 
 
 t The cistern may be made of wood, 
 or, what is better, of copper, of any con- 
 venient dimensions. One five feet long, 
 twenty inches wide, and twenty inches 
 in height, is sufficiently large for com- 
 mon purposes. 
 
 X It may be freed from carbonate of lime by washing it in dilute 
 hydrochloric acid. 
 
Physical and Chemical Properties. 
 
 139 
 
 or in an iron retort.* It first becomes liquid, and is then 
 resolved into oxygen and chloride of potassium. 
 
 Theory. The chlorate of potassa is composed of chloric acid and 
 potassa, and the theory of the process may be thus explained : KO -f- 
 CLO 5 are resolved into K-f- CL, which remains in the flask, and 6 
 equiv. of oxygen, which are collected over the cistern. One ounce of 
 chlorate of potassa will give about C40 cubic inches of oxygen. 
 
 Physical Properties. Oxygen is transparent, colorless, 
 tasteless, and inodorous. In the sinjple state, it always exists 
 in the form of a gas. It cannot ak condensed to a liquid 
 or a solid, by pressure or cold. It-refracts light the least 
 of all substances; is a non-conductor pT electricity; is the 
 only substance whose electric state is absolutely negative; 
 and of course it always goes to the positive pole in the 
 galvanic circuit. Its specific gravity is 1.1026; conse- 
 quently, 100 cubic inches, when the thermometer is at 60° 
 Fahr. and the barometer at 30 inches, will weigh 34.1872 
 grains. It is a little heavier than atmospheric air. 
 
 Chemical Properties. Oxygen pcjjjesses more extensive 
 
 powers of combination than any otheraj&bstance. It may be 
 
 made to combine with all the simple su^tances. For acids 
 
 and alkalies it has little affinity, becau* 1 these substances. 
 
 have ^already received their proportion of it. Some of its 
 
 combinations with the metals, and with combustibles, are 
 
 very energetic. 
 
 Exp. 1. Let down a pendent candle into ajar of the gas, (Fig. 67,) 
 and it will burn with great brilliancy. 
 
 * The iron retort is an iron bottle with 
 a long neck. After the salt or the man- 
 ganese is put into it, it may be placed 
 in a furnace, and a lead pipe, as b or a, 
 (Fig. 66.) adapted to the mouth, by 
 means of a cork, «, a. The cork is first 
 perforated by a hot, sharp iron, and en- 
 larged, so as exactly to fit the tube, by a 
 round file ; it is then pressed into the 
 mouth of the bottle. The other end 
 mny then be convoyed to any part of 
 the pneumatic cistern, or to the gas- 
 ometers. This is the simplest mode of 
 connecting apparatus together ; and it 
 may be done either with glass or lead 
 tubes. 
 
 Fig. 66 
 
140 
 
 Oxygen. — Theory. 
 
 Fisr. 68. 
 
 Fig. 63. 
 
 Exp. 2. Blow out a candle, leaving a red wick, 
 and let it down into a jar of the gas, when it will be 
 relighted with a slight explosion. This process may- 
 be repeated several times in rapid succession with 
 the same jar of gas. 
 
 Exp. 3. If a bit of lighted phosphorus, in a capsule, 
 be immersed in this gas, (Fig. 68.) it will burn with 
 great energy and intense brilliancy. Substitute for 
 the phosphorus a small ball formed of turnings of 
 zinc, in which a small bit of phosphorus is enclosed, 
 and set fire to the phosphorus, as before. The zinc 
 will be inflamed, and burn with a beautiful white 
 light. Metallic arsenic, moistened with spirits of 
 turpentine, and various other metals, in fine powder, 
 may be burned in a similar manner. Homberg's 
 pyrophorus flashes spontaneously, like inflamed gun- 
 powder. 
 
 Exp. 4. If iron wire, with a small lighted match 
 attached to one end, be let down into a tubulated 
 bell glass of oxygen, it will burn rapidly ; and if a 
 watch-spring be used, (Fig. 69,) the bell glass will 
 be filled with beautiful star-shaped scintillations. 
 
 Exp. 5. Or, let a stream of oxygen upon ignited 
 charcoal, upon which is placed the end of a watch- 
 spring ; it will burn with, great brilliancy, and throw out 
 immense numbers of the star-shaped scintillations. 
 
 Exp. 6. Put a small bit of phosphorus into a test- 
 glass tube, and fill the tube with warm water, so as to 
 melt the phosphorus. Direct, now, a stream of oxygen 
 gas from the gas bag, or a bladder, to which a tube 
 is attached, upon the phosphorus. A brilliant combus- 
 tion will be produced under water. 
 
 All substances, by combustion in oxygen, increase in weight, 
 in the proportion of about ^ of a grain for every cubic foot of gas. 
 
 Exp. 7. Fill the bowl of a tobacco-pipe with iron wire, coiled in a 
 spiral form, and carefully weighed ; heat the bowl of the pipe red hot, 
 and then attach the pipe to a bladder filled with oxygen gas. By 
 forcing a stream of the gas through the pipe, the iron will burn, and 
 will be found, when weighed, to be heavier than before. When com- 
 pletely oxidized, 100 parts of iron will gain an addition of about 30. 
 
 Theory. In these experiments, the oxygen combines with 
 the combustible substance, and forms a compound, which, 
 being now oxidized, is incapable of further combustion. In 
 case of the iron, an oxide is formed, the weight of which is 
 exactly equal to that of the iron and the oxygen together. In 
 case of the phosphorus, an acid is formed, which is absorbed 
 by water, if present, or appears as a fine powder. The heat 
 and light appear to arise from the condensation of the gas.* 
 
 * In the case of combustion, the common opinion that the matter is 
 destroyed, is erroneous. If the products are collected, they will be 
 found equal in weight to the substances burned. It is a universal law 
 that no particle of matter is annihilated. 
 
Chlorine. 141 
 
 The combination of oxygen with other substances is called 
 oxygenation, and if the compound be an oxide, oxidation* 
 Oxygen is slightly absorbed by several substances; luO cubic 
 inches of water absorb three or four cubic inches of the gas. 
 
 The relation of oxygen to animal life is very intimate and 
 important. It is the only substance which will, for any length 
 of time, support respiration. No animal can live without it. 
 If confined in gases destitute of oxygen, death is the certain 
 consequence. A few years since, 148 persons were confined 
 in a prison called ' Black Hole,' in Calcutta, for a night, and, 
 although there were two windows open in the west end of the 
 building, only twenty-three were found alive in the morning. 
 
 Pure oxygen gas is generally destructive to animal life. 
 The animal confined in it lives too fast; breathing becomes 
 difficult, and if it remain for any time, death will ensue. 
 
 If the quantity be small, it will support life longer than the 
 same quantity of common air. A bird will live five or six 
 times as long in a few gallons of oxygen as in the same 
 quantity of confined air. In order to its most salutary 
 effects, it should be diluted with nitrogen, as we find it in the 
 atmosphere. The Creator has, in this respect, adapted it to the 
 support of life, as any thing which destroys the relation thus 
 established, renders it deleterious to the animal constitution. 
 
 Uses. Oxygen has been used with good results in certain 
 diseases, such as paralysis of the thorax, and general debility. 
 Its effect upon the blood is to change it from dark red to a 
 bright vermilion. 
 
 Sect. 2. Chlorine. 
 
 Symb . CI. Equi v. { ^ « 2 S P . G, { £« Ah d = I. 
 
 History. Chlorine was discovered by Scheele in 1774, 
 and described under the name of dephlogisticated marine 
 
 * It has been customary with many to call oxygen, and some other 
 kindred substances, c; supporters of combustion," while the substances 
 with which they combine are called combustibles. Eut the supporters of 
 combustion and the combustibles are alike essential to the combustion, 
 and both are consumed in the process. Indeed, if the latter be in ex- 
 
142 Chlorine. — History 
 
 acid. The French chemists called it oxygenized muriatic 
 acid, afterwards contracted to oxy-muriatic acid. This name 
 implied a theory of its composition, suggested by Berthollet, 
 that it was a compound of muriatic acid and oxygen. Gay 
 Lussac and Thenard, in 1809, first suggested that it might 
 be a simple substance. Sir H. Davy, after subjecting it to 
 the most powerful decomposing agents, without in the least 
 affecting its character, denied its compound nature, and 
 maintained that, according to the true logic of chemistry, it 
 should be regarded as a simple body. The views of Davy 
 were for a long time combated. Drs. Murray and Thomp- 
 son in England, and Berthollet, Gay Lussac, and Thenard in 
 France, engaged with great warmth in the controversy. 
 But the name chlorine, suggested by Davy from a Greek 
 word* signifying green, not implying any theory as to its 
 nature, came gradually into use, and the contest subsided. \ 
 It is now universally regarded as a simple substance. 
 
 The introduction of chlorine into the class of simple 
 bodies changed entirely the views of chemists relative to the { 
 theory of combustion. Previous to the discovery of oxygen, 
 the Stahlian theory of combustion was generally adopted. 
 According to this theory, combustion was the escape from 
 combustibles of a certain principle called phlogiston, which 
 pervaded most bodies. Soon after the discovery of oxygen, 
 Lavoisier made an attack upon the phlogistic or Stahlian 
 theory, and proved that combustion was produced by the 
 union of oxygen with some combustible body. But when the 
 properties of chlorine were investigated, and it was viewed as 
 a simple substance, it was found to produce all the phenomena 
 of combustion. Hence the theory of Lavoisier, that combus- 
 tion was owing to the union of oxygen with a combustible, was 
 extended ; and the phenomena of combustion are not referred 
 to any more specific cause than intensity of chemical action. 
 
 Natural History. Chlorine is one of the constituents of 
 common salt, and therefore exists in the ocean in large quan- ' 
 tity. Other compounds irt the mineral kingdom are numerous. [ 
 
 cess, a portion of it will remain, while the former will be entirely con- 
 sumed. Generally, the supporter of combustion, as it is called, is a gas 
 which envelops the combustible ; but there is no scientific distinction. 
 * XXwqo$. 
 
Physical and Chemical Properties. 143 
 
 Processes. 1. It may be obtained in the form of a gas, by 
 the action of hydrochloric acid upon the binoxide of manga- 
 nese. Take the latter, finely powdered, in a retort, and pour 
 on twice its weight of concentrated hydrochloric acid. Collect 
 the gas over the cistern in inverted bottles containing warm 
 water, or, more conveniently, over a small cistern of warm 
 water. The water should be raised to 70° or 80° Fahr., as 
 cold water rapidly absorbs the gas. Apply a moderate heat ; 
 and, when the bottles are filled, they should be stopped with 
 ground glass stoppers smeared with tallow. 
 
 Theory. In this process, the binoxide of manganese is 
 decomposed into protoxide and oxygen. A part of the acid 
 combines with the protoxide, and another is decomposed, its 
 hydrogen uniting with the oxygen, and forming water, and 
 the chlorine is set free. In other words, the MnO 2 and HC1 
 are converted into MnO -f- HC1, and HO, which remain in 
 the retort, and CI, which comes over. 
 
 2. The cheapest mode of obtaining chlorine is the follow- 
 ing: — Put eight ounces of common salt, with three ounces 
 of pulverized peroxide of manganese, and five ounces of 
 sulphuric acid, diluted with equal weights of water, into a 
 Florence flask or retort, and apply heat as before. The 
 MnO 2 , Na + Cl, and 2S0 3 are converted into MnO + 
 S03, NaO + S03, and CI. 
 
 * 
 
 Physical Properties. Chlorine gas is of a greenish-yellow 
 
 color ; has an astringent taste, and a disagreeable odor ; is a 
 non-conductor of electricity, and goes to the positive pole in 
 the galvanic circuit. By the pressure of four atmospheres, 
 or 60 lbs. to the square inch, it is condensed into a yeilow 
 liquid, and into a solid by the reduction of the temperature 
 below 32°.* 100 cubic inches of this gas at 69° Fahr., and 
 3D barometer, weigh 76.59S8 grains. 
 
 Chemical Properties. Chlorine unites with many sub- 
 stances with great energy, producing combustion; but its 
 range of affinity is more limited than that of oxygen. 
 
 * Air. Faraday succeeded in condensing it in a bent tube, sealed 
 
 hermetically. Trie pressure is produced by the accumulation of the gas 
 
 evolved by the affinities between the materials in the short end of the 
 
 , tube. The experiment is attended with the hazard of breaking the tube, 
 
 ! and should not be attempted, unless t.ae hands and face are protected. 
 
144 Chlorine. 
 
 Exp. 1. If a small lighted taper be immersed in a jar of the gas, the 
 taper will burn for a short time with a small red flame, evolving large 
 quantities of smoke, and then go out. The reason is. that the flame is 
 mostly composed of carbon and hydrogen; the chlorine unites with the 
 hydrogen, but not with the carbon; the latter is therefore precipitated 
 in the form of smoke, and soon puts the light out. 
 
 Exp. 2. Into a tall glass vessel, filled with chlorine, throw finely- 
 pulverized antimony \ the metal will burn as it falls through the gas. 
 
 Exp. 3. A rag wet with oil of turpentine will instantly be inflamed, 
 when immersed in the gas. . 
 
 Exp. 4. Introduce phosphorus into ajar of chlorine; the phosphorus 
 will soon ignite, and burn with a pale-green flame. 
 
 Exp. 5. Instead of the phosphorus, drop in a few drops of liquid 
 ammonia; the ammonia will be decomposed; a flash and a white 
 smoke will be instantly produced. 
 
 Several other metals and combustibles combine with chlo- 
 rine with such energy as to exhibit the phenomena of com- 
 bustion. 
 
 Chlorine is readily absorbed by icater. Recently-boiled 
 
 water, when cold, absorbs twice its bulk, but gives it off when 
 
 heated. 
 
 Exp. Into a jar furnished with a well-fitted glass stopper, and filled 
 with cold water, let up chlorine gas enough to displace half the water; 
 stop it tight, and shake it. and most of the gas will be absorbed by the 
 water. Open the jar under more cold water, which will rush into it to 
 fill the vacuum occasioned by the absorption of the chlorine ; then re- 
 peat the process once or twice, and the water will be saturated with 
 chlorine, and possess most of its properties. If the water in this ex- 
 periment be at the temperature of 32° Fahr., the chlorine will form a 
 definite solid compound with it, in-yellow crystals, which will be seen 
 on the sides of the jar. The crystals are composed of 35.42 or 1 atom 
 of chlorine, and 90 or 10 atoms of water. 
 
 Chlorine forms with hydrogen, if the vapor of water be 
 present, a mixture which explodes violently when exposed 
 to the direct rays of the sun, or even in a bright day with- 
 out such exposure, the violet ray produces this effect.* 
 
 Exp. Mix, in a dark place, equal measures of hydrogen and chlorine. 
 Expose the mixture to the light of day, and a slow action will take 
 place. Cover the glass with a black cloth, to which a string is attached, 
 and place the vessel in the direct rays of the sun. Remove the cloth 
 by means of the string, taking care to have some object, as a door, be- 
 tween you and the receiver; as soon as the rays of light strike the 
 mixture, a violent explosion will occur, and an acid compound will 
 be formed. 
 
 Chlorine possesses remarkable bleaching properties. 
 Exp. 1. Immerse in the gas strips of calico, flowers, etc., and they 
 will be bleached in a short time ; or the saturated water may be used. 
 
 * Chlorine thus appears to exist in two states, called AUotropi3m. Prepared in 
 the dark, U i? indifferent to hydrogen, but light gives it a most powerful affinity for it. 
 
 ; 
 
Uses of Chlorine. 145 
 
 Exp. 2. Pour some of the saturated water into a small quantity of 
 ink. and the color will be discharged; or put into it some writing, 
 which will become invisible, but will be restored if immersed in a solu- 
 tion of prussiate of potassa. Printers-' ink will not be affected-, and 
 hence chlorine water may be used for removing blots from books. 
 
 Chlorine is not an acid; for it does not redden vegetable 
 purples, and it combines directly in definite proportions with 
 the metals, which is not true of any acid. It is not alkaline. 
 
 Chlorine is very destructive to animal life. A few bubbles 
 of gas, in the atmosphere of a room, will bring on coughing. 
 Half a gill undiluted in the lungs would cause death. If 
 diluted largely with air, it irritates the throat and lungs, and 
 if pure, destroys their texture. Pelletier is said to have fallen 
 a victim to its effects. The antidote is ammonia. 
 
 Uses. 1. The bleaching properties of chlorine are turned 
 to great account in the art of bleaching. Both the gas and 
 the water saturated with it were employed as early as 1784-5 
 for bleaching cloths ; but it proved injurious to the workmen. 
 In 1789, the gas was condensed in a solution of pearlashes, 
 and went by the name of " Liquid javelle." But this sub- 
 stance soon gave place to Mr. Tennant's preparation of the 
 chloride of lime, in 1798. Since that period, most of the 
 bleaching; of cotton and linen goods has been effected by this 
 substance. The articles to be bleached are first steeped in hot 
 water, boiled in a weak alkali, and then immersed in a solu- 
 tion of the chloride of lime. They are next taken out, and 
 washed in water ; sometimes diluted sulphuric acid is applied 
 to increase their whiteness ; and, finally, they are boiled in 
 pearlashes and soap, to render them free from the odor of 
 chlorine. Chloride of soda, magnesia, and potassa, are some- 
 times used, but they are more expensive.* 
 
 Theory. The theory of this process, perhaps, would be better un- 
 derstood after learning the composition of water; but it can be given 
 
 * The advantages of this mode of bleaching, over the one formerly 
 employed, are very great. By the old method, large fields in the 
 vicinity of every manufactory were devoted to the purpose of spread- 
 ing the cloths. These fields are now devoted to agriculture. It re- 
 quired also several weeks, and even months, to complete a process 
 which may now be performed in as many days. In the former case, 
 they were dependent upon the light of the sun and fair weather; 
 in the latter, they are independent of the weather, and of the seasons 
 of the year. 
 
 7 
 
146 Chlorine and Oxygen 
 
 here with a little explanation. Water is necessary to the bleaching 
 effects of chlorine. It is composed of oxygen and hydrogen. The 
 chlorine, having a strong affinity for the hydrogen, decomposes the 
 water, and leaves the oxygen to combine with the coloring matter. 
 The coloring matter may also contain hydrogen, and thus be directly 
 decomposed by the chlorine. The coloring matter is rendered soluble 
 by combination with oxygen, and is removed by the alkali. The pro- 
 cess of bleaching by chlorine is but one out of many useful con- 
 tributions of science to art. 
 
 2. Another use of chlorine arises from its disinfecting 
 agency, It seizes hold of every species of animal and vege- 
 table effluvia, and decomposes them. Hence its utility in 
 contagious diseases. The chloride of lime is used for this 
 purpose. Moisten the dry chloride with water, and place it 
 in the infected apartment, which will soon be purified. It is 
 thus very useful for dissecting-rooms, for cleaning drains, 
 sewers, vessels, and even the atmosphere, when charged with 
 miasma. Its use in medicine is mostly confined to the puri- 
 fication of apartments of the sick. The chloride of soda is, 
 however, used in certain cases of inflammation, such as 
 ulcers, mortification, and cutaneous diseases. It is also used 
 as a wash for the teeth.* The compounds of chlorine with 
 the metals are called chlorides. 
 
 Chlorine and Oxygen, 
 
 The compounds of chlorine and oxygen are held together 
 by very feeble affinities, and are never met with in nature. 
 They cannot be made to combine directly, unless they are in 
 the nascent state, that is, at the instant of their formation. 
 
 Hypochlorous Acid. Symb. CI -f- O or CIO. Equiv. 35.42 -f- 
 8 = 43.42. Sp. gr. 3.0212. It was discovered by H. Davy, 
 in 1811, and called enclilorine from its being of a brighter 
 color than chlorine. 
 
 Preparation. Put two parts of the chlorate of potassa and one of 
 hydrochloric acid into a retort, and apply the heat of water under 
 200° Fahr. Collect over mercury; or it may be more conveniently 
 prepared for experiment by placing the materials in a flask, 
 
 * So many and great are the advantages of cleanliness and pure air, 
 that chloride of lime should be kept in every family, especially in cities 
 and large towns ; but an apartment in which it has been used should 
 be thoroughly ventilated before it is again occupied, or weak lungs may 
 be seriously injured. 
 
Chlorine and Oxygen, 147 
 
 a, (Fig. 70,) connected by a glass tube, bent twice 
 at right angles, with a tall receiver, b. Apply 
 heat as before ; the gas, being heavier than the 
 air, will displace it, and fill the receiver.* 
 
 Theory. The hydrochloric acid and the chlo- 
 ric acid in the chlorate of potassa mutually decom- 
 pose each other, and the results are water and the 
 hypochlorous acid. 2 equiv. HC1, and one of 
 KG -f- CIO 5 , are converted into KO, 2 Aq, and 
 3C10. 
 
 a 
 
 If the gas be collected over mercury, the chlorine unites 
 with the mercury, and the acid remains in a pure state. 
 
 Properties. Greenish yellow color, more brilliant than 
 chlorine ; odor like burned sugar ; absorbed rapidly by water, 
 and gives to it an orange color ; bleaches vegetable sub- 
 stances ; gives vegetable blues a red tint before destroying 
 them ; does not unite with alkalies, and hence has been con- 
 sidered as a protoxide of chlorine ; highly explosive, the heat 
 of the hand being sufficient often to explode it. Many sub- 
 stances take fire in it spontaneously. 
 
 Exp. A rag dipped in spirits of turpentine will kindle in it with a 
 slight explosion. 
 
 Eocp. Phosphorus explodes in it spontaneously. Fifty measures of 
 this gas, and eighty of hydrogen, form an explosive mixture. 
 
 Chhrmis Acicl Symb. C1 + 4G, or CIO*. Equiv. 35.42 
 -f 33 = 67.42. Sp. gr. 2.3374. Discovered by Davy, in 
 1815, and soon after by Count Stadion, of Vienna, and has 
 been heretofore described as peroxide of chlorine. 
 
 Preparation. Make a paste of strong sulphuric acid and chlorate of 
 potassa ; put it into a retort, and apply the heat of warm water under 
 2\ 2° Fahr. Collect over mercury, or as in Fig. 64. For the purposes 
 of experiment, take a wine or champagne glass, and put into it a few 
 grains of chlorate of potassa; then pour on sulphuric acid ; the gas will 
 soon fill the glass. As the gas often explodes spontaneously, this is the 
 safest mode of collecting it. The preceding compound may be formed 
 in the- same way. 
 
 Properties. Color, bright orange-green, richer than the 
 preceding compound ; aromatic odor ; is absorbed rapidly by 
 water, and gives it its peculiar color; bleaches powerfully, 
 and is more explosive than hypochlorous acid. 
 
 Exp. Put a bit of phosphorus into a wine glass filled with the gas. 
 It will instantly ignite, with a slight explosion. 
 
 Chloric Acid. Symb. CI + 50, or CIO 5 . Equiv. 35.42 + 
 40 ■— 75.42. It was first noticed by Mr. Chenevix, and ob- 
 tained in a separate state by Gay Lussac. 
 
 *■ To avoid the danger of explosion, a wine-glass had better be used, 
 ts directed for chlorous acid. 
 
148 Iodine. 
 
 Preparation. To a dilute solution of chlorate of baryta add dilute 
 sulphuric acid sufficient to combine with the baryta. Pure chloric acid 
 will remain after the baryta subsides. 
 
 Theory. The sulphuric acid has a stronger affinity for baryta than 
 the chloric acid with which it has combined, decomposes it, and leaves 
 the chloric acid. 
 
 Properties. Sour to the taste ; reddens vegetable blue 
 colors, but possesses no bleaching properties, by which it is 
 distinguished from the preceding compounds. It may be 
 concentrated by gentle heat into an oily liquid of a yellow 
 tint, emitting the odor of nitric acid. In this state, it sets 
 fire to paper and dry organic matter, and converts alcohol 
 into acetic acid. 
 
 Perchloric Acid. Symb. CI + TO or CIO 7 . Equiv. 35.42 
 -j- 56 = 91.4:2. Sp. gr. 1.G5, waters 1. It was first described 
 by Count Stadion, of Vienna. 
 
 Process. It may be obtained by heating a mixture of 1 part of water, 
 3 of sulphuric acid, and 5 of perchlorate of potassa. At a temperature 
 of 261°, white vapors arise in the receiver, which are soon condensed into 
 a colorless liquid. By admixture with sulphuric acid, and distillation, 
 it crystallizes in elongated prisms. 
 
 It is a very stable compound ; absorbs moisture from the 
 air powerfully, and boils at 392° Fahr. When thrown into 
 water, it hisses like red-hot iron. 
 
 Sect. 3. Iodine. 
 
 a v i v • (by vol 100. c n ( 4.948 Water = l. 
 
 Symb. I. Equiv. J £ wgt . l26 . 3 . Sp. Gr. J ^ Ajr = 1 
 
 History. Iodine was discovered in 1812, by a manu- 
 facturer of saltpetre — M. Courtois, of Paris. The substance 
 in which it was first noticed, was the residual liquor after the 
 preparation of soda from the ashes of sea-weeds. This dark- 
 colored liquor possessed the peculiar property of powerfully 
 corroding metallic vessels ; on the application of sulphuric 
 acid, he noticed that it threw down a dark-colored substance, 
 which was converted into a violet-colored vapor on the ap- 
 plication of heat. This attracted his attention, and he gave 
 some of it to M. Clement, who, in 1313, described it as a 
 new body. Gay Lussac and Davy soon after proved it to be 
 a simple non-metallic substance, analogous to chlorine. The 
 
Physical Properties. 149 
 
 name iodine is derived from a Greek word,* significant of 
 the beautiful violet color of its vapor. 
 
 Natural History. Iodine exists in nature but in small 
 quantities. It is found mostly in sea-weeds, in sponges, in 
 the oyster and some other mollusca, in many salt and mineral 
 springs, both in Europe and America. Vauquelin found it in 
 combination with silver ; marine animals and plants derive it 
 from sea-water. Most of the iodine of commerce is obtained 
 from the impure carbonate of soda, called kelp. This is 
 nothing but the ashes of sea-weed, great quantities of which 
 are prepared on the shores of Scotland. Iodine exists, in 
 combination with sodium and potassium, in the liquor which 
 is left after the carbonate of soda crystallizes. 
 
 Process. Iodine may be obtained by lixiviating the pow- 
 dered kelp in cold water. Evaporate the lye till the car- 
 bonate of soda crystallizes; take the residual liquor, and 
 evaporate it to dryness ; pour on to this ^ its weight of sul 
 phuric acid ; it may then be put into a common retort, to 
 which is attached a globe receiver, and the retort heated ; 
 violet-colored fumes will soon arise, and be condensed in 
 the receiver, in the form of opaque crystals, of a metallic 
 lustre. These are to be washed in water, and dried on a 
 filter of unglazed paper. 
 
 Physical Properties. Iodine, at the common temperature, 
 is a soft, pliable, opaque solid, of a bluish-black color, and 
 of a metallic lustre. It is generally found in small crystalline 
 scales, resembling micaceous iron ore, or the scales from a 
 smith's forge. But it may be made to crystallize in large 
 rhomboidal plates, whose primary form is a rhombic octohe- 
 dron, by saturating hot alcohol, or hydriodic acid, with it, 
 and evaporating in the open air. It is very acrid to the 
 taste, and has the odor of chlorine. Like O and CI, it is a 
 non-conductor of electricity, and goes to the positive pole in 
 the galvanic circuit. It acts as a powerful poison to the 
 animal" system ; fuses at 225°, and boils at 347° Fahr. If 
 moisture be present, it volatilizes at the common temperature., 
 
150 Iodine 
 
 and sublimes rapidly under 212°. The rich violet vapor of 
 
 iodine is remarkably dense, more than eight times as heavy as 
 
 air. One hundred cubic inches would weigh 269.8638 grs. . 
 
 Exp. This vapor may be shown by putting a few grains of the 
 iodine into a glass flask, and applying a gentle heat. 
 
 Chemical Properties. Iodine has an extensive range of 
 
 affinity. Like chlorine, it destroys vegetable colors, though 
 
 in a less degree, and, like oxygen and chlorine, it unites 
 
 directly with the metals and with non-metallic combustibles 
 
 with great energy. 
 
 Exp. Drop a bit of phosphorus upon a few grains of iodine, con- 
 tained in a wine-glass, and it will be instantly inflamed. 
 
 The compounds thus formed resemble those of oxvgen and 
 chlorine. It has little affinity for metallic oxides. It is not 
 inflammable, but a supporter of combustion. The im- 
 ponderables have no effect to change its character, and hence 
 it is regarded as a simple body. It is largely soluble in 
 alcohol, and but sparingly soluble in water, requiring seven 
 thousand times its weight of water for solution. 
 
 Tests. Starch is a very delicate test of iodine. It gives to the solu- 
 tion a deep blue color. A liquid contain'ng ^^proo" part of its weight 
 of iodine, receives a blue tinge from a solution of starch. 
 
 Jodine is sometimes adulterated wilh black lead. This may be de- 
 tached by dissolving it in alcohol, when the lead will not be held in 
 solution. 
 
 Uses. Used in medicine in the form of a hydriodate of 
 potassa, for certain glandular diseases. The goitre is a kir 
 of wen growing from the neck, which is very common 
 Switzerland, in the treatment of which iodine has been of 
 great service. 
 
 Its vapor is irritatincr to the lungs, and produces copious 
 secretions in the eyes and nostrils. The compounds of 
 iodine with non-metallic combustibles are termed iodurets ; 
 its compounds with the metals, iodides. 
 
 Iodine forms with oxygen three, perhaps four compounds : ■ 
 
 1. Oxide of iodine, ) -,. ■, 
 
 a T , ., ' > composition unknown. 
 
 Z. lodous acid, ) r 
 
 3. Iodic acid, 1 eq. 1, 126.3 -j- 5 eq. 0,40=^166.3 eq 
 Symb. I-foO or IO 5 . 
 
 4. Periodic acid, 1 eq. I, 126.3 + 7 eq. O, 56^182.a 
 Symb. I -|- 70 or IO 7 . 
 
Bromine. 151 
 
 The first two compounds, oxide of iodine and iodous acid, 
 are yet doubtful. The first is described by M. Sementmi, of 
 Naples, and the second by Mitscherlich. The oxide is a 
 yellow solid, and the acid a similar liquid, but their properties 
 have not been examined. 
 
 Iodic Acid was discovered by Davy and Gay Lussac about 
 the same time. Davy, who first obtained it in a pure state, 
 called it oziodine. 
 
 Preparation. When iodine is brought in contact with the hypochlo- 
 lous acid, two compounds are formed. The one is a volatile orange- 
 colored substance, chloride of iodine, and the olher a white solid, which 
 is iodic acid. Apply heat to expel the chloride, and the iodic acid re- 
 mains in a pure state. (See Turner, for other- processes.) In this 
 state, it is anhydrous iodic acid, that is, destitute of water. 
 
 Properties. It exists as a white, semi-transparent, crystal- 
 line solid, of a strong, astringent, sour taste, and no odor; 
 fuses at 500° Fahr., and is resolved into oxygen and iodine. 
 
 It is soluble in water, with which it combines, and forms 
 hydrous iodic acid ; deliquesces in moist air ; reddens vege- 
 table blu.es, and finally destroys them. With charcoal, sul- 
 phur, sugar, and similar combustibles, it forms detonating 
 mixtures. 
 
 Periodic Acid, was discovered by Ammermuller and Mag- 
 nus, and is obtained from the periodate of silver, by adding 
 cold water. It has decided acid properties, and is analogous 
 in composition to perchloric acid. 
 
 Chloriodic Acid was discovered by Davy and Gay Lussac. 
 It may be formed by the direct union of chlorine and iodine. 
 If the iodine is fully saturated with chlorine, it forms a yellow 
 solid ; but if the iodine is in excess, the color is a reddish 
 orange. It is easily fused, and converted into vapor ; deli- 
 quesces in the air ; forms a colorless solution in water ; very 
 sour to the taste ; reddens vegetable blues, and finally de- 
 stroys them; does not unite with alkalies, and hence has 
 been considered a chloride of iodine. 
 
 Souberaine has lately distinguished a compound of 3 eq. 
 of chlorine and 1 of iodine. 
 
 Sect. 4. Bromine. 
 
 a . „ „ ■ C by vol. 100. „ C 3. Water = 1. 
 
 Symb. Br. Equiv. J J wg{ ^ Sp. gr. > 5m7 Ajr = L 
 
 History. Bromine was discovered in 182G, by M. Balard, 
 a young French chemist, of montpelier, who named it muride, 
 
1 52 Bro:: 
 
 because obtained from the sea ; but, in order to correspond 
 with chlorine and iodine, it was. called bromine, from a Greek 
 word,* signifying rank odor. 
 
 Natural History. It exists in nature in very small quan- 
 tities. It is found in sea-water and marine plants, combined 
 with sodium and magnesium. It is found in every sea whose 
 waters have been tested for it, and in many mineral and salt 
 springs. 
 
 Process. It is obtained by passing a current of chlorine 
 gas through the bittern of sea-water, and agitating the liquor 
 with a portion of .sulphuric ether. The ether dissolves the 
 bromine, from which it receives a beautiful hyacinth-red tint, 
 and, on standing, rises to the surface. Agitate this solution 
 with caustic potassa, and the bromide of potassium and bro- 
 mate of potassa will be formed. Evaporate the liquor, and 
 the bromide of potassium will be left, from which the bromine 
 may be distilled. 
 
 Physical Properties. Bromine, at common temperatures, 
 is a deep reddish-brown colored liquor, of a disagreeable odor 
 and caustic taste; and, like oxygen, chlorine, and iodine, is a 
 non-conductor of electricity, and a negative electric ; boils at 
 116.5° Fahr., and congeals at -4° Fahr. into a brittle solid. 
 It volatilizes at the common temperature and pressure. 
 
 Exp. This may be shown by pouring a few drops of the liquid into 
 a glass flask; it will soon be converted into a beautiful vapor, some- 
 what resembling the vapor of iodine, having a density of 5.54. 100 
 cubic inches at 00° Fahr. should weigh 167.5153 grains. 
 
 Chemical Properties. Its chemical properties are very 
 analogous to those of chlorine and iodine. It readily bleaches 
 litmus paper, and discharges the blue color of indigo. A 
 lighted taper burns for a few moments in the vapor of bro- 
 mine, with a flame green at its base and red at the top, and 
 is then extinguished. 
 
 Bromine unites with great energy with many combustibles. 
 
 Exp. Pour a few drops of bromine into a strong wine-glass, and then 
 pour upon it tin or antimony, in fine powder, from a glass fastened tc 
 
 B^tapios. 
 
Fluorine. 153 
 
 the end of a long rod ; the metals will be instantly inflamed. If potas- 
 sium be used, it will cause a violent explosion. 
 
 Bromine is soluble in water, alcohol, and ether ; the latter 
 is the best solvent. With water at, 32° F., it forms a hydrate, 
 in crystals of a fine red color. It gives to a solution of starch 
 an orange color. Chlorine will displace it from all its com- 
 binations with hydrogen. It acts powerfully upon the animal 
 system, and is very poisonous ; a single drop upon the beak 
 of a bird, destroys it instantly. 
 
 Bromic Acid (Symb. Br-f 50 or BrO 5 . Equiv. 78.4 + 
 49 = 118.4,) may be obtained by pouring sulphuric acid 
 upon a dilute solution of bromate of baryta, and evaporating 
 the solution. 
 
 Properties. It has scarcely any odor, acrid to the taste, 
 though not corrosive. It first reddens litmus paper, and then 
 destroys the color. 
 
 Chloride of Bromine may be formed by transmitting a current of 
 chlorine through bromine, and condensing the disengaged vapors hy 
 a freezing mixture. It is a volatile liquid, of a reddish-yellow color, 
 less brilliant than bromine. Its vapor is a deep yellow, taste very dis- 
 agreeable, and odor penetrating, causing a discharge of tears from the 
 eyes. Soluble in water which possesses bleaching properties. 
 
 Bromides of Iodine. Bromine and iodine unite and form two com- 
 pounds. 
 
 The pr-'to-brmnide is a solid easily converted by heat into a reddish- 
 brown vapor, which, on cooling, is condensed into crystals of the same 
 color, and of a form resembling fern leaves. By the addition of bro- 
 mine to these crystals, they are converted into a liquid resembling a 
 strong- solution of iodine and hydriodic acid; but the nature of it is not 
 satisfactorily established. 
 
 Sect. 5. Fluorine. 
 Symb. F. Equiv. 18.68, eq. vol. 100. 
 
 Fluorine is a name applied to a substance which has not 
 as yet been obtained in a simple state. It is inferred from 
 the nature of its compounds to be similar to oxygen, chlorine, 
 bromine, and iodme. It has a strong affinity for hydrogen 
 and the metals. 
 
 \ural History. It exists abundantly in nature, in fluor- 
 spar combined with calcium, (fluoride of calcium.) Baudri- 
 
 7* 
 
J 54 
 
 Hydrogen. 
 
 mont is said to have obtained it, mixed with hydrofluoric and 
 fluosilicic acid gases, by treating a mixture of fluoride of cal- 
 cium and peroxide of manganese with strong sulphuric acid 
 It appears to be a gaseous body, similar to chlorine, 
 
 Sect. 6. Hydrogen. 
 
 Symb. H. Equiv. 
 
 by vol. 100. 
 " wgt. 1. 
 
 Sp. gr. 
 
 0.0689 Air 
 1. Hyd 
 
 = 1. 
 
 History. The name hydrogen is formed from two Greek 
 words,* and means a generator of water. It was known for 
 many centuries, but was first distinctly described by Mr. Cav- 
 endish, in 1776. Nine years previous, Dr. Black discovered 
 
 except 
 
 carbonic acid gas, which was the first gas discovered, 
 the atmosphere, and hydrogen was the second. 
 
 Natural History. Hydrogen is a very abundant substance. 
 It forms £ part by weight of water. Its chief repository, 
 therefore, is the ocean ; but it is widely disseminated through 
 the animal, vegetable, and mineral kingdoms. It is the basis 
 of most liquids. 
 
 Processes. .1. Water is always employed for obtaining 
 hydrogen. It is composed of oxygen and hydrogen, and the 
 object is to decompose it by presenting some substance, with 
 which the oxygen will combine, and leave the hydrogen to 
 escape in the form of a gas. Iron is such a substance, and 
 '""Will decompose the water slowly at common temperatures ; 
 the oxygen combining with it, and forming the well-known 
 substance called iron rust. But if the temperature of the iron 
 be raised to 100:)° 
 Fahr., and the va- 
 por of water passed 
 over it, it will de- 
 compose it more 
 rapidly. For this 
 purpose, clean iron 
 turnings, or bright 
 iron wire, are pla- 
 ced in the centre 
 
 Jf<Jw§ and ysvvuta, 
 
Pi*occsses — Theory. 155 
 
 of a gun-barrel, C, (Fig. 71,) open at both ends, and passed 
 through a furnace, b. Into one end the vapor of water is 
 made to pass from the retort a, and the other end is con- 
 nected by a lead pipe with the pneumatic cistern. As the 
 vapor passes over the iron, its oxygen combines with it, and 
 its hydrogen passes over into the receiver /t.* 
 
 2. It is rhore conveniently obtained by putting small 
 pieces of zinc,f or iron turnings, into a glass or lead retort, 
 and pouring on one part of sulphuric acid, diluted with four 
 parts by weight of water, and collecting as above. 
 
 Tlicory. In this process, the oxygen of the water unites 
 with the zinc, and forms oxide of zinc, which combines with 
 the acid, while the hydrogen of the water escapes. This was 
 formerly supposed to be a case of what was called disposing 
 affinity, in which the acid disposed the oxygen and zinc to 
 unite, that it might combine with the compound ; for it has 
 no affinity for them separately. This is sufficiently absurd. 
 The process commences with zinc and water alone, without 
 the aid of the acid, and is immediately arrested by the forma- 
 tion of a coat of oxide of zinc, which protects the zinc from 
 the action of the water. The acid dissolves away this coat- 
 ing of oxide as fast as formed, and thus the action of the 
 metal and the water is uninterrupted. But the change is 
 best explained by referring it to galvanic action. 
 
 For every 9 grs. of water which are decomposed, 1 of hydro- 
 gen is set free. 8 grs. of oxygen unite with 28 of iron, forming^. 
 36 of the protoxide of iron. 1 oz. of iron yields 782 cubic 
 inches, and 1 oz. of zinc 676 cubic inches, of hydrogen. 
 
 Impurities. The hydrogen, obtained in these processes, is not quite 
 pure. That from the iron contains a volatile oil, produced by the hy- 
 drogen and the carbon in the iron; this may be removed by passing 
 the gas through alcohol. "When zinc is employed, (and it is generally 
 
 * If the water and the iron are weighed before the experiment, and 
 the iron and the hydrogen after it, the increase in the weight of iron 
 and the weight of the hydrogen is just equal to that of the water, 
 In this way the exact composition of water is determined analytically, 
 and is found to be 8 parts of oxygen to 1 of hydrogen, and 1 vol. of the 
 former to 2 of the latter. 
 
 t The zinc may be conveniently prepared by pouring a stream of the 
 melted metal into cold water. 
 
156 
 
 Hydrogen. — Physical Properties. 
 
 preferred.) 4he impurities result from the sulphur which it generally 
 contains — hydrosulphuric acid is formed, and there are also traces of 
 metallic zinc and carbureted hydrogen. These, except the last, maj 
 be removed by passing the hydrogen through pure potassa. When 
 hydrogen of great purity is required, distilled zinc should be used. 
 
 Physical Properties. Hydrogen gas is colorless, tasteless, 
 and, when perfectly pure, inodorous. But as it is generally 
 obtained, it has a fetid odor, arising from the oily matter 
 which it contains, and the hydrosulphuric acid. It is a pow- 
 erful refractor of light, and has never been condensed to a 
 liquid. 
 
 It is the lightest body in nature, It is sixteen times lighter 
 than oxygen, 36 times lighter than chlorine, 230,000 timea 
 lighter than mercury, and 390 000 times lighter than 
 platinum ! 
 
 Exp. Fill a gas bag with Fig. 72. 
 
 hydrogen,* (Fig. 72 :) con- 
 nect it with a bubble-pipe, 
 and inflate soap bubbles with 
 the gas; they will ascend 
 rapidly, being forced up by 
 the superior weight of the 
 air. Or, if a jar of hydrogen 
 be removed from the cistern, 
 and inverted in the open air, 
 the gas will immediately escape. 
 
 In consequence of its extreme lightness, hydrogen is used 
 for nliino- balloons. 
 
 * The method of filling gas hags with 
 gases from the pneumatic cistern, is repre- 
 sented in Fig. 73. b is the cistern contain- 
 ing water; the receiver has a stop-cock in 
 its top. upon which another stop-cock, C, 
 connected with the bag a, may be screw- 
 ed. The receiver is filled with gas, and, 
 the stop-cocks being both open, is pressed 
 down into the well, and the water presses 
 the gas into the bag. Then, by closing 
 both stop-cocks, the bag may be* removed 
 from the receiver. 
 
 Fisr. 73. 
 
 // 1 ^^f — 
 
 // '■' ==: 
 
 ■: -A == 
 
 ft ■-: — _ 1, 
 
 ! 
 
 // 
 
 ■ . : ^-= 
 
 // r-S^= ^1~' 
 
 i':!^ 
 
 // (4^=^==^= 
 
 ^ = ^ = ~~ = ~ 
 
Chemical Properties. 
 
 157 
 
 Aerostation. Roger Bacon first suggested the pos- 
 sibility of navigating the air by mechanical contri- 
 vances; bnt nothing of consequence was effected until 
 17d2. The substance first employed to raise balloons 
 was rarefied air, confined in a silk bag. Since the 
 discovery of hydrogen, it has been universally em- 
 ployed for this purpose. Balloons are made of various 
 shapes and capacities. The spherical form (Fig. 74) 
 is the best, for the reason that a given quantity of can- 
 vass, or silk, made in the form of a sphere, will contain 
 more than any other form, and hence offers the least 
 resistance to the air. The substance employed for bal- 
 loons is either varnished silk or gold-beaters' skin, and 
 the size varies from 1 to 40 feet in diameter. They 
 are generally covered with a net, n, connected by cords to a small boat, 
 c, in which the aeronaut is stationed when he ascends. The hydrogen 
 is prepared by putting iron turnings, sulphuric acid, and water, into 
 several large casks, and connecting each with the balloon ; the hydrogen 
 is then rapidly evolved, and the balloon tied down until ready for use. 
 
 Chemical Properties.*' Hydrogen has a strong affinity for 
 many substances, and the energy of its combinations fre- 
 quently produces the phenomena of combustion. 
 
 Hydrogen is a combustible body, but not a supporter of 
 combustion. 
 
 Exp. Plunge a lighted taper into an inverted jar of hy- 
 drogen ; the gas will instantly be inflamed at the mouth of 
 the jar, and burn with a blue light; but the taper, if wholly 
 immersed in the gas, will be extinguished, and relighted 
 again when the wick touches the flame. 
 
 Exp. Burn a jet of hydrogen. If the hydrogen be 
 forced rapidly through a tube, &, (Fig. 75,) with a small 
 orifice, ignited at the orifice, and cylinders of glass, as «,"Dr 
 other substances, put over the flame, musical tones will be 
 produced. The tones will'vary with the size and kind of 
 tube. 
 
 Exp. Mix two measures of hydrogen with one of oxy- 
 gen, and apply the flame of a candle to a small portion 
 confined in an exploding tube, or gas pistol, a, (Fig. 7G;) 
 there will be a violent explosion. This effect is also pro- 
 duced by mixing one part of hydrogen with three of com- 
 mon air ; but the explosions are much more violent when 
 two vols of hydrogen and one of oxygen are mixed, and 
 ignited with the flame of a candle; or by the electric 
 spark. Soap-bubbles may be formed and exploded as they 
 rise. A large bladder, filled with the mixture, may also be 
 pxploded by piercing it with a sharp wire on the end of a 
 lonir rod, having about it ignited tow. 
 
 Exp. This mixture also explodes when suddenty com- 
 pressed by the fire-syringe ; this is owing to the develop- 
 ment of its latent caloric, or because the particles are then 
 Drought within the sphere of each other's attraction ; but 
 the experiment is hazardous 
 
 Fig. 75, 
 
 Fig. 76, 
 
 tie 
 
 HyUrugen, though it has never been corrdaUied, ptfisesscs many of the proper- 
 i of a meiaf, (See pugs 235.} 
 
158 Hydrogen and Oxygen. 
 
 Tticory. The report arises from the collapse of the air, 
 and consequent expansion of the vapor of water, produced 
 by the liberated caloric at the moment combination takes 
 place. The musical tones arise from continued explosions, 
 consequent upon the union of the h)-drogen with the oxygen 
 of the air. 
 
 Exp. TTJien a stream of hydrogen gas is brought in contact icith 
 spongy platinum, it is immediately set on fire. This heat is supposed to 
 be due to the condensation of the gas upon the surface of the plati- 
 num, by which its latent caloric becomes sensible, and inflames the gas, 
 
 This singular fact was discovered by Prof. Doebereiner, of 
 Jena, in 1824. The sponge is prepared by dissolving plati- 
 num in nitro-muriatic acid, and then precipitating it with 
 ammonia. Rhodium and iridium produce the same effect, 
 This property has been applied to the construction of lamps, 
 by which light can be easily and conveniently produced. 
 
 Under pressure, the combustion of hydrogen produces a very ' 
 
 ise heat, 
 Exp. Burn a jet of hydrogen, and throw on iron filings ; they will be 
 ignited, and produce beautiful scintillations. One pound of hydrogen, 
 in burning, will develop sufficient heat, according to Dalton. to melt 
 320 lbs. of ice. 
 
 Relations to Animals, An animal soon dies when confined 
 in it. This is not owing to the noxious properties of the 
 hydrogen, since an atmosphere of oxygen and hydrogen will 
 support respiration for a considerable time ; but is due to the 
 fact, that it excludes ihe oxygen, and thus suffocates. An 
 atmosphere of oxygen and hydrogen has the singular property 
 of producing a most profound sltep. 
 
 Hydrogen and Oxygen. 
 
 Protoxide of Hydrogen, or Water.. 1 eq. H 1 -}- J eq. O 8 
 
 = 9 eq. Symb. H -f O or Aq. Sp. gr. — 1. 
 
 Process. Water is the sole product of the combustion of 
 hydrogen gas in common air, or oxygen. This may be shown 
 by burning a jet of hydrogen in a large globe receiver ; or, 
 what will render the effect more striking, by burning a jet of 
 2 vols, of hydrogen to 1 of oxygen, with the compound 
 blowpipe : the sides of the receiver will soon become hazy, 
 from the deposition of water upon its interior surface ; and if 
 the process be continued, large drops will form and run down 
 the sides. This fact was first demonstrated by Mr. Caven- 
 
jrnysical and Chemical Properties. 159 
 
 dish, by burning the gases as above ; and the weight of the 
 water produced was exactly equal to that of the gases con- 
 sumed. 
 
 Physical Properties. These are well known. It is trans- 
 parent, colorless, inodorous, and tasteless ; slightly com- 
 pressible by a very strong pressure ; elastic ; converted into 
 vapor by heat ; boils at 212° F., and congeals at 32° F. It is 
 the standard of weight, with which all solid and liquid bodies 
 are compared ; its specific gravity is therefore 1. One cubic 
 mch weighs 252.458 grs. It is 815 times heavier than the 
 atmosphere, which is the standard of weight for gaseous 
 bodies. 
 
 Chemical Properties. 1. Water has the power of ab- 
 sorbing a great number of gaseous bodies. It always con- 
 tains air. 
 
 ' Exp. This may be shown by placing it under the receiver of an air- 
 pump, and exhausting the air, when bubbles of air will rise up through 
 the water. 
 
 It is the air contained in water from which fishes obtain 
 
 the oxygen necessary to purify their blood. 
 
 At the mean temperature and pressure, water will absorb* 
 according to Henry and Dalton, of 
 
 1 l( 
 ST 
 1 it 
 
 F4 
 
 But if the gas be passed through the water under great 
 pressure, a greater quantity will be absorbed. Carbonic acid 
 gas. for example, is absorbed according to the pressure ap- 
 plied, to an unlimited extent. 
 
 2. Water is one of the most powerful solvents in nature. 
 It enters into combination with various bodies ; sometimes in 
 indefinite proportions, as in solutions ; at others in definite pro- 
 portions, as in the acids, some of the metallic oxides, and many 
 salts, in whose cn f stallization it is taken up, and in which it 
 is therefore called the water of crystallization. The definite 
 
 Carbonic acid gas, . 
 
 1 vol. 
 
 Carbonic oxide, 
 
 Sulphureted hydrogen, 
 
 1 " 
 
 Carbureted hydrogen 
 
 Nitrous acid, . . . 
 
 1 " 
 
 Nitrogen, . . . 
 
 Olefiant gas, . 
 
 i " 
 
 Hydrogen, 
 
 Oxygen, .... 
 
 i " 
 
 FT 
 
 
160 
 
 Hydrogen and Oxygen. 
 
 compounds are called hydrates* The affinity of water foi 
 some substances is so strong, that it cannot be entirely 
 separated from them without at the same time decomposing 
 the substance. 
 
 Composition of Water. This has been Fig. 77. , 
 
 accurately determined, both by analysis 
 and synthesis. By synthesis, by burning r 
 2 vols, of hydrogen and 1 of oxygen, the ^_ 
 product is water. Also, by exploding 2 
 vols, of hydrogen and one of .oxygen, in a 
 strong glass tube, or Eudiometer, o, (Fig. 
 77,) over mercury, by the electric spark, 
 there will be a perfect vacuum produced, 
 and the mercury will rise, and fill the tube. 
 Instead of inflaming the gases by the 
 electric spark, spongy platinum may be 
 employed to produce a combination of 
 the oxygen and hydrogen. 
 
 Exp. Take three parts of spongy platinum, one of pipe-play, 
 moistened with water, and a small quantity of hydrochlorate of am- 
 monia, make it into a small ball, and ignite it, to separate the water 
 and ammonia. Introduce it, while hot, into the mixture, and the 
 oxygen and hydrogen will combine slowly, without explosion. If the 
 gases are mixed in the proportions of 1 vol. of oxygen to 2 of hy- 
 drogen, they will wholly disappear, and water will be the only product 
 
 Water may be decomposed by the galvanic battery, and the 
 products are 2 vols, of hydrogen to 1 of oxygen. The same 
 results are obtained by passing its vapor over red-hot iron, 
 and collecting the products. 
 
 Compound Blowpipe. This apparatus was invented by Dr. 
 Hare, in 1804. The best construction for experimental pur- 
 poses is the following : A,B, (Fig. 78,) are two cylinders of 
 wood or copper open at the top; c, et, two similar cylinders 
 open at the bottom, placed within the others, leaving spices 
 of \ of an inch in width between them, and passing around 
 cylinders of wood which nearly nil them. The spaces ?, r, are 
 filled with water, and the gases are conducted by a lead pipe 
 into c and d, which are the gasometers. As they are filled, 
 they are lifted up by the weights.! The tubes h, o, connect 
 
 * The term hydrous is prefixed to substances containing water, and 
 anhydrous to thnse deprived of it. 
 
 t A method for raising and depress'ino- the gasometers has lately 
 been devised, which answers a better purpose than weights. A bar or 
 
Hydrogen and Oxygen. 
 Fig. 78. 
 
 161 
 
 the gasometers with the blowpipe ; the gases are let out by 
 means of stop-cocks, d, being filled with oxygen, the gas 
 passes in the tube o through the centre of the blowpipe ; c, 
 at the same time, being filled with hydrogen, the gas passes in 
 the tube h to the side of the blowpipe, and issues at the 
 point, so as to encircle the oxygen. By igniting the two 
 gases, as they issue from the pipe, the heat is so intense as to 
 melt the most refractory substances. It is only surpassed by 
 that from a powerful galvanic battery. In burning the metals 
 under the blowpipe, an opportunity is afforded for many in- 
 teresting and beautiful experiments.* 
 
 Binoxide of Hydrogen. Symb. H-f-20or HO 2 . Eqniv. 1 + 16 = 17. 
 Sp. gr. 1 45:2, water = 1. This singular compound was discovered by 
 Thenard in 1818, and is sometimes called oxygenized icater, and peroxide 
 of hydrogen. It is formed by the action of hydrochloric acid upon the 
 peroxide of barium. 
 
 Properties. The binoxide of hydrogen is a colorless, transparent 
 liquid, without odor, caustic to the skin, giving it a white stain, and 
 possesses powerful bleaching properties. When heated to 59° Fahr., 
 it is decomposed so rapidly as to cause explosion; the same effect is 
 also produced by throwing it on to several of the oxides of metals, 
 such as the peroxide of silver, lead, mercury, gold, and some others. 
 
 rod of iron is fastened by one end to the centre of the gasometers. 
 The other end passes up through the cross-bar S ; on one side of this 
 bar are teeth, which lit into a cog-wheel, and the gasometers are raised 
 and lowe-ed by a crank attached to the wheel. 
 
 * In experiments with the blowpipe, the hydrogen should first be 
 inflamed, and then the oxygen let out gradually, until the substance to 
 be melted is fully ignited; the hydrogen may then be shut off, and the 
 combustion kept up by oxygen alone. 
 
162 Hydrogen and Chlorine. 
 
 Hydrogen and Chlorine — Hydrochloric Acid. 
 
 Syinb. H + Cl. Eq. by vol. 200, by wgt. 35.42 -f 1 = 
 36.42. Sp. gr. 18.21 Hyd. == 1, 1.2694 air = 1 . 
 
 History. This compound has been long known under the 
 names of spirit of salt, and muriatic acid; but was dis- 
 covered in its gaseous state by Dr. Priestley, in 1772. 
 
 Natural History. It issues from the craters of volcanoes, 
 and is found in the warm springs of Mexico ; it exists in com- 
 bination with ammonia, (the hydrochlorate of ammonia.) 
 
 Process. 1. It can be obtained in the gaseous state, by 
 simply heating the common hydrous hydrochloric acid of 
 commerce in a glass flask, or retort, and collecting the gas 
 over mercury. 
 
 2. Put equal parts of common salt and sulphuric acid into 
 a retort, and collect as above. 
 
 Theory. Salt is a chloride of sodium, and sulphuric acid is com- 
 posed of real acid and water ; the oxygen of the water goes to the 
 sodium, and forms soda, which unites with the acid, and the hydrogen 
 of the water unites with the chlorine, forming hydrochloric acid. 2Sa 
 -f CI, SO 3 and HO, are converted into NaO-f SO 3 and HC1. 
 
 Instead of collecting the gas over mercury, it may be col- 
 lected in large vials or bottles, in the following manner : — 
 
 Put the materials into a flask, a, (see Fig. 64,) and connec, 
 the flask with a glass tube, bent twice at right angles, and 
 extending to the bottom of a bottle or receiver, b ; as the gas is 
 heavier than the atmosphere, it will expel it, and fill the bottle. 
 By the application of ammonia to the mouth of the bottle, a 
 white cloud will arise when the bottle is filled.* 
 
 Liquid Hydrochloric Acid. This is obtained in the arts 
 by passing the gas through water ; foinhis purpose Woulfe's 
 apparatus may be employed. 
 
 It consists of several bottles, b, c, d, e, (Fig. 79.) The first 
 bottle is connected, by a lead tube, with a glass retort, a, which 
 contains the materials ; b is one trgrd filled with water ; the 
 tube from b descends to the bottom^of c, and the gas passes 
 up through the water. As soon as the water is saturated, 
 
 * All gases that are heavier than the atmosphere, may be coller.tecl 
 in this way, and those that are lighter may be collected by inverting 
 the bottle, and allowing the gas to press the air down, instead of lifting it n« 
 
Physical and Chemical Properties 
 Fig. 79. 
 
 163 
 
 the gas passes through the tube to the bottom of d, and as- 
 cends a^ain through the water ; thence to" e, in a similar 
 manner. Through the centre of each bottle there is a safety 
 tube, extending nearly to the bottom, to prevent the danger 
 that might arise from a too sudden evolution of gas. The 
 gas presses upon the surface of the water, and forces it up 
 the centre tubes, which prevents it from bursting the bottles. 
 The acid in the first bottle is thrown away; the rest is the 
 acid of commerce. The bottles should be surrounded with 
 ice, to aid the absorption : water will thus absorb 480 times 
 its volume, and the solution has a density of 1.2109. 
 
 Physical Properties. Hydrochloric acid gas is colorless, 
 of a pungent odor, and acid taste, a little heavier than the 
 air; sp. gr. 1.289 ; under a pressure of forty atmospheres, or 
 690 lbs. on the square inch, it is condensed into a liquid. 
 
 Chemical Properties. It possesses decidedly acid proper- 
 ties, changes the vegetable infusions red, and combines with 
 alkalies, and forms salts. It supports combustion feebly, and 
 extinguishes a lighted taper, the flame of which assumes a 
 greenish hue before it goes out. Water absorbs it rapidly. 
 
 Exp. A drop or two of cold water, introduced into a flask, of the 
 acid, will absorb it readily; and if a jar of it be inverted over water, 
 the water will rush in with nearly the same violence as into a vacuum. 
 
 Exp. So strong is its affinity for water, that a piece of ice introduced 
 into ajar of it over mercury, will be dissolved almost as soon as if 
 thrown into a furnace. 
 
 It is readily decomposed by voltaic electricity, the hydrogen 
 appearing at the negative and the chlorine at the positive 
 pole. A discharge of ordinary electricity will decompose it, 
 but, according to Henry, the second shock causes it to com- 
 bine again. It is decomposed by those substances which 
 
164 Hydrochloric Acid. 
 
 yield oxygen readily, such as the peroxide of manganese, 
 cobalt, and lead ; the oxygen combines with the hydrogen of 
 the acid, and sets the chlorine at liberty. 
 
 It is nearly as suffocating, when taken into the lungs, as 
 chlorine, causes spasms of the glottis, and combines with the 
 saliva, or water, and forms the liquid acid. 
 
 Constitution. It was formerly supposed to be a simple 
 body, combining with oxygen to form oxymuriatic acid, now 
 found to be chlorine. But its composition may be determined 
 synthetically, by mixing equal portions of hydrogen and chlo- 
 rine in a glass tube, and exposing them to the solar rays, 
 when they instantly combine, with explosion, and hydrochlo- 
 ric acid is the only product ; or their union may be effected 
 by passing an electric spark through the mixture contained 
 in the eudiometer.* If the gases are mixed, they will com- 
 bine slowly in diffuse daylight. The light from the point, of 
 charcoal, at the poles of a galvanic battery, has the same 
 effect as the sun's rays. 
 
 Uses. Hydrochloric acid is one of the three great acids 
 used in the arts; it is used for preparing the chloride of tin 
 for dyers, as a re-agent in various chemical processes, and 
 in medicine as a tonic. 
 
 Impurities. The acid of commerce is not quite pure, containing 
 the chloride of iron, and chlorine. This gives the liquid a yellow 
 color; but, v. hen perfectly pure, it is limpid. 
 
 Hydriodic Acid. Symb. H + 1. Eq. 126.3 + 1 = 127.3. 
 Sp. gr. 4.3S54, air=l. Discovered by Gay Lussac, of Paris 
 
 Preparation. It may be obtained by passing iodine vapor 
 and hydrogen gas through a red-hot porcelain tube. But a 
 more convenient process, by which it may be obtained for 
 the purposes of experiment, is to put a small bit of phosphorus 
 into a glass tube, filled with water, and drop upon it a few 
 grains of iodme. 
 
 Theory. The iodine unites with the phosphorus, forming 
 the periodide of phosphorus, and then the water and the 
 periodide mutually decompose each other. The oxygen of 
 
 * The fact being established that hydrochloric acid is composed 
 of hvdrogen and chlorine, the old theory that oxygen was the only 
 acidifying principle is proved false; there are many acids of hydrogen 
 which have no oxygen in them. They are called kydr acids. 
 
Hydrofluoric Acid. 165 
 
 the water unites with the phosphorus, and the hydrogen with 
 the iodine, giving rise to phosphoric and hydriodic acids ; the 
 latter passes over in the form of a colorless gas, and may be 
 collected in a receiver of common air; it may be passed 
 through water, and absorbed by it. It cannot be collected 
 ffcer mercury, because it acts upon it. 
 
 Properties. Hydriodic acid is a colorless, transparent gas, 
 very sour to the taste, and gives an odor like hydrochloric 
 acid ; reddens vegetable blues without destroying them, and, 
 when mixed with air, produces dense white fumes ; has a 
 strong affinity for water ; is decomposed by several of the 
 metals, such as potassium, sodium, zinc, iron, and mercury, 
 and even when exposed to the air. 
 
 Uses. This acid may be employed to form pigments. 
 
 Exp. Take some of the salts of lead (acetate or nitrate of lead) in 
 solution, and pour on hydriodic acid; it will decompose the salt, and 
 form paints of a yellow color. 
 
 Tests. The most delicate test of this acid is bichloride of 
 platinum, a single drop of which, in solution, will give to a 
 liquid containing the acid, a reddish-brown color, and a dark 
 precipitate will subside. 
 
 Exp. Starch is also a sure test. A few drops of sulphuric acid will 
 give to a solution of the acid, mixed with a cold solution of starch, a 
 blue color. 
 
 Hydrobromic Acid. Symb. Br -f- H or BrH. Eq. 78.4 -j- J 
 = 79.4. Sp. gr. 2.7353. Discovered by M. Balard, and may 
 be obtained by immersing a red-hot iron into a mixture of 
 the vapor of bromine and hydrogen ; the combination takes 
 place slowly, without explosion; or it may be formed, for ex- 
 perimental purposes, by a process similar to that for obtaining 
 hydriodic acid, using bromine instead of iodine. 
 
 Properties. It is colorless, with an acid taste and pungent odor; 
 irritates the glottis, so as to excite coughing ; exposed to moist air, it 
 yields white dense vapors, and is rapidly absorbed by water ; decom- 
 posed by chlorine instantly; nitric acid also effects its decomposition. 
 
 Hydrofluoric Acid. Symb. F + H or FH. Eq. 18.63 + 1 
 = 19.63." Sp. gr. 1.0699. 
 
 History. First procured in a pure state in 1810, by Gay 
 Lussac and Thenard. 
 
 Process. It is formed by the action of sulphuric acid on 
 fluor-spar, (fluoride of calcium ) This mineral is pulverized, 
 
166 JS'itrogen. 
 
 petjnto a lead or silver retort, with twice its weight of sul- 
 phuric acid, and heat applied. The acid will distil over, and 
 mast be collected in a vessel of the same material, surrounded 
 with ice, to condense the acid. 
 
 7 ry. The hydrogen of the water in the sulphuric aeid combing 
 with the fluorine in the mineral, and the oxygen with the caJciun^l 
 the sulphuric acid unites with the oxide of calcium : the products are 
 hydrofluoric acid, and sulphate of the protoxide of calcium. Ca, F, SO 3 
 and HO, are converted into CaO + SO 3 and FH. 
 
 Properties. At 3'2 D F. it is a colorless liquid, and remains 
 in that state at 59°, if preserved in well-stopped bottles; but, 
 exposed to the air, it assumes the gaseous form, unites with 
 the water of the atmosphere, producing white fumes. Its 
 affinity for water is greater than strong sulphuric acid. Its 
 vapor is much more pungent than chlorine or any of the irri- 
 tating gases : the most destructive to animal matter of any 
 known substance, a single drop of the concentrated acid 
 causing deep and almost incurable ulcers. It is distinguished 
 for the remarkable property of acting on glass. It readily dis- 
 solves silex. and an acid is produced called the jluo-silicic 
 acid; and hence it cannot be preserved in glass vessels. 
 
 It is used for etching on glass. 
 
 Exp. For this purpose, prepare some resin or beeswax, and form a 
 coat over the g : nted instrument, remove the 
 
 coating where jou wish the glass to be etched: pour on the acid, 
 and in a few minutes the etching is completed. Then, by wash- 
 ing the glass in water, and removing the coating, the figures will 
 appear. The liquor in the retort will answer for this experiment, es- 
 pecially if used within a day or two after the acid and the fluor-spar 
 are mixed. 
 
 "iTFvOGEN. 
 
 q»ttt,>> X f™;^ f bT To1 - *°®- d„ ~r f 0.9727 Air = 1. 
 
 Symb. N. Equiv. ^ i ^ ]4 15 Sp. gr. ^ uM Rj± = f 
 
 H :::-■. X.trogen was discovered by Dr. Rutherford, of 
 Edinburgh, in 1772. Three years after, Lavoisier discovered 
 that it was a constituent of the atmosphere. Scheele also 
 made the same discovery. It was called by Lavoisier azote, 
 (from two Greek words,*) because it deprived animals of life ; 
 but this is not the only ga? which is azotic. Its present 
 name, nitrogen, is derived from nitre, (nitrate of potassa,) 
 
 * A and 
 
Physical and Chemical Properties. 167 
 
 Natural History. Nitrogen exists in all animals, in fun- 
 gous plants, and constitutes ^ of the atmosphere; also in 
 some hot springs in Scotland, and in the Alps. It is also 
 evolved from certain springs in the state of New York. 
 
 -? Process. It may be obtained from the atmosphere, either 
 by burning out the oxygen of a confined portion of air with 
 some combustible, or by abstracting the oxygen in a more 
 gradual way, by its affinity for some of the simple substances. 
 
 Exp. 1. Put a small piece of phosphorus in a cup 
 which will float on water, (Fig. 80,) and invert over Fig. 80. 
 
 it a receiver of common air. On igniting the phos- 
 phorus, it will unite with the oxygen, and burn until 
 all the oxygen is consumed, forming white fumes — 
 the pyrophosphoric acid. This- acid, in a short time, 
 will be absorbed by the water, which will rise and fill 
 trie jar -I full. This is sufficiently pure for common 
 experiments, but contains vapor of phosphorus and 
 carbonic acid, which may be removed by passing the 
 gas through pure potassa. 
 
 Exp. 2. Make a paste of flowers of sulphur and iron filings, and invert 
 over it a receiver; the oxygen will combine slowly with the iron, and 
 leave the nitrogen. A stick of phosphorus will produce the same ef- 
 fect. If the proto-sulphate of iron, charged with the binoxide of nitro- 
 gen, be substituted for the paste, the process is more rapid. 
 
 Exp. 3. It may also be obtained by pouring nitric acid on fresh 
 muscle, and subjecting it to a moderate heat. 
 
 Theory. On account of the strong affinity of oxygen for 
 these substances, it leaves the nitrogen, and combines with 
 them. 
 
 Physical Properties. Nitrogen is colorless, tasteless, 
 inodorous, not condensed into a solid by pressure or cold. 
 100 cubic inches weigh 30.1G50 grains. 
 
 Chemical Properties. Water, recently boiled, absorbs H 
 volumes of the gas. 
 
 Nitrogen will not support combustion. 
 
 Exp. Put a lighted candle into a jar of it, and it will be immediately 
 extinguished ; hence it docs not support 
 
 Respiration. No animal can live in it, not because of the 
 active properties of the gas, but because it excludes the oxy- 
 "gen. It kills by its negative properties, for which it seems 
 alone to be distinguished. The effect is like that of 
 drowning. 
 
 Nature of Nitrogen. Nitrogen has been supposed by 
 
168 Nitrogen and Oxygen. 
 
 some, among whom is Berzelius, to be a body composed of 
 oxygen and an unknown base. But this base has never been 
 exhibited in a separate state ; and, until that is done, it must 
 be regarded as a simple substance. 
 
 Although pure nitrogen is the most inert of substances, 
 some of its compounds are among the most active and useful. 
 
 Nitrogen and Oxygen. 
 
 Common Air. Symb. 2N + O. Equiv. 23.30 + S — 
 36.30, eq. vol. 4N -j- O. Sp. gr. = 1. The earth is sur- 
 rounded by a gaseous fluid or atmosphere, consisting chiefly 
 of common air, extending about forty-five miles from its sur- 
 face, and revolving with it around the sun. 
 
 Physical Properties. The atmosphere is a permanent, 
 elastic fluid, transparent, inodorous, and tasteless. 
 
 The air is very compressible and elastic 
 
 Exp. The compressibility of the air may be shown by the fire-syringe, 
 by which it may be compressed into a very small compass. If 100 
 measures of confined air. under pressure of 1 lb., be subjected to double 
 the pressure, or 2 lbs., it will be diminished to 50 measures; double 
 this pressure, or 4 lbs., will compress it to 25 measures. On the other 
 hand, if the pressure be diminished, its elasticity will restore it to its 
 former state. Then, if ^ lb. be applied to the 100 measures, it will ex- 
 pand to 200 measures. Halve this, or \ of a pound, and the volume 
 will be double, or 400 measures. The same is true of all other gaseous 
 bodies, while they retain their gaseous state. Hence the following 
 law, that 
 
 The volume of air and of other gaseous fiuids is inversely 
 as the pressure applied. 
 
 Exp. The elasticity of the air may be further shown by putting a 
 bladder, half filled with air, under the receiver of an air-pump, and 
 exhausting the air from the receiver; the external pressure being thu3 
 taken off, the air within the bladder will expand, fill the bladder, and 
 even burst it. This force is often so great, as to burst the strongest 
 vessels. Hence the danger of forcing too much air into the ball of an 
 air-gun, or carbonic acid into a soda fountain. 
 
 Winds. In consequence of the great elasticity and compressibility 
 of the air, it gives rise to the phenomena of winds. It is subject to the 
 laws of elastic fluids in g-eneral ; as one portion therefore becomes ex- 
 panded by heat, the colder or more dense portions rush rapidly into 
 its place, and force it to ascend. From the same properties, also, vi- 
 brations are easily produced in it, which give rise to the sensation of 
 sound, musical tones, etc. 
 
 Pressure of the Air. That the air had weight, was first 
 noticed by Galileo, in 1640. Torricelli, his pupil, carried out 
 
Common Air. 169 
 
 his suororestions, and in 1G43 invented the barometer* by 
 which variations of pressure could be accurately measured. 
 The exact weight of the atmosphere is of great importance 
 in physical and chemical researches, and has been accurately 
 determined by Dr. Prout. At the level of the sea, its pressure 
 is 15 lbs. on every square inch of surface. 
 
 Exp. This pressure may be illustrated by exhausting the air from 
 the receiver or' an air-pump; the pressure on the external surface of* 
 the receiver will fix it immovably to the plate. 
 
 The body of a man sustains constantly a pressure of about 
 14 tons ! 
 
 As we ascend above the level of the sea, the mercury sinks 
 in the barometer, because the column of air is shorter ; hence 
 the height of mountains may be measured in a very expeditious 
 nanner. Aeronauts m this manner determine the height to 
 which they ascend.f 
 
 Extent of the Atmosphere. The height of the atmosphere, 
 as estimated by the phenomena of refraction, is found to be 
 about forty-five miles. Above that height, no refraction takes 
 place in the rays of light. Dr. Wollaston estimates its ex- 
 tent, by the law of the expansion of gases, at forty miles; 
 that is, the iceight of the particles of air (gravity) will over- 
 come their elasticity arlLhat height. 
 
 Composition of the Atmosphere. Chemists are not agreed 
 whether the atmosphere is a chemical or a mechanical com- 
 pound. The proportions 20 or 21 parts of oxygen and 79 or 
 80 of nitrogen in 100 never vary, from whatever parts of the 
 earth, or regions of the atmosphere, it may be taken. Gay 
 Lussac brought air from an altitude of 21,735 feet, and its 
 composition did not vary from that on the surface of the earth. 
 
 Exp. That the atmosphere is composed of 4 parts of nitrogen and 
 1 of oxygen, by measure, may be shown by a graduated glass tube of 
 
 * Torricelli first filled a glass tube three feet in length with mercury, 
 and, on inverting it in a vessel of the same liquid, found that the mer- 
 cury fell about six inches; hence the atmosphere sustained a column 
 oi' mercury of about thirty inches. The space abandoned by the 
 mercury is called the Torricellian vacuum, and is the most perfect 
 mat can be formed. 
 
 t There seems to be a constant relation between the pressure of the 
 atmosphere and the weather. During a storm, the mercury in the 
 baromotej sinks, indicating that the atmosphere is lighter, and rises 
 again when fair weather returns, proving its greater weight. Invalids 
 often complain of the oppressive weight of air in foul weather; the 
 fact, as we have seen, is the reverse; they feel a difficulty in respira- 
 tion, because the air is too light. The same difficulty is felt by aero- 
 nauts, and those who. ascend high mountains, 
 
 3 
 
170 
 
 Xitrog 
 
 known capacity, and g. 81. Putabitof Fi?. SI. 
 
 phosphorus into the bent end, and place the open 
 end in a Yessel of water, keeping - the finger oTer the 
 end to prevent the air from escaping. Bring now 
 near the phosphorus a red-hot iron; the phospho- 
 rus will be inflamed, and will burn out the oxygen 
 of the air ; phosphoric acid will be formed, and 
 absorbed by the water ; the latter will rise, and fill 
 the tube 1-oth full; the remaining 4-oths is nitro- 
 gen. 
 
 This xuiiformitY in the composition of the 
 
 atmosphere has : -:\ reg i a decisive 
 
 proof of its che.- it has 
 
 been show; >y I n, that it is the results of 
 
 a mechanical, rather than of a chemical law. 
 
 This law may be illustrated in the following manner : — 
 
 one with oxygen and the other with hydrogen gas. Close the tube con 
 taining oxygen . : -.../_'. 7 : .-. r :: •-_ :„ 5 i.-.^frtf i 3 
 
 small glass tube. Hai sag inverted the lube containing the oxygen 
 place upon it Ih n g the hydrogen, so that one cork shall close 
 
 both tubes ; let them remain in an upright position. As the oxygen in 
 the lower vessel is sixteen times as heavy as the hydrogen in the upper, 
 we should expect that each would maintain its position: but the faet 
 is otherwise. They mutually ittlertsiagie. as is proved by their forming 
 explosive mixtures in both tubes. 
 
 Similar experiments have been made npon a great number 
 '.5 e 5 . and it is uniformly found that, after a little time, they 
 will distribute themselves equally through the space occupied 
 by both, whatever be their difference of density ; hen 
 
 pert 
 is each ether; that foes not prevent the en- 
 
 1 :e of another into my more 
 
 than the vacuum of an air-pump, although it will flow 
 more slowly in in the latter case. Ail r 
 
 and vapors follow Iienee there are as many at- 
 
 mosphere 1 the earth as there are gases upon its 
 
 surface, each occupying the same space which it would oc- 
 cupy if it were entirely alone. 
 
 diffusion to confine 
 
 gases in biac rn over water in the pneumatic cistern. 
 
 By placing hydrogen gas in a glass tube, one end of which is 
 stopped by plaster of Paris., over water, the hydrogen will force itself 
 out through th is -to prevent the entrance of the 
 
 air, and the water w be tube ; but, as the water rises, the at- 
 
 mt "pheric pre ; 5 . as to force the air into the tube, and the 
 
 wa *r will fall. By igniting the gas, it will explode ; which shows that 
 theie has been a mingling of the air with the hydrogen. 
 
Protoxide of Nitrogeh. 171 
 
 Impurities. The air usually contains other gases; car- 
 bonic acid and watery vapor are the most abundant. The 
 quantity of water is determined by the hygrometer. It never 
 amounts to more than one per cent. Carbonic acid rarely 
 exceeds j^ir- Traces of hydrochloric acid are frequently 
 found in the vicinity of the ocean, and of nitric acid in rain 
 water, produced by lightning. 
 
 The air near cities often contains other substances, organic 
 matter, sulphuric acid, and ammonia. The odoriferous par- 
 ticles of flowers, and other vegetable and mineral substances, 
 are often detected in it. 
 
 It was formerly supposed, that the healthy state of the air 
 depended upon the proportion of oxygen in it ; hence the 
 origin of the term eudiometry , which was applied to the 
 process of analyzing the air : but, since the oxygen of the 
 air is found to be constant, it is now applied also to the 
 modes of ascertaining its purity. This is effected either 
 by exploding a given portion of air with hydrogen in the 
 eudiometer, (see page 152,) or by placing in a portion of 
 confined air some substance to abstract the oxygen. 
 
 Uses of the Mr. The utility of the atmosphere in the economy of 
 nature cannot be too highly rated. It is absolutely essential to animal 
 and vegetable life. Its constitution is one of the most beautiful illus- 
 trations of the wisdom and goodness of the Creator. 
 
 Protoxide of Nitrogen. Symb. NO. Equiv. 14.15 -|-8 — 
 22.15. Sp. gr. 1.5239. 100 cubic inches weigh 47.2586 grains. 
 
 History. Discovered by Priestley, 1772, and named by 
 him depldogisticated nitrous air. Davy called it nitrous oxide. 
 
 Process. This gas may be formed by decomposing nitrate 
 of ammonia. 
 
 Exp. Put a few grains of this salt into a glass retort, and apply 
 heat. At a temperature of between 400° and 500° Fahr. it liquefies, 
 bubbles of gas begin to appear, and in a short time brisk effervescence. 
 The gas may then be collected in the ordinary way over warm water, 
 and suffered to remain a short time, until the water absorbs the nitrous 
 acid which is often formed with it. 
 
 Theory. The changes which take place may be thus ex- 
 plained : the NH 3 + NO 5 , containing 2N, 50, and 3H, are 
 converted into 3HO, or water, and 2NO. 
 
 Properties. The protoxide of nitrogen is a colorless, in- 
 odorous eras, of a sweetish taste, and does not affect the vege-* 
 table blues ; it is not, therefore, an acid or an alkali. 
 
172 Nitrogen and Oxygen. 
 
 It supports combustion almost as pmocrfully as oxygen gas* 
 
 Exp. A candle is relighted in the same manner as in oxygen gas. 
 Iron wire, charcoal, and most combustibles, burn in it. Phosphorus 
 burns with nearly the same brilliancy as in oxygen gas. 
 
 Exp. Mix equal volumes of the protoxide and hydrogen gas, and it will 
 form an explosive mixture, which may be exploded in Ihe gas pistol 
 by flame, or the electric spark; but generally it requires the temperature 
 of the substance to be raised to a higher degree than oxygen, because 
 the heat is necessary to decompose the gas, so that its oxygen may 
 unite with the combustible, and ltd nitrogen escape into the air. 
 
 Respiration of this Gas. When respired, it is a powerful 
 stimulant. Its effects upon the animal system were first in- 
 vestigated by Sir H. Davy in 1799. In his experiments on 
 the effects of respiring the various gases, he breathed nine 
 quarts of this gas for three minutes, and twelve quarts for 
 four. No quantity would support respiration for a longer 
 period. The effects are pleasurable in the highest degree, 
 resembling the first stages of intoxication. The effect varies 
 very much with temperament, bat generally gives an unusual 
 propensity to muscular action, a rapid flow of vivid ideas, 
 and the more prominent traits of character are made still 
 more prominent. 
 
 This excitement continues but for a few minutes, and gen- 
 erally is not succeeded by the languor and exhaustion conse- 
 quent upon other stimulants.* Its effects, however, upon some 
 temperaments, have proved decidedly injurious. It is hoped 
 that so powerful a stimulant will be applied to some good use 
 in medicine. 
 
 Binoxide of Nitrogen. Symb. N-f 20, NO 2 or N. Eq. 
 14.15 -f- 16 = 30.15. Sp. gr. 1.0375. 
 
 History. Discovered by Dr. Hales ; but its properties were 
 first investigated by Dr. Priestley, in 1772, who gave it the 
 name of nitrous air. Nitric oxide and nitrous gas have also 
 been applied to it. 
 
 Process. It may be formed by the action of dilute nitric 
 acid (2 parts of water to 1 of acid) upon copper filings, or 
 
 * It may be administered from a silk or India-rubber bag, furnished 
 with a stop-cock, by repeatedly breathing it from the bag and back 
 again, as long as it will support easy respiration. 
 
Nitrous Acid. 173 
 
 mercury. Place the materials in a retort, and collect over 
 water. 
 
 Theory. In this process, the nitric acid is decomposed. 3 equiv. of 
 oxygen unite with the copper, forming the peroxide of copper, and 2 
 equiv. of oxygen combine with the nitrogen, and form the binoxide ; the 
 peroxide of copper is then united to some undecomposed nitric acid, 
 and forms the nitrate of copper. Cu and 2N0 5 are converted into 
 Cu0 3 -f NOand NO 2 . 
 
 Properties. This gas is colorless, and slightly absorbed 
 by water. It is perfectly irrespirable, exciting spasms in the 
 glottis, which immediately closes to prevent its passage into 
 the lungs. It extinguishes most burning bodies, although 
 phosphorus and charcoal, introduced in a state of vivid com- 
 bustion, burn with increased brilliancy, owing, doubtless, to 
 its decomposition, which is easily effected by heat or elec- 
 tricity. 
 
 Binoxide of nitrogen has a strong affinity for oxygen. 
 
 Exp. Pass oxygen into a jar of it, and red fumes will be formed. 
 This is a test of the gas. Atmospheric air will produce a similar ef- 
 fect;* hence it may be used to separate the oxygen from the nitrogen 
 of the air. 
 
 Hyponitrous Acid. Syrnb. N + 30, NO 3 or N. Equiv. 
 14.15 -{-24 = 38.15. This compound was discovered by 
 Gay Lussac, and is said to be formed when 400 measures of 
 binoxide of nitrogen are mixed with 100 of oxygen, both 
 quite dry. When the resulting orange fumes are exposed to 
 a cold of zero, Fahr., they are condensed into a liquid. 
 
 Properties. The anhydrous acid is colorless at zero, and 
 green at common temperatures. It is so volatile, that, in open 
 vessels, the green fluid wholly and rapidly passes off in the 
 form of an orange-colored vapor, density of 1.72. In the 
 manufacture of sulphuric acid, it exerts an important agency, 
 by forming with water and sulphuric acid a crystalline com- 
 pound, the production of which seems essential to the 
 process. 
 
 Nitrous Acid, Symb. N + 40, NO 4 or N. Eq. 14.15 + 
 32 z= 46.15. 
 
 History. Known for some time under the name of fuming 
 nitrous acid. Its true nature has been ascertained by Davy, 
 Gay Lussac, and Dulong. 
 
 * Owing to this property, an attempt has been made to introduce it 
 into eudiometry ; but the results are not perfectly satisfactory. 
 
174 Nitrogen and Oxygen. 
 
 Processes. 1. It is formed by adding oxygen gas in excess 
 to the binoxide of nitrogen over mercury, and putting a strong 
 solution of potassa into the receiver before mixing the gases ; 
 red fumes appear, and combine"with the potassa. 
 
 2. It may be obtained in the form of a gas, by exhausting 
 a glass globe of air, and introducing 100 volumes of oxygen 
 to 200 volumes of the binoxide of nitrogen.* 
 
 3. The best mode is to expose, in an earthen retort, nitrate 
 of lead, carefully dried, to a red heat, and collect the gas in 
 a tube surrounded by ice. For the purposes of experiment, 
 it may be formed by introducing oxygen, or common air, into 
 a jar of the binoxide, over water ; deep orange-red colored 
 fumes appear, which are rapidly absorbed by the water ; or 
 by simply taking up a jar of the binoxide, and exposing it to 
 the air. In each case, nitrous acid is formed, and may be 
 known by its red fumes. 
 
 Properties. The vapor is of an orange-red color, rapidly 
 absorbed by water. At common temperatures, the liquid is 
 orange-red ; below 32°, yellow, and nearly colorless at zero, 
 Fahr. ; density, 1.451 ; anhydrous, exceedingly volatile, pun- 
 gent to the taste, and powerfully corrosive, giving a yellow 
 stain to the skin. ^. 
 
 It has decided acid properties, f both in the gaseous and 
 
 liquid states. 
 
 Exp. Into a long glass tube, filled partly with vegetable infusion, 
 and partly with the binoxide, introduce a few bubbles of oxygen; the 
 infusion will immediately turn red, owing to the formation of nitrous 
 acid, and the absorption of it by-the infusion. 
 
 Respiration of Nitrous Acid. It is highly suffocating and 
 poisonous, exciting great irritation and spasms in the glottis, 
 even when moderately diluted with air. 
 
 Nitric Acid. Symb. N + 50, NO 5 or N. Equiv. 14.15 
 + 40 = 54.15. 
 
 History. This acid was first discovered in distilling a 
 mixture of nitrate of potassa and clay, by Raymond Lully, 
 
 * If collected over water, it is converted into nitric acid; if over 
 mercury, it is decomposed, and the mercury is oxidized. 
 
 t Some chemists believe it to be a compound of nitric and hyponi- 
 trous acids, from the fact that, when it is added to an alkaline solution, 
 the products are a nitrate and a hyponitrite of the base. 
 
Nitric Acid. 
 
 175 
 
 Fig. 82. 
 
 a chemist of the Island of Majorca. Basil Valet.tine, in the 
 loth century, describes a process of obtaining it, and calls it 
 the icater of nitre. Its composition, however, was first de- 
 termined by Mr. Cavendish, in 1785, by exposing oxygen and 
 nitrogen in a glass tube over mercury, in which some water 
 was present, to the action of the electric battery. It has 
 since been examined by Davy, Dalton, Henry, Berzelius, and 
 Gay Lussac. 
 
 Process. Gay Lussac ob- 
 tained nitric acid by adding the \> 
 binoxide of nitrogen slowly to 
 an excess of oxygen over water. 
 By this process, it is found to 
 be composed of 250 volumes of " 
 oxygen to 100 of nitrogen. But 
 the usual process for obtaining 
 it, is to heat, in a large tubulated 
 retort, a, (Fig. 82,) a mixture 
 of 3 parts of nitre (nitrate of po- 
 tassa) and 2 of sulphuric acid,* 
 and condensing the gas in the 
 globe receiver h, by dropping 
 
 ice-cold water from the : tunnel t upon the tube of the retort, 
 or by surrounding the receiver b with ice. The liquid, as it 
 is condensed, passes into the bottle C. 
 
 Impurities. The acid of commerce is not perfectly pure ; three 
 acids are generated in the process — the.nitrous, hyponitrous, and nitric. 
 It also contains hydrochloric and sulphuric acids Nitrous acid gives 
 it a color varying from yellow to orange and green, and may be ex- 
 pelled by heat ; the hydrochloric may be detected and separated by a 
 few drops of the nitrate of silver, with which it will combine and form 
 a white solid. The sulphuric acid is separated by re-distilling it with 
 nitre. 
 
 Properties. Nitric acid, in its most concentrated state, is 
 
 a white or limpid liquid, specific gravity of 1.55, and of a 
 
 peculiarly nauseous odor. It boils at 248°, and freezes at 
 
 -50° Fahr, 
 
 * The London College of Physicians employ equal weights of nitrate 
 of potassa and sulphuric acid. The Edinburgh and Dublin Colleges 
 employ 3 of nitre to 2 of acid. According to Thompson, the strongest 
 acid is obtained from (U "parts of sulphuric acid to 12| of nitre; the 
 specific gravity of wlnca in 1.55. 
 
176 Nitric Acid. 
 
 Chemical Properties. It is one of the most energetic of 
 substances. It acts upon the skin, and gives it a yellow 
 stain ; it is eminently poisonous ; has a very strong affinity 
 for water, and cannot be wholly separated from it, before 
 decomposition takes place. 
 
 It acts as a supporter of combustion ; in this case, it is 
 decomposed, and the oxygen combines with the combustible. 
 
 Exp. Pass hydrogen and nitric acid through an ig- Fig. 83. 
 nited porcelain tube ; a violent detonation will be pro- 
 duced, which is due to the combination of the oxygen of 
 the acid and the hydrogen. 
 
 Exp. Pour strong nitric acid on dry, powdered char- 
 coal ; the charcoal will be ignited, with the evolution 
 of dense fumes. 
 
 Exp. Phosphorus takes fire in it. (Fig. 83,) sometimes 
 with violent explosion. 
 
 Exp. Pour nitric acid on to some of the essential oils, 
 as spirits of turpentine, and they will be inflamed. 
 
 The acid in these experiments should be pour- 
 ed from a wine-glass, attached to the end of a 
 long rod. 
 
 Nitric acid unites with various metals, such as iron, tin, 
 copper, w T ith great energy, and is decomposed by them. It 
 also suffers decomposition by boiling it in contact with 
 sulphur, or by exposing it to the solar rays. In this case, 
 the color changes to a yellow, and deep orange, in conse- 
 quence of the formation of nitrous acid. The action of 
 the binoxide of ritrogen produces the same effect, as may 
 be shown by passing it through nitric acid. In consequence 
 of its yielding up its oxygen so readily, it is one of the most 
 powerful oxidizing agents. 
 
 Uses. It is used extensively in chemistry and the arts ; 
 for etching on copper, and as a solvent of t'n to form a mor 
 dant for some of the finest dyes; in metallurgy and assaying, 
 to bring the metals to their maximum of oxidation ; in medi- 
 cine, as a tonic. The nitric acid of commerce is £ water, 
 and called double aquafortis ; another kind, f- water, is called 
 simply aquafortis. 
 
 Nitrohydrochloric Acid. This is the aqua rcgia of the 
 alchemists, and is formed of I part of nitric to 4 of hydro* 
 
Nitrogen and Chlorine. 177 
 
 chloric acid. It possesses the remarkable property of dissolv- 
 ing gold and platinum, but does not form a distinct class 
 of salts. 
 
 Nitroliydrofiuoric A cid. This acid is formed by a mixture 
 of nitric and hydrofluoric acids, and dissolves metals, which 
 are not dis'solved by the preceding acid, and is therefore an 
 important re-agent. 
 
 Nitrogen and Chlorine. 
 
 Quadrochloride of Nitrogen. Symb. N -f- 4C1 or NCI 4 . 
 
 Eq. 14.15 -f 141.68 == 155.83. Sp. gr. 1.653. Discovered 
 
 in 1811 by Dulong, and subsequently examined by Davy and 
 
 others. 
 
 Process. This very extraordinary substance may be formed by the 
 union of nitrogen and chlorine in their nascent state, or the chlorine 
 may be obtained in ajar, and inverted over a solution of ] part of hy- 
 drochlorate of ammonia to 12 of water; apart of the chlorine unites 
 with the tgrdrogen of the ammonia, forming hydrochloric acid, and 
 another portion unites with the nitrogen of the ammonia, and forms 
 the qnadro-chloride of nitrogen, which appears in the form of yellow, 
 oily drops on the surface of the solution. 
 
 Properties. A. yellow, oily liquid, of an irritating and pe- 
 culiar odor; it retains the liquid state below zero, Fahr. It 
 may be distilled at 160° Fahr., but explodes between 200° and 
 212°, and suffers decomposition. It is one of the most explo- 
 sive substances yet known. A drop of the size of a pea, 
 brought in contact with phosphorus, or with any of the oils, 
 will explode with great violence. It is dangerous to experi- 
 ment with it, even in so small portions. Dulong lost an eye 
 and a finger, and Davy had both eyes injured by exploding 
 small quantities of it. As it is liable to explode without 
 any assignable cause, great care should be used in its prepa- 
 ration. 
 
 Nitrogen and Iodine. 
 
 Teriodide of Nitrogen. Symb. N + 31 or NF. Eq. 14.15 -J- 
 378.9 — 392.24. This compound, discovered by M. Cour- 
 tois, is obtained in a similar maimer with the preceding. 
 
 Exp. Put iodine in a solution of ammonia, and there will be precip- 
 itated a blackish powder, which may be thrown, in the course of half 
 an hour, upon a filter, washed and dried. When dry, it explodes by 
 the slightest touch, or even spontaneously. 
 - 8* 
 
178 
 
 Nitrogen and Hydrogen. 
 
 Nitrogen and Hydrogen. 
 
 Ammonia. Symb. N + 3H or NH 3 . Eq. 14.15 + 3 = 
 17.15. 
 
 History. This substance was known to the alchemists by 
 the names of hartshorn, volatile alkali, spirit of sahammo* 
 niac, etc., but was first noticed as a distinct gas by Dr. Priest- 
 ley, who gave it the name of alkaline air. The name ammo- 
 nia is derived from one of the salts from which it was pro- 
 cured, the hydrochlorate of ammonia, or sal-ammoniac, and 
 this from the temple of Jupiter Ammon, in Lybia, from 
 which place it was first obtained. 
 
 Process. Mix together equal parts of pulverized Fig. 84. 
 hydrochlorate of ammonia and recently-slacked lime 
 in a common retort, and apply heat. The gas may 
 be collected over mercury, or, in consequence of its 
 being lighter than the air, the materials may be put 
 into a Florence flask, a, (Fig. 84,) to which is at- 
 tached a long glass tube. Invert over it a receiver, 
 r, and the gas will displace the air, and fill the re- 
 ceiver ; (for a test of the gas, hydrochloric acid 
 may be used, which produces a white cloud.) It 
 may also be obtained by simply heating the com- 
 mon aqua ammonia of commerce. The liquid ammonia, oi 
 aqua ammonia, is prepared by passing the gas through watei 
 in Woulfe's apparatus, in the same manner as in the prepa- 
 ration of hydrochloric acid. (Seepage 162.) 
 
 Theory. When lime and the hydrochlorate of ammonia are used, 
 the hydrochloric acid deserts the ammonia, and combines with the lime, 
 leaving the former to escape in the gaseous form. 
 
 Properties. Ammonia is a colorless gas, of a strong, pun- 
 gent odor ; becomes a transparent liquid under pressure of 
 6.5 atmospheres, and at a temperature of 50° Fahr. It cannot 
 support respiration in its pure state, but may be inhaled with 
 safety when mixed with the air. 
 
 It is inflammable, but extinguishes the flame of most burn- 
 ing bodies. 
 
 Exp. A candle immersed in this gas, burns with increased flame, 
 tinged with yellow before it goes out. When expelled from an orifice 
 
Nitrogen and Hydrogen. 179 
 
 surrounded by oxygen gas, and ignited, it burns with a pale yellow 
 flame. The products are water and nitrogen. 
 
 It has a strong affinity for tvater and for alcohol. 
 
 Exp. A few drops of water, introduced into a jar of the gas over 
 mercury, will instantly absorb it, and the mercury will rise. 
 Ice placed in ajar of it over mercury, is melted rapidly. 
 
 Alcohol absorbs several volumes of this gas, and the solu- 
 tion has a strong odor, commonly called spirits of hartshorn. 
 The decomposition of ammonia is effected by chlorine and 
 
 iodine. 
 
 * 
 
 Exp. Place a flask of ammonia over a bottle with a wide mouth, 
 containing chlorine gas. The gases will instantly combine, as will be 
 seen by a sheet of white flame. 
 
 Theory. The chlorine unites with the hydrogen of the ammonia, 
 forming hydrochloric acid ; and this unites with some undecomposed 
 ammonia, and forms hydrochlorate of ammonia, and will be deposited 
 on the sides of the flask in a solid state. 
 
 Ammonia, both in the gaseous and liquid form, possesses 
 
 decided alkaline properties* 
 
 Exp. Place ajar of ammoniacal gas on a plate containing vegetable 
 infusion, and the infusion will become green. 
 
 Uses. Ammonia is used in the arts and in medicine. In 
 chemistry, it is employed to neutralize acids. 
 
 Exp. Colors changed by acids may often be restored by ammonia. 
 Hence clothing spotted by acids, especially woollen clothes, may have 
 the color restored by moistening the spots with the liquid ammonia. 
 
 In medicine, it is used as a tonic. It is a powerful and 
 
 * Ammonium (Eq. NH 4 ) is a hypothetical compound of nitrogen and 
 hydrogen. Although it has never been isolated, yet many chemists have 
 inferred its existence. When ammonia is decomposed by a voltaic cur- 
 rent, the nitrogen escapes at the positive and the hydrogen at the negative 
 pole; but if the negative pole terminate in a cup of mercury, the hydro- 
 gen unites, it is supposed, with the nitrogen in the proportion of NH*, 
 forming a compound which unites with the mercury, causing it to swell 
 up and assume the consistency of soft butter. But this spongy mass be- 
 gins to sutfer decomposition as soon as the current ceases, yielding ammo- 
 nia and hydrogen, while the mercury regains its original state. 
 
 Ammidogen (NH 2 ) is another hypothetical compound similar to the above, 
 which has been supposed to be the base or radical of all the ammonia 
 compounds. Thus, when ammoniacal gas (NH 3 ) is heated with potas- 
 sium, there is formed a compound having the composition NH 2 K, or con- 
 taining one equivalent of hydrogen less, the H being evolved in the 
 process. So ammonia may be considered as composed of NH 2 -f-H. See 
 Organic Chemistry. 
 
180 Carbon, 
 
 grateful stimulant, producing the useful effects of alcohol, 
 without its injurious consequences. Ammonia is the sub 
 stance employed for smelling-bottles.* 
 
 Sect. 8. Carbon. 
 
 ti ' . .:« -n ■ (by vol. 100. c C 3.52 Water = 1 . 
 
 Symb. C. Eqniy. ^ * ^ g ]2 Sp. gr. J fi J2 Hyd = ^ 
 
 Natural History. Carbon is one of the most important 
 and useful of substances. Like all other substances of ex- 
 tensive utility, it is widely diffused. It exists abundantly in 
 the animal, vegetable, and mineral kingdoms. The greater 
 part of the substance of trees, and of animal bodies, is car- 
 bon It is rarely found quite pure in nature, and cannot 
 be formed perfectly pure by art. The only pure carbon is 
 the diamond. 
 
 The diamond is found in the East Indies and in Brazil, 
 S. A. They generally occur in alluvial soils, in detached crys- 
 tals, the primitive form of which is the regular octohedron. 
 but sometimes have twenty-four, and even forty-eight faces. 
 They are of various colors, brown, black, red, blue, and green, 
 or colorless and transparent ; the latter are the most valued. f 
 The diamond is the hardest body in nature. It is a powerful 
 refractor of light, a property which led Newton to predict its 
 combustion. Lavoisier first proved it to contain carbon, by 
 exposing it in oxygen gas to the solar focus. The product 
 was carbonic acid. In 1807, the combustion of the diamond 
 in oxygen was found by Allen and Pepys to,be attended by 
 the same results as that of charcoal. Davy confirmed these 
 results by comparing the combustion of the diamond with 
 that of various kinds of charcoal. Another proof of its iden- 
 tity is the fact, that diamond converts iron into steel in the 
 same manner as charcoal. 
 
 * To prepare a smelling-bottle, it is only necessary to put a small 
 ouantity of quick lime and hydrochlorate of ammonia into a small bot- 
 tle, and keep it corked tight, only when it is used. 
 
 t Diamonds are of various sizes; some are as large as a pigeon's 
 egg, and the value increases with the siae in a very rapid ratio. 
 
Carbon. 181 
 
 Uses. The diamond is the most valued of gems; used in 
 jewelry, and for the purpose of cutting glass. 
 
 The other kinds of carbon are the following : — 
 
 Plumbago. This is carbon nearly pure, containing four 
 or five per cent, of iron. It is sometimes called black lead, 
 and used for pencils, crayons, etc. It is found native in 
 primitive formations, and is next to the diamond in purity. 
 
 Anthracite is a species of fossil coal, the next in purity. 
 
 Bituminous coal is similar to the preceding, with the addi- 
 tion of bitumen, when the bituminous and volatile matter is 
 driven off by heat ; it is called coke, which is nearly pure 
 carbon. 
 
 Peat is an impure kind of carbon, containing uncarbon- 
 ized vegetable matter, mixed with earthy substances. 
 
 Lampblack is a kind of carbon which is obtained by the 
 combustion of turpentine, pitch-pine, camphor, and almost 
 any species of combustible matter, containing carbon. It is 
 deposited from flame in the form of a fine black powder. 
 For use in the arts, it is chiefly made to^fcirpentine manufac- 
 turers, from the refuse resin. This flBped in a furnace, 
 and the smoke, carrying up the carboflML conducted to a 
 room hung with sacking, upon which the lHl^lack is depos- 
 ited. It is collected and sold without further preparation. 
 It is used extensively as a paint — that from camphor is the 
 best. 
 
 Ivory black is a kind of lampblack obtained from burning 
 bones, sometimes called animal charcoal. 
 
 Charcoal. If wood be burned in the open air, nothing 
 remains but ashes; but if the air is mostly excluded, so that 
 it undergoes a smothered combustion, a black, brittle sub- 
 stance remains, called charcoal, which is nearly pure carbon 
 
 Processes. 1. For the common purposes of fuel, it is pre- 
 pared by forming the wood into a conical pile, and covering 
 it with earth. The combustion is slow, in consequence of 
 the small quantity of air which is admitted; the volatile parts 
 are driven off, and the carbon remains. 
 
 2. It is also prepared by distillation of wood, in large iron 
 
1S2 Carbon. 
 
 cylinders. This is the mode of preparing it for the manufac- 
 ture of gunpowder. Beside the charcoal, two valuable sub- 
 stances, the pvroligneous acid and tar. are obtained. 
 
 3. But the purest charcoal is prepared by charring wood 
 under sand or melted lead. It should be put immediately 
 into bottles, corked tight, to exclude the air. 
 
 Properties, Carbon is a black, brittle, shining, inodorous 
 substance, easily .pulverized, a good conductor of electricity, 
 and a bad conductor of caloric. 
 
 It is the hardest substance in nature. Common charcoal 
 appears soft, but this is in consequence of its pores. If 
 rubbed upon glass, it will scratch it. 
 
 It has the property of absorbing various gaseous bodies. 
 
 Exp. Heat a piece of charcoal, and plunge it into mercury until 
 cool, then place it under a 2"lass receiver over mercury. In the course 
 of twenty-four or thirty-six hours, it will absorb of ammonia 90 times 
 the volume of the charcoal: 
 
 Hydrochloric acid, . ... 85 
 
 Sulphurous acid, Bo 
 
 H^r: sulphuric acid, ... 5-5 
 
 x:de of nitrogen, ... 40 
 
 Carbonic acid. 35 
 
 defiant gas, 35 
 
 Carbonic oxide, .... 9.42 
 
 Oxygen, 9.25 
 
 ^Nitrogen, 75 
 
 Hvdroiren, 1.75 
 
 The gases will be given up again by heating the charcoal, 
 or partially by plunging it into water. 
 
 Theory. This power cannot .be attributed wholly to chemical action. 
 but is due to the porous texture of the charcoal; and the 
 
 i sorbed in the same manner that sponges and other porous 
 r.bsorb liquids. The property is most remarkable in the com- 
 pact varieties, such as that from box-wood, where the pores are numer- 
 ous and small. By reducing it to powder, this power is diminished. 
 In plumbago, and in the diamond, it is wholly wanting. 
 
 But how does this account for its absorbing more of one gas than of 
 ; Chemical affinity has doubtless rue inSue:. 
 ::ue to the e'asticity of the gases. Those gases, easily converted 
 into liquids, are absorbed in greater quantities than those more perma- 
 nent; hence vapors are absorbed more easily than gases, and 
 than ether. Hence, too, charcoal, when exposed to the 
 gases, increases in weight* 
 
 ■ The increase varies with the kind of wood from which it is made. 
 According to the experiment of Allen and Pepys. charcoal from fo 
 gains 13 per cent. ; lignumvitae, 9.6 per cent. : that from 
 
 Box 14. I Oak, 1 
 
 Birch, 1*33 j Mahogany, 
 
Properties. 183 
 
 The absorption is the most rapid during the first twenty- 
 four hours ; it absorbs oxygen from the air more rapidly than 
 nitrogen. 
 
 Ii also absorbs the odoriferous and coloring principles 
 from most animal and vegetable substances. 
 
 Exp. Pass ink through pulverized charcoal, and the color will be 
 discharged. Red wines, rum, and brandy, may be rendered colorless 
 Dy nitration through it. 
 
 It is used extensively for refining sugar, and for preparing 
 colorless crystals of citric acid, and other vegetable produc- 
 tions. Stagnant water, and most animal and vegetable sub- 
 stances, in a putrescent state, will be cleansed and purified 
 by this substance ; hence its use to purify docks, vessels, etc. 
 Putrescent meat is purified by rubbing it with charcoal ; 
 and, generally, all substances subject to putrescence may 
 be preserved for a long time, by surrounding them with 
 charcoal. 
 
 In consequence of this property, it is used in medicine as 
 an antiseptic in putrescent diseases. Animal charcoal is the 
 best for these purposes, and as its efficacy depends upon its 
 power of absorption, it should be heated, to expel all the gas, 
 before it is used, or kept in well-stopped bottles as soon as 
 prepared. 
 
 It is very combustible. It requires a strong heat to ignite 
 it, but then it will burn for a long time, the oxygen of the 
 air uniting with it and forming carbonic acid.* In conse- 
 quence of this property, it is one of the most useful substances 
 in nature. 
 
 It is the most durable substance known. Grains of wheat 
 and rye charred in Herculaneum by the volcanic eruption, 
 A. D. 79, were easily distinguished from each other, eighteen 
 centuries afterward ; an arrow head has been charred, and 
 even the form of the feather preserved. The stakes driven 
 down in the bed of the Thames, by the Britons, to prevent the 
 army of Julius Caesar from passing the river, were discovered 
 about fifty years since, and were all charred to a consider- 
 able depth. They were as perfect as when driven ; were 
 made into knife-handles, and sold as antiques at a high 
 price. Farmers char their troughs and posts to prevent 
 decay. 
 
 * Large quantities of powdered charcoal often ignite spontaneously, 
 owing, doubtless, to the small quantity of potassium which is gener- 
 ally found in connection with it 
 
184 Carbon. 
 
 It is infusible by any degree of heat, except that from a 
 powerful galvanic battery ; and in this case there is reason to 
 doubt whether there is a fusion of any thing but of some im- 
 purities in the carbon. 
 
 Uses. The uses of carbon have already been stated, and 
 are generally well known. It is one of those substances 
 which are indispensable to the wants, to the existence of our 
 race ; and the Creator has given us, in its character and 
 abundance, the most decisive proofs of his wisdom and 
 benevolence. 
 
 Carbon possesses extensive powers of combination, and 
 forms a class of substances of great and permanent utility in 
 chemistry, the arts, and the common business of life. 
 
 Carbonic Oxide. Symb. CO or C. Equiv. 6.12 +8 = 14.12. 
 Sp. gr. 0.9727, air = l. 
 
 History. Discovered by Priestley by the distillation of 
 charcoal with the oxide of zinc ; but its composition was 
 first determined by Mr. Cruick?hank. 
 
 Process. The best and most convenient mode of obtain 
 ing this substance, is to put 2 parts of well-dried chalk, 
 pulverized, to 1 of iron filings, into a gun-barrel, and raise 
 the temperature to a red heat. The gas may then be col- 
 lected over water ; it may be obtained, also, by heating the 
 oxides of several of the metals with powdered charcoal. 
 
 Theory. Chal&is composed of carbonic acid and lime. One equiv- 
 alent of oxygen contained in the acid, goes to the iron, and convert* 
 the acid to the carbonic oxide ; oxide of iron and lime remain, or CO 2 
 -|-CaO and Fe are converted into FeO, CaO, and (JO. 
 
 Properties. A colorless, insipid gas, of an offensive odor. 
 
 It is highly inflammable, and burns with a pale blue flame 
 
 when a lighted taper is plunged into it, but does not support 
 
 combustion. A mixture of 1 part of oxygen to 2 of the 
 
 gas is explosive ; the result is carbonic acid. It is dcstruc 
 
 tive to animal life ; an animal immersed in it soon dies. 
 
 When diluted with air, it causes fainting and giddiness. 
 
 Carbonic Acid. Symb. C + 20, CO 2 or C. Equh. 6.12 
 + 16 = 22.12. Sp. gr. 1.5239, air= 1. 
 
 History. Discovered in 1757 by Dr. Black, who called 
 
Carbonic Acid. 185 
 
 it fixed air.* This was the first gas known, except the 
 atmosphere, and laid the foundation of pneumatic chemistry. 
 Natural History. Carbonic acid exists very abundantly 
 in nature, generally in combination with lime, forming the 
 carbonate of lime, or marble. 
 
 Process. It is obtained by the combustion of the diamond 
 in oxygen gas, or by burning charcoal in the air, or oxygen ; 
 but it is more easily obtained by decomposing some of the 
 carbonates. Take pulverized carbonate of lime (marble or 
 chalk) in a glass retort, and pour on sulphuric or hydro- 
 chloric acid, diluted with five or six parts of water, and 
 collect over water, or in a globe receiver, in the same man- 
 ner as hypochlorous acid gas.f (See page 133.) 
 
 Theory. In this process, the sulphuric acid combines with the lime, 
 forming the sulphate of lime, and liberates the carbonic acid. SO 3 , 
 C0 2 -f-CaO are converted into S0 3 -f-CaO and CO 2 . * ^A 
 
 Properties. It is colorless, inodorous,jmd ^^ii^0Kf^X" 
 ing a pressure of thirty*six atmospheres, 540 lbs., to the 
 square inch, to condense it into a liquid — more than I J times 
 as heavy as atmospheric air, and hence may be poured from 
 one vessel to another, like water. 
 
 It is neither a combustible nor a supporter of combustion. 
 
 Exp. Tnto ajar of carbonic acid, let down a pendent candle. It will 
 be extinguished as soon as it reaches the gas, or it may be poured upon 
 the candle from a vessel. The flame does not cease from want of oxy- 
 gen, since four measures of air and one of carbonic acid will extin* 
 guish flame ; hence a positive influence is exerted upon it. 
 
 It is rapidly absorbed by water. 
 
 Exp. If a small quantity of water be agitated in a bottle containing 
 carbonic acid gas, it will soon absorb it, and acquire acid properties. 
 
 Recently-boiled water will absorb one volume of the gas at the com- 
 mon temperature and pressure, but increases in its absorbing power in 
 proportion to the pressure applied. It absorbs twice its volume when 
 the presbure is doubled, three times its volume when the pressure is 
 trebled, etc. 
 
 * Its composition was first demonstrated synthetically by Lavoisier, 
 who obtained it by the Gombustion of charcoal in oxygen gas. Smith- 
 son Tennant proved its composition analytically by passing the vapor 
 of phosphorus over chalk, heated to redness in a glass tube. 
 
 t If intended to be kept long, it should be transferred from the cis- 
 tern in bottles, as the water rapidly absorbs it, 
 
186 
 
 Carbon. 
 
 Fig. 85. 
 
 Water may be acidulated with it, by employing Wbutfc's 
 apparatus, in the same manner as with hydrochloric acid. 
 (See page 162.) In the common soda fountains, the water 
 is confined in a strong brass or copper vessel, and charged 
 with the gas by a forcing-pump. The pleasant, pungent 
 taste and sparkling appearance of fermented liquors, soda, 
 and Seidlitz waters, and the waters of many mineral springs, 
 are due to the carbonic acid which they hold in solution. 
 The water saturated with it makes a pleasant and healthful 
 drink. 
 
 But the gas escapes on exposure to air and heat. Hence 
 all such drinks soon become insipid. 
 
 If the pressure is removed, the escape 
 of gas is much more rapid. 
 
 ffJPI ace a tumbler of water, (Tig. 85.) satu- 
 rated iW^fcAbis gas, under the receiver a of an 
 air-pump b, ana exhaust the air. The gas will 
 escape so rapidly as to present the appearance 
 of boiling. Any of the fermented liquors will 
 produce similar phenomena. 
 
 If the water saturated with the acid 
 be rapidly congealed, the frozen water 
 has the appearance of snow, its bulk 
 being greatly increased by the immense 
 number of bubbles formed by the liber- s 
 ated gas. 
 
 It is an acid, as shown by chemical tests, 
 
 Exp. Put apiece of litmus paper into water saturated with it, and 
 it is turned red ; but by heat, or exposure to the air, the color returns, 
 owing to the escape of the acid. 
 
 This is not the case with any other acid ; the colors they 
 form are generally permanent, unless changed by alkalies. 
 
 The best test of carbonic acid is June water, which is ren« 
 dered turbid by the gas. 
 
 Theory. Carbonic acid unites with the lime which the water holds 
 in solution, and forms the carbonate of lime, which is soluble in water, 
 and is precipitated in fine powder. This gives to the w T ater a milky 
 appearance. If, however, you continue to add carbonic acid, it will 
 dissolve the carbonate, and the water will become clear again, carbon* 
 ate of lime being very soluble in excess of carbonic acid. 
 
 Solidification of Carbonic Acid. It has lately been ascer- 
 
Carbonic Acid. 187 
 
 tained, that when the gaseous carbonic acid is subjected to a 
 pressure of thirty-six atmospheres, it is condensed into a 
 liquid, and at -85° into a solid resembling compact snow.* 
 
 Relations to Animal Life. Although water saturated with 
 carbonic acid proves a healthful and invigorating drink, the 
 free acid cannot be taken into the lungs without producing 
 almost instant death ; in fact, the glottis closes at its ap- 
 proach, and will not suffer it to enter. If it be diluted with 
 air, it acts upon the system as a narcotic poison ; an animal 
 thrown into it is usually suffocated. f Carbonic acid is 
 heavier than the air, and hence often remains in wells and 
 deep pits, where it is generated, and called by the miners 
 choke-damp. Before descending, a candle should be let 
 down, and if it will not burn, life cannot be supported. The 
 acid may be absorbed by pouring down large quantities of 
 water ; it may be partially expelled by exploding gunpow- 
 der near the bottom ; or it may be drawn up with large 
 buckets. •**. 
 
 Production of Carbonic Acid. Causes are in constant 
 operation to form carbonic acid, and throw it off into the 
 
 * Mr. Faraday first condensed carbonic acid into a liquid by placing 
 carbonate of ammonia in one end of a strong glass tube, bent twice at 
 right angles, and sulphuric acid in the other end, which is sealed her- 
 metically. "When the acid is poured upon the ammonia, it combines 
 with it and liberates the gas, which, by the pressure, is condensed; 
 but this process is attended with much danger, from the bursting of 
 the tube. A safer method has been contrived by Thillorier, in which 
 the gas is condensed in a strong metallic cylinder. By allowing the 
 liquid acid to escape through tlje stop-cock, it expands so rapidly as to 
 become frozen, owing to the absorption of its sensible caloric. A re- 
 duction of temperature to -162° is said to have been produced by this 
 means. The solid acid thus formed is about the weight of carbonate 
 of magnesia, perfectly white, and of a soft, spongy texture. It evapo- 
 rates so rapidly that mercury, and even alcohol, (sp. gr. .820,) are frozen. 
 According to the experiments of Mitchell, of Philadelphia, the greatest 
 cold produced by the solid acid in the air was -109°, and under an 
 exhausted receiver -136°. The pressure at 32° was 36 atmospheres, 
 at 66°, 60 atmospheres, and at 86°, 72 atmospheres, or ]290 lbs. to the 
 square inch. When obtained in a liquid form in a glass tube, it is 
 colorless and extremely fluid In attempting to open the tubes at one 
 end, they uniformly burst into fragments, with violent explosions. 
 
 f Caution. This gas is always produced in burning charcoal ; and 
 hence the danger and criminality of placing pans of hot coals in 
 sleeping apartments, or in rooms not ventilated by a chimney. The 
 acid gradually mixes with the air, causing drowsiness, and even death, 
 before the person can escape. Every year adds new proofs, in the loss 
 of many lives, to the folly and danger of such practices. 
 
188 Carbon, 
 
 « atmosphere. It is evolved in great quantities from the earth, 
 from ordinary combustion, and by the respiration of animals. 
 In the two last cases, the oxygen of the air is consumed, and 
 carbonic acid takes its place ; hence we should expect, if 
 there were nothing to counteract this process, that the whole 
 atmosphere would, in time, be rendered unfit to support 
 respiration ; but not more than yoVo - part of the atmosphere 
 is carbonic acid. In places near cities, or where it is evolved 
 from the earth, the proportion may be greater. This ten- 
 dencv. however, may be counteracted by the vegetable king- 
 dom. During the daytime, plants absorb carbonic acid, de- 
 compose it, retain its carbon, and throw off its oxygen. In 
 the night, the process is reversed ; oxygen is consumed, and 
 carbonic acid is thrown off; but more of oxygen is emitted 
 in the daytime than is consumed in the night : more carbonic 
 acid also is consumed during the day than is given off dur- 
 ing the night. The balance from this process is needed to 
 meet the demands of the animal kingdom, which constantly 
 consumes oxygen, and generates carbonic acid in the process 
 of respiration. Thus the equilibrium of the atmosphere is 
 preserved, and both kingdoms flourish together. 
 
 Eip. That carbonic acid is given off in respiration, may be shown 
 by breathing with a quill through lime water, which will become tur- 
 bid. This fact enables us to understand the process of 
 
 Respiration. The blood, in its progress through the sys- 
 tem, becomes filled with carbon, which gives to it a dark 
 color. When it passes into the lun^s, the air is brought in 
 contact with it : the carbon unites with the oxygen, forming 
 carbonic acid, which is expelled, and the blood is changed 
 to a bright red ; it is now fitted to nourish the system. Some 
 suppose that the oxygen enters into the blood, and that the 
 nation takes place during the course of circulation ; but 
 whichever theory be adopted, carbonic acid is thrown off 
 and oxygen is consumed. Hence, in crowded assemblies, 
 great quantities of this gas are formed, and, as a consequence, 
 dulness and fainting often ensue. Hence, also, the neces- 
 sity of having large public rooms well ventilated. 
 
 Bichloride of Carbon (Symb. C 2 C1. Equiv. 12.24 + 35 42 = 47.Cfi) 
 :"-9bd by M. Julio. It occurs in small, soft, adhesive fibres, 
 of a wir a pectiliar odor, resembling spermaceti, and is taste- 
 
 less : burns wun a red flame, emitting- much smoke, and fumes of hy- 
 drochloric acid gas. 
 
 Protochhride of Carbon. Symb. CC1. Equiv. 6.12 + 3542 = 41 .54. 
 It is obtained by passing the vapor of perchlonde of carbon through a 
 
Compounds of Carbon. 189 
 
 heated glass tube, filled with fragments of rock crystal, to increase the 
 heated surface. It id a limpid, colorless liquid; density, 1.5520. 
 
 |- Chloride of Curb m. Symb. C 4 C1 5 . Equiv 24.48+177.1 = 201.58 
 Discovered by Liebig, and sometimes called the new chloride of 
 Liebig; obtained by boiling chloral with a solution of lime, potassa, or 
 baryta. It is a limpid, colorless liquid, similar in odor and appearance 
 to the oily fluid which chlorine forms with defiant gas; density, 1.43; 
 boils at 141° Fahr 
 
 Perchhride of Carbon. Symb. C 2 C1 3 . 12.24 -f 106,2G = 118.5. Dis- 
 covered by Faraday. When olefiant gas is mixed with chlorine, com- 
 bination takes place between them, and an oil-like liquid is formed, 
 consisting of carbon, hydrogen, and chlorine. Expose this liquid, in a 
 jar of chlorine, to the solar rays, and hydrochloric acid is set free, and 
 the chloiine unites with the carbon. 
 
 Properties. At common temperatures, it is a colorless, transparent 
 solid, of an aromatic odor, resembling that of camphor; fuses at 320°, 
 and boils at 300°. 
 
 Chloro-carbonic Acid. Symb. O -f C -f CI. Equiv. 8 -f 6.12 -f- 35.42 
 = 49.54. This singular compound of oxygen, chlorine, and carbon, 
 affords a somewhat unusual instance of two acidifying principles 
 uniting with one base to form an acid. It was discovered by Dr. 
 Davy, who called it Phosgene gtos. It is formed by exposing equal 
 volumes of chlorine and carbonic oxide to the solar rays, when rapid 
 but silent combustion takes place, and they contract to one half their 
 volume. 
 
 Properties. A colorless gas, with a strong odor ; reddens litmus pa- 
 per, and combines with four times its volume of ammohiacal gas. Wa- 
 ter and several of the metals decompose it. 
 
 Chloral (Symb. C C C1 6 4 . Equiv. 299.60) is a new compound of 
 carbon, oxygen, and chlorine, discovered by Liebig, and prepared by 
 the mutual action of alcohol and chlorine. It is a colorless, transparent .. 
 liquid, of a penetrating, pungent odor, nearly tasteless, oily to the 
 touch ; density, 1.502, and boils at 201°. 
 
 Periodide of Carbon was discovered by Serullas, and is obtained by 
 mixing an alcoholic solution of pure potassa and of iodine. It forms 
 crystals of a pearly lustre, sweet to the taste, and of a strong, aromatic 
 odor, resembling saffron. 
 
 The Protiodide is formed by distilling a mixture of the preceding 
 compound with corrosive sublimate. It is a liquid of a sweet taste, and 
 penetrating, ethereal odor. 
 
 Bromide of Carbon. Formed by mixing 1 part of periodide of 
 carbon with 2 of bromine : two Compounds are formed, the bromide 
 of carbon and the sub- bromide of iodine; the latter is removed by a 
 solution of caustic potassa. It is liquid at common temperatures, but 
 crystallizes at 32° Fahr. ; sweet to the taste, and of a penetralSmg, ethe- 
 real odor ; distinguished from the protiodide by the vapor which it emits 
 on exposure to heat. 
 
190 Carbon and Hydrogen. 
 
 Carbon and Hydrogen. 
 
 Two compounds of carbon and hydrogen have been known 
 for some time, but of late the number has been increased to 
 at least twelve. 
 
 Dicarburet of Hydrogen. Symb. C -|-2H or CH 2 . Equiv. 
 6.12 + 2 — 8.12. Sp. gr. 0.5593, air = 1. 
 
 History. This substance is generally known under the 
 name of light carbureted hydrogen. The names heavy in* 
 flammable air, the inflammable air of marshes, and hydro* 
 carburet^ have also been applied to it; but, taking carbon as 
 the electro-negative element, it is more agreeable with the 
 principles of nomenclature to call it a dicarburet of hydrogen. 
 Dalton first ascertained its real nature, but it was subse- 
 quently examined by Davy, Thompson, and Henry. 
 
 Process. This gas is formed naturally by the decomposi- 
 tion of vegetable matter in marshes. It may be obtained by 
 inverting a receiver in almost any stagnant pool, and stirring 
 the sediment at the bottom. In this state it contains one 
 twentieth part of carbonic acid, and one fifteenth of nitrogen ; 
 the former may be removed by lime water or pure potassa. 
 This is the best mode to obtain the pure ^as. 
 
 It is formed also by the distillation of mineral coal, con- 
 taining carbonic acid and olefiarrt gas ; the former may be 
 removed by lime water, the latter by chlorine. 
 
 Properties. Colorless, tasteless, and nearly inodorous. 
 Water absorbs -£$ of its volume. It extinguishes all burning 
 bodies, but is highly combustible. It burns in a jet with a 
 yellow flame, brighter than hydrogen ; destructive to animal 
 life when respired ; partially decomposed by a very intense 
 heat. 
 
 Exp. Mixed with rather move than ticice its volume of oxygen, it is cx~ 
 plosive ; exactly two volumes of oxygen are consumed, and the prod- 
 ucts are carbonic acid and water. 
 
 Exp. Mixed with chlorine, and exposed to the solar light, it is de- 
 composed, and hydrochloric and carbonic acids are formed ; though the 
 products will depend upon the quantity of chlorine. 
 
 Oleflant Gas, or §• Carburet of Hydrogen. Symb. 2C -f- 
 
 2H. Equiv. 12.24+2=14.24. Sp. gr. 0.9808, air = 1. 
 
Carbon and Hydrogen. 191 
 
 History. Discovered in 1796 by some associated Dutch 
 chemists, who called it olefiant gas from its forming an oil- 
 like liquid with chlorine. It has been called hyduret of car 
 bon, bicarbureted or percarburcted hydrogen ; but § carburet 
 of hydrogen accurately designates its composition, and is, on 
 this account, preferable. 
 
 Process. Mix in a large retort 1 measure of alcohol with 
 
 2 of concentrated sulphuric acid, and apply the heat of a 
 
 spirit lamp. The mixture soon turns black, and rises up in 
 
 the retort ; the gas is rapidly disengaged, and may be col-* 
 
 lected over water or mercury ; carbonic and sulphuric acids 
 
 are formed during the process, and may be separated by pure 
 
 potassa or lime water. 
 
 Theory. Alcohol is a compound of defiant gas and water. The 
 sulphuric acid unites with the water, and the gas is evolved. C 2 H 3 
 and SO 3 are converted into SO 3 , HO, and C 2 H 2 . At the commence- 
 ment of the process, ether is formed, which differs from alcohol by hav- 
 ing 2 equiv. of olefiant gas combined with water, while alcohol has but 
 1. The ether is condensed in the cistern. 
 
 Properties. It is a colorless, tasteless gas, and has scarcely 
 any odor when pure. Water absorbs £ of its volume. It 
 extinguishes a lighted taper when immersed in it, and there- 
 fore does not support respiration. It burns with a clear, white 
 light. 
 
 Mixed with oxygen, it is highly explosive. 
 
 Exp. Mixed with oxygen in the proportions of 1 volume of the gas 
 to 3 of oxygen, and kindled by flame, or the electric spark, it explodes 
 with great violence. This may he shown by the gas pistol. There is, 
 however, much danger of bursting the pistol; glass vessels should 
 -not be employed to explode it. 
 
 Exp. Bubbles of the mixture may be passed up through the water 
 of the cistern, and exploded upon the surface ; but care should be taken 
 that the fire is not communicated to the vessel containing the mixture, 
 through the bubbles as they rise. 
 
 It is decomposed by heat. By passing it through a porce- 
 lain tube at a low red heat, charcoal is deposited, and the 
 bicarburet evolved, which, at a white heat, is also decom- 
 posed. It is also resolved into hydrogen and carbon by a 
 succession of electric shocks. 
 
 Action of Chlorine. When 2 volumes of chlorine and 1 
 of olefiant gas are mixed and ignited, they burn rapidly, 
 
192 Carbon. — Gas Lights. 
 
 and form hydrochloric acid, while the carbon is deposited; 
 
 but, if the gases remain at rest, they slowly combine, and form 
 
 an oily liquid, of a yellow color, called chloride of hydro' 
 
 carbon. 
 
 f- Carburet of Hydrogln, Etherine, (Syrab. 4C + 4H. Equiv. 24.48 
 + 4 = 28.48. Sp. gr. 0.627, water = 1.) was first obtained by 
 Faraday in the process of compressing oil gas into strong copper 
 globes, for the supply of portable gas. It is a highly volatile liquid, 
 the lightest liquid body known. At 60°, it is exceedingly combustible, 
 and burns with a brilliant flame. 
 
 f Carburet of Hydrogen (Symb. 6C -f 3H. Equiv. 36.72 + 3 = 
 39.72. Sp. gr. 0.85) was obtained by Faraday from the same oil gas 
 liquid which yielded etherine. At common temperatures, it is a color- 
 less, transparent liquid, smells like oil gas, with a slight odor of almonds. 
 It is highly combustible, and forms with oxygen a powerful detonating 
 mixture. 
 
 Parrqffine is a compound of carbon and hydrogen, obtained by the 
 distillation of the petroleum of Rangoon, and also by that of tar de- 
 rived from beech wood. It is a fatty substance, without taste or odor, 
 and burns with a pure white flame. 
 
 Eupione differs from the preceding compound only in containing a 
 smaller portion of carbon. It is obtained by distillation of the tar 
 derived from bones or horns. It is a tasteless, inodorous liquid, similar 
 to oils, but as limpid as alcohol. 
 
 Naphtha (Symb. 6C + 5H. Equiv. 36.72 + 5 = 41.72. Sp. gr. 
 0.753) is obtained from coal tar by distillation. It is a volatile, limpid 
 liquid, of a strong, peculiar odor, and generally of a light yellow color. 
 It is very inflammable, burning with a white flame and much smoke. 
 It is used to preserve potassium. 
 
 Naphthaline (Symb. C 10 H 4 . Equiv. 61 .2 + 4 = 65.2) is obtained in 
 the same manner as the preceding compound. It is a white, crys- 
 talline solid, heavier than watefj has an aromatic pungent taste, and 
 faintly-aromatic odor. With sulphuric acid, it forms a compound, first 
 described by Faraday in 1826, under the name of sulpho-naphthalic acid, 
 which has a bitter taste and acid properties. 
 
 Paranaphth aline (Symb. C 15 H 6 . Equiv. 91.8 + 6 = 97.8) is allied 
 to the preceding, and obtained from coal tar. 
 
 Idrialine is also similar, and obtained from a mineral in the quick- 
 silver mines at Idria, in Carniola. 
 
 Camphene and Citrene. Symb. C ,0 H S . Equiv. 61.2 + 8 = 69.2. 
 Camphene is the basis of camphor ; colorless, volatile, and inflammable 
 odor like the oil of turpentine. Citrene is almost the sole ingredient 
 of the oil of lemons. 
 
 Gas Lights. 
 
 History. The gas, now so generally employed for the 
 purpose of lighting cities, is probably a mixture of several of 
 
Gas Lights. 1#3 
 
 the preceding substances, composed mostly, however, of 
 olcfiant gas. This gas was first employed for the purposes of 
 illumination by Dr. Clayton, in 1739, but was soon given up 
 for more than sixty years. The subject was investigated, 
 about fifty years since, by Mr. Murdock ; and since that time 
 gas lights have come into general use, both in Europe and 
 America. The gas was obtained chiefly from the distillation 
 of coal; but that obtained from oil (spermaceti is the best) is 
 much purer, and possesses a greater illuminating power. 
 Gas from rosin is about equal to that from oil. 
 
 Process. When oil is used, several large cylindrical cast- 
 iron retorts are laid across a furnace, and partially filled with 
 brick and bits of iron, to increase the heated surface. The 
 oil is contained in a reservoir, and conveyed to the retorts by 
 separate tubes. When the retorts are heated to the proper 
 temperature, the oil is admitted by a stop-cock, in a small 
 stream, so that it is immediately decomposed, and the gas 
 passes out of the retorts by other tubes, running into a large 
 one, which conveys it to the gasometer.* 
 
 When coal is used, the process is similar : the gas needs 
 to be purified by passing it through lime water, to deprive it 
 of carbonic acid and other impurities, which give it a very 
 disagreeable odor ; 1 12 pounds of coal yield from 450 to 500 
 cubic feet of gas ; sp* gr. 0.459 to 0.700 ; and £ a cubic foot 
 of gas per hour is equivalent to a candle, six to the pound, 
 burning durino- the same time. But oil gas, though much 
 more expensive, possesses nearly twice the illuminating power 
 According to Henry, it requires vessels and tubes of but half 
 the size. 20 cubic feet of coal gas, or 10 of oil gas, is equal 
 to a pound of tallow.f 
 
 Portable* Gas. In consequence of the greater cheapness 
 of gas lights, as compared with candles and oil, it seemed 
 
 * The gasometer is made of iron, in some cases 40 feet in diameter 
 and 20 feet hiofh, containing 20,000 cubic feet."'"' 'This is immersed in 
 a vat containing wafer, and the air permitted to lescape by a valve in 
 the top. When it is filled with water, the gas from the large pipe is 
 conducted to the bottom, and passes up through the water into the 
 gasometer, which rises as fast as it is filled. The gas is now con- 
 veyed in a cast-iron pipe, laid under ground, to which small pipes are 
 attached, branching off to every part of the city where it is wanted. 
 
 t Coal gas costs about two thirds as much as oil gas, and about one 
 fifth as much as spermaceti candles. 
 9 
 
194 Carbon. — Fire-Damp. 
 
 desirable to contrive some method by which it could be made 
 portable. This object has been effected by what are called 
 'portable hemps. The gas, by means of a forcing-pump, is 
 compressed into strong brass globes, and ignited as it escapes 
 through an aperture which is furnished with a stop-cock to 
 regulate the quantity. These can be carried about like com- 
 mon oil lamps. For this purpose, the gas obtained from rosin 
 is employed. 
 
 Fire-Damp. This term is applied to several gaseous com- 
 pounds of carbon and hydrogen, which are produced in the 
 mines of bituminous coal. It is mostly light carbureted hy- 
 drogen, and was generated in the original process of forming 
 the coal. It issues from various parts of the coal beds, in 
 such quantities as to render the whole atmosphere of the mines 
 explosive, and often irrespirable. Hence the miners were 
 exposed to frequent explosion, and to suffocation. Many ex- 
 plosions have occurred in the coal mines of England : the 
 older mines extend miles under the ground, and, in some 
 cases, are several hundred feet deep. As the gases are 
 lighter than the air, they rise and mingle with the air near 
 the top, and gradually descend until they reach the miner's 
 lamp, when the whole is instantly exploded.* In conse- 
 quence of the great expense of human life, and the constant 
 fear of the miners, Sir H. Davy undertook the investigation 
 of the subject for the purpose of inventing some means of 
 safety. He went with the miners into the region of the fire- 
 damp, obtained specimens of the gas, and subjected it to 
 chemical examination. He found that the most explosive 
 mixture was 1 part of gas to 7 or 8 of air ; 5 or 6 volumes of 
 air would explode but feebly, and above 14 volumes of air to 
 1 of gas did not explode at all. It was also found that it re- 
 quired the heat of flame to explode it. Iron at a red heat, 
 and even at a white heat, would not affect it. But the fact 
 which led immediately to the invention of the safety lamp, 
 had been observed by Dr. Wollaston, that " an explosive mix- 
 ture cannot be kindled through a glass tube so narrow as j- of 
 an inch in diameter.''' It was also noticed that the mixture 
 could not be exploded through fine wire sieves, or gauze 
 wire, which acts on the same principle as longer tubes. 
 
 * In 181*2, an explosion occurred in Felling colliery, in Northumber- 
 land, by which ninety-two men lost their lives. The explosion \\k?, 
 heard three or four miles ; thirty-two persons only were saved alive. 
 In 1815, a similar occurrence happened at Durham, and destroyed 
 fifty -S3ven persons; and in another, twenty-two lost their lives. 
 
Oaf boh. — Safety Lamp. 
 
 195 
 
 Fig. 86. 
 
 Exp. Place the gauze 
 wire a (Fig. 86) over a jet 
 of the gas; the flame may 
 be pressed down, and will 
 not pass through the wire. 
 
 Exp. Let a stream of 
 the gas pass through the 
 wire c ; the gas may be ig- 
 nited on the top of the 
 
 wire, but will not communicate through it to the tube Fig. 87. 
 
 b. The same is true of flame,* by whatever substance 
 it is produced. The wires conduct off the heat, so 
 that they do not gain the temperature requisite to 
 ignite the gas. 
 
 Saftty Lamp. This consists simply of a 
 common lamp, c/, (Fig. 87,) with a gauze wire, 
 b, surrounding the flame. The wire should 
 have at least 625 apertures to the square inch. 
 Furnished with this lamp, the miners can 
 enter the mines in perfect safety from explo- 
 sion, but are exposed to suffocation, when 
 there is not sufficient oxygen in the mines to 
 support the combustion of the oil. 
 ' To enable the miner to escape from the 
 mine when the atmosphere becomes such 
 as to extinguish the flame of the lamp, a 
 platinum coil may be inserted around the 
 wick. Thus, in the lamp b, (Fig. 88,) let 
 a platinum coil a be inserted around the 
 wick ; when the flame ceases, the combus- 
 tion will continue slowly for hours, so as 
 to heat the platinum red-hot. This will 
 give sufficient light to enable the miner to 
 escape. 
 
 This is founded on the fact, that plati- 
 num wire or foil will, if heated, cause certain gases to com- 
 bine gradually, with the production of a red heat, but with- 
 out flame. 
 
 Exp. Pour a small quantity of ether into the lamp, and, having 
 heated the coil of platinum, plunge it into the ether ; the heat, of the 
 wire will cause the vapor of ether and the oxygen of the air to com- 
 
 * The flames of candles, lamps, gas lights, &c, are hollow, as may 
 be shown by holding a plate of glass over them. Flames formed by a 
 mixture of oxygen with the combustible are solid ; hence the use of 
 the blowpipe, bellows, &.c., to render the flame solid and increase the 
 heating power. 
 
196 Carbon and Nitrogen. 
 
 bine, so as to keep the wire red-hot, and sometimes even at a white 
 heat, when the ether will burst into a flame 
 
 Carbon and Nitrogen. 
 
 Bicarburet of Nitrogen, or Cyanogen. Symb. NC- or Cy , 
 Equiv. 14.15 -f- 1*2.24 = 26.39. Sp. gr. 1,804. air = 1. 
 
 History. This gas was discovered in 1815. by G gf Lussac 
 It is sometimes called nituret of carbon, but bicarburet of 
 nitrogen expresses definitely its composition. 
 
 Process. It is obtained from the bicyanide of mercury, 
 by heating the salt in a small glass retort, with a spirit lamp. 
 The retort should be covered with lute, to prevent its 
 melting. At a red heat, it is decomposed. The cyanogen 
 passes over in the form of a gas, and the mercury is sublimed, 
 and remains in the neck of the retort in small globules. 
 Collect over mercury or air. 
 
 Properties. This gas is colorless, with a strong, pungent 
 odor ; not a sopporter of combustion, but burns itself with 
 a beautiful purple flame, resembling the peach blossom 
 Water, at the common temperature and pressure, absorbs 4i 
 times its volume, and alcohol *25 times its volume. At the tem- 
 perature of 45°, and under a pressure of 3=6 atmospheres, if is 
 condensed into a limpid liquid, but resume- the gaseous 
 state when the pressure is removed. The most remarkable 
 chemical property of this substance is, that it acts like a 
 simple body in most of its combinations, forming subsl 
 consisting of three elementary bodies, analogous to those, 
 formed in other cases by two. 
 
 Cyanic Acid (Symb. Cy -f- O. Equiv. 26.39 -f 8 == 34.39) 
 
 may be obtained by exposing cyanuric acid to a dull red heat. 
 It has a penetrating odor, pungent, and caustic to the skin, 
 producing great irritation of the e volatile, giving 
 
 off an inflammable vapor. 
 
 Puhninic Acid. This is isomeric with the preceding 
 identical in composition, but possessed of different properties, 
 It is called fulnrinic because its compounds of mercury and 
 silver are highly explos: 
 
 Cyanuric Acid (Symb. Cy 3 5 H 3 . Equiv. 130.17) was 
 obtained by Serullas by gently boiling bichloride of cyanogen 
 
Compounds of Carbon. 197 
 
 in water : cyanunc and hydrochloric acids are the results. 
 The hydrochloric is removed by evaporation, and the cyan- 
 uric deposited, on cooling, in oblique rhomboidal crystals. 
 The crystals are further purified by solution and evaporation. 
 Paracyanuric Acid is identical in composition with the 
 preceding, but different in properties ; it *f* 'ults from the 
 spontaneous decomposition of hydrous cyanic acid. 
 
 Chloride of Cyanogen. Symb. Cy -f- CI. Eq. 61.81. First obtained 
 in a pure state by Serullas, in 1829, by exposing bicyanuret of mercury 
 in powder, and moistened with chlorine gas in a well-stopped vial. It 
 congeals at zero in needle-shaped crystals ; is liquid between 5° and 
 10°, but above this it is a colorless gas, of a very offensive odor, irri- 
 tating to the eyes, corrosive to the skin, and highly injurious to ani- 
 mal life. 
 
 Bichloride of Cyanogen. Symb. Cy-(-2Cl. Eq. 97.23. Discovered 
 also by Serullas, by putting 155 grains of pure hydrocyanic acid into a 
 bottle containing sixty cubic inches of dry chlorine, and exposing it to 
 the solar rays. The acid is vaporized, and, in the course of a few 
 hours, a colorless liquid is formed on the surface of the bottle, gradu- 
 ally growing thicker, until, in the space of twenty-four hours, it sets 
 into a white solid, with shining crystals. This is the bichloride of 
 cyanogen. It is exceedingly poisonous, caustic to the taste, and pene- 
 trating odor, similar to the Qhloride. 
 
 Bromide of Cyanogen is similar to the preceding. 
 Hydrocyanic Acid, or Prussic Acid, (Symb. Cy-f-H. 
 Equiv. 26.39 + 1=27.39,) was discovered by Scheele, in 
 1782. Berthollet afterwards ascertained that it was a com- 
 pound of carbon, nitrogen, and hydrogen; but it was first 
 procured in a pure state by Gay Lussac, * 
 
 Process. The best process is that of Vauquelin. Fill a 
 narrow tube, placed horizontally, with fragments of bicyan- 
 uret of mercury, and then pass a current of dry hydrosul- 
 phuric acid gas very slowly through it. Double decomposi- 
 tion ensues as soon as the gas comes in contact with the 
 bicyanuret, when hydrocyanic acid and bisulphate of mercury 
 are formed. When the bicyanuret becomes black, the acid 
 is expelled by a gentle heat, and collected in a receiver sur- 
 rounded with ice. 
 % 
 
 Properties. It is a limpid, colorless liquid, of a strong, 
 
 but agreeable odor, similar to^that of peach blossoms. It 
 excites, at first, a sensation of coolness on the tongue, which 
 is soon followed by heat ; but, when diluted, it has the flavor 
 of bitter almonds; exceedingly volatile; boils at 79°, and 
 
198 Sulphur. 
 
 congeals at zero ; unites with alcohol and water in all 
 proportions, but possesses very feeble acid properties. 
 
 It is a most virulent poison. A single drop, if placed on 
 the tongue of a dog, causes instant death. A girl swallowed 
 a small quantity of it diluted with alcohol, and fell instantly, 
 as if struck with lightning, and died in two minutes. 
 
 A professor of Vienna put drops upon his arm, and was 
 deprived of life in a few minutes. But though a most potent 
 poison in its pure state, when much diluted, it has been em- 
 ployed as a medicine, in cases of consumption, with beneficial 
 effects. This, like many other violent poisons, cannot be 
 employed for criminal purposes, without the almost, certain 
 risk of being discovered. It exists in the laurel, peach, and 
 in beef-steak. 
 
 Sect. 9. Sulphur. 
 
 q~™v> a v„„;^ f by vol. 16.66. «, M C 66553 Air =1. 
 Svmb. S. Equ.v. £ y wgL 16J Sp. gr. | ] gg Water = 1 . 
 
 Sulphur has been known from the remotest antiquity. 
 
 Natural Historij. It exists in nature, in a pure state, in 
 the vicinity of volcanoes. It collects in the craters, either in 
 fine powder or in crystalline solids ; but it exists more abun- 
 dantly in combination with the metals, forming the sulphurets 
 of <iron, copper, lead, silver, etc., from which it may be sub- 
 limed by heat, but is not quite pure. It is found also in many 
 mineral waters ; in many minerals, such as gypsum, sulphate 
 of strontia, etc. ; in all animals, and some plants. 
 
 Process. The sulphur of commerce exists in two states ; 
 in rolls, called roll brimstone, and in fine powder, called flow- 
 ers of sulphur ; but the two varieties are readily resolved into 
 each other by the application of heat. 
 
 Exp. Heat a brick, or small iron cup, to nearly a red heat. Place 
 upon it roll brimstone, and invert over it a bell-alass receiver ; the 
 sulphur will sublime* i.e., pass into a fine powder, like vapor, and col- 
 
 * This may serve to illustrate the process of sublimation as applied 
 to other substances. Camphor and gum benzoin are easily sublimed 
 The process of converting mercury into vapor, and condensing it, is 
 also called sublimation, although it is a liquid. 
 
Sulphur. — Properties. 
 
 199 
 
 lect on the sides of the vessel. In this way the flowers of sulphur are 
 prepared. 
 
 Properties. Sulphur is a brittle solid, of a lemon-yellow 
 color, nearly tasteless, and inodorous, except when rubbed or 
 heated. It is a non-conductor of electricity, but becomes neg- 
 atively electrified by friction ; fuses at 216° Fahr. ; possesses 
 the highest degree of fluidity between 230° and 280°, and is 
 of an amber color ; at 820°, it begins to thicken, acquiring a 
 red tint; between 423° and 482°, it is so tenacious as to re- 
 main in the vessel when inverted ; but, from 482° to its boilino- 
 point, it grows fluid again, and sublimes rapidly from 550° to 
 600° Fahr. 
 
 When cooled from the several temperatures above named t it 
 
 possesses different degrees of consistency. Cooled suddenly 
 
 from the most fluid state, it is hard and brittle : but if plunged 
 
 into cold water between the temperatures of 320° and 482°, 
 
 it is soft, and may be drawn out like wax; cooled from the 
 
 boiling point, it is of a deep red-brown color, very scTft and 
 
 transparent. It is prepared in this way for taking seals. 
 
 The native crystals are octahedrons, with rhombic bases; 
 
 those formed artificially occur in oblique rhombic prisms 
 
 Exp. Melt a few pounds of sulphur in an 
 earthen crucible." (Fig. 69,) and, when it is 
 pnrtialiy cooled, pierce the erust so that the 
 fluid parts may flow out; on breaking the 
 mass when cooled, the interior will exhibit a 
 cluster of beautiful crystals. Fig. SS rep- 
 resents a section of the crucible containing 
 the sulphur after it has cooled. 
 
 Fisr. 89* 
 
 Sulphur is soluble in boiling oil of 
 turpentine, which is a test of its puri- 
 ty. Sulphur is highly combustible ; it 
 burns with a pale blue flame, and com- 
 bines readily with the metals. 
 
 ^ Exp. Mix copper or iron filings with sulphur, and heat them in a 
 glass tube, or crucible, by a spirit lamp. The sulphur will combine, 
 and form sulphurets of these metals. 
 
 Impurities. Sulphur contains some hydrogen in its purest 
 
 * There are four principal varieties of crucibles : — 1. Wedgicoodcru> 
 cities are made of a mixture of burned and unburned clay; 2. Black 
 
200 
 
 Sulphur. — Sulphurous Acid, 
 
 state; but the more common ingredients are earthy sub- 
 stances and arsenic ; the latter is tested by ammonia. 
 
 Uses. Employed extensively in the manufacture of gun- 
 powder, for seals, medallions, and as a cement for iron. 
 Used in medicine, for the diseases of the skin, humors, etc. 
 The milk of sulphur, which is sulphur combined with water, 
 and precipitated from some of its alkaline solutions by an 
 acid, occurs in a gray powder, and is sometimes used in 
 medicine. 
 
 Hyposulphnrous Acid. Symb. 2S + 20. Eq. 32.2 -f 16 = 
 48.2. It is difficult to procure this in a pure state. It may 
 be formed by digesting sulphur in a solution of any sulphite. 
 It is distinguished by uniting with the oxide of silver, which 
 separates the acid from soda. 
 
 Sulphurous Acid. Symb. S + 20 or SO 2 . Eq. 16.1 -f 
 16 = 32.1. Sp. gr. 2.2117, air=l. 
 
 History. Sulphurous acid appears to have been known 
 from an early period. Stahl first pointed it out as a distinct 
 substance; bat its discovery in a pure state was made by 
 Priestley, in 1774, and accurately analyzed since, by Gay 
 Lussac and Berzelius. It exists in nature in the vicinity of 
 volcanoes, and issues from the fissures in the craters, and 
 from the lava, often in immense quantities, 
 
 Process. Burn sulphur in common air, or in dry oxygen 
 gas, over mercury ; but the best method is to put 2 parts 
 of mercury and 3 of sulphuric acid into a retort, and 
 apply the heat of a lamp, and collect over mercury. 
 
 Theory. The sulphuric acid has 3 equiv. of oxygen, one of which 
 unites with the mercury, forming the oxide of mercury, which com- 
 bines with some undecomposed sulphuric aeid, and forms the sul- 
 
 lead crucibles are formed by a mixture 
 of clay and plumbago ; 3. Hessian 
 crucibles are composed of a mixture 
 of sand and clay ; 4. Metallic cruci- 
 bles are made of silver, platina, &o. 
 These latter are used with the spirit 
 lamp in analytical processes. The 
 form of these vessels is represented 
 jn Fig. 90. Metallic and porcelain 
 crucibles are generally provided with 
 covers and stands, as in the figure, 
 but the best stand is a piece of fire- 
 brick. 
 
 Fig. 90. 
 
Sulphurous Acid. 201 
 
 phate of mercury, which remains in the retort, and the sulphurous acid 
 comes over in the gaseous state. The gas is heavier than the air, and 
 can be collected in a manner described on page 139, fig. C4. 
 
 Properties. A transparent, colorless gas, sour to the 
 taste, and pungent, suffocating odor, by which it is distin- 
 guished from all other gases ; extinguishes burning bodies, 
 but is not combustible. 
 
 Exp. A candle immersed in a jar of this gas is instantly extin- 
 guished. 
 
 It is irrespirable, and fatal to animal life. When largely 
 diluted with air, it excites coughing, and uneasiness about 
 the chest ; when perfectly pure, it excites spasms of the glot- 
 tis, which prevent its introduction into the lungs ; of course, 
 an animal confined in it is instantly suffocated. 
 
 It reddens vegetable colors, and then discharges them. 
 
 Exp. Place a rose over an ignited sulphur match in the open air, 
 and it will turn white ; hence it is used for bleaching straw, silk, and 
 for removing fruit-stains from woollen cloths, etc. 
 
 It has a strong attraction for water and oxygen. Water 
 absorbs it so rapidly, that, if ajar of the gas be inverted over 
 it, the atmosphere will force the water into the jar with great 
 violence ; recently-boiled water absorbs 33 times its volume. 
 
 Sulphurous acid will remain with dry oxygen without 
 change, but if water be present, it combines with oxygen, 
 and forms sulphuric acid. It instantly decomposes those 
 oxides, the metals of which have a weak affinity for oxygen, 
 such as those of gold, platinum, and mercury. Nitric acid 
 yields to it one proportion of oxygen, and converts it to sul- 
 phuric acid. 
 
 Liquid Sulphurous Acid. It becomes liquid by the pres- 
 sure of two atmospheres, and even by surrounding it with a 
 freezing mixture. In this state it is anhydrous, a little 
 heavier than water, (sp. gr. 1.45,) and boils at 14° Fahr. 
 
 By its evaporation, it produces so intense a degree of 
 cold, that mercury may be frozen, and several of the gases 
 rendered liquid. 
 
 Exp. Pour liquid sulphurous acid upon water contained in a shal- 
 9* 
 
; Sulphur. 
 
 low vessel ; the acid will boil, and its vapor will absorb so much 
 caloric that the water will soon be frozen. 
 
 Erp. Or poor it upon mercury in a shallow dish, and place it under 
 the exhausted receirer of an air-pump ; the mercury itself will soon 
 congeal. 
 
 It may be obtained in the solid form in crystals containing 
 water, by passing the moist gas throngh a receiver, cooled 
 from 50° to 14 3 Fahr. 
 
 Uses. Sulphnrous acid is often employed for bleaching 
 purposes, for whitening straw and silks, and for the barbarous 
 purpose of killing bees. 
 
 Hyposulphurie Acid. Symb. 2S -}- 50. Equir — 
 
 = 72.2. This acid was discovered in 1819, by Welter and 
 
 Gij L-..5--.C 
 
 Pn It Formed by passing sulphurov 
 
 gas through crater containing peroxide of manganese. E 
 the interchange of elements, the sulphate of the protoxid and 
 the hyposulphite cf the protoxide of manganese are formed ; 
 the latte: in solution. The manganese is thrown 
 
 down by purr and the hypcsulphate of baryta ob- 
 
 tained, which ; evaporation, and is then decom- 
 
 pose !iric acid, by which the sulphate of baryta is 
 
 precipitated, and hyposulphuric acid remains in solution. 
 
 Properties. Colorless, inodorous, sour to the taste, red- 
 dens litmus, and cannot be wholly freed from w 
 
 S -f 30, SO 3 , or S. Equiv. 16.1 
 — . 1 = . ; Jphuric acid wis discovered by B 
 
 Valentine, near the close of the fifteenth century. It is 
 lied oil of vitriol, because it was first obtained 
 ion of green vitriol, {sulphate of iron or cop- 
 peras.) I nature abundantly in the sulphate of lime, 
 (gypsum.) 
 
 Process. Anhydrous sulphuric acid may be obtained from 
 the hydrous acid, manufactured at Nordhiusen, in Germany, 
 from the prolosulphate of iron, and called fuming sulp J - 
 arid. But the best method is that of Prefe 
 Stockholm. — Saturate the oxide of antimony with e: 
 sulphuric acid, and then, by a slow heat, drire off the ei\ 
 
Sulphurous Acid. 203 
 
 of acid, when the salt will crystallize as a dry sulphate of 
 antimony. Expose this salt to a dull red heat in a retort, and 
 the anhydrous acid will be driven off, and may be collected 
 in a dry receiver, surrounded with ice. 
 
 Properties. In this state, the acid has some peculiar prop- 
 erties. It is a white, opaque solid ; fuses at 66° Fahr. ; sp. 
 gr. 1.99 ; boils between 104° and 122°, forming a transparent 
 vapor ; has a powerful affinity for water, so that, on exposing 
 it to the air, it flies off in white fumes, forming 4 definite 
 compounds with water, which are thus constituted : 
 
 2S0 3 -fHO S0 3 -fHO S0 8 +2HO S0 3 +3HO 
 
 Exp. Burn a mixture of 8 parts of sulphur to 1 of nitre in a vessel 
 of oxygen gas containing a vegetable infusion ; the acid will be ab- 
 sorbed by the water, and change the infusion red. 
 
 But the process for manufacturing this acid in the arts, is 
 done in chambers lined with sheet lead* 8 parts of sul- 
 phur to I of nitre, coarsely bruised and mixed together, 
 are put upon iron plates, 1 lb. to 390 cubic feet of air. The 
 mixture is ignited by a hot iron, and the door closed. Water, 
 to the depth of 6 inches, covers the floor, and absorbs the 
 acid as fast as formed. The room is then ventilated, and the 
 process repeated every four hours, until the water is suffi- 
 ciently acid ; or, by an improvement in the structure of the 
 room, the sulphur is burned in a separate room, and the air, 
 admitted continually, carries the acid vapor into the chamber, 
 where it is condensed by the water. This acidulated water 
 is then drawn off and concentrated by heat, in leaden boilers, 
 until it is of the specific gravity 1.459, and the concentration 
 is finished in glass or platinum dishes placed in sand baths. 
 
 Theory. By the combustion two gases are formed — sulphurous acid 
 from the sulphur, and binoxide of nitrogen from the nitre. The latter 
 combines with the oxygen of the air, and is converted into the nitrous 
 acid. The sulphurous and nitrous acids then combine with the watery 
 vapor, and foMi a ctystaHine solid, composed of sulphuric acid, hyponi- 
 trous acid, and water. When this solid drops into the water, it is 
 instantly decomposed, the sulphuric acid is retained in the water, and 
 nitrous acid and binoxide of nitrogen escape. The nitrous acid thus 
 set free, as well as that formed by the binoxide and oxygen of the air, 
 ngiin combines with the moist sulphurous acid, and forms the solid, 
 vhich sinks to the water, and is decomposed again. This process con- 
 
 * The usual size of the chamber is 20 feet long, and 12 wide; but 
 in mie establishment in England, the chamber is 120 feet by 40, and 20 
 high, containing 96,000 cubic feet. 
 
204 Sulphur. 
 
 tinues, until the whole is converted into sulphuric acid, and absorbed 
 by the water. 
 
 Properties. Hydrous sulphuric acid, when pure, is an 
 oily, limpid liquid, colorless, inodorous, intensely sour and 
 corrosive; destroys, by the aid of heat, all animal and vege- 
 table bodies, with the deposition of charcoal, and formation 
 of water ; hence the acid often attains a brown tinge by 
 charring substances which accidentally fall into it ; boils at 
 620° Fahr., and freezes at -15°. When its specific gravity is 
 1.78, it congeals above 32°, and remains solid up to 45° ; 
 but when mixed with twice its weight of water, it congeals 
 at -36°. 
 
 It has a powerful affinity for water. It combines with 
 the water of the air, even at boiling temperatures, so power- 
 fully that its greatest concentration can be effected only by 
 glass or platinum retorts with narrow mouths. 
 
 Exp. 4 parts of sulphuric acid and I of water, each at 50°, when 
 poured together, have a temperature of 300°. The heat is occasioned 
 by the diminution of bulk, by which the insensible caloric becomes free. 
 
 Exp. 2 parts of acid and 3 of snow form a mixture which will 
 freeze water, and the thermometer will sink even to -23°. The cold 
 results from its affinity for water; it dissolves the snow to obtain it; 
 and the heat necessary to render the water liquid is absorbed from the 
 acid and the snow, and passes into an insensible state. 
 
 Exp. 1 part of snow to 3 of acid will produce a heating mixture, 
 because the condensation develops more heat than is required to melt 
 the snow. 
 
 The decomposition of sulphuric acid is effected by heat, 
 and by the non-metallic combustibles. 
 
 Exp. Pass hydrogen gas and sulphuric acid through a red-hot por 
 celain tube. 
 
 Exp. Heat this acid with charcoal, or put into it vegetable sub- 
 stances. 
 
 Exp. Expose the acid to the galvanic battery; the sulphur will 
 appear at the negative, and the oxygen at the positive pole. Its spe- 
 cific gravity never exceeds 1.9. 
 
 Its strength is tested by its specific gravity, and by the 
 quantity required to saturate a given portion of an alkali. 
 100 grains of the carbonate of soda will neutralize 92 of 
 pure sulphuric acid. It may be detected in any solution by 
 the chloride of barium, by which a white, insoluble solid is 
 precipitated — the sulphate of baryta. 
 
Sulphur and Hydrogen. 205 
 
 It is one of the most powerful of acids, reddens the vege- 
 table infusions, unites with bases, and forms salts, which are 
 called sulphates. 
 
 It is a most violent poison. The best antidote is dry mag- 
 nesia. If water be taken, it will produce a very great heat, 
 and thus increase its injurious effects. 
 
 Uses. It is one of the principal acids of chemistry and 
 of the arts, in which greater quantities are employed than 
 of any other acid ; for the formation of most of the other 
 acids ; for the preparation of soda from salt, of alum from 
 sulphate of iron ; for obtaining chlorine and other gases ; for 
 dissolving indigo for dyes. It is used in medicine as a tonic. 
 
 Bichloride of Sulphur (Symb. 2S -f CI. Eq. 67.62. Sp. gr. 1.687) 
 was discovered by Dr. Thompson, in 1804. Prepared by passing a 
 current of chlorine gas over flowers of sulphur, gently heated, till 
 nearly all the sulphur disappears. The dichloride is then obtained by 
 distillation in the form of a reddish liquid. 
 
 Iodide of Sulphur. First described by Gay Lussac. Formed by 
 heating 4 parts of iodine with 1 of sulphur. A dark-colored substance, 
 easily decomposed by heat. 
 
 Bromide of Sulphur is obtained by pouring bromine on sublimed 
 sulphur. The product is an oily liquid, of a reddish tint; odor resem- 
 bles the dichloride of sulphur. 
 
 Sulphur and Hydrogen. 
 
 Hydrosulphuric Acid. Symb. SH. Equiv. 16.1 -)— 1 = 
 17.1. Equiv. vol. 100. Sp. gr. 1.1782, air =3*1. This sub- 
 stance was discovered by Scheele, in 1777, and has been 
 variously named, sulphurcted hydrogen and hydrothionic 
 acid. 
 
 Process. It may be obtained from the sulphurets of the 
 metals. The one generally emplt^ 3d is the protosulphuret 
 of iron, which is a native product, but can be prepared by 
 heating 2 parts of iron filings with 1J of sulphur to a red 
 heat, in a covered crucible ; upon this, in a retort, pour dilute 
 sulphuric acid, apply gentle heat, and collect over water. 
 Stsquisulphuret of antimony, treated in the same manner 
 with hydrochloric acid, will yield a purer gas : the former 
 contains a little iron and hydrogen. 
 
 Theory. The oxygen of the water unites with the iron, and its 
 hydrogen with the sulphur, and the sulphuric acid unites with the 
 oxide of iron ; the products are hydrosulphuric acid and sulphate of 
 
Sulphur and R. 
 
 Fe>. ?C : and HO are c::. — 
 
 ■nd SH. 
 
 P It is a colorless gas, but has an f7 
 
 and odor; it is this gas which 
 
 to putrescent eggs, sewers, and the f sulphurous 
 
 sprm:- If gmshes burning bodies, but burns with a 
 
 flame : forms an ex-jJosivc mixture with oxygen, 
 
 that y-Vo P art oi : ; 
 
 troys small birds : T ±- part killed a middle-sized 
 
 2± tJ part a horse. If placed on th : 
 
 surface of animals, it will pre ■: . to them. Reddens lit- 
 
 unites with bases and forms salts. 
 
 "\Vater absorbs 3 volumes of the rless 
 
 md odor. This water is a 
 T rae a precipitate of 
 
 sulphur • and if poured into a bottle <: : 
 
 :_nd sulphur and ni 
 be produced. If exposed to the ; sulphur 
 
 : 
 bur combines : 
 
 the hydrogen is liberated. 
 
 Iso decomposed 
 their ^ps 
 
 to purify places rendered noxious by t: 
 
 :i tube. 
 
 .id Hydrosu'pkta 
 
 spheres, it is col 
 and excessively fluid ; compared with it, ether appears ten: 
 
 ■ 
 ite. 
 
 The best 
 rf the gas 
 
 who use prep -rations of lead to improve their beauty, on 
 coming into t: ften Chang 
 
 "rite on paper with any of the salts of lead in . and 
 
 m of the gas 
 
 In medicine for cutaneous eruptions, in the I 
 
 as a test of metals; hen. 
 
Sulphur and Carbon. 
 
 207 
 
 Production of Sulphur in Volcanoes by the Meeting of Sul- 
 phurous and Hydrosulphuric Acids. These acids are gener- 
 ated in volcanoes, and, as they meet, are decomposed, and 
 sulphur is deposited. This may be shown in the following 
 manner : — 
 
 Let two small retorts 
 a, a, (Fig. 91,) pass into 
 a globe receiver, b, so 
 that their mouths shall 
 nearly touch each other. 
 Put the materials for sul- 
 phurous acid into one, 
 and for hydrosulphuric 
 acid in the other, and 
 9 apply heat ; as the two 
 gases meet in the receiver, they will be decomposed, and the 
 sulphur will be deposited upon the interior surface, in fine 
 powder. 
 
 Hijdrcsulphurous Arid. Symb. 2S-f-II. Equiv. 33.2. Discovered 
 by Scheele, who called it supersulphureted hydrogen. The names 
 hydrothionotis acid, per or bisulphareted hydrogen, and persulphuret of 
 hydrogen, have also been applied to it. 
 
 It is similar in taste and odor to hydrosulphuric acid, but not so 
 powerful ; semi-fluid, inflammable, and easily decomposed by heat into 
 sulphur and hydrosulphuric acid. 
 
 Sulphur and Carbon. 
 
 Bisulphuret of Carbon, or Alcohol of Sulphur, Carbosul- 
 phuric Acid. Discovered accidentally by Professor Lampa- 
 dius, in 1776; but its true nature was first pointed out by 
 Clement and Desormes. 
 
 Process. It is obtained by heating, in a close vessel, the native 
 bisulphuret of iron (iron pyrites) with one fifth of its weight of dry 
 charcoal. "The compound, as it is formed, should be conducted, by 
 means of a glass tulJ?, into a vessel of cold water, at the bottom of which 
 it is collected. To free it from moisture and adhering sulphur, it should 
 be distilled at a low temperature, in contact with chloride of calci- 
 um." — T. 
 
 Properties. A transparent, colorless liquid, remarkable 
 for its high refractive power, acid, pungent, and somewhat 
 aromatic taste, and fetid odor; specific gravity, 1.272, ex- 
 ceedingly volatile; boils at 110°; very inflammable, and 
 burns with a pale blue flame. With oxygen, its vapor forms 
 an explosive mixture ; with binoxide of nitrogen, it forms a 
 
208 Cyanogen and Sulphur. 
 
 mixture which burns with dazzling brilliancy; dissolves in 
 alcohol and ether, and is precipitated by water ; dissolves 
 phosphorus, sulphur, and iodine, giving to a solution of the 
 latter a beautiful pink color. It is decomposed by chlorine. 
 
 Cyanogen and Sulphur. 
 
 Sulphuret of Cyanogen was discovered in 1828, by M. Lassaigne, by 
 the action of bicyanuret of mercury, in fine powder, upon half its 
 weight of bichloride of sulphur, confined in a small glass globe, and 
 exposed for two or three weeks to daylight. A small quantity of crys- 
 tals, biting to the tongue, and of a penetrating odor, collected in the up- 
 per part of the vessel, which form red-colored compounds with per 
 salts of iron. 
 
 Bisulpkuret of Cyanogen (Symb. 2S -j- Cy) was discovered by Liebig, 
 by exposing fused sulphocyanuret of potassium to a current of dry chlo- 
 rine gas ; it forms a dry, yellow powder. 
 
 Hydrosulphocyanic Acid. Symb. S 2 CyH. Equiv. 59.59. Dis- 
 covered in 1808, by Mr. Porritt, who ascertained it to be a compound 
 of sulphur, carbon, hydrogen, and nitrogen. It is sometimes called 
 sulphocyanic acid, and may be formed by suspending sulphocyanuret 
 of silver or mercury in water, and by transmitting through it a current 
 of hydrosulphuric acid gas; sulphuret of silver or mercury, and hydro- 
 sulphocyanic acid, are generated ; filter the solution, and expel the 
 excess of gas by heat. 
 
 Properties. A liquid, either colorless, or a shade of pink ; 
 odor resembling vinegar ; sp. gr. 1.002 ; boils at 216.5° ; crys- 
 tallizes in six-sided prisms at 45.5° Fahr. ; acid to the taste, 
 and by the chemical tests. It also unites with alkalies. 
 
 Test of its Presence. A salt of the peroxide of iron, to 
 which it gives a deep blood-red solution; decomposed by 
 exposure to the air, and by chloric or nitric acid. 
 
 Cyanohydro sulphuric Acid (Symb. S 2 CyH 2 . Equiv. 
 60.59) may be obtained by passing a current of hydrosul- 
 phuric acid through a saturated solution of cyanogen in alco- 
 hol. The liquid acquires a reddish-brown tint, and numer- 
 ous small crystals, of an orange-red color, are generated. It 
 is considered by Liebig to be similar in composition to the 
 preceding, but to have one equivalent more of hydrogen. 
 
 Sect. 10. Phosphorus. 
 
 « u -o r? • (by vol. 25. G C 1.77 Water = 1. 
 
 feymb.P. Eqmv.^ / wgt 157 Sp. gr.J 4 ^ Aif = t 
 
 History. Phosphorus received its name from the property 
 of shining in the dark.* 
 
 * cpaj$, light, and (ftou, to carry. 
 
Phosphorus. 209 
 
 It was discovered by Bran It, an alchemist of Hamburg, in 
 1609. It was formerly obtained from urine, but -the process 
 of obtaining it was for a long time kept secret, and small 
 quantities only were procured. Scheele obtained it from 
 bones, and invented the method now generally employed. It 
 exists in the bones of all animals, in the state of phosphate 
 of lime. A middle-sized man has about one pound of phos- 
 phorus in his bones. 
 
 Process. The bones are calcined in an open fire, reduced 
 to a fine powder, and digested for a few days with one half 
 their weight of sulphuric acid, with sufficient water to give 
 them the consistency of paste. The phosphate of lime is 
 decomposed, and the sparingly-soluble sulphate and soluble 
 superphosphate of lime are generated. The latter is then 
 dissolved in warm water, filtered and evaporated to the con- 
 sistency of sirup. 
 
 It is then mixed with £ part of charcoal, in an earthen re- 
 tort lined with clay, heated in a furnace to a high tempera- 
 ture, when the vapor of the phosphorus comes over, and is 
 conducted by a tube into a bowl of water, where it is con- 
 densed into a reddish-brown solid. This is then fused in hot 
 water, and distilled in hydrogen, or passed through chamois 
 leather. 
 
 Properties. When pure, it is transparent and nearly col* 
 orless, or of a wax color ; easily cut with a knife, and the sur- 
 face has a waxy appearance and texture ; fuses at 108°, and 
 at' 550° is converted into vapor; soluble by the aid of heat in 
 naphtha, in fixed and volatile oils, and in the chloride of sul- 
 phur, sulphuret of carbon, and sulphuret of phosphorus. On 
 cooling a solution of the latter, it crystallizes in dodeca- 
 hedrons. 
 
 It is very inflammable. At common temperatures, it com- 
 bines slowly with the oxygen of the air, giving a luminous 
 appearance in the dark. 
 
 Exp. If a stick be placed in a receiver of air, it will absorb the oxy- 
 gen, and leave the nitrogen. 
 
 Exp. If a stick of phosphorus be dusted over with charcoal or resin, 
 and placed under the receiver of an air-pump, it will inflame on ex- 
 hausting the air. 
 
 Exp. By friction it instantly ignites, and hence is employed for 
 matches. 
 
210 Phosphorus. 
 
 Exp. When ignited in oxygen, it Fig* 92» 
 
 burns with great brilliancy. This L^f&^113£E3£8B§| 
 experiment should be conducted 
 in a large globe receiver. (Fig. 
 92,) filled with oxygen, and the 
 phosphorus placed in the centre 
 by a pendent copper spoon. Dense 
 white fumes of phosphoric acid are 
 formed ; these often mingle with 
 the vapors of phosphorus and oxy- 
 gen, which renders the whole in- 
 flammable; and hence the danger 
 of breaking the receiver. 
 
 Exp. Let a stream of oxygen 
 gas upon phosphorus in a fused 
 state, under water, and flashes 
 of light will pass up through the 
 water. 
 
 Exp. Or put a few grains of chlorate of potassa into a glass of water, 
 in which is a piece of phosphorus, and from the dropping tube pour 
 on nitric or sulphuric acids; flashes of light will appear. 
 
 Exp. Drop a small piece into a glass containing a small quantity of 
 strong nitric acid ; it will burn vividly, and often explode xcith great tic- 
 lence. (See Fig. 77.) 
 
 Exp. Sweet oil dissolves it by the aid of heat, and the phosphorized 
 oil can be put on the face and hair so as to render it luminous in 
 the dark. 
 
 Tlieory. In all these cases, the light results from the union 
 of phosphorus with oxygen; so strong is its affinity for oxy- 
 gen, that it should always be kept under water. If exposed 
 to the air, and held in the hands in a dry state, there is dan- 
 ger of its entering into a state of combustion, especially if 
 any friction is applied to it. 
 
 Relation to Animals. It is very poisonous: acts as an 
 excitant, and in large doses it proves fatal ; but it is used 
 sometimes as a medicine. It renders water poisonous in 
 which it is kept. 
 
 Phosphorus and Oxygen. 
 
 Oxide of Phosphorus. Symb. 3P -f- O. Equi v. 47.1 + 8 = 55. 1 . It 
 is obtained by burning phosphorus under hot water, by a jet of oxygen 
 gas. The substance which remains after combustion is of a red color, 
 without taste or odor ; insoluble in water, alcohol, ether, and oil ; is 
 not volatilized at 662° Fahr., but takes fire at a low red heat, in the air 
 and in chlorine gas. This substance has been examined by M. Pelouse, 
 and found to be an oxide of phosphorus. 
 
 Ilupophosphorous Acid (Symb. 2P-J-0. Equiv. 31.4 -f- 
 
Phosphoric Acid. 211 
 
 8 = 39.4) was discovered by Dulong, in 1816, and is obtained 
 by the action of water upon the phosphuret of. barium. Hy- 
 pophosphite of baryta is formed soluble in water ; on filtering 
 the solution, and adding sulphuric acid to precipitate the 
 baryta, the hypophosphorous acid remains, and is concentra- 
 ted by evaporation into a viscid liquid, capable of crystalliza- 
 tion; this is the hydrate of the acid, and is a powerful deox- 
 idizing* agent. 
 
 Phosphorous Aci'd (Symb. 2P + 30. Equiv. 31.4-|-24 = 
 55.4) was discovered by Davy, and may be obtained by sub- 
 liming phosphorus through the bichloride of mercury, in a 
 glass tube; a limpid liquid distils over, which is a compound 
 of phosphorus and chlorine. Put this into water, and the 
 hydrogen of the water unites with the chlorine, forming hy- 
 drochloric acid, and the oxygen of the water combines with 
 the phosphorus, forming the phosphorous acid. The solution 
 is then evaporated to the consistency of sirup, to expeythe 
 hydrochloric acid, and the phosphorous acid crystallizes as 
 a hydrate. The anhydrous acid may be obtained by burning 
 the phosphorus in highly-rarefied air. 
 
 Properties. Sour to the taste, odor like garlic, and pos- 
 sesses acid properties ; has a strong affinity for oxygen, and 
 is hence easily converted into phosphoric acid ; precipitates 
 mercury, silver, platinum, and gold, from their saline solu 
 tions, in the metallic form. 
 
 Phosphoric Acid. Symb. 2P + 50. Eq. 31.4 + 40 = 
 •71.4. Under the term of phosphoric acid, three compounds 
 ■ nave formerly been described, affording a remarkable in- 
 stance of a class of bodies, called isomeric, which are identical 
 in composition, but possess different properties. The names 
 given to the three compounds are, phosphoric, pyrophosphoric, 
 and met a or paraphosphoric acids. 
 
 1. The Phosphoric Acid has hitherto been obtained only 
 in combination with water or an alkaline base. 
 
 Process. The superphosphate of lime is boiled for a few 
 
 * Bodies are said to deoxidize when they abstract oxygen from its 
 combinations with other bodies. They are said to oxidize when they 
 yield oxygen to other bodies. 
 
212 Phosphorus, 
 
 minutes with excess of carbonate m ammonia, by which the 
 lime is precipitated as a phosphate. After filtration, the liquid 
 is evaporated to dryness, and then ignited in a platinum 
 crucible, to expel the ammonia and sulphuric acid. 
 
 Properties, Colorless, intensely sour, reddens vegetable 
 infusions powerfully, and neutralizes alkalies. In the state 
 of greatest concentration, it is composed of three equivalents 
 of water, and one equivalent of acid, and may be made to 
 crystallize in thin plates. It is remarkable for uniting 
 with bases, in the proportion of 1 equivalent of the acid to 
 3 of the base, or the oxygen of the base and the acid as 
 3 to 5. 
 
 2. The Pyrophosphoric Acid is obtained by exposing 
 concentrated phosphoric acid to a temperature of 145°. 
 
 Its properties are generally similar to the preceding, but 
 it is distinguished from it by yielding a snow-white pre- 
 cipitate, when neutralized with ammonia, and mixed with 
 the nitrate of the oxide of silver. It is remarkable for its 
 tendency to unite with 2 equivalents of a base to 1 of the 
 acid. 
 
 - 3. Meta or Paraphosphoric Acid is obtained by burning 
 phosphorus in dry air, or oxygen gas. The acid appears in 
 small crystals, like snow, on the interior of the vessel. It is 
 formed, combined with water, by heating to redness the two 
 preceding acids ; when fused, it cools into a . brittle and 
 transparent solid, resembling ice, hence called glacial phos- 
 phoric acid, very deliquescent, and hence must be kept in 
 close bottles. It is distinguished from the others by uniting 
 1 equivalent of a base to 1 of the acid. 
 
 Phosphorus and Chlorine. 
 
 The Sesquichloride of Phosphorus (Symb. 2P-J-3C1. 
 Equiv. 31.4 + 106.26=137.66". Sp. gr. 1.45) may be 
 formed bypassing the vapor of phosphorus over corrosive 
 sublimate, in a glass tube, or by heating the perchloride with 
 the phosphorus. 
 
 Properties. It is a clear, limpid liquid, not acid by the 
 
Phosphorus and Hydrogen. 213 
 
 chemical tests, though it emits acid fumes when exposed to 
 the air. This is due to the affinity of the chlorine for the 
 hydrogen of the water contained in the air. When mixed 
 with water, mutual decomposition takes place, with evolution 
 of heat, and the formation of hydrochloric and phosphoric 
 acids. 
 
 The Pcrchloride of Phosphorus is formed by the spon- 
 taneous combustion of phosphorus in chlorine gas. Symb. 
 2P + 5C1. Eq. 208.5. 
 
 Properties. A white solid, volatile at a temperature below 212° j 
 heated under pressure, it fuses, and forms, in cooling 1 , transparent, 
 prismatic crystals. Thrown into water, mutual decomposition ensues. 
 
 Iodides of Phosphorus. There appear to be three com* 
 pounds of iodine and phosphorus, produced by the spontane- 
 ous combustion of the two substances; 
 
 The Protiodidc (Symb. P-f^I. Equiv. 142) has a yellow color, 
 fuses at 212°, sublimes by heat unchanged, and is decomposed by 
 water. 
 
 The Sesquiodide (Symb. 2P -f- 31. Equit. 410.3) is a dark-gray 
 crystalline mass, fuses at 84°. 
 
 The Periodide (Symb. 2P + 5I. Equiv. 662.9) is a black com- 
 pound, fusible at 114°. 
 
 Bromides of Phosphorus are formed by bringing 1 phospho- 
 rus and bromine into contact, in a flask filled with carbonic 
 acid. 
 
 The Protobromide (Symb. P -J- Br. Equiv. 94.1) is a liquid formed 
 at the bottom of the flask, easily converted into vapor by heat, acts 
 energetically upon water, and mutual decomposition takes place. 
 
 The Perbromide (Symb. 2P -f-5Br. Equiv. 423.4) is a yellow solid, 
 converted by heat into a red-colored liquid, and into a vapor of a simi- 
 lar tint. When cooled from fusion, it yields rhombic crystals. Emits 
 dense, penetrating fumes when exposed to the air, and is decomposed 
 by water and chlorine. 
 
 Phosphorus and Hydrogen. 
 
 Phosphuret of Hydrogen, (Symb. 2P + 3H. Equiv. 31.4 
 -j- 3 = 34.4,) called also hyduret of phosphorus, was discov- 
 ered in 1812, by Sir H. Davy, by heating hydrated phospho- 
 rous acid in a retort. 
 
 Properties. It is colorless, with the odor of garlic ; does 
 not take fire spontaneously in air, but instantly inflames in 
 
214 
 
 'lorus. 
 
 chlorine eras, with a white light ; forms 
 on at in g mixture. 
 
 Perpliosphunt of Hydrogen is isomeric with the prece- 
 ding. It was discovered in 1753. by Gengenibre, and has 
 been since examined by Dalton, Thompson, and others, 
 naiiir phosphu ." hydrogen and hyduret of horus 
 
 have also been applied i : 
 
 F r the purposes of experiment, h 
 prepared in the following manner : Fill a pint retort half full 
 of recently-slacked lime, and put into it a stick of phosphorus 
 two or three inches long, cut into stfi ; Then pour en a 
 strong solution of carbonate of potassa, filling the retort quite 
 full. Place the beak of the retort in the cistern, and apply 
 heat.* The _ : form and inflame when 
 
 in contact with the air, forming beautiful wreaths of sm 
 which rise up from the '_ it may be collected like 
 
 any other g 1 
 
 Properties. This gas is colorless, and has a highly-offen- 
 sive odor, and bitter : : U neither support name nor 
 respiration. 
 
 He. 03. 
 
 Inflames spontaneously icheti admitted into air, and 
 sivelu with is. As the bubbles 
 
 rise through the water in the cistern b into th: 
 inflame successively, the phosphoric acid and vapor flMkp a 
 series of rings, as c. of dens smoke, continually 
 
 .lode of obtaining this gas is to beat phosp. 
 connection with quicklime, forming the phosphuret of lime 
 this into water acidulated with hydrochloric acid. The wa: 
 composed, and its fa 
 
 and form hypophosphorous acid, phosphoric acid, and pHBsphuret of 
 hydrogen. 
 
■ 
 
 Boron. ^i5 
 
 increasing in size as they arise, and producing one of the 
 most striking and beautiful appearances in experimental 
 chemistry. If a bubble Of the gas is admitted into a receiver 
 of oxygen gas, a bright flash of light is seen, and the Receiver 
 is jarred by the concussion. This is one of the most re- 
 markable properties of this gas, and distinguishes it from all 
 ither gases. It is often produced by the decomposition of 
 >ones, in swamps and graveyards, and gives rise to those 
 ights which are frequently seen about such places. It is the 
 •^eal " Jack o' the lantern," or " Will o' the wisp." 
 
 Water absorbs one eighth volume of this gas, and, if the gas 
 is suffered to remain over water for a few days, it loses its 
 spontaneous inflammability, but will inflame on the applica- 
 tion of a lighted taper. 
 
 Phosphorus and Sulphur. 
 
 Sulphuret of Phosphorus. The nature of this compound is 
 not accurately settled ; it is formed by bringing sulphur in 
 contact with fused phosphorus. They act on each other 
 with great violence, producing a compound of a reddish- 
 brown color, which fuses at 16° Fahr.^ and is highly combus- 
 tible. 
 
 Sect. 11. Boron. 
 Symb. B. Eq. 10.9. Equiv. vol. 100. 
 
 This substance was discovered in 1807, by Sir H. Davy, 
 by exposing boracic acid to a powerful galvanic battery ; but 
 its properties were first investigated by Gay Lussac and The- 
 nard, who obtained it in greater quantity by heating boracic 
 acid with potassium. 
 
 The easiest method of obtaining it is to decompose boro- 
 fluoride of potassium by means of potassium and heat. 
 
 Properties. A dark olive-colored solid, without taste or 
 odor; -& non-conductor of electricity ; sp. gr. nearly 2 ; insolu- 
 ble^ in water, alcohol, ether, and oils; does not decompose 
 water at any temperature, and may be subjected to intense 
 heat in close vessels without change ; heated to 600° in the 
 air, it i unites, and is converted into boracic acid. When 
 
216 
 
 Boron and Oxygen. 
 
 heated with nitric acid, or with any substance which yields 
 oxygen freely, it passes into boracic acid. 
 
 Boron and Oxygen. 
 
 Boracic Acid. Symb. B -f- 30. Equiv. 34.9. Sp. gr. 
 
 1.479, water 1. This substance exists in nature in small 
 quantities in the Lipari Islands, and the hot springs of Lasso. 
 in the Florentine territory : in combination with soda, in 
 the well-known substance borax, the biboratc of soda, used 
 b / smiths as a flux. It is also a constituent of the minerals 
 boracite and datholite. 
 
 Process. To a solution of purified borax in boiling water, 
 add half its weight of sulphuric acid, diluted with an equal 
 quantity of water. On evaporation* and cooling, shining 
 crystals of boracic acid will be deposited ; it may be purified 
 by repeated solution in hot water and crystallization. This 
 is a hydrate, containing 1 eq. of acid and 3 of water. The 
 anhydrous acid may be obtained by heating this in a plati- 
 num crucible. 
 
 Properties. The hydrous acid exists in the form of thin, 
 white scales, without odor, and nearly tasteless, sparingly 
 soluble in water, which reddens vegetable blue colors, and, 
 like the alkalies, turns turmeric paper brown, soluble in boil- 
 ing alcohol, and gives a beautiful green color to flame. 
 
 The anhydrous acid is a hard, colorless, transparent g ' : ; : 
 absorbs water rapidly from the air, and should be kept id 
 well-stopped vials : exceedingly fusible, and communicates 
 this property to the substances with which it unites. Hence 
 its use in the arts as a flux. 
 
 Tis. 94. 
 
 * Fig. 94 represents the form of evaporating 
 dishes ; some are made of clay and sand, oth- 
 ers of porcelain, srlass, silver, platinum, and 
 gold. The substance to be evaporated is 
 poured into them, and they are placed in a 
 sand bath, which is simply a quantity of com- 
 mon sand contained in an iron vessel, and 
 connected generally with the furnace or fire- 
 place, so as to be kept constantly at a tem- 
 perature below the boiling point. 
 
Selenium. 217 
 
 Boron and Chlorine. 
 
 Terchloride of Boron. Symb. B + 3C1. Eq. 117.16. Pro- 
 duced by the spontaneous combustion of boron in chlorine 
 gas. It is rapidly absorbed by water, and unites with am- 
 monia, forming a volatile fluid. It is also formed, according 
 to Despretz, by passing dry chlorine gas over charcoal and 
 boracic acid, ignited in a porcelain tube. It was first 
 noticed by Davy, and examined by Berzelius, Dumas, and 
 Despretz. 
 
 Boron and Fluorine. 
 
 Fluoboric Acid. Symb. B + 3F. Equiv. 66.94. Sp. gr. 
 2.3622. Discovered by Gay Lussac and Thenard, in 1810. . 
 
 Process. Mix 1 part of pure boracic acid and 2 of fluor- 
 spar with 12 of sulphuric acid, in a glass flask, and apply heat ; 
 or heat a strong solution of hydrofluoric and boracic acids in 
 a metallic retort. 
 
 Properties. A colorless gas, of a penetrating, pungent 
 odor ; extinguishes flame, reddens litmus powerfully, and 
 unites with bases forming salts called fiuoborates. 
 
 It lias a powerful affinity for ivater, which absorbs 700 
 volumes of the gas ; becomes hot, fuming, and caustic ; 
 attacks animal and vegetable substances with great energy. 
 Some doubt yet exists concerning its true nature. 
 
 Boron and Sulphur. 
 
 Sulphuret of Boron is formed, according to Berzelius, by 
 burning boron in the vapor of sulphur. The product is a 
 white, opaque mass, readily decomposed by water. 
 
 Sect. 12. Selenium. 
 Symb. Se. Equiv. 39.6. Sp. gr. 4.32. 
 
 Selenium was discovered by Berzelius, in 1818, and 
 named Selenium, from Selene, the moon, because he at first 
 mistook it for tellurium. 
 
 Natural History. It is found in small quantities among 
 10 
 
218 ' Selenium, 
 
 the volcanic products of the Lipari Islands, in Clausthal in 
 the Hartz, combined with lead, cobalt, silver, mercury, and 
 copper. Berzelius obtained it from the iron pyrites of 
 Fahlun. 
 
 Process. Mix the native sulphuret of selenium with 8 
 times its weight of peroxide of manganese, and expose it to a 
 low red heat in a glass retort, the beak of which dips into 
 water. The manganese yields its oxygen to the sulphur, 
 and the selenium sublimes pure, or in the form of selenious 
 acid. 
 
 Properties. A brittle, opaque solid, without taste or odor ; 
 its lustre is metallic,, resembling lead in the mass, but the 
 powder has a deep red color ; softens at 212°, and may be 
 drawn out into fine, transparent threads, which appear red by 
 transmitted light ; becomes fluid a little above 212°, and boils 
 at 650°, yielding an inodorous vapor of a deep yellow color ; 
 sublimes, in close vessels, without change, and condenses 
 into dark globules, or into a cinnabar-red powder, if the ves- 
 sels are large. Heated in the open air, or in oxygen, it com- 
 bines with the oxygen ; under the blowpipe, it emits the 
 strong odor of horseradish 
 
 \yf Selenium and Oxygen. 
 
 Oxide of SJeMum (Symb. Se + O. Equiv. 47.6) is 
 formed by heating selenium in a limited quantity of air, and 
 washing the product to clear it from selenious acid. It is a 
 colorless gas, which gives the peculiar odor to the selenium, 
 when burned in the wick of a lamp. 
 
 Selenious Acid (Symb. Se-j-20. Equiv. 55.6) is formed 
 by dissolving selenium in nitrohydrochloric acid. On evap- 
 oration, the acid is left as a white, crystalline solid, of a sour 
 and burning taste; dissolves readily in water and alcohol, 
 and attracts moisture from the air. It has distinct acid 
 properties, and its salts are called selcnites. It is decom- 
 posed by all substances which have a strong attraction for 
 oxygen. 
 
Compounds of Selenium. 219 
 
 Sclcnic Arid (Symb. Se+3C Equiv. 63.6) was first 
 noticed by M. Nitzsch, and described by Mitscherlich in 
 
 1827. 
 
 Process. It is obtained by fusing nitrate of potassa or 
 soda with selenium ; a metallic seleniuret with selenious acid, 
 or any of its salts. (For process, see Turner, 6th ed. p. 209.) 
 
 Properties. A colorless liquid: sp. gr. at 329°, 2.524; at 
 512°, 2.63. It is decomposed by heat at 536°, and is resolved 
 into oxygen and selenious acid; has a powerful affinity for 
 water, with which it combines, with the evolution of as much 
 caloric as sulphuric acid and water. It dissolves zinc, iron, 
 copper, and gold; unites with bases, and forms salts analo- 
 gous, in composition and form, to those of sulphuric acid. 
 
 Chloride of Selenium is a white'solid, obtained by placing 
 selenium in chlorine gas. 
 
 Bromide of Selenium is an orange-colored solid; soluble 
 in water, and obtained by dropping selenium into bromine. 
 The combination is violent, with the evolution of much heat. 
 
 Selenium and Hydrogen. 
 
 Hydroselenic Acid. Symb. Se-f-Ii. Eq. 41. This acid 
 was discovered by Berzelius, and some doubt exists as to its 
 composition. 
 
 Process. It may be obtained by the action of hydrochloric acid upon 
 a concentrated solution of any hydroselcyiiate. 
 
 Properties. A colorless gas, with an odor resembling hy- 
 drosulphuric acid. It irritates the membrane of the nose, 
 exciting catarrhal symptoms, and produces temporary insen- 
 sibility. Water absorbs it readily, and the solution reddens 
 litmus, and leaves a brown stain upon the skin. On exposure 
 to the air, it is decomposed, but decomposes all the salts of 
 the common metals, formincr seleniurcts of the metal. 
 
 Selenium and Sulphur. 
 
 Bisulphiret of Selenium (Symb. Se-j-2S. Eq. 718) was 
 obtained by Berzelius, by adding hydrosulphuric acid to a 
 solution of selenious acid, when it is precipitated as an 
 orange-colored powder; fuses at 212°, sublimes at a high 
 
220 Silicon. 
 
 temperature without change ; when heated m the open air, it 
 inflames, and is decomposed by nitrohydrochloric acid. 
 
 Seleniuret of Phosphorus, or Phosphuret of Sdenium, is 
 prepared in the same manner as the sulphuret of phosphorus. 
 JJ^is a very fusible substance ; imfammable, and decomposes 
 Water slowly, yielding seleniuret of hydrogen, and one of the 
 acids of phosphorus. 
 
 Sect. 13. Silicon. 
 Symbol, Si. Equivalent, 22.5. 
 
 Silicon was obtained by Berzelius, in 1S24, by the action of 
 potassium on fluosilicic acid gas. It was at first called sili- 
 cium, and regarded as a metal, but it is destitute of the me- 
 tallic properties. 
 
 Properties. Silicon is a solid, of a dark brown color, and 
 a non-conductor of electricity. 
 
 Before ignition it is not oxidized, or dissolved by hot sul- 
 phuric or nitrohydrochloric acids, but is soluble in hydro- 
 fluoric acid, and in a hot, concentrated solution of caustic 
 potassa. It burns readily in air, and vividly in oxygen gas ; 
 but after ignition, it is insoluble and non-combustible. It is 
 oxidized by heating it with nitrate of potassa, and explodes 
 when dropped upon fused hydrate of potassa, soda, or baryta, 
 in consequence of the evolution of hydrogen. 
 
 Silicon and Oxygen. 
 
 Silicic Acid, Silica. Symb. Si-f-30. Equiv. 22.5 -f- 
 24 = 46.5. 
 
 Natural History. Silicic acid, also called silica, siliceous 
 earth, and silex, constitutes nearly 40 per cent, of the crust 
 of the globe. Hence it is the principal ingredient of exten- 
 sive mountain masses, of sand, and of several minerals, such 
 as quartz, flint, chalcedony, rock-crystal, etc. It is the most 
 abundant ingredient in nearly all soils. 
 
 Process. It may be prepared by heating rock-crystals, and 
 throwing them, red-hot, into cold water. 
 
Compounds of Silicon. 221 
 
 Properties. When reduced to powder, it is white, insipid, 
 and inodorous. It is very infusible, requiring the heat of the 
 compound blowpipe to fuse it; insoluble in water, unless 
 presented in the nascent state ; does not act upon test paper, 
 but in every other respect, has the properties of an acid. Its 
 combination with the fixed alkalies is effected by mixing 
 pure sand with carbonate of potassa. If 3 parts of the car- 
 bonate to 1 of sand are mingled, the fused silicate is solu- 
 ble in water; but if 1 part of the carbonate to 3 of sand 
 be employed and fused, the well-known substance glass is 
 formed, which is transparent, brittle, insoluble in water, and 
 affected by no acid except the hydrofluoric. 
 
 Every kind of common glass is a silicate, and the different 
 varieties are due to the proportions of the constituents, to the 
 nature of the alkali, or the presence of foreign matter. Thus 
 green bottle glass is made of materials containing iron; 
 Crown glass, of pure alkali and sand, free from iron. Plate 
 glass, for mirrors, is made of the purest materials. Flint glass 
 contains red lead ; and sometimes peroxide of manganese, 
 or nitre, is added to oxidize the carbon contained in the 
 materials. 
 
 Chloride of Silicon (Symb. Si-j-Cl. Equiv. 57.92) is 
 prepared by burning silicon in chlorine gas. The product is 
 a limpid, volatile liquid, flying off in white vapor when ex- 
 posed to the air, with a suffocating odor resembling cyano- 
 gen; boils at 124° Fahr. 
 
 Bromide of Silicon (Symb. Si -f- Br. Equiv. 100.6) was obtained by 
 Serullas, in the same manner as the chloride. It is a very dense, color- 
 less liquid, emitting dense fumes. 
 
 Sulphur et of Silicon (Symb. Si-f-S- Equiv. 38.6) is formed by heat- 
 ing silicon in the vapor of sulphur. It is a white, earthy substance, 
 instantly converted by the action of water into hydrosulphuric and 
 silicic acids. 
 
 Fiuosilicic Acid (Symb. Si + F. Equiv. 41.18) is formed by bring- 
 ing hydrofluoric and silicic acids into contact. It is a colorless gas, 
 which extinguishes flame, destroys animals immersed in it, and acts 
 powerfully upon the respiratory organs. Water acts upon this gaa 
 with some change of properties, and the solution is called silicohy- 
 drofiuoric acid. 
 
222 Metals, with their Binary Compounds. 
 
 «• 
 
 CHAPTER II. 
 Class II. Metals, with their binary Compounds, 
 
 General Properties of Metals. 
 
 Metals are the most important of substances. They are 
 distinguished from other substances by the following prop- 
 erties : — 
 
 1. They are all conductors of electricity and of caloric. 
 
 2. When combined with oxygen, chlorine, iodine, sulphur, 
 and similar substances, and subjected to the voltaic battery, 
 they always go to the negative electrode or pole, and hence 
 are called positive electrics. 
 
 3. Metals are opaque ; that is, they do not permit the light 
 to pass through them, although reduced to thin leaves. 
 
 4. They are good reflectors of light, and possess a peculiar 
 lustre, which is termed the metallic lustre. Any substance 
 which has the above properties, may be regarded as a metal. 
 
 Metals differ greatly in their Properties. 
 
 1. In their specific gravity. Most of the metals are re- 
 markable for their weight, such as gold and platinum, whic 
 are more than nineteen times as heavy as an equal bulk ot 
 water ; while some, potassium and sodium, are lighter than 
 water. 
 
 2. In their malleability, or the property of being beaten 
 into thin leaves by hammering. Gold, silver, copper, tin, 
 platinum, palladium, cadmium, lead, zinc, iron, nickel, po- 
 tassium, sodium, and frozen mercury, are malleable. The 
 others are malleable only in a slight degree, or, like arsenic, 
 antimony, and bismuth, brittle. Gold is the most malleable 
 of metals; one grain of which may be extended so as to 
 cover fifty-two square inches of surface, and to have a thick- 
 ness not exceeding g-virW? °^ an mcn * 
 
General Properties of 3Ietals. 223 
 
 3. In their ductility, or the property of being drawn out 
 into wires. Most of the malleable metals are also ductile. 
 Gold, silver, platinum, iron, and copper, are the most ductile. 
 Gold wire may be obtained so fine that it shall not exceed 
 TuW of an mcn m diameter, and platinum ^^jju of an 
 inch. The tenacity of a metal is measured by the weight 
 which a wire of a certain diameter can support without 
 parting. 
 
 4. In hardness. Titanium, manganese, iron, nickel, cop- 
 per, zinc, and palladium, are hard metals. Gold, silver, and 
 platinum, are softer than these, lead still softer, and po- 
 tassium and sodium yield readily to the pressure of the 
 fingers. 
 
 5. In their structure. Many have a crystalline structure. 
 Iron is fibrous; zinc, bismuth, and antimony, are lamellated: 
 gold, sjjver, and copper, are found naturally in crystals, and 
 others may be made to assume the form of crystals, when 
 they pass gradually from a liquid to a solid state. Most of 
 them, in crystallizing, assume the figure of a cube, the reg- 
 ular octohedron, or some form allied to it 
 
 6. In their fusibility. All are solid, at the common tem- 
 perature of the atmosphere, except mercury, which is solid 
 at -43° Fahr. Mercury, potassium, sodium, cadmium, tin, 
 bismuth, lead, tellurium, antimony, and probably arsenic, are 
 fusible below red heat. The rest require a higher tempera- 
 ture to fuse them-, and some of these, such as platinum, ceri- 
 um, rhodium, and coiumbium, require the heat of the com- 
 pound blowpipe to render them liquid 
 
 7. In volatility. Cadmium, mercury, arsenic, tellurium, 
 potassium, sodium, and zinc, are volatilized by heat Most 
 of the others may be exposed to the most intense heat of a 
 smith's forge, without being converted into vapor. 
 
 8. In their affinity for the other simple substances. Metals 
 generally have an extensive range of affinity ; hence they 
 are rarely found in the earth in their simple or pure state, but 
 are generally combined with other bodies, especially with 
 
224 Metals. — General Properties. 
 
 oxygen and sulphur, in which state they are said to be 
 mineralized. 
 
 It is a remarkable fact, that they are not disposed to com 
 bine with compound bodies They combine with each other, 
 and with other simple substances, generally in a few definite 
 proportions. 
 
 They all combine with oxygen, though with different de- 
 grees of energy. Iron and copper are slowly oxidized at 
 common temperatures, while gold will sustain the most in- 
 tense heat of furnaces without oxidation. Potassium and 
 sodium will even decompose water, to obtain the oxygen, the 
 moment they come in contact with it. In all these cases, 
 they produce the phenomena of combustion. Hence they 
 are said to be combustible. With chlorine, iodine, bromine, 
 etc., they combine with more or less energy, giving rise 
 to the same phenomena. Some unite with oxygen in one 
 proportion only, but most have two or three degrees of 
 oxidation. The protoxides form the strong alkaline oases, 
 combining with acids to form neutral salts. They are gene- 
 rally the only salifiable bases. 
 
 The binoxides and peroxides, with a few exceptions, are 
 either neutral or acid in their properties ; the acids generally 
 contain the largest amount of oxygen. 
 
 When metals unite with chlorine, iodine, bromine, sulphur, 
 &c, the compounds they form are similar in composition to 
 the oxides of the same metals, so that if we know the com- 
 position of the one, we can infer that of the other : thus the 
 two oxides of iron unite in the proportions of FeO and Fe 9 3 ; 
 the sulphurets and chlorides. of iron have a similar com- 
 position, FeS, Fe 2 S 3 — FeCl, and Fe 5 Cl 5 . To this rule there 
 are a few exceptions. Sulphur sometimes forms a greater 
 number of compounds with a metal than oxygefT ; in which 
 case there can be no corresponding oxides. This is the case 
 with iron, arsenic, potassium, and a few others. The chlo- 
 rides of any metal generally correspond in number with its 
 oxides, never greater and in but few cases less in number. 
 
Metals. — General Properties. 225 
 
 x^mong the norirmetallic bodies, hydrogen alone forms an 
 oxide, (water,) which is capable of uniting with acids, and in 
 this respect it bears a striking analogy to the metals. Hy- 
 drogen has been regarded as a metal in the gaseous state. 
 
 Many metals form acids with oxygen, as well as oxides ; 
 only three, arsenic, antimony, and tellurium, are incapable 
 of forming protoxides, but are distinguished for forming strong 
 oxygen acids. 
 
 Oxides sometimes combine with each other, and form defi- 
 nite compounds. The action of the metals upon the simple 
 non-metallic substances will be noticed in their proper place. 
 
 Metallic oxides may be reduced to the metallic state by 
 heat, by the united agency of heat and combustible matter, 
 by voltaic electricity, and by the action of the deoxidizing 
 agents on metallic solutions. 
 
 When the hydracids, such as hydrochloric, hydrobromic, 
 hydriodic, and hydrofluoric acids are poured upon the metals, 
 their action is different from thajt of oxygen acids. In the 
 latter case, the metal becomes oxidized, and the acid unites 
 to form a ternary compound, or salt ; but in the former case, 
 the acid is decomposed, its hydrogen escapes, and the chlo- 
 rine, bromine, iodine, and fluorine combine directly with the 
 metal, forming a binary compound. Thus hydrochloric acid 
 poured on zinc, will form chloride of zinc, ZnCl, or on so- 
 dium will form chloride of sodium, (common salt.) 
 
 It should be observed here, that most chemists place such 
 compounds among the salts, dividing the latter into two 
 classes ; thus extending the definition of a salt so as to in- 
 clude such compounds (see page 298), The reason for such 
 a classification is, that though they resemble oxides in com- 
 position, they are more nearly allied to salts, in their proper- 
 ties. Thus common salt, the substance from which we 
 derive the name of salts, is a chloride of sodium, a binary 
 compound, but in its properties it resembles the ternary com- 
 pounds or oxygen salts. 
 10* 
 
226 Metals. — General Properties. 
 
 It was formerly supposed that when common salt and other 
 compounds having a similar constitution,- sometimes called 
 haloid salts, — that is. after the form of sea-salt, — were dis- 
 solved in water, they formed a compound precisely similar 
 to an oxygen salt. For example, when common salt was 
 dissolved in water, it was supposed that the oxygen of the 
 water united with the sodium, forming an oxide, and its hy- 
 drogen united with the chlorine, and formed hydrochloric 
 acid, these combined and formed hydrochlorate of soda. But 
 no such compound exists. 
 
 The water is not decomposed, and hence the hydracids do 
 not form any compounds similar to the oxygen acids, unless it 
 be in the case of their action on ammonia, which more prop- 
 erly belongs to the subject of organic chemistry. The true 
 explanation of the action of the hydracids on the metallic ox- 
 ides has been given above. But perhaps the changes which 
 take place may be more clearly exhibited by means of a dia- 
 gram : thus, take hydrochloric acid and soda. 
 
 Hydrochloric { Chlorine <l ___ — = ^*- Water. 
 
 acid / Hvdrosen 
 
 c 4 S Sodium — -^^ ^^- Chloride of 
 
 boda < ~ ^^ .. 
 
 ( Oxygen sodium. 
 
 Thus it appears that the action of a hydrogen acid on a 
 metallic oxide rp 3 ults in the formation of a binary compound, 
 one of which is water and the other is an ide of the metal, 
 similar in constitution to the oxides and the sulphurets. 
 
 If therefore we class the chlorides, iodides, &c, of the 
 metals with the oxygen salts, the reason for it cannot be found 
 in their constitution, but simply because they agree in physi- 
 cal properties with true salts ; we have therefore concluded to 
 retain them among the ides of the metals. 
 
 The number of metals is generally reckoned at 42, to 
 which three or four have lately been added, but are of very 
 rare occurrence. Most of the metals are known only to 
 chemists. Many of them have scarcely been examined, ex- 
 cept by those who discovered them. The following table 
 contains their names, with the date at which they were dis- 
 covered, and the names of the chemists by whom the dis- 
 covery was made : — 
 
Table of tjic Discovery of Metals. 
 
 227 
 
 Names of Metals. 
 
 Authors of the Discovery. 
 
 Dates of the 
 Discovery 
 
 Gold . 
 
 -j 
 
 
 
 Silver . 
 
 
 
 
 Iron 
 
 
 
 
 Copper 
 
 ■ > 
 
 Known to the Ancients. 
 
 
 Mercury 
 
 
 
 
 Lead 
 
 
 
 
 Tin 
 
 
 
 
 Antimony 
 
 
 Described by Basil Valentine . 
 
 1490. 
 
 Bismuth 
 
 
 Described by Agricola 
 
 1530. 
 
 Zinc 
 
 
 First mentioned by Paracelsus 
 
 16th century. 
 
 Arsenic 
 Cobalt 
 
 '} 
 
 Brandt ..... 
 
 1733. 
 
 Platinum 
 
 
 Wood, assay-master, Jamaica 
 
 1741 
 
 Nickel 
 
 
 Cronstedt ..... 
 
 1751. 
 
 Manganese 
 
 
 Galm and Scheele . 
 
 1774. 
 
 rungsten 
 
 
 D'Elhuyart .... 
 
 2781. 
 
 Tellurium 
 
 
 Mii Her 
 
 1782. 
 
 iVIoh ■bdenur 
 
 a 
 
 Hielm , . 
 
 1782. 
 
 Uranium 
 
 
 Klaproth ..... 
 
 1789. 
 
 Titanium 
 
 
 Gregor ..... 
 
 1791. 
 
 Chromium 
 
 
 V.tuquelin .... 
 
 1797. 
 
 Columbium 
 
 
 Hatchett 
 
 1802. 
 
 Palladium 
 Rhodium 
 
 } 
 
 Wollaston .... 
 
 1803. 
 
 Iridium 
 
 
 Descotils and Smithson Tennant 
 
 1803. 
 
 Osmium 
 
 
 S-nithson Tennant . 
 
 1803. 
 
 Cerium 
 
 
 Hisinger and Berzelius 
 
 1804. 
 
 Potassium . 
 
 ^ 
 
 
 
 Sodium 
 
 
 
 
 Barium 
 
 y 
 
 Davy 
 
 1807. 
 
 Strontium . 
 
 
 
 
 Calcium 
 
 j 
 
 
 
 Cadmium . 
 
 
 Stromeyer .... 
 
 1818. 
 
 Lithium 
 
 
 Arfvvedson .... 
 
 1818. 
 
 Zirconium 
 
 
 Berzelius .... 
 
 1824. 
 
 Aluminium 
 
 
 
 
 Glucinium 
 
 W5hler 
 
 1828. 
 
 Yttrium 
 
 
 
 Thorium 
 
 
 Berzelius ..... 
 
 1829. 
 
 Magnesium 
 
 
 Bussy ..... 
 
 1829. 
 
 Vanadium 
 
 
 Sef'strom .... 
 
 1830. 
 
 Latanium . 
 
 
 Mosander .... 
 
 1839. 
 
 It will be found convenient, in studying the properties of 
 the metals, to arrange them in groups. They may be divided, 
 for this purpose, into the two following orders : — 
 
 Order I. Metals which, by oxidation, yield alkalies or earths. 
 
 Order II Metals, the oxides of which are neither alka- 
 lies nor earths-. 
 
228 IMttals.— Potassium. 
 
 Order I. includes twelve metals, which may be arranged 
 in three sections or divisions ; — 
 
 Section I. Metallic bases of the alkalies. These are, 
 
 Potassium, Sodium. Lithium. 
 
 Section 2. Metallic bases of the alkaline earths. These 
 are, 
 
 Barium, Strontium, Calcium, Magnesium. 
 
 Section 3. Metallic bases of the earths. These are, 
 
 Aluminium, Yttrium, Zirconium. 
 
 Glucinium, Thorium,. 
 
 Order II. The metals belonging to this order are ar- 
 ranged in the three following; sections : — 
 
 Section 1. Metals which decompose water at a red heat ■ — 
 
 Manganese, Cadmium, Cobalt, 
 
 Iron, Tin, Nickel. 
 
 Zinc, 
 
 Section 2. Metals which do not decompose water at any 
 
 temperature, and the oxides of which are not reduced to the 
 
 metallic state by the sole action of heat : — 
 
 Arsenic, Colurnbium, Titanium, 
 
 Chromium, Antimony, Tellurium, 
 
 Vanadium, Uranium, Copper, 
 
 Molybdenum, Cerium, Lead. 
 
 Tungsten, Bismuth, 
 
 Section 3. Metals, the oxides of which are decomposed by 
 a red heat : — 
 
 Mercury, 
 
 Platinum, 
 
 Osmium, 
 
 
 Silver, 
 
 1 um, 
 
 Iridium. 
 
 
 Gold, 
 
 Rhodium, 
 
 
 T. 
 
 Sect. 1. Metallic Basf.s of the Alkalies. 
 
 POTASSIUM. Symb. K. Equir. 39.15. Sp. gr. O.Sbo. 
 
 History. The discovery of potassium, or kaJinm, as it 
 was at first called, was made by Davy, in 1S07, and consti- 
 tutes an era in the history of chemical philosophy, as it led 
 
Properties of Potassium. 229 
 
 to the discovery of the metallic bases of the other alkalies 
 and alkaline earths, apd to the decomposition of a variety of 
 compounds which were before regarded as simple bodies. 
 
 The discovery was made by subjecting the hydrate of 
 potassa to the influence of a powerful galvanic battery of 
 200 pair of plates ; oxygen appeared at the positive, and a 
 small globule of a metallic lustre at the negative pole, which 
 proved to be the metal potassium. 
 
 Process. Potassium is obtained in small quantities by 
 galvanism ; but the best method is that of M. Curaudau, 
 which was improved by Brunner, and modified by Wohler. 
 The substance employed is carbonate of potassa, prepared 
 by heating cream of tartar to redness in a covered crucible. 
 This is raised to a high temperature, in connection with 
 charcoal, in an iron retort ; the oxygen of the potassa com- 
 bines with the carbon, and the potassium distils over. 
 
 Properties. Potassium, at common temperatures, is a 
 soft, malleable solid, yielding to the pressure of the fingers, 
 like wax; of a decidedly metallic lustre; similar to mercury 
 in color ; somewhat fluid at 70°, and perfectly liquid at 150° ; 
 cooled to 32°, it is brittle; sublimes at a low red heat in 
 close vessels secluded from the air ; a good conductor of 
 electricity and of caloric. 
 
 But its most remarkable property is its affinity for oxygen. 
 It oxidizes rapidly in the air or oxygen gas ; but if a piece be 
 thrown upon water, it will decompose it rapidly, disengaging 
 so much heat that the potassium takes fire, and burns with a 
 beautiful purple flame. The evolution of hydrogen gas 
 causes it to move about upon the surface of the water, and, 
 combining with the potassium, augments the brilliancy of 
 the combustion. 
 
 Exp. Invert a wine-glass filled with water in the cistern, and in- 
 troduce a small piece of potassium ; it will rapidly decompose the 
 water, and the escape of hydrogen gas will displace the water in the 
 glas*;. This gas may then be ignited. 
 
 Exp. Heat a small piece of iron, and drop upon it potassium; th^n 
 invert over it a jar of* oxygen gas. 
 
 Exp. Drop a piece upon ice, and it will instantly inflame ; a deep 
 hole is made in the ice, containing pure potassa with water. 
 
 Exp. To show that the action of potassium upon water produces an 
 
$30 3Ietal$. — Compounds of Potassium. 
 
 alkali, drop a small piece into a bottle containing vegetable infusion, 
 and it will instantly turn it green. In consequence of its affinity for 
 oxygen, it must be kept under naphtha, or the essential oil of copaiba. 
 
 Remark. In the description of the metallic compounds, 
 the abbreviations symb. and equiv. will be omitted, and the 
 symbols and equivalents placed immediately after the names 
 of the substances. 
 
 Compounds of Potassium. 
 
 Protoxide of Potassium, (K-j-O. 47.15,) commonly called 
 potash, or potassa, is always formed when potassium is put 
 into water, or burned in oxygen gas. It exists in nature in 
 the minerals, feldspar, mica, and several others ; in all vege- 
 tables, from which it is obtained by leaching their ashes, and 
 boiling the lye. 
 
 Properties. The pure potassa is a white solid, very caus- 
 tic, possessing powerful alkaline properties ; easily fused by 
 heat, but not decomposed ; deliquesces in the air, and hence 
 is very soluble in water, forming with it a hydrate, which 
 retains the water under the most intense heat. 
 
 The Hydrate of Potassa contains 1 eq. of water, and is 
 similar in its properties to the anhydrous potassa. The 
 aqueous solution of the hydrate, called aqua potasses, may- 
 be prepared by decomposing the carbonate with lime. 
 
 Exp. Put quick lime, with half its weight of carbonate of potassa, 
 dissolved m 8 or 10 times its weight of water, into a clean iron vessel, 
 and put it into well-stopped bottles, to exclude the air, from which it 
 will absorb carbonic acid. If the solution is pure, it will not eifervesce 
 with acids. 
 
 The solid hydrate may be made from this by evaporation, and further 
 purification by alcohol, which dissolves only the pure hydrate ; the 
 alcohol is then driven off by heat. This was formerly called lapis 
 caustlcus, but the colleges of Edinburgh and London called it potassa 
 fusa. 
 
 Tests. Potassa may be distinguished from all other sub- 
 stances by the precipitates thrown down from its salts in 
 solution. 
 
 B.cp. 1. Take any of the salts of potassa in solution, and pour into 
 them tartaric acid ; a white precipitate will be thrown down — the bi- 
 tartrate of potassa. 
 
Compounds of Potassium. 231 
 
 Exp. 2. Chloride of platinum will give a yellow, and when dissolved 
 in alcohol, a. pate yellow, precipitate. 
 
 Exp. 3. Alcoholic solution of carbazotic acid throws down yellow 
 crystals of carbazotate of potassa. This is the most delicate test. 
 
 Uses. Potassa, being a very powerful alkali, is of great 
 use in chemistry and the arts. It forms the bases of most 
 soaps; the crude potash is employed for making glass. 
 
 Owing to its affinity for carbonic acid, it is used for ab- 
 stracting that substance from gaseous mixtures, and for 
 depriving them of moisture. 
 
 Teroxide of Potassium (K-f-^O. 63.15) is formed when 
 potassium is burned in the air or oxygen gas. It is an 
 orange-colored substance, caustic, alkaline, heavier than 
 potassium, and decomposed by galvanism and by water ; by 
 the latter it is resolved into the protoxide and oxygen ; fuses 
 below a red beat, in which state it burns vividly, in contact 
 with combustibles. 
 
 Chloride, of Potassium (K -f- CI. 74.57) was long known by the 
 names l febrifuge salt of Sylvias,' ' regenerated sea-salt? 
 
 It may be formed by the spontaneous combustion of potassium in 
 chlorine, or by dissolving potassium in hydrochloric acid, and evapo- 
 rating the solution slowly to dryness. 
 
 Properties. It occurs in cubic crystals, colorless, of a 
 
 saline and bitter taste, insoluble in alcohol, and soluble in 3 
 
 parts of water at 60°, and in less at 212° Fahr. 
 
 L/dide of Potassium (K-f-L 1G5.45) is formed by heating potassium 
 with iodine, or by heating the iodate of potassa. 
 
 Properties. Fuses readily, and is converted into vapor 
 below a red heat ; deliquesces in air ; very soluble in water ; 
 dissolves in strong alcohol, and, by evaporating the solution, 
 yields colorless cubic crystals of iodide of potassium. 
 
 Bromide of Potassium, (K-f-Br. 117.55,) formed by a 
 
 process similar to that for the iodide, (using bromine instead 
 
 of iodine,) and has similar properties; very soluble in water, 
 
 which, by evaporation, yields anhydrous cubic crystals; 
 
 easily fused, and decrepitates, like sea-salt, when heated. 
 
 Exp. Put a small piece of potassium into a wine-glass containing a 
 few drops of bromine ; the two bodies will combine with explosive 
 violence. 
 
 FluoHde of Potassium (K + F. 57.83) is formed by 
 
232 Metals. — Compounds of Potassium 
 
 merely saturating hydrofluoric acid with carbonate of potass?, 
 evaporating to dryness, and igniting to expel excess of acid. 
 
 Properties. It has a sharp, saline taste, alkaline to the 
 test papers, soluble in water, and the solution acts on glass. 
 It is obtained from its solution, by evaporation at 100°, in 
 cubes or rectangular four-sided prisms, very deliquescent. 
 
 Hydruret of Potassium. Discovered by Gay Lussac and 
 Thenard, and may be formed by heating potassium in hydro- 
 gen gas. It is a gray solid, readily decomposed by heat or 
 water. Gaseous hyduret of potassium is produced when 
 hydrate of potassa is decomposed by iron, at a white heat. 
 It is a colorless gas, and burns, spontaneously in air or oxy- 
 gen gas, but loses its inflammability by standing over mercury. 
 
 Nituret of Potassium consists, according to Thenard, of 100 parts of 
 potassium to 11.728 of nitrogen, and is formed by heating potassium 
 with ammoniacal gas. 
 
 Sulphurets of Potassium. These are five in number, de- 
 pendent on the quantity of sulphur. 
 
 The Protosvlphurct of Potassium (K-j-S. 55.25) is prepared by 
 burning potassium and sulphur in the air, or by decomposing the sul- 
 phate of potassa by charcoal or hydrogen gas at a red heat. Mixed 
 with powdered charcoal, it kindles spontaneously. 
 
 The Bisulphurct of Potassium (K-}-2S. 71.35) is formed by ex- 
 posing a saturated alcoholic solution of hydrosulphate of sulphuret of 
 potassium, until a pellicle begins to form, and then evaporating to 
 dryness. 
 
 The Tersulphuret of Potassium (K -4- 3S. 87.45) is formed by heating 
 carbonate of potassa to low redness, wilh half its weight of sulphur, 
 known by the name of liver of su'phur. 
 
 The Quodrosulphurct of Potassium (K-J-4S. 103.55) is prepared Yy 
 transmitting the vapor of bisulphuret of carbon over sulphate of potassa 
 at a red heat, until carbonic acid gas ceases to be disengaged. 
 
 The QuintosulpJmrct of Potassium (K-J-5S. U<J.05) is formed by 
 fusing carbonate of potassa with its own weight of sulphur. 
 
 The properties of the four last compounds are similar ; 
 they are deliquescent, have a sulphureous odor, and are 
 soluble in water. A solution of the last dissolves sulphur, 
 and renders U probable that other compounds may be 
 formed. 
 
 Phosphurets of Potassium. Several compounds exist, but 
 their composition is unknown. Obtained by burning potas- 
 sium in phosphuret ofiiydrogen. 
 
 Seleniuret of Potassium. Formed by fusing potassium and 
 selenium together. They combine with explosive violence, 
 
Sodium. 233 
 
 and a crystalline, fusible compound results, of an iron-gray 
 color, and metallic lustre. 
 
 Cyanide, of potassium (K-|-Cy. 65.54) is formed by heating to red- 
 ness the anhydrous ferrccyanide of potassium in an iron bottle. 
 
 Properties. Easily fused, and crystallizes in colorless 
 cubes : pungent and alkaline to the taste, ana* poisonous, act- 
 ing like the hydrocyanic acid ; deliquescent, and very solu- 
 ble in water ; used sometimes as a medicine. 
 
 Sulpho cyanide of Potassium K -|- CyS 2 . 97.74. 
 
 SODIUM. Symb. Na. Equiv. 23.3. Sp. gr. 0.972. 
 
 Sodium was discovered by Sir H. Davy^n 1807, a few 
 days after the discovery of potassium, and by a similar 
 process. 
 
 Process. It may be obtained in small quantities by gal- 
 vanism. But the process of obtaining it from soda, now 
 generally practised, is precisely the same as that for potas- 
 sium. 
 
 Properties. Sodium resembles potassium in many of its 
 properties. It is a white, opaque solid, of a metallic lustre, 
 resembling silver ; yields readily to the pressure of the 
 fingers, and may be formed readily into leaves ; fuses at 200° 
 Fahr., and is vaporized at a red heat. 
 
 Sodium has so strong an affinity for oxygen that it rapidly 
 decomposes water to obtain it, but does not inflame unless 
 the water is heated, in which case it throws out beautiful 
 scintillations, often with violent combustion. 
 
 Exp. Thrown upon water, it moves about upon its surface, having 
 the appearance of a silver ball, gradually growing less till the wnole 
 disappears. 
 
 Exp. Drop a piece of sodium into a test-tube partly filled with warrr. 
 water; it will soon burst into a flame, and often explode with violence. 
 
 It oxidizes in the air or oxygen gas, but not so rapidly as 
 
 potassium ; hence, like that metal, it must be kept under 
 
 naphtha. The product of its combustion in oxygen, and its 
 
 action upon water, is soda, the alkaline properties of which 
 
 may be tested by dropping a small piece of the metal into a 
 
 bottle containing a vegetable infusion. 
 
234 Metals. — Compounds of Sodium, 
 
 Compounds of Sodium. 
 
 Protoxide of Sodium, (NaO. 31.3,) commonly called soda y 
 and by the Germans natron, is formed by the oxidation of 
 sodium in air or water. 
 
 Properties. A gray solid, similar to potassa, which it 
 resembles in most of its properties; very caustic, and has 
 powerful alkaline properties. 
 
 The hydrate has 1 eq. of water, and is easily fused. In 
 other respects, it is similar to the anhydrous soda ; absorbs 
 carbonic acid from the air, and passes into carbonate. 
 
 It is distinguished from other alkaline bases by yielding, 
 with sulphuric acid, the well-known substance called GJau 
 bcr's salts. All its salts are soluble in water, and are not 
 precipitated by any re-agent, and give a rich color to the 
 blowpipe flame. The soda of commerce is generally a car- 
 bonate prepared from the ashes of marine plants, in the 
 same manner as potash is from land plants. 
 
 Uses. Employed for the manufacture of hard soaps, and 
 for culinary and medical purposes. 
 
 Sesquioxide of Sodium (2Na -f- 30. 70.6) is formed when 
 sodium is heated to redness, in excess of oxygen gas. It has 
 an orange color, but no acid or alkaline properties. It is 
 resolved by water into soda and oxygen. 
 
 Chloride of Sodium. Na-j-Cl. 58.72. This substance is 
 formed by burning sodium in chlorine gas, or by saturating 
 soda with hydrochloric acid, and evaporating to dryness. It 
 is a very abundant natural product, under the name of rock 
 sail. It exists in sea-water and salt-springs, from which it 
 is obtained bv evaporation. Great quantities are manufac- 
 tured on the sea-coast of New England, and at Salina, X. Y. 
 The water at the latter place, according to the analysis of 
 Beck, contains one seventh of its weight of pure dry chloride 
 of sodium. 
 
 Properties. A well-known solid, crystallizing in regular 
 cubes, and by sudden evaporation, in hollow, quadrangular 
 pyramids. It is dissolved in 2 J times its weight of water, at 
 
Compounds of Sodium. 235 
 
 , 60° Fahr. ; gradually fuses when heated, and decrepitates 
 when thrown into the fire ; is decomposed by carbonate of 
 potassa and nitric acid. The different kinds of salt, such as 
 stored, fishery, bay, &c, arise from its different forms, and 
 not from a difference of chemical constitution. It contains 
 small quantities of sulphate of magnesia and lime, and chlo- 
 ride of magnesium. 
 
 Uses. The utility of salt depends on its property of pre- 
 serving animal and vegetable substances from putrescence. 
 
 Iodide of Sodium, (Na-4-I. 149.6,) prepared in the same manner 
 as the iodide of potassium, exists in sea-water, salt-springs, and in the 
 residual liquor from kelp. 
 
 Bromide of Sodium, (Na-f-Br. 101.7,) analogous to sea-salt, exists 
 in sea- water and salt-springs, and crystallizes in cubes. 
 
 Fluoride of Sodium (Na-f-F. 41.98) is formed by neutralizing hydro- 
 fluoric acid with soda ; crystallizes in cubes, and when carbonate of 
 soda is present, in octohedrons. Nearly insoluble in alcohol; soluble in 
 twenty-five times its weight of water ; attacks glass vessels when 
 evaporated in them — a property which is common to most of the com,' 
 •pounds of fluorine. 
 
 Sulphur et of Sodium (Na-f-S. 39.4) is obtained in the same manner 
 as the protosulphuret of potassa, and has similar properties. 
 
 The Cyanide of Sodium (Na-f-Cy. 49.69) and the Sulphocyanide 
 of Sodium (Na-j-CyS 2 . 81.89) are similar to the corresponding com- 
 pounds of potassium. 
 
 Chloride of Soda is prepared by passing a current of chlo- 
 rine gas into a cold solution of caustic soda. This liquor 
 has received the name of Labarraqut s Disinfecting Soda 
 Liquid, and is used extensively in the arts, and in med- 
 icine. 
 
 Properties. A liquid of a pale yellow color, with slight 
 odor of chlorine. Its taste is sharp, saline, and but little 
 alkaline; reddens Jurmeric, and then bleaches it. When 
 evaporated, it yields damp crystals; decomposed by exposure 
 to the air. 
 
 Uses. It may be used for all the purposes of bleaching to 
 which chlorine was formerly applied, in medicine to purify 
 apartments, dissecting-rooms, for destroying the fetor of 
 ulcers, and for removing the offensive odors of sewers, drains, 
 and ail kinds of animal putrescence. 
 
 Alloy of Sodium and Potassium. 10 parts of potassium, 
 
236 Metals. — Lithium. 
 
 and 1 of sodium, form an alloy which is liquid at zero, Fahr., 
 
 and is lighter than naphtha, or rectified petroleum. 
 
 LITHIUM, gymb. L. Equir. 6.44. 
 
 This substance was obtained by Davy, by means of gal 
 vanism, as a white-colored metal, like sodium ; but it oxidized 
 so rapidly that he was unable to examine its properties. 
 
 Compounds of Lithium. 
 
 Protoxide of Lithium, Lithia, (L-j-O. 14.44,) was dis- 
 covered, in ISIS, by M. Arfwedson, in the mineral petalite; 
 it exists in spodumene, Ie_pidoIite, and several varieties of 
 mica. 
 
 Process. One part of petalite to two of fluor-spar are 
 finely pulverized, and the mixture heated with four times 
 its weight of sulphuric acid, till the acid vapors are disen- 
 gaged. Sulphate of lithia and alumina are formed. These 
 salts are then dissolved in water, and boiled with pure am- 
 monia, to precipitate the alumina; filter and evaporate to dry- 
 ness, and then expel the sulphate of ammonia by a red heat. 
 The result is a pure sulphite of Lithia, which mu 
 decomposed by acetate of baryta, and the acetate, by a red 
 heat, is converted into the carbonate, and this reduced to the 
 caustic hydrate, by boiling it with lime. 
 
 Properties. Similar to potcssa and soda in its alkalinity 
 and chemical relations. It is distinguished from them by its 
 greater neutralizing power ; when exposed to the air, it ab- 
 sorbs carbonic acid, and becomes opaque. 
 
 Chloride of Lithium (L-f-Cl. 41.86) is obtained by dissolving lithia 
 in hydrochloric acid, evaporating to dryness, and fusing the residue. 
 
 Properties. A white, semi-transparent solid, and, like 
 the chlorides of potassium and sodium, forms, by evaporation, 
 colorless, anhydrous, cubic crystals, which differ from those 
 chlorides in being very deliquescent, dissolving freely in 
 water and alcohol, and tinging the name of alco 
 
 Fluoride of Lithium. (L-j-F. 25.12.> prepared by dissolving iithia in 
 
 hydrofluoric acid, aud is a very fusible solid. 
 
Barium 237 
 
 Sect. 2. Metallic Bases of the Alkaline Earths. 
 
 BARIUM. Symb. Ba. Equiv. 68.7. 
 
 Barium was discovered by Davy, in 1808. 
 
 Process. The process consisted in forming the carbonate 
 of baryta into a paste with water, placing a globule of mer- 
 cury in a small hollow made in its surface, and laying the 
 paste on a platinum tray, which communicated with the posi- 
 tive pole of a galvanic battery of 100 double plates, while the 
 negative wire was in contact with the mercury. The baryta 
 was decomposed, and its barium entered into combination 
 with the mercury. This amalgam was heated in a vessel 
 free from air, by which means the mercury was expelled, 
 and the barium obtained in a pure state. — T. 
 
 Properties. The metal, thus obtained, has a dark gray 
 color, with a lustre inferior to cast iron. It is much heavier 
 than water ; it even sinks in sulphuric acid. Its attraction 
 for oxygen is scarcely less than that of the preceding metals; 
 is converted into baryta by exposure to the air ; decomposes 
 water with effervescence, from the escape of hydrogen gas. 
 It has been obtained but in small quantities, and its proper- 
 ties are not accurately defined. 
 
 Compounds of Barium. 
 
 Protoxide of Barium, or Baryta, (Ba-j-O. 76.7,) was 
 discovered by Scheele, in 1774, and called barytes or baryta, 
 from the great density of its compounds. 
 
 Process It is the sole product of the oxidation of barium 
 in the air and in water. It is also obtained by exposing the 
 nitrate of baryta to a red heat, or the carbonate, mixed with 
 charcoal, to an intense white heat. 
 
 Properties. Baryta is a gray powder, (sp. gr. 4,) very dif- 
 ficult of fusion ; has a sharp, caustic, alkaline taste, with 
 other alkaline properties ; insoluble in alcohol, but has a 
 strong affinity for water, and slacks like lime, but with the 
 evolution of more intense heat, and is converted into a white, 
 bulky hydrate, which fuses at a red heat, but cannot be 
 
23S Metals. — Compounds of Barium. 
 
 deprived of its water at the highest temperature of a smith's 
 forge. A saturated solution yields, on evaporation, trans- 
 parent, flattened, prismatic crystals, containing 10 atoms of 
 water to 1 of baryta. 
 
 This solution is an excellent test of carbonic acid, or other 
 gaseous mixtures in the atmosphere. The acid gives a 
 milky appearance to the clear solution, due to the solid car- 
 bonate of baryta, which is precipitated. 
 
 Distinguished by the fact, that all its soluble salts are 
 precipitated by alkaline carbonates, and by the insoluble 
 sulphate, which latter cannot be separated by any other acid. 
 
 Binoxide of Barium (Ba-}-20. 84.7) is formed by conducting dry 
 oxygen gas over pure baryta, at a red heat. It is a grayish-white sub- 
 stance, employed by Thenard in obtaining the binoxide of hydrogen. 
 
 Chloride of Barium (Ba-f-CL 104.12) is prepared by decomposing a 
 solution of sulphuret of barium with hydrochloric acid, or by conduct- 
 ing chlorine gas over baryta, at a red heat. On concentrating the solu- 
 tion, the chloride crystallizes in flat, four-sided tables, beveled at the 
 edges like crystals of heavy-spar. They consist of 1 eq. of the chlo- 
 ride to 2 of water. 
 
 Properties. Pungent and acrid to the taste. The crys- 
 tals do not change in moist air ; but in a very dry air, at 60° 
 they lose their water of crystallization, and are rendered 
 anhydrous at a full red heat ; decomposed by sulphuric acid 
 and alkaline carbonates. 
 
 Iodide of Barium (Ba-j-I. 195) is formed by acting on 
 baryta with hydriodic acid, and evaporating the solution. 
 Soluble in water, and forms colorless, needle-shaped crystals. 
 
 Bromide of Barium (Ba-j-Br. 147.1) is prepared by 
 boiling protobromide of iron with moist carbonate of baryta, 
 evaporating the filtered solution, and heating the residue to 
 redness. The product crystallizes, by careful evaporation, 
 in white rhombic prisms, which have a bitter taste, are 
 slightly deliquescent, and soluble in water and alcohol. — -T. 
 
 Fluoride of Barium (Ba-f-F. 87.38) is prepared by 
 digesting moist carbonate of baryta in hydrofluoric acid. It 
 is a white powder, soluble in nitric and hydrochloric acids. 
 
 Sulphuret of Barium (Ba-j-S. 84.8) is prepared by pass- 
 ing dry hydrosulphuric acid over pure baryta, at a red heat. 
 It dissolves readily in hot water, and deposits colorless 
 crystals on cooling. It may be employed for obtaining pure 
 baryta by a process described by Turner, 5th ed. p. 308 
 
Strontium. 239 
 
 Cyanide of Barium (Ba-f-Cy. 95.09) is procured by 
 the action of hydrocyanic acid on baryta. It is slightly 
 soluble in water, has an alkaline reaction, and is decomposed 
 by the carbonic acid of the air. 
 
 Sulphocyanide of Barium (Ba-j-CyS 2 . 127.29) is ob- 
 tained in the same way as the sulphocyanide of potassium. 
 It is very soluble in water, and crystallizes in beautiful 
 needles, slightly deliauescent. 
 
 Phosphvrct of Barium is formed by heating to redness anhydrous 
 caustic baryta, and throwing into it pieces of phosphorus. It decom- 
 poses water, and forms phosphuret of hydrogen. 
 
 STRONTIUM. Symb. Sr. Equiv. 43.8. 
 
 Strontium was discovered by a process similar to that for 
 barium, which it resembles in most of its properties ; oxi- 
 dizes in the air ; decomposes water, by which process it is 
 converted into strontia. 
 
 Compounds of Strontium. 
 Protoxide of Strontium (Sr-f-O. 51.8) was discovered 
 by Dr. Hope, in 1792 ; also by Klaproth. 
 
 Process. It was formerly extracted from strontianite, (a 
 carbonate of strontia,) found at Strontian, in Scotland ; 
 hence its name. It may be prepared from the nitrate or 
 carbonate of strontia, in the same manner as baryta. 
 
 Properties. It resembles baryta in most of its properties. 
 A gray substance, pungent and acrid to the taste; slacked 
 with water, it produces intense heat, and is converted into a 
 hydrate which fuses readily, but the highest temperature of 
 a blast furnace will not separate the water; soluble in boil- 
 ing water, and crystallizes on cooling. The solution, like 
 baryta, is an excellent test of carbonic acid. 
 
 Peroxide of Strontium (Sr-j-20. 59.8) is prepared in the 
 same way as the peroxide of barium, and, like it, is em- 
 ployed to form binoxide of hydrogen ; decomposed by dilute 
 acids into strontia and oxygen. It is white, of a brilliant 
 lustre, inodorous, and nearly tasteless. 
 
 Chloride of Strontium (Sr-f-CI. 79.22) is obtained in a 
 manner precisely similar to the chloride of barium; crys- 
 
 ' 
 
240 Metals. — Calcium 
 
 tallizes from its solutions in colorless prismatic crystals, 
 which are distinguished from baryta by being soluble in twice 
 their weight of water at 60° , and by the red tinge which it 
 gives to the flame of an alcoholic solution. The anhydrous 
 chloride fuses at a red heat, and yields a white, crystalline, 
 brittle mass on cooling. — T. 
 
 Iodide of Strontium (Sr-f- 1. 170.1) is prepared in the same maimer 
 as iodide of barium. It is very soluble in water, fuses without decom- 
 position in close vessels, but is resolved into iodine and strontia, by a 
 red heat, in the open air. 
 
 Fluoride of Strontium (Sr-f-F 1 . 62.48) is obtained in the same way as 
 the fluoride of barium. It is a white powder, sparingly soluble. 
 
 Protosulphuret of Strantium (Sr-j-SS. 59.9) is similar in its proper- 
 ties, and modes of preparation, to the corresponding compound of 
 barium 
 
 CALCIUM. Symb. Ca. Equiv. 20.5. 
 
 Calcium was discovered by Davy, in 1S0S, by exposing 
 lime to the action of the galvanic battery. 
 
 Properties. It is of a whiter color than barium, and is 
 converted into lime by oxidation. Its other properties are 
 unknown. 
 
 Compounds of Calcium. 
 
 Protoxide of Calcium (Ca -f- O. 28.5) is generally obtained 
 by burning common limestone (carbonate of lime) in kilns, 
 for three or four days, to expel the carbonic acid. It is 
 then called lime, or quick lime. The purest lime is prepared 
 from the Iceland spar, or Carrara marble. 
 
 Properties. A brittle, grayish-white, earthy solid, of an 
 acrid, caustic, and alkaline taste ; sp. gr. 2.3 ; difficult of fusion, 
 but promotes the fusion of other bodies, and is hence used 
 as a flux in smelting the ores of the metals. It has a strong 
 affinity for water, with which it combines with the disengage- 
 ment of heat, and forms the hydrate — a bulky, white sub- 
 stance, called slacked lime. This parts with its water at a 
 red heat, and is more soluble in cold than in hot water. 
 
 Lime Water. This is simply a solution of the hydrate, and 
 possesses similar properties, absorbs carbonic acid from the 
 air, and should therefore be kept in close vessels. It is a 
 
 
Compounds of Calcium. 241 
 
 most delicate test of carbonic acid — a property already no- 
 ticed under carbon. 
 
 Uses. The uses of lime are well known for a cement, for 
 plaster, and as an anti-acid in medicine ; a substance almost 
 indispensable in every civilized country, and hence the Cre- 
 ator has made it very abundant and widely diffused, (the 
 carbonate forming ^ part of the crust of the globe.) 
 
 Peroxide of Calcium (Ca-j-20. 36.5) is similar in prop* 
 erties, and in the mode of preparation, to the peroxide of 
 barium. 
 
 Chloride of Calcium (Ca -f- CI. 55.92) exists in sea-water 
 and some saline springs, and may be formed by dissolving 
 marble in hydrochloric acid. On evaporation, the solution 
 yields colorless prismatic crystals, which consist of 10 equiv. 
 of water to 1 of the chloride ; these are rendered anhydrous 
 by heat, and fuse at a red heat, but absorb the water again 
 from the air, and deliquesce, owing to their strong attraction 
 for water. It is much used for freezing mixtures with snow. 
 Soluble in alcohol, with which it forms a definite compound. 
 
 Iodide of Calcium (Ca -|~ I. 146.8) is prepared by digesting 
 hydrate of lime with protiodide of iron. It is a white, fusible 
 compound, deliquescent, and very soluble in water ; the solu- 
 tion will dissolve a large quantity of iodine, and, on evapo- 
 ration, yield the periodide of calcium, in black prismatic 
 crystals. 
 
 Bromide of Calcium (Ca-|-Br. 98.9) is prepared in the 
 same manner as the iodide, which it resembles in its prop- 
 erties. 
 
 Fluoride of Calcium. Ca-j-R 39.18. This is an abundant 
 natural product, generally called fluor-spar or Derbyshire 
 spar. It occurs in beautiful cubic crystals, the primary form 
 of which is an octohedron, used extensively for ornamental 
 purposes, and is justly celebrated for the variety and beauty 
 of its colors ; fuses at a red heat, insoluble in water, and is 
 decomposed by sulphuric acid; thrown in coarse powder on 
 hot iron, it emits beautiful phosphorescent light, varying from 
 red to purple and green. 
 
 Protosulphuret of Calcium (Ca-f-S. 33.6) may be pre- 
 pared by exposing sulphate of lime to ri strong heat in a 
 charcoal crucible. It is white, with a reddish tint, and pos- 
 sesses the remarkable property of becoming phosphorescent 
 by exposure to the light. It is the essential ingredient in 
 Canton' ~ -*—*--■---- 
 
 
242 Metals. — Magnesium. 
 
 Bisidphuret of Calcium (Ca-f-2S. 52.7) occurs in orange-colored 
 crystals, prepared by boiling 3 parts of slacked lime, 1 of sulphur, and 
 20 of water, for a few hours, and setting the solution aside in bottles 
 corked tight for several days. When either of the above solutions is 
 boiled with sulphur, the solution contains calcium, with 5 equiv. of' 
 sulphur — the quintosulphuret of calcium, (Ca-f-oS. 101.) 
 
 Phosphurct of Calcium (Ca -f-P. 36.2) is formed by passing the vapoi 
 of phosphorus over quick lime, at a low red heat. It is a brown sub- 
 stance, and, when thrown into water, forms, by mutual decomposition, 
 phosphureted hydrogen, hypopkosphoroits acid, and phosphoric acid. 
 
 Chloride of Lime. Ca-f-O-fCl. 63.92. This substance, 
 commonly called oxymuriate of lime, or bleaching poicder, is 
 prepared by exposing recently-slacked lime to an atmosphere 
 of chlorine. The gas is rapidly absorbed, and enters into 
 direct combination with the lime, although Dr. Ure thinks 
 that no definite compound is formed. 
 
 Properties. A dry, white powder, similar to quick lime, 
 having the odor of chlorine, which it readily yields up when 
 moistened with water ; possesses powerful bleaching proper- 
 ties, for which purpose it is extensively used in the arts. 
 The strength of the chloride is estimated by the quantity of 
 indigo which a given portion of the bleaching solution will 
 deprive of its color. Used also in medicine, as a disinfecting 
 agent ; it should be kept in every family. 
 
 MAGNESIUM. Symb. Mg. Equiv. 12.7. 
 
 Magnesium was discovered and obtained in small quantities 
 by Sir H. Davy, by means of galvanism ; but M. Bussy, in 
 1S30, obtained it in greater abundance by the action of po- 
 tassium on chloride of magnesium. 
 
 Process. For this purpose, five or six pieces of potassium, 
 of the size of peas, were introduced into a glass tube, the 
 sealed extremity of which was bent into the form of a retort, 
 and upon the potassium were laid fragments of chloride of 
 magnesium; the latter being then heated to near its point of 
 fusion, a lamp was applied to the potassium, and its vapoi 
 transmitted through the mass of the heated chloride. Vivid 
 incandescence immediately took place; and, on putting the 
 mass, after cooling, iito water, the chloride of potassium, wit!* 
 undecomposed chloride of magnesium, was dissolved, and 
 metallic magnesium ' nh«ir1pH — T 
 
 ' 
 
Compounds of Magnesium. 243 
 
 Properties. A very malleable solid, of a white color, like 
 silver, and of a brilliant, metallic lustre. Dry, air and water 
 do not oxidize it, but moist air does; heated to redness in 
 oxygen gas, it burns vividly, and forms magnesia. In chlo- 
 rine gas it inflames spontaneously. 
 
 Compounds of Magnesium. 
 
 Protoxide of Magnesium, (Mg-|-0. 20.7,) commonly known 
 by the name of magnesia, is prepared by exposing the car- 
 bonate to a strong heat, to expel the carbonic acid. 
 
 Properties. A white, infusible powder, of an earthy appear- 
 ance, without taste or odor; sp. gr. 2.3; very infusible, and 
 sparingly soluble in water, requiring 5142 times its weight 
 at 60°, and 36,000 of boiling water to dissolve it. The prod- 
 uct is a hydrate. It changes vegetable infusions slightly, 
 but possesses the properties of an alkali, by forming neutral 
 salts with acids ; absorbs water and carbonic acid from the 
 air, and should be kept in close bottles. It exists in nature 
 in serpentine, steatite^ magnesite, and in sea-water, in con- 
 siderable abundance. 
 
 Chloride of Magnesium (Mg-j-Cl. 4S.12) is prepared by 
 dissolving magnesia in hydrochloric acid, evaporating to dry- 
 ness, mixing the residue with its own weight of hydrochlorate 
 of ammonia, and projecting the mixture, in successive portions, 
 into a platinum crucible, at a red heat. The ammonia is 
 expelled, and the chloride remains a transparent, colorless 
 mass ; very deliquescent, and soluble in water and alcohol. 
 
 Iodide of Magnesium (Mg-|-L 139) is formed by dissolving magnesia 
 in hydriodic acid ; known only in solution with water. 
 
 Bromide of Magnesium, (Mg-f-Br. 91.1) is prepared by dissolving 
 magnesia in hydrobromic acid. It occurs in small acicular crystals, 
 of a sharp taste, very deliquescent and soluble ; it is decomposed by a 
 strong heat. 
 
 Fluoride of Magnesium (Mg-f-F. 31.33) is formed by digesting mag- 
 nesia in excess of hydrofluoric acid ; it is insoluble, and bears a red heat 
 without decomposition. 
 
 
244 Met ah. — Aluminium. 
 
 Sect. 3. Metallic Bases of the Earths. 
 
 ALUMINIUM. Syrnb. Al. Equiv. 13.7. 
 
 Sir H. Davy proved that alumina was an oxidized body, 
 and Wohler succeeded in decomposing it, from which he ob- 
 tained the pure metal, aluminium. 
 
 Process. This metal may be obtained by heating the 
 chloride of aluminium with potassium in a covered platinum 
 or porcelain crucible. Intense heat is evolved during the 
 process. After cooling the mass, it is put into water, by 
 which the saline matter is dissolved : hydrogen gas, of 
 an offensive odor, is evolved, and a gray powder subsides. 
 This powder, after being washed in cold water, is pure 
 aluminium. 
 
 Properties. Aluminium, as thus prepared, is a gray powder, 
 similar to platinum, but when rubbed in a mortar, exhibits 
 distinctly a metallic lustre. Fuses at a higher temperature 
 than cast iron, and in this state is a conductor of electricity, 
 but a non-conductor when cold. 
 
 Exp. Heated in the air to redness, it burns brilliantly, and forms 
 alumina ; but when introduced into oxygen gas, at a red heat, it burns 
 with such splendor, that the eye can hardly support the liorht. and with 
 so much heat, that the resulting alumina is partially fused into yellow 
 fragments, as hard as corundum, which not only scratch, but abso- 
 lutely cut glass. 
 
 Exp. Takes fire in chlorine gas at a red heat, but is not oxidized by 
 water at common temperatures, nor attacked by cold sulphuric and 
 nitric acids ; soluble in solutions of potassa and ammonia, and in hot 
 sulphuric, or dilute sulphuric and hydrochloric acids. 
 
 Compounds of Aluminium. 
 
 Sesquioxiele of Aluminium (2A1 -f- 30. 27.4 -(-24 = 51.4) 
 
 is the only known oxide of aluminium, and is commonly 
 called alumina, or aluminous earth. 
 
 Natural History. Alumina is very abundant in nature, 
 being found in every region of the globe, and in rocks of all 
 ages ; hence it is one of the principal ingredients in most 
 soils. The different kinds of clay, of which bricks, pipes, and 
 earthen-ware are made, consist mostly of hydrate of alumina. 
 
Compounds of Aluminium. 245 
 
 [t is also found beautifully crystallized, in some of the most 
 beautiful gems. The ruby and the sapphire are nearly pure 
 alumina. 
 
 Process. It may be prepared for chemical purposes from 
 alum, which is a sulphate of alumina and potassa. Dissolve 
 pure alum in water, and precipitate the alumina by carbonate 
 of ammonia. This, when washed in hot water and filtered, 
 is the hydrate, which may be rendered pure by a white heat. 
 An easier process is to expose the sulphate of alumina and 
 ammonia to a strong heat, so as to expel the ammonia and 
 sulphuric acid. M. Gaudin has succeeded in forming rubies, 
 by mixing ammoniacal alum with -^Vo" P ar * °f chromate of 
 potassa, and exposing to a high heat. 
 
 Properties. Inodorous, tasteless, and possesses the proper- 
 ties both of an acid and an alkali ; insoluble in water, but has 
 a powerful affinity for it ; when moistened, it forms a ductile 
 mass, which gives it its great utility in the arts. It is a re- 
 markable exception to the law, that heat expands all bodies. 
 There are probably several hydrates of alumina. 
 
 Uses. Used for bricks, and various kinds of pottery. 
 
 Sesquichloride of Aluminium (2A1 -)-3Cl. 133.66) was dis- 
 covered by Wohler, by transmitting dry chlorine gas over a 
 mixture of alumina and charcoal, heated to redness. It is of 
 a pale, greenish-yellow color, partially translucent, of a highly 
 crystalline, lamellated texture, somewhat like talc, but with- 
 out regular crystals. On exposure to the air, it fumes slightly, 
 emitting an odor, like hydrochloric acid gas. 
 
 Exp. When thrown into water, it is speedily dissolved with a hiss- 
 ing noise, and so much heat is evolved, that the water, if in small 
 quantities, is brought into a state of brisk ebullition, and forms the 
 hydrochl orate of alumina. 
 
 Scsquisulphuret of Aluminium. (2Al-f-3S. 75.7) is prepared by drop- 
 ing a piece of sulphur on to aluminium, strongly heated. It is a vitri- 
 fied, semi-metallic substance, of a dark color. 
 
 Sesquiphospkuret of Mv minium (2A1-J- 3P. 74.5) is formed by heat- 
 ing aluminium in contact with the vapor of phosphorus ; it is a black- 
 ish-gray, pulverulent mass, which, by friction, acquires a dark gray 
 metallic lustre, and, in the air, has the odor of phosphureted hy- 
 drogen. 
 
 Sesquiscleniuret of Aluminium (2Al-|-3Se. 146.2) is obtained by 
 heating to redness a mixture of selenium and aluminium. It is a 
 black, pulverulent substance, which acquires a metallic lustre when 
 rubbed. 
 
246 Metals. — Glucinium — Yttrium. 
 
 GLUCmiUM. Symb. G. Equiv. 26.5. Sp. gr. 3. 
 
 Glucinium was obtained by Wohler, in 1828, by the action 
 of potassium upon the chloride of glucinium. The process is 
 similar to that for obtaining aluminium. It appears in the 
 form of a gray powder, which acquires the metallic lustre by 
 burnishing, and is easily oxidized. 
 
 Sesquioxide of Glucinium, or Glucina, (2G-[-30. .77,) 
 was discovered by Vauquelin, in 1798. It is found only in 
 the minerals emerald, beryl, and euclasc. 
 
 Process. It is obtained by exposing beryl in fine powder, 
 with three times its weight of carbonate of potassa, to a strong 
 red heat. The fused mass is dissolved in dilute hydrochloric 
 acid, evaporated to dryness, re-dissolved in acidulated water, 
 and the alumina and glucina are thrown down by ammonia, 
 the precipitate macerated by carbonate of ammonia, which 
 dissolves the glucina, and on boiling the filtered liquor, car- 
 bonate of glucina subsides ; the carbonic acid is then expelled 
 by a red heat. 
 
 Properties. A white powder, without taste or odor, quite 
 insoluble in water. Pure potassa or soda precipitates it from 
 its salts; distinguished from alumina by being precipitated 
 from its solution with carbonate of ammonia, when the solu- 
 tion is boiled. 
 
 YTTRIUM. Symb. Y. Equiv. 32.2. 
 
 Yttrium was prepared by Wohler, in 1828, by a process 
 similar to that for obtaining glucinium. 
 
 Properties. It has a scaly texture, a grayish-black color, 
 and a perfectly metallic lustre. It is a brittle metal, and 
 burns with splendor in common air, and with still greater 
 brilliancy in oxygen gas. The result of this combustion is 
 the earth yttria, which was discovered in 1794, by Gadolin, 
 m a mineral at Ytterby, Sweden. It is of a white color, 
 soluble in sulphuric acid, and combines with sulphur, sele- 
 nium, and phosphorus. Its salts have a sweetish taste, and 
 some of them have an amethystine color. 
 
"Thorium — Zirconium. 247 
 
 THORIUM. Symb. Th. Equiv. 59.6. 
 
 This metal was procured by the action of potassium on the 
 mloride of thorium ; decomposition being accompanied by a 
 slight detonation. On washing the mass, thorium is left, in 
 the form of a heavy, metallic powder, of a deep leaden-gray 
 color ; and, when pressed in an agate mortar, it acquires 
 metallic lustre and an iron-gray tint. — T. 
 
 Properties. Thorium is not easily oxidized at common 
 temperatures, but burns with great brilliancy in the air. It 
 is not acted upon by alkalies, scarcely at all by nitric, and 
 slowly by sulphuric acid ; but is readily dissolved by hydro- 
 chloric acid, with the disengagement of hydrogen gas. 
 
 Protoxide of Thorium, or Thorina, (ThO. 67.6,) was dis- 
 covered by Berzelius, in 1828, in a rare mineral from Nor- 
 way, called thorite. It is a white, earthy substance, soluble 
 in none of the acids, except the sulphuric, and is precipitated 
 from its solutions by the caustic alkalies as a hydrate, in 
 which state it absorbs carbonic acid from the atmosphere, 
 and dissolves in acids. 
 
 It is distinguished from alumina and glucina, by its insolu- 
 bility in pure potassa, and from yttria, by forming with sul- 
 phate of potassa a double salt, insoluble in a cold, saturated 
 solution of sulphate of potassa. 
 
 ZIRCONIUM. Symb. Zr. Equiv. 33.7. r 
 
 Zirconium was discovered by Berzelius, in 1824. 
 
 Process. It is obtained by heating the double fluoride of 
 zirconia and potassa, carefully dried and mixed with potassium, 
 in a glass or iron retort. The mass is then washed in hot 
 water, and digested for some time in hydrochloric acid. 
 
 Properties. This substance exists in the form of a black 
 
 powder. It may be pressed out into thin, shining scales, but 
 
 its particles adhere very slightly. It is a non-conductor of 
 
 electricity. It takes fire, when heated in the open air, at a 
 
 temperature below a red heat ; the product is zirconia. 
 
 Sesquioxide of Zirconium, or Zirconia, (2Zr-f-30. 91.4,) was dis- 
 covered by Klaproth, in 1789, from the Zreon. or Jargon, of Ceylon. 
 
V_~ — Manganese. 
 
 17 parte of this substance, finely pulverized, and mbced with 21 of 
 litharge, may be fused, and a glass obtained, soluble in acids, from 
 which the zirconia is derived ; or it can be formed directly by the com- 
 bustion of the metal in oxygen or common air. 
 
 Properties. A fine, white powder, inodorous and taste- 
 less ; sp. gr. 4 ; exposed to a strong heat, it loses, assuming a 
 light gray color ; when cool, it is so hard as to strike fire with 
 
 s:ee!. ir.i ::■ =:ri:::". cuir:z crvs:.?.:. 
 
 ORDER II. MeTALS. THE OxiDES 07 WHICH ARE- NEITHER 
 
 Alkali t E . i .7 :-: s 
 
 Sect. 1. JL:taIs which decompose TVater at a red Heat 
 
 Mm HSL Symb. Mn. Eq.27.7. Sp. gr. 8.013. 
 
 Hi rfory. In 1774, Scheele described the black oxide of 
 nese as " a pecnliar earth." Gahn subsequently dis- 
 covered that it contained a new metal, to which he gave the 
 gene of magnesium, a term applied afterwards to the metallic 
 as e : f magnesia ; and for which the words manganesium and 
 manganium have been substituted. The metal is not found 
 in the native or uncombined state, but its oxides are very 
 l": ■".::: 'I l:::. 
 
 Process. Make a paste with finely-pulverized oxide of 
 manganese and oil, and expose it to^the heat of a smith's 
 forge, in a Hessian crucible, lined with charcoal, for the 
 space of two hours. 
 
 Prop A hard, brittle metal, of a grayish-white color, 
 
 and granular texture; very infusible; not attracted by the mag- 
 i :ept when it contains iron ; soon tarnishes on exposure 
 to the air, and absorbs oxygen rapidly when heated to redness. 
 Decomposes water slowly at common temperatures, but rapidly 
 at a red heat 
 
 pounds of Manga/ 
 
 Protorid I — 5.7) may be formed, 
 
 as shown by Berthier, by he peroxide, sesquioxide, 
 
 or red oxide of manganese, to the combined agency of char- 
 
Compounds of Manganese. 249 
 
 coal, and a white heat; or by exposing either of the oxides, 
 contained in a glass tube, to a current of hydrogen gas, at an 
 elevated temperature. 
 
 Properties. When pure, it is of a light green, or moun- 
 tain-green color, undergoing little if any change in the open 
 air, but oxidizes rapidly at 600° Fahr., and is instantly 
 converted into the red oxide, at a low red heat, and some- 
 times takes fire. It is the salifiable base of the metal, and is 
 contained in all its salts; hence its strong affinity for acids. 
 
 Scsquioxide of Manganese (2Mn -|-30, or Mii-\-1^0. 79.4) occurs 
 nearly pure in nature, and may be formed by exposing the peroxide to 
 a red heat. It is the chief residue of the usual process of obtaining 
 oxygen gas, but it is difficult to regulate the heat so as to obtain it in a 
 pure state. 
 
 Properties. The color is brown or black, according to 
 the source from which it is obtained ; unites with nitric and 
 sulphuric acids, and is converted, by exposure to the air, into 
 the peroxide. 
 
 Peroxide of Manganese. Mn-j-20. 43.7. This is a well- 
 known native product, commonly called black oxide of man- 
 ganese. 
 
 Properties. It occurs generally in masses, of an earthy 
 appearance, and black color, mixed with other substances; 
 but it is frequently found in small prismatic crystals. It is 
 not affected by exposure to the air or water, but yields oxy- 
 gen when heated to redness, and is the substance most 
 generally employed for that purpose, (see page 130;) does 
 not unite with acids or alkalies. 
 
 Uses. Employed in the arts for coloring glass, in prepar-' 
 ing chlorine gas, and in forming the salts of manganese. 
 
 Red Oxide of Manganese. 3Mn-)-4G. 115.1. This is 
 identical with the oxidum manganoso-manganium of Arfwed- 
 son, and occurs as a natural product. It may be formed arti- 
 ficially by exposing the peroxide or sesquioxide to a white heat. 
 
 Properties. Color, when finely rubbed, is nearly black 
 
 when warm, and brownish-red when cold. It is permanent 
 
 in the air at all temperatures, dissolves in small quantities by 
 
 cold sulphuric acid, and more rapidly by the aid of chlorine ; 
 
 11* 
 
250 Metals. — Manganese, 
 
 the solution has an amethystine tint. It is the catfse of the 
 
 rich color of the amethyst. 
 
 Varvicite. 4Mn-{-70. 166.8. Sp. gr. 4.531. Known only as a 
 natural production, and first noticed by Mr. Phillips among some ores 
 of manganese, found at Hartshill in Warwickshire. It resembles the 
 peroxide in color, for which it was first mistaken, but may be distin- 
 guished from it by its stronger lustre, greater hardness, more lamel- 
 lated texture, and by yielding water when heated to redness. It is 
 probably, like the red oxide, a compound of two oxides, consisting of 
 2 equivalents of the peroxide, and 1 of the sesquioxide of manganese, 
 with 1 of water. — T. 
 
 Manganic Acid. Mn + 30. 51.7. When peroxide of 
 manganese is mixed with equal weights of nitre, or carbon- 
 ate of potassa, and heated to redness, it fuses, and a green- 
 colored mass is formed, known by the name of mineral 
 chameleon, from the property of its solution to pass through 
 several shades of color. 
 
 Exp. On the addition of cold water, a green solution is formed, 
 which soon becomes blue, purple, and red; and ultimately a brown, 
 flocculent matter — hydrated peroxide of manganese — subsides. — T. 
 
 Theory. These changes are owing to the formation of 
 manganate of potassa, of a green color, which passes to the . 
 permanganate of potassa, which is red, the blue and purple 
 being due to a mixture of these compounds ; but the man- 
 ganic acid has not been obtained in a separate state, owing 
 to its ready decomposition. 
 
 Permanganic Acid. 2Mn-|-70. 111.4. This acid . is 
 more permanent, though easily decomposed, even by contact 
 with paper or linen in filtering. It may be obtained from 
 the permanganate of baryta, by sulphuric acid. 
 
 Properties. Color red ; decomposed by water at 86° ; col- 
 oring matter is bleached by it, but particles of organic matter 
 floating in the air decompose it rapidly. 
 
 Protochloride of Manganese (Mn-j-Cl. 63.12) is prepared by evap- 
 orating a solution of the chloride to dryness, and heating it to redness 
 in a glass tube, while a current of hydrochloric acid gas is transmitted 
 through it ; fuses at a red heat, and forms a pink-colored lamellated 
 mass on cooling; deliquescent, and very soluble in water. — T. 
 
 Per chloride of Manganese (2Mn -J-7C1. 303.34) w 7 as discovered by 
 Dumas, and formed by putting a solution of permanganic into sul- 
 phuric acid, and adding fused sea-salt. 
 
 Properties. When first formed, it is a greenish-colored 
 vapor ; but by passing it through a glass tube cooled to -5°, 
 
 
Iron. 251 
 
 it condenses into a greenish-brown liquid, decomposed in- 
 stantly by water. 
 
 Perfluoridc of Manganese (2Mn-f-7F. 186.16) was discovered by 
 ITifmas and Wohler. Prepared by mixing the mineral chameleon with 
 half its weight of fluor-spar in a platinum vessel, and decomposing the 
 mixture with fuming sulphuric acid. 
 
 Properties. A yellowish-green gas, or vapor, which ac- 
 quires a beautiful purple-red color when mixed with air ; 
 freely absorbed by water, giving to the solution the same .red 
 tint; acts on glass with the formation of fluosilicic acid gas, 
 and the deposition of a brown matter, which acquires a deep 
 purple-red tint by the addition of water. 
 
 P rote sulphur et of Manganese (Mn-f-S. 43.8) is found native in 
 Cornwall, England, and may be formed by igniting the sulphate with 
 one sixth of its weight of charcoal, in powder. 
 
 Cyanide of Manganese. Mn-f-Cy. 27.7 -\- 26.39 = 54.09, equiv. 
 
 Phosphuret and Carburet of Manganese maybe obtained by heating 
 the metal in contact with phosphorus or carbon. 
 
 Alloys of Manganese. Manganese unites with several of 
 the metals, forming alloys of little importance. 
 
 IRON. Symb. Fe. Equiv. 28. Sp. gr. 7.78. 
 
 History. Iron is decidedly the most important and useful 
 of the metals. It appears essential to a state of civilization; 
 hence it is the most abundant, and widely diffused throughout 
 different parts of the earth. Hence, too, it seems- to have 
 been made known to the first inhabitants of the earth, and 
 used in all acres where men have emerged even to the state 
 of barbarians. It was formerly called 3Iars. 
 
 Natural History: Iron is rarely found pure in nature. 
 Even meteoric iron is alloyed with cobalt and nickel ; but its 
 oxides are very abundant. In combination with oxygen and 
 sulphur, it is so widely diffused, that few minerals can be 
 found that do not contain traces of it. It enters also into 
 plants and animals. The ores of iron are the red oxides, 
 including red and brown hematite, the black oxide, or mag- 
 netic iron ore, and the carbonate of the protoxide, either pure 
 or in the form of clay iron ore. 
 
 Process. The extraction of the iron from the ores is ef- 
 
252 3Ietals. — Iron. 
 
 fected by subjecting them, after being roasted and reduced to 
 a coarse powder, to the action of charcoal, lime, and caloric; 
 this is the cast iron, which contains some impurities, es- 
 pecially carbon. The malleable or wrought iron is prepared 
 from this, by continuing the process until the carbonaceous 
 matter is burned out ; it then becomes solid again, and is 
 put undef a roller or hammer and drawn out into bars. 
 Steel is the wrought iron combined with carbon. The best 
 wrought-iron bars are surrounded by dry charcoal and heated 
 to a high temperature. 
 
 Properties. Iron has a peculiar gray color, and strong 
 metallic lustre, which is brightened by polishing, of which it 
 is capable of receiving a higher degree than any other metal. 
 It is less ductile and malleable than some others, but the most 
 tenacious of all ; hence it may be drawn out into fine wire, 
 but not into thin leaves. Its texture is fibrous, and when 
 heated, is soft, and possesses the property of being welded to 
 other heated iron. When cooled suddenly, it is brittle, but 
 may be rendered malleable again by heat; it is very infusible, 
 and when combined with carbon, very hard. In this state. 
 it is capable of being made permanently magnetic : it is the 
 great repository of natural magnets, and the only substance, 
 save cobalt and nickel, which possesses magnetic properties, 
 
 Its uses in the arts are well known. 
 
 Compounds of Iron. 
 
 Protoxide of Iron. Fe-|-0. 38. The existence of this ox- 
 ide was first inferred by Gay Lussac ; but Stromever obtained 
 it in an insulated form, by transmitting dry hydrogen gas 
 over the proxide at a low temperature. It may also be 
 precipitated from its salts as a white hydrate by pure alkalies, 
 as a carburet by alkaline carbonates, as a white ferrocyanuret 
 by ferrocyanuret of potassium, and as a protosulphuret by 
 alkaline hydrosulphates. 
 
 Properties. Color dark blue, and communicates a blue 
 tint to substances melted with k. It is magnetic, and so 
 combustible, that it takes fire spontaneously in the open air, 
 and is converted into the peroxide. Its salts absorb oxygen 
 so rapidly from the air ; as to be useful in eudiometry. It is 
 
Compounds of Iron. 253 
 
 the base of the native carbonate, and the green vitriol of 
 commerce. 
 
 Peroxide of Iron. 2Fe + 30 or Fe + 1 JO. 80. This is the 
 red hematite of mineralogists, a very abundant natural pro- 
 duction. 
 
 Process. It is made chemically by dissolving iron in nitro- 
 hydrochloric acid, and adding an alkali. 
 
 The precipitate is of a brownish color, and is identical with 
 the mineral called brown hematite, and consists of 1 equiv- 
 alent of the peroxide and 2 of water. 
 
 Properties. It is a brownish-red compound, not attracted 
 
 by the magnet. It is precipitated from its salts by the pure 
 
 alkalies. With ferrocyanuret of potassium it forms Prussian 
 
 blue ; with infusion of nutgalls it forms ink. 
 
 Tests of the presence of iron in any composition, may be made by 
 boiling it with nitric acid, which converts the iron into the peroxide ; 
 the ferrocyanuret of potassium will then form a blue precipitate. 
 
 Black Oxide. (Fe + 0) + (2Fe-J-30.) 116. This com- 
 pound is called, by Berzelius, oxidum ferroso-ferrdcum, and 
 is supposed to be a mixture or combination of the two pre- 
 ceding oxides. 
 
 It occurs native, often in regular octohedral crystals. It 
 is formed also when iron is heated in the open air, or in con- 
 tact with moisture. It is not only magnetic, but is itself 
 often a magnet. With sulphuric acid, an olive-colored so- 
 lution is formed, containing two salts, the sulphate of the 
 protoxide, and peroxide, which may be separated from each 
 other by means of alcohol. The black oxide is the cause 
 of the green color of glass. 
 
 ProtochJoride of Iron (Fe -f- CI. 63.42) is formed by dissolving iron 
 in hydrochloric acid, evaporating to dryness, and heating the product 
 to redness, in a tube deprived of air. It is a gray, crystalline substance, 
 fusing at a red heat, and is easily converted into the hydrochlorate of 
 the protoxide of iron. 
 
 Per chloride of Iron (2Fe-f-3Cl. 162.26) is formed by the combustion 
 of iron in chlorine gas. It is a yellowish-brown substance, crystal- 
 lizes in small iridescent plates, of a red color ; volatilizes at little above 
 212°; deliquesces readily, and dissolves in water, alcohol, and ether, 
 and is converted by water into the hydrochlorate of the peroxide of 
 iron. 
 
 Protiodide of Iron (Fe-f-I. 154.3) is prepared by digest- 
 
£54 Metals.-— Iron* 
 
 ing iodine in water and iron wire. On evaporating the solu- 
 tion to dryness, without exposure to the air, and heating it 
 moderately, it yields crystals of an iron-gr.ay color and metal- 
 lic lustre, deliquescent, very soluble in water and alcohol, 
 and used in medicine as a tonic. 
 
 TJie Periodide of Iron (2F-J-3I. 434.9) is obtained by exposing a so- 
 lution of the protiodide to the air. It is a volatile, red compound, solu- 
 ble in water and alcohol. 
 
 The Protobromide of Iron (Fe-f-Br. 106.4) and the Perbromide of 
 Iron (2Fe -j-3Br. 291.2) are formed in a similar manner with the iodides, 
 and have similar properties. Protofiuoride of Iron. Fe-f-F. 46.63. 
 
 Perfluoridc of Iron (2Fe-f-3F. 112.04) is formed by dissolving per- 
 oxide of iron in hydrofluoric acid. As the acid becomes saturated, 
 crystals are formed in small, white, square tables, which are sparingly 
 soluble in water. 
 
 Protosulphuret of Iron (Fe-j-S. 44.1) is prepared by 
 heating equal parts of sulphur and iron-filings in a covered 
 Hessian crucible; considerable heat is evolved, and a yel- 
 lowish-gray substance is formed ; this is completely dissolved, 
 if pure, by dilute sulphuric acid, yielding hydrosulphuric 
 acid. It exists in nature, in the variegated copper pyrites, 
 and forms a black precipitate, when hydrosulphate of ammo- 
 nia is mixed with the sulphate of the protoxide of iron. 
 
 Sesquisulphurct of Iron (2Fe-f- 3S. 104.3) is formed by the action of 
 -he hydrosulphuric acid on the hydrated peroxide of iron. 
 
 It has a yellowish-gray color, and dissolves in dilute sul- 
 phuric and hydrochloric acids, with the formation of hydro- 
 sulphuric acid and bisulphuret of iron. 
 
 Bi sulphur ct of Iron. Fe-f2S. 60.2. This is the iron 
 pyrites of mineralogists, and occurs abundantly in cubes, or 
 in some analogous form, of a yellow color, and metallic lus- 
 tre ; sp. gr. 4.981 ; so hard as to strike fire with steel ; hence 
 its name. 
 
 It is dissolved by nitrohydrochloric acid, but by no other 
 acid, except the nitric. By heat, it is converted into magnet- 
 ic iron pyrites, if in close vessels, but exposed to the air, into 
 the peroxide of iron. 
 
 Magnetic Iron Pyrites. (5Fe + S) + (Fe+2S.) 280.7. 
 This natural product appears to be composed of 5 equivs. 
 of the protosulphuret and 1 of the bisulphuret. It may 
 be formed as above. It is much more easily oxidized than 
 the bisulphuret. % 
 
 Tetra sulphur et of Iron (4Fe + S. 128.1) and the Disulpkuret of Iron 
 (2Fe + S. .72) may be formed by passing hydrogen gas, at a red heat, 
 over the anhydrous sulphate of the protoxide of iron, to obtain the di 
 
Compounds of Iron. 255 
 
 sulphuret, and over the disulpliate of the peroxide of iron, for the tetra- 
 sulphuret. 
 
 Properties. They exist in a grayish-black powder, soluble 
 in dilute sulphuric acid, with the evolution of hydrogen and 
 hydrofluoric acid gases. 
 
 Diphosphuret of Iron (2Fe-|-P. 71.7) is prepared by heating the 
 phosphuret in a covered crucible, lined with charcoal. 
 
 Properties. It is a fused, granular substance, which re- 
 sembles iron in color and lustre, but is very brittle, and ren- 
 ders iron brittle, when contained in it, as it sometimes is. 
 
 Pcrphosphuret of Iron (3Fe -}-4P. 146.8) is obtained by the action of 
 phosphuret of hydrogen on sulphuret of iron, and resembles the pre- 
 ceding in most of its properties. 
 
 Carburets of Iron. Carbon and iron unite in several pro- 
 portions; only three seem worthy of notice — graphite, cast 
 or pig iron, and steel. 
 
 Graphite is known as a natural product, under the names 
 of plumbago and black-lead. There is not more than 10 per 
 cent, of iron, and often not 5. Used for pencils, crayons, 
 crucibles, and for burnishing iron. 
 
 Cast Iron is a compound of carbon and iron, and is the 
 product of melting the ores of iron with charcoal. Its uses 
 are well known. 
 
 Steel is formed by filling a furnace with bars of the best 
 malleable iron, with layers of charcoal between, and subject- 
 ing them to strong heat away from the air; about 1.3 to 1.75 
 percent, of carbon combines with the -iron. This is Uie 
 substance used for the various purposes of the arts. It- is 
 much harder than iron, but more brittle, also less ductile and 
 malleable, but more firm in its texture, and capable of a 
 higher polish. By fusion it forms cast steel. 
 
 Proto cyanide of Iron (Fe -j- Cy. 54.39) is prepared by mixing in 
 solution cyanide of potassium with sulphate of protoxide of iron ; on 
 exposure to the air, it passes to Prussian blue. 
 
 Protosulpkocyanide of Iron (Fe-f- CyS 2 . 86.59) is obtained by dis- 
 solving iron in hydrosulphocyanuric acid, and evaporating the pale 
 green solution to dryness in vacuo. 
 
 Sequisulpkocyanide of Iron (2Fe -f- 3CyS 2 . 231.77) is prepared by 
 mixing the sulphocyanide of potassium with any salt of the peroxide 
 of iron. It has a blood-red color, and is a very delicate test of the 
 presence of iron. 
 
256 Metals —£i 
 
 inc 
 
 ZINC. Symb. Zn. Equiv. 32.3. Sp. gr. 7.00. 
 
 Zinc has long been known in the East, India and China, 
 but was first distinctly noticed in the sixteenth century, by 
 Paracelsus, under the name of zinelnm. Henckel is the first 
 who obtained the metal from calamine, in the year 1721. 
 Von Swab first obtained it by distillation in 1742; and Mar- 
 grafF published a process in the Berlin Memoirs in 1746. 
 
 Natural History. Zinc, like most of the metals, is rarely 
 found pure in nature, but is an abundant substance in com- 
 bination with oxygen, carbon, and sulphur. 
 
 Process. Commercial zinc, or spelter, is generally ob- 
 tained from calamine, native carbonate of zinc, or from the 
 native sulphuret, called by mineralogists zinc blende. This 
 is oxidized by heating it in the open air, called roasting. It 
 is then distilled ; that is, it is heated in a crucible open at 
 the bottom and closed at the top, to which is affixed a tube, 
 which terminates just above a basin of water ; the gaseous 
 products, with the vapor of zinc, pass through the tube, and 
 the zinc is condensed. The first portions are impure, con- 
 taining cadmium and arsenic, which give the brown blaze ; 
 when the blue blaze is seen, the zinc is collected. It con- 
 tains now some impurities, which are removed by a white 
 heat in an earthen retort, to which a receiver full of water is 
 adapted. 
 
 * Properties. This metal is bluish-white, with a strong 
 metallic lustre and lamellated texture. It is a hard and brittle 
 metal ; but between the temperatures of 210° and 300° Fahr., 
 it is malleable and ductile, and in this state is rolled out into 
 plates; fuses at 773° Fahr., and when slowly cooled, crystal- 
 lizes in four or six-sided prisms. It is easily pulverized 
 when heated to a certain temperature below redness, and 
 sublimes at a high temperature in close vessels, without 
 change. 
 
 Uses. Zinc is used extensively in the aits, for the construction of 
 voltaic instruments, and for covering buildings. It has been pro- 
 posed to use it for culinary vessels, water-pipes, and sheathing for 
 ships; but it is so easily oxidized and acted upon by the weakest 
 acids, that it is unfit for these uses. 
 
Compounds of Zinc. 257 
 
 Compounds of Zinc. 
 
 Protoxide of Zinc. Zn-|-0. 40.3. This is the only known 
 oxide of zinc, formerly called flowers of zinc, nihil album, 
 and philosopher's wool. 
 
 Process. It is obtained by the combustion of zinc in the 
 open air, in oxygen gas, or by heating the carbonate to red- 
 ness. It is found native in Franklin, New Jersey. 
 
 Exp. Melt zinc in a covered crucible, and when it is at a white 
 heat, remove the cover ; it will burst out into a white flame, forming 
 the oxide. 
 
 The Hudrated Oxide of Zinc may be obtained by uniting 
 a rod of iron and zinc, and placing them in caustic ammonia, 
 in a close vessel. 
 
 Properties. At common temperatures it is white, but as- 
 sumes a yellow color when heated to redness ; insoluble in 
 water, and is a strong salifiable base. 
 
 The oxide is precipitated from its solutions, as a white hy- 
 drate, by pure potassa and ammonia, and as a carbonate 
 by alkaline carbonates. The oxide is sometimes substituted 
 for white lead for paint; it is more durable, but not so white. 
 
 Berzelius describes a suboxide, and Thenard a binoxide, 
 but they are doubtful substances. 
 
 Chloride of Zinc (Zn -f- CI. 67.72) is formed by burning zinc-filings 
 in chlorine. It \p colorless, fusible a little above 212°, and has so soft 
 a consistency at common temperatures, as to be called butter of zinc. 
 
 Iodide of Zinc (Zn -j- I. 158.6) is prepared by digesting iodine in 
 water with zinc-filings. 
 
 Bromide of Zinc (Zn -j- Br. 110.7) is formed in a similar manner 
 with the preceding. 
 
 Fluoride of Zinc (Zn -f-F. 50. 08) is prepared by the action of hydro- 
 fluoric acid on the oxide of zinc. It exists as a white solid. 
 
 Sulphuret of Zinc (Zn-|-S. 48.4) is a native product, 
 known by the name of zinc blende. It may be formed by 
 heating sulphur with the oxide; it crystallizes in dodeca- 
 hedrons; lamellated structure ; adamantine lustre; color red, 
 yellow, brown, or black. Cyanide of Zinc. ZnCy. 58.69. 
 
 CADMIUM. Symb. Cd. Equiv. 55.8. Sp. gr. 8.604. 
 
 History. Cadmium was discovered in 1817, by Stromeyer, 
 of Gottingen, in an oxide of zinc which had been prepared 
 
258 Metals. — Cadmium. 
 
 for medical use. Dr. Clark detected it in the zinc ores of 
 Derbyshire, and in the common zinc of commerce, and 
 Mr. Herapath found it in considerable quantities in the zinc 
 works near Bristol, England. 
 
 Process. The following is the process of Stromeyer : 
 The ore of cadmium is dissolved in hydrochloric or sulphuric 
 acid in excess. The sutphuret of cadmium is precipitated 
 by hydrosulphuric acid. Nitric acid decomposes this, and 
 forms a nitrate, which is evaporated to dryness. To a solu- 
 tion of this in water, an excess of carbonate of ammonia is 
 added, and the white carbonate of the oxide of cadmium is 
 precipitated, which, when subjected to a "Ped heat, yields a 
 pure oxide. The metallic cadmium is obtained from the ox- 
 ide, by heating it with charcoal. 
 
 Properties. Cadmium resembles tin in its color and lus- 
 tre, but is harder and more tenacious; very ductile and 
 malleable; melts at about the same temperature as tin, and 
 is nearly as volatile as mercury. Heated in the open air, it 
 absorbs oxygen, and is converted into the 
 
 Oxide of Cadmium, (Cd-j-O. 63.8,) which is the only 
 known oxide; is a strong alkaline base, forming neutral salts 
 with acids; insoluble in water; fixed in the fire ; and pre- 
 cipitated by all the alkaline carbonates, and by pure ammonia 
 and potassa, 
 
 Chloride of Cadmium. Cd -j- CI. 91.22. This compound 
 is formed by dissolving oxide of cadmium in hydrochloric 
 acid. By concentration, the chloride crystallizes in four- 
 sided rectangular prisms, which lose their water of crystal- 
 lization by heat, and even in dry air; fused below redness, 
 and sublimes at a high temperature. 
 
 Iodide of Cadmium (Cd-j-I 182.1) is formed in the same way as 
 the iodide of zinc ; soluble in water and alcohol, and crystallizes in 
 large, colorless, transparent, hexagonal tables, which do not change in 
 the air, and have a pearly lustre. By heat they lose water, and then 
 fuse. 
 
 Suiphuret of Cadmium (Cd-f-S. 71.9) occurs in nature in 
 zinc blende, and is prepared by the action of hydrosulphuric 
 acid on the salts of cadmium. It has a yellowish-orange 
 color, and may be distinguished from the suiphuret of arsenic 
 by being insoluble in pure potassa, and by sustaining a white 
 heat without subli miner. 
 
Tin. 259 
 
 Phosphufet of Cadmium is a gray compound, very brittle and 
 fusible. 
 
 TW. Syrnb. Sn. Equiv. 58.9. Sp. gr. 7.2. 
 
 Tin was known to the ancients, in the time of Moses ; 
 and was obtained, chiefly from Cornwall, England, and Spain, 
 at a very early period, by the Phoenicians. 
 
 Process. The tin of commerce is obtained from the 
 native oxide by heat and charcoal, and in the form of block 
 and grain tin. 
 
 Stream Tin is the native oxide of Cornwall, which is 
 found in rounded pebbles, occasioned by the action of water. 
 Tin is seldom perfectly pure, containing a little copper, iron, 
 and arsenic. That from Malacca is the purest. 
 
 Tin Foil is often an alloy of tin and lead. Block tin is 
 less pure than grain tin. 
 
 Properties. Tin has a color and lustre resembling silver. 
 It is very malleable. Tin foil does not exceed TTr \j^ of an 
 inch in thickness, but its ductility and tenacity are inferior to 
 many of the metals. When bent backward and forward, a 
 crackling noise is produced, by which it may be readily dis- 
 tinguished from lead, zinc, etc. It fuses at 240° Fahr. When 
 heated to whiteness, it takes fire. If a drop of the fused tin 
 fall upon a board, it will divide into several globules, and 
 burn with a beautiful white light. The brilliancy of its sur- 
 face tarnishes slowly when exposed to the air at common 
 temperatures, but oxidizes at a high temperature. 
 
 Compounds of Tin. 
 
 Protoxide of Tin (Sn + O. 66.9'. sp. gr. 6.666) is formed 
 by fusing tin for some time in an open vessel, or it may be 
 precipitated, as a hydrated oxide, from a solution of chloride 
 of tin, by an alkaline carbonate. 
 
 Properties. It is a gray powder, permanent in the air, un- 
 less touched by a red-hot body, when it takes fire, and is con- 
 verted into the peroxide. It is dissolved in the strong acids, 
 and the pure, fixed alkalies. Its salts readily absorb oxygen 
 from the air and other compounds; hence it throws down 
 
260 Metals. — Tin. 
 
 mercury, silver, and platinum, from their salts. With gold, 
 it causes the purple precipitate of Cassius ; by this charac- 
 ter it is readily distinguished. It is precipitated from its 
 solutions by hydrosulphuric acid as a black protosulphuret. 
 
 Sesquioxide of Tin (2Sn -j- 30. 139.8) is prepared by mixing recently- 
 precipitated and moist hydrated peroxide of iron with a solution of 
 protochloride of tin. The sesquioxide is precipitated in a slimy, gray 
 matter, of a yellowish tint, from oxide of iron ; distinguished from the 
 protoxide by being soluble in ammonia. 
 
 Binoxide of Tin (Sn-)-20. 74.9) is prepared by the action 
 of nitric acid on metallic tin. The concentrated acid does 
 not act on the tin, but, on the addition of water, violent effer- 
 vescence takes place, and a white powder — the hydrated bi- 
 noxide of tin — is formed. The water is expelled by heat, and 
 the pure binoxide, of a straw-yellow color, results. The hy- 
 drated oxide may also be precipitated from the protochloride 
 by potassa, ammonia, or the alkaline carbonates; but the 
 properties differ from that formed in the other way, the latter 
 being dissolved in the strong acids, while the former is not. 
 It acts the part of a feeble acid, uniting with the pure alka- 
 lies, and forming a class of compounds — the stannates. 
 
 Binoxide of tin is recognized by its being precipitated 
 from its solutions by hydrochloric acids as a bulky hydrate, 
 and by any of the alkalies or alkaline carbonates. When 
 melted with glass, it forms a white enamel. 
 
 Protochloride of Tin (Sn -f- CI. 94.32) is obtained by distilling equal 
 weights of tin and bichloride of mercury. It is a gray solid, of resin- 
 ous lustre ; fuses below redness, and sublimes at a high temperature ; 
 crystallizes in small, wJlite needles. A solution of the protochloride 
 may be prepared for deoxidizing purposes, by heating granulated tin 
 in strong hydrochloric acid, as long as hydrogen gas is evolved. 
 
 Bichloride of Tin (Sn-j-2Cl. 129.74) is formed by distilling 8 parts 
 of granulated tin with 24 of bichloride of mercury, or by heating the 
 protochloride in chlorine gas. 
 
 Properties. It is a colorless liquid, very volatile, yielding 
 white fumes in an open vessel ; hence formerly called the 
 fuming liquor, of Libavius; boils at 248°; sp. gr. of its 
 vapor, 9.1997; mixed with ^ of its weight of water, it forms 
 a solid hydrate, but dissolves in a larger quantity of water. 
 
 Uses. The solution called pennuriate of tin is used in dyeing, and 
 is prepared by dissolving tin in nitrohydrochloric acid. 
 
 Protiodide of Tin (Sn -J- I. 185.2) is prepared by heating granulated 
 tin with 2£ times its weight of iodine. It is a brownish-red substance, 
 very fusible, volatile, and soluble. 
 
 Biniodide of Tin (Sn-j-2I. 311.5) is prepared by dissolving the hy- 
 
Cobalt. 261 
 
 drate of the peroxide, precipitated by alkalies, from the bichloride, in 
 hydriodic acid. It forms yellow crystals of a silky lustre. 
 
 Protosulphuret of Tin (Sn-J-S. 75) is prepared by pouring melted 
 tin upon its own weight of sulphur, and stirring rapidly with a stick. 
 It has a bluish-gray, or nearly black color, and metallic lustre ; fuses 
 at red heat, and has a lamellated texture when cool. 
 
 Sesqu< sulphur ct of Tin (2 Sn-f-3S. 166.1) is obtained by heating to 
 low redness the protosulphuret with \ of its weight of sulphur. It is 
 a deep grayish-yellow compound. 
 
 Bisul planet of Tin. Sn-j-2S. 91.1. This compound was formerly 
 called Mosaic gold, and may be prepared by heating a mixture of 2 
 parts of peroxide of tin, 2 of sulphur, and 1 part of hydrochlorate 
 of ammonia, in a glass or earthen retort, to a low red heat, till sulphur- 
 ous acid ceases to be evolved. 
 
 Properties. It occurs in crystalline scales, of a golden- 
 yellow color, and metallic lustre ; soluble in pure potassa, 
 and its only solvent among the acids is the nitrohydrochlo- 
 ric acid. It is obtained, as a hydrate, by the action of hy- 
 drosulphuric acid, and the bichloride of tin, in solution. 
 
 Terphosphuret of Tin (Sn-f-3P. 106) is formed, according to Rose, 
 by the action of phosphuret of hydrogen on a solution of protochlo- 
 ride of tin. It oxidizes rapidly in the air. 
 
 COBALT. Syinb. Co. Equiv. 29.5. Sp. gr. 7.834. 
 
 Cobalt was discovered by Brandt, and derives its name, 
 KoboM, an evil spirit, from the belief of the German miners 
 that its presence was unfavorable to that of valuable metals. 
 
 Natural History. It exists in nature, generally, in com- 
 bination with arsenic. It is also a constant ingredient in 
 meteoric iron, and is found combined with sulphur and other 
 combustibles. 
 
 Process. It may be obtained from the oxide, by heating 
 it in connection with charcoal, and then passing over it a 
 stream of hydrogen gas, to combine with the oxjgen. 
 
 Properties. Cobalt is a brittle solid, of a reddish-gray 
 color, and weak metallic lustre; fuses at 130° Wedgwood, 
 and crystallizes when slowly cooled. It is attracted by the 
 magnet, and is susceptible of being rendered permanently 
 magnetic ; absorbs oxygen when heated in open vessels. It 
 is also oxidized by nitric acid, and decomposes water at a 
 red heat. 
 
262 Metals. — Cobalt. 
 
 Compounds of Cobalt. 
 
 Protoxide of Cobalt (Co-(-0. 37.5) is obtained by de- 
 composing the carbonate, by heat, in a vessel from which the 
 air is excluded. 
 
 Properties. It has an ash-gray color, and is the base of 
 all the salts of the metal, most of which are a pink-blue. 
 When heated, it absorbs oxygen, and is converted into the 
 peroxide. It is distinguished by giving a blue tint to borax 
 when melted with it. 
 
 Zajfre is an impure oxide of cobalt, obtained by heating 
 the arseniuret in a reverberatory furnace. When this sub- 
 stance is heated with sand and potassa, a beautiful blue- 
 colored glass is formed, known by the name of smalt, and 
 used in the arts for communicating the blue color to glass, 
 porcelain, and earthen-ware. 
 
 The protoxide is easily precipitated from its salts by alka- 
 lies; the precipitates are of a blue or pale pink color; dis- 
 solved in excess of alkali. 
 
 f Oxide of Cobalt (3Co-J-40. 120.5) is probably a compound of the 
 peroxide and the protoxide. 
 
 Peroxide of Cobalt (2Co-|-30. 83) is obtained as a black 
 hydrate with 2 equivs. of water, when chloride of cobalt is 
 decomposed by chloride of lime. The water is driven off 
 by exposure to a heat of 600° or 700°. It combines with 
 none of the acids, and, when strongly heated, is decomposed, 
 and resolved into the protoxide and oxygen. 
 
 Chloride of Cobalt (Co + Cl. 64.92) is obtained by dis- 
 solving metallic cobalt, or .either of its oxides, in hydrochlo- 
 ric acid. The solution is of a pink color, and yields, on 
 evaporation, small crystals of the same color. When these 
 crystals are deprived of their water of crystallization, they 
 assume a blue color — a property on which is founded its 
 use as a sympathetic ink. 
 
 Exp. Write on paper with a dilute solution of the chloride, and 
 expose it to a gentle heat; it becomes blue. This solution is called 
 Hill of s sympathetic ink, and is described by some chemists as a mu- 
 riate of cobalt; but Turner thinks it a chloride, analogous to several 
 other compounds generally described as muriates of the metals. 
 
 Exp. Draw the branches of a tree, with India ink, and put on the 
 foliage with the chloride of cobalt. When cold, the foliage does not 
 appear, but shows itself on the application of heat. A landscape may 
 
Compounds of Nickel. 263 
 
 be represented, in this manner, as wintry or vernal, according as the 
 heat is increased or diminished. 
 
 Sutphurets of Cobalt. Cobalt unites with sulphur in three 
 proportions. 
 
 The Protosulphurct (Co -f- S. 45.6) is formed by throwing fragments 
 of sulphur on red-hot cobalt; has a gray color, a metallic lustre, and 
 crystalline texture. 
 
 "The Sesquisulphuret of Cobalt (2Co-f-3S. 107.3) is formed by pass- 
 ing a current of hydrosulphuric acid gas over the ozysulphuret, at a 
 red heat. 
 
 Tlie Blsulphuret (Co-j-2S. CI. 7) is prepared by heating below red- 
 ness, in a glass tube, 2 parts of the carbonate of the oxide of cobalt, 
 intimately mixed with 3 of sulphur. 
 
 Subphosphuret of Cobalt (3Co-f-2P. 119.9) is obtained by the action 
 of phosphureted hydrogen on chloride of cobalt. It is a pulverulent 
 gray solid. 
 
 NICKEL. Symb. Ni. Equiv. 29.5. Sp. gr. 8.2579. 
 
 Nickel was discovered by Cronstedt in 1751, in the kup- 
 fer nickel [copper nickel) of Westphalia. The term nickel 
 was applied to the ore because it looked like copper, but did 
 not yield it. It exists also in meteoric iron. 
 
 Process. Nickel may be extracted from the ore, — which 
 is an arseniurct of nickel, containing small quantities of 
 sulphur, copper, cobalt, and iron, — or from spciss ; also an 
 arseniuret which is obtained in forming srnalt from the 
 roasted ores of cobalt. This metal is obtained by heating 
 the oxalate or the oxide with charcoal in close vessels.* 
 
 Properties. Color white, intermediate between tin and 
 silver; strong metallic lustre; ductile and malleable; at- 
 tracted by the magnet, and, like iron and cobalt, may be 
 rendered permanently magnetic; a little less infusible than 
 iron ; oxidized at a red heat, and by nitric acid. 
 
 Compounds of Nickel. 
 
 Protoxide of Nickel (Ni + O. 37.5) is formed by heating 
 the carbonate, oxalate, or nitrate, to redness, to drive off the 
 acid. 
 
 "■ For processes, see Turner's Elements, p. 331 
 
264 Metals. — Arsenic. 
 
 Properties. Color at first an ash-gray, but, when exposed 
 to a white heat, it is of a dull olive-green. This is the 
 strong alkaline base of the metal, and nearly all the salts 
 have a green tint. Pure alkalies precipitate this oxide from 
 its salts, as a hydrate of a pale green color. The alkaline 
 carbonates and hydrosulphurets also precipitate it from its 
 salts, the former as a carbonate, the latter as a sulphuret of a 
 black color. 
 
 Sesquioxide of JVickel (2Ni-(-30. 83) is formed by transmitting 
 chlorine through water, in which the hydrate of the protoxide is sus- 
 pended. It has a black color, does not unite with acids, and is decom- 
 posed at a red heat. 
 
 Chloride of Nickel (Ni-f-Cl. 64.92) is formed by the action of hydro- 
 chloric acid upon metallic nickel, or one of its oxides; an emerald- 
 green solution is formed, and, on evaporation, yields crystals of the 
 same tint, which deliquesce in moist air, and effloresce if the air is dry. 
 
 Protosulphuret of Nickel (Ni-j-S. 45.6) is formed by a similar pro- 
 cess with the protosulphuret of cobalt ; occurs native in acicular 
 crystals — the haarkies of the Germans. When dry, it is of a grayish- 
 yellow color, while the precipitates are dark brown ; soluble in nitric 
 or nitrohydrochloric acid. 
 
 Disulphuret of Nickel (2Ni-f-S. 75.1) is obtained by passing hydro- 
 gen gas over the sulphate of nickel at a red heat; color light yellow, 
 and is more fusible than the preceding. 
 
 Subphosphuret of Nickel (3Ni-f-2P. 119.9) is obtained by the action 
 of hydrogen on subphosphate of oxide of nickel. Color black, solu- 
 ble in nitric acid, and burns with a flame under the blowpipe. 
 
 Cyanide of Nickel (JNi-f-Cy. 55.89) is obtained by mixing in solu- 
 tion a salt of nickel with cyanide of potassium. A precipitate is 
 formed, of a pale, apple-green color, which becomes tinged with yellow 
 on drying. 
 
 Sect. 2. Metals which do not decompose Water at 
 • any Temperature, and the Oxides of which are not 
 
 reduced to the metallic State by the sole Action 
 
 op Heat. 
 
 ARSENIC. Symb. As. Equiv. 37.7.* Sp. gr. 5.8853. 
 
 Arsenic was first discovered by Dioscorides, who called 
 it Sandarac; but its properties were first investigated by 
 Brandt, in 1733. 
 
 Natural History. It exists in nature, in small quantities, 
 rarely in a metallic state. It is generally found in com- 
 * By some chemists the equiv. for arsenic is 75.34. 
 
Compounds of Arsenic. 265 
 
 bination with cobalt and iron, and occasionally with other 
 metals. 
 
 Process. Metallic arsenic is obtained by roasting the ores 
 in a reverberatory furnace ; as the arsenic is expelled by heat, 
 it combines with oxygen, and condenses into thick cakes on 
 the chimney. These cakes are purified by a second sublima- 
 tion, and constitute the white oxide of arsenic — a virulent 
 poison. This substance is then mixed with twice its weight 
 of black flux * exposed with charcoal to a red heat in a Hes- 
 sian crucible; and the metal is sublimed and collected in an 
 empty crucible, which is placed over the other, and kept cool 
 for the purpose of condensation. 
 
 Properties. Arsenic is a very brittle metal, of a steel-gray 
 color, high metallic lustre, and of a crystalline structure. 
 When heated to 356°, it sublimes without fusion, and may be 
 collected in close vessels without change ; but, when thrown 
 on a red-hot iron, it burns with a blue flame and white 
 smoke, giving off a strong odor of garlic — a property which 
 belongs to no other metal, unless it be zinc; when thus 
 heated in the open air, it is converted into the white oxide 
 of arsenic. Exposed at common temperatures of the air, it 
 oxidizes slowly, forming the substance called fly-powder; 
 which is a mixture of the oxide and the metal. 
 
 Arsenic detonates with some of the salts, and decomposes 
 
 them. 
 
 Exp. Take 3 parts of chlorate of potassa, and 1 of arsenic, finely 
 powdered, and cautiously mixed together. 
 
 1. Place a small quantity on an anvil, and strike it with a hammer; 
 the arsenic will instantly combine with the salt, producing an explosion 
 with flame. 
 
 2. Set it on fire, and it will burn rapidly. 
 
 3. Throw it into concentrated sulphuric acid, and a bright flash of 
 h£ht will be perceived at the moment of contact. 
 
 Uses. Arsenic is used in the arts. It renders glass 
 white. 
 
 Compounds of Arsenic. 
 
 Arsenious acid, (2As-|-30. 99.4,) commonly called white 
 arsenic and white oxide of arsenic, may be formed by the 
 
 * Prepared by detonating, in a crucible, 1 part of nitre with 2 of 
 the crystals of tartar. 12 
 
266 Metals. — A rsenic. 
 
 combustion of the metal ; but the white arsenic of commerce 
 is obtained from the arseniurets of cobalt, by sublimation. 
 
 Properties. Arsenious acid is white, semitransparent, 
 and, when first formed, of a Titreous lustre and conchoid al 
 fracture. Its acid taste is owing to the inflammation which 
 it produces ; it has a faint impression of sweetness. Its 
 S P- § r - is 3 7 ; has two crystalline forms, but is usually found 
 in six-sided scales, derived from a rhombic prism; soluble 
 in water. 
 
 It is one of the most virulent poisons Icnovrn ; and, as it is 
 sometimes accidentally or intentionally taken, it is a frequent 
 cause of death, and a subject of judicial investigation. Hence 
 the importance of pointing out the most effectual modes of 
 detecting its presence. 
 
 Tests. The most valuable are the ammoniaco-nitrate of 
 silver, ammoniaco-sulphate of copper, hydrosulpliuric acid, 
 and hydrogen gas, 
 
 1. Obtain as large a quantity of the liquid from the stom- 
 ach as possible. This, with parts of the stomach, should be 
 put into pure water, filtered and evaporated, so as to obtain 
 a concentrated solution; add to this, ammoniacal nitrate of 
 silver,* and if arsenic is present, a yellow — arseniate of sil- 
 ver — will be thrown down. 
 
 2. Add to the suspected liquid ammoniacal sulphate of 
 copper,f and a green precipitate will be formed, called 
 Scheele's green. 
 
 3. Pass into the liquid, hydrosulphuric acid, and if arseni- 
 ous acid is present, orpiment, or the sesquisulphuret of 
 arsenic will be formed, giving to the liquor a yellow, turbid 
 appearance. This sulphuret should then be dried, mixed 
 with black flux, carefully introduced into a glass tube, and 
 heated by a spirit lamp; the sulphuret will be decomposed, 
 and metallic arsenic appear on the cool parts of the tube. 
 This is a very satisfactory test ; but if, on heating the sub- 
 
 * Prepared by dropping into a strong solution of nitrate of silver, 
 ammonia, till the oxide of silver, first precipitated, is nearly all dis- 
 solved. 
 
 t Prepared in the same way with the preceding, by using the sul- 
 phate of copper, instead of the nitrate of silver 
 
Compounds of Arsenic. 267 
 
 stance thus deposited, it rises up in white fumes, with an 
 alliaceous odor, and is deposited in white,, octohedral crystals, 
 we may be sure that arsenic is present. 
 
 4. Introduce a quantity of the suspected liquid into a 
 Florence flask, having a jet pipe and a stop-cock attached, 
 with zinc and sulphuric acid; the water will be decomposed, 
 and the nascent hydrogen, in passing through the water con- 
 taining arsenious acid, will form arseniureted hydrogen; 
 and on burning the gas, as it issues from the jet, metallic 
 arsenic will be deposited on a plate of glass or porcelain, 
 held over the flame. 
 
 Any one of these tests, however^ should not be depended 
 upon in a case where the life of a fellow-being is at stake, as 
 other metals, such as antimony, will sometimes present a 
 similar appearance; but if the suspected substance be tested 
 by each of the four ways mentioned, there can be no doubt 
 but that it contains arsenious acid. 
 
 Its action upon animals, whether taken into the stomach, or applied 
 to wounds, is attended by pain and vomiting; and if life be prolonged 
 beyond twenty-four hours, diarrhoea, a sensation of heat, and extreme 
 pain in the stomach and intestines, succeed, pulse feeble, countenance 
 anxious, skin livid, often attended by eruptions. 
 
 The best antidote is perkydrate of iron, with a small quantity of am- 
 monia. In case3 rapidly fatal, extreme faintness, cold sweats, attended 
 with plight convulsions, are experienced. (See Christison on Poisons.) 
 
 Arsenic has the property of preserving from decay the bodies of 
 those poisoned with it. The stomach and intestines have thus been 
 found entire two years and a half after death. 
 
 Arsenic Acid (2As-|-50. 115.4) is formed by dissolving 
 arsenious acid in concentrated nitric, mixed with a small 
 quantity of hydrochloric acid, distilling in a glass vessel until 
 it acquires the consistency of sirup, and then heating nearly 
 to redness, in a platinum crucible, to expel the nitric acid. 
 
 Properties. It has a sour, metallic taste, reddens the vege- 
 table blue colors, and combines with alkalies, forming arse- 
 nates. It is decomposed by hydrosulphuric acid. This 
 acid is also an active poison. 
 
 Protochloride of Arsenic (AsCl. 73.12) is prepared by heating in a 
 retort, to nearly '212°, arsenious acid, with ten times its weight of con- 
 centrated sulphuric acid, and throwing them in fragments of common 
 salt. 
 
 Sesquichloride of Arsenic (As 2 Cl 3 . 181.66) is formed by the sponta* 
 neous combustion of powdered arsenic in chlorine gas. It is a color- 
 
26S Met ah. - — Chromium* 
 
 less, volatile liquid, giving off fumes, on exposure to the air; henee 
 called fu m ing liquor of arsenic. 
 
 Per iodide "of Arsenic (2As-f-51. 706.9) is formed by gently heating 
 arsenic with iodine. It is a deep red compound, decomposed by 
 waters 
 
 Protohydurct of Arsenic (As-(-H. 33.7) is prepared by the action of 
 water on an alloy of arsenic and potassium. 
 
 Sesquibromide of Arsenic. 2As-)-3Br. 310.6. When arsenic and 
 bromine are brought into contact, they instantly unite with vivid evo- 
 lution of light and heat. 
 
 Hyduret of Arsenic. 2As-j-3H. 78.4. This gas 
 was discovered by Scheele. It is generally made by digest- 
 ing an alloy of tin and arsenic in hydrochloric acid. It is 
 colorless; nas a fetid odor resembling garlic; sp. gr, 2.695 ; 
 extinguishes burning bodies, but burns with a blue flame. 
 It is poisonous in a high degree, having proved fatal to M. 
 Gehleu. It is decomposed by chlorine, iodine, caloric, and 
 even atmospheric air; it form3 with oxygen an explosive 
 mixture. 
 
 Protosulphuret of Arsenic. As-{-S. 53.8. This substance 
 exists in the mineral kingdom, and is called realgar. It 
 may be formed by heating arsenious acid with half its weight 
 of sulphur, until the mixture is perfectly fused. It is crys- 
 talline, transparent, and of a ruby-red color. 
 
 Sesqui sulphur ct of Arsenic. 2As-j-3S. 123.7, This in 
 the native state is called orpiment. 
 
 Process, ft may be formed by fusing arsenious acid and sulphur; 
 but it is purer, if obtained by passing hydrosulphuric acid gas through 
 a solution of arsenious acid. 
 
 Properties. This substance has a rich, yellow color, and 
 is employed as a pigment. It is the coloring principle in 
 the paint called Icing's yelloio. 
 
 Per sulphur et of Arsenic (2As-f-5S. 155.9) is formed by passing 
 hydrosulphuric acid through a moderately strong solution of arsenic 
 acid. It resembles orpiment in color. The sulphurets of arsenic are 
 poisonous. 
 
 CHROMIUM. Symb. Cr. Equiv. 23. Sp. gr. 5.9. 
 
 Chromium* was discovered in 1797, by Vauquelin, in a 
 beautiful red mineral, the native chromate of lead. It exists 
 
 * Xba5,ua, color, from its remarkable tendency to form colored com- 
 pounds. 
 
Compounds of Chromium. 269 
 
 also in chromate of iron, a native mineral found aoundantly 
 in Europe, and also in this country. 
 
 Process. This metal has been obtained only in small 
 quantities, owing to its affinity for oxygen. The oxide may 
 be deprived of its oxygen, by heating it with charcoal in a 
 smith's forge. 
 
 Properties. A brittle metal, of a grayish-white color, and 
 very infusible. It is oxidized by heating it with nitre, and 
 converted into chromic acid. 
 
 Compounds of Chromium, 
 
 Sesquioxide of Chromium. 2Cr -j- 30. 80. Exists native 
 in the emerald. 
 
 Process. It is prepared by dissolving chromate of potassa in water, 
 and mixing it with a solution of nitrate of mercury, when a yellow- 
 colored precipitate — the chromate of mercury — is formed. When this 
 salt is heated to redness in an earthen crucible, the mercury is driven 
 off, and the chromic acid is resolved into oxygen, and oxide of chro- 
 mium. 
 
 Properties. Oxide of chromium is of a green color, very 
 infusible, insoluble in water, and after being strongly heated, 
 resists the action of the most powerful acids ; heated with 
 nitre, it is converted into chromic acid. Fused with borax 
 or vitreous substances, it communicates to them a beautiful 
 green color. Hence its utility in the arts. It unites with 
 acids, and forms green-colored salts. 
 
 Chromic Acid (Cr-|^30. Equiv. 52) may be obtained 
 
 from the native chromate of iron. 
 
 Process. It is best prepared by transmitting the gaseous fluoride 
 of chromium into water contained in a vessel of silver or platinum; 
 when, by mutual decomposition of the gas and the water, hydrofluoric 
 and chromic acids are generated. — T. 
 
 Properties. This acid is black while warm, and dark red 
 when cold. When dry, according to Hayes, it is yellowish- 
 brown, very soluble in water, rendering it red and yellow. 
 When a heated concentrated solution cools, it deposits red 
 crystals, very deliquescent. The solution has an acid, astrin- 
 gent taste, and bleaches litmus paper. It destroys most vege- 
 table and animal coloring matters. Hence its use in calico- 
 printing. It is characterized by its color, and by forming 
 colored salts with alkaline bases. 
 
278 Metals. — - Vanadium. 
 
 Sesquichloride of Chromium. (2Cr-f-3Cl. 162.26) may be prepared 
 by transmitting c: jas over a mixture of oxide of chromium 
 
 and charcoal, heated to redness in a porcelain tube ; when the sesqui- 
 chloride gradually collects as a crystalline sublimate of a peach-purple 
 color. — T. 
 
 Terchleride of Chromium (Cr-f- 3C1. 134.26) k formed by the actioD 
 of fuming sulphuric acid on a mixture of chromate of lead and chloride 
 i : um. 
 
 Orychloride of Chromium. CtCF+2CfO» 235.26. 
 
 Sesquifiuoride of Chromium (2Cr -f- 3F. 112.04) is formed by dissolv- 
 ing the oxide in hydrofluoric acid, and evaporating to dryness. 
 of Chromh. '. . - ■ \7 58 -f- 56.04=* 
 
 Sesquisulphvrti of Chromium 2Gt — 3S. 104.3) may be obtained by 
 heating in close vessels a mixture of sulphur and the hydrated oxide. 
 It is of a dark-gray color, acquiring a metallic lustre by friction. 
 
 Proiophosphurei of Cftroinium (Cr-t-P or CrP. 43. T) is prepared by 
 passing phosphureted hydrogen gas oyer the sesquichloride of chro- 
 mium at a red heat : a black compound, burning before the blowpipe, 
 with a flame of phosphorus. 
 
 VANADIUM. Symb. V. Equiv. 6S.5. 
 
 Vanadium was discovered by Sefstrom, in 1530. It de- 
 rives its name from Vanadis, a Scandinavian deity. 
 
 Natural History. It exists in the iron ore of Taberg, 
 Sweden, and is found in great abundance in the slag formed 
 by converting the cast iron of Taberg into malleable iron. 
 It was also found by Johnson, at Wanlock-Head. Scotland, 
 where it occurs as a vanadiate of lead. 
 
 Process. It has been obtained in various ways — by heat- 
 ing vanadic acid with potassium, and by the decomposition 
 of the chloride of vanadium.* 
 
 Properties. When obtained by means of potassium, it is 
 a brittle, black substance; but when prepared by decompo- 
 sing the chloride, it is white, resembling silver, of a strong 
 metallic lustre. It is not oxidized by air or water ; boiling 
 sulphuric, hydrochloric, and hydrofluoric acids do not affect 
 it, but it is dissolved by nitric and nitrohydrochloric acids, 
 and the solution has a fine, dark blue color. 
 
 For processes, see Turner's Elements. 
 
Compounds of Vanadium — Molybdenum. 271 
 
 Compounds of Vanadium^ 
 
 Protoxide of Vanadium (V-4-O. 76.5) may be obtained by heating 
 vanadic acid with charcoal or hydrogen gas. ; It is a dark brown, or 
 black, substance, soluble in nitric acid. 
 
 Binoxide of Vanadium (V-4-20. 84.5) may be prepared by heating 
 to full redness 10 parts of the protoxide, with 12 of vanadic acid, in a 
 vessel filled with earbonic acid. It is black, ve,ry infusible, and insolu- 
 ble in water. Its salts have a blue color. It acts the part of an acid 
 by uniting with alkaline bases. 
 
 . * 
 
 Vanadic A cid (V -j- 30. 92.5) is tasteless, insoluble in 
 
 alcohol, and very slightly soluble in water. It is easily de- 
 composed by heating it with combustible matter, and in solu- 
 tion by all deoxidizing agents. It unites with bases often in 
 two or more proportions ; most of its neutral salts are yellow. 
 It is distinguished from all other acids, except the chromic, 
 by its color, and from this acid by the action of deoxidizing 
 substances, which give a blue solution with the former, and 
 green with the latter.* 
 
 MOLYBDENUM. Symb. Mo. Equiv. 47.7. Sp. gr. 8.615. 
 Molybdenum was discovered in 1775. 
 
 Process. It was obtained from the native sulphuret, by 
 digesting it in nitrohydrochloric acid, and heating the mo- 
 ?ybdic acid, thus formed, in connection with charcoal. 
 
 Properties. It is a brittle metal, of a white color, and 
 very infusible. Its propertied are imperfectly known. 
 
 Protoxide of Molybdenum (Mo -f- O. 55.7) is obtained by 
 precipitating the hydrochloric solution of molybdic acid by 
 zinc, when a brown hydrate is formed, giving dark colored 
 solutions with the acids. 
 
 Binoxide of Molybdenum (Mo -4- O. 63.7) is prepared by putting a 
 mixture of molybdate of soda and sal-ammoniac, in fine powder, in a 
 red-hot crucible, instantly covering it, and continuing the heat until 
 
 
 * The bichloride of vanadium, (V CI 2 . 68.5 + 70.34 = 139.34;) the 
 terchloride of vanadium, (TCP. 68.5 -4- 106.26 = 174.76 ;) the bibromide 
 of vanadium, (VBr 2 . 66\5 -4- 156.8 = 225.3 ;) the bisulphuret of vana- 
 dium, (VS*. 68.5 4-32.2=100.7;) the lersulphuret, (VS 3 . 68.5 + 48.3 
 = 116.8,) are unimportant compounds, for a description of which, see 
 Turner's Elements, p. 365, 
 
 
272 
 
 _/ 
 
 _" : " : - 5 inae5ds. 
 
 Mdybdic Acid (Mo-f- 30, or MO 3 71.7) may be obtained 
 by roasting the native solphuret in an open crucible, kept at 
 
 escape. The yellow powder, thus formed, is treated with 
 ammonia; the filtered solution evaporated, again dissolved 
 in water and ammonia, and crystallized ; the ammonia is 
 
 then irTZ'i'.'.i :j r-E-ntir r.ri: 
 
 is a white powder ; sp. gr. 34.9 ; fuses at a red heat into 
 a yellow liquid ; slightly soluble in water.* 
 
 Tungsten is found native in the mineral wolfram. 
 
 l 
 acid and charcoal to a strong heat. 
 
 Properties. It is a very hard, brittle metal, resembling 
 iron in color, and, by the action of heat and air, converted 
 
 Compounds of Tungsten, 
 
 Binoiide of Tungsten (W-f-20. 110.8) is prepared by 
 the action of hydrogen gaa Long - : i c aeid, at a low red 
 
 heat. It has a brown colofc, resembling copper when 
 
 T&ngsfic Ad I (W-f-30. liS.S) may be obtained by 
 heating the binoxide to redness in- open vesf - sofa 
 
 yeflmr color, insoluble in water, and has no action on litmus 
 
 ^V _ :CL 165.64) is formed by 
 
 : 
 I 
 
 i :: i'..r -:■:- 'r\- ~ :: vie 
 
 ; '-•--<£ . 
 
 iMfjMrcsm, (MoS>. 11 
 i E 1 rinenfcs,, p 3t&. 
 
 _ : 
 
Columbium — Antimony. 273 
 
 C0LUMB1UM. Symb. Ta. Equiv. 185. 
 
 Columbium was discovered in 1801 , by Hatchett, in a 
 black mineral in the British Museum, which had been sent 
 by Governor Winthrop to Sir Hans Sloane, from Haddam, in 
 Connecticut.* 
 
 Process. It is obtained by heating potassium with the 
 double fluoride of potassium and columbium. 
 
 Properties. Obtained in this way, it is a black powder, 
 and a non-conductor of electricity, but a perfect conductor 
 in a more dense state. It acquires a metallic lustre by pres- 
 sure ; of an iron-gray color ; fuses at a higher temperature 
 than glass ; heated in the open air, it takes fire, and is con- 
 verted into columbic acid. It is easily dissolved in nitro- 
 hydrofluoric acid. 
 
 Compounds of Columbium. 
 
 Binoxide of Columlium (Ta -{- 20. 201) may be formed by exposing 
 columbic acid in a crucible, lined with charcoal, and luted to exclude 
 the air, for an hour and a half, to an intense heat. When reduced to 
 powder, it is a dark brown suBstance, not acted upon by acids, but con- 
 verted into columbic acid by fusion with potassa or nitre. 
 
 Columbic Acid (Ta -(- 30. 209) is formed from the native columbates, 
 Dy fusing the ores with three or four times their weight of carbonate of 
 potassa, and precipitating the white hydrate by acids. 
 
 Properties. Hydrated columbic acid is tasteless, insolu- 
 ble in water, and communicates a red tinge to moistened lit- 
 mus paper ; heated to redness, the water is expelled, and the 
 anhydrous columbic acid remains.f 
 
 ANTIMONY. Symb. Sb. Equiv. 64.6. Sp. gr. 6.702. 
 
 History. Antimony was discovered by Basil Valentine, 
 m the fifteenth century. It derived its name from anti monk, 
 
 * Tantalum, discovered by Ekeberg, is identical with this metal. 
 
 t The equiv. for antimony is considered by many late writers on chem- 
 istry to be double the number in the text, 129.2. The same is true of a 
 few other substances, which are noticed in their proper places. 
 12* 
 
274 Metals. — Antimony. 
 
 from its having proved fatal to some monks, to whom it was 
 given as a medicine. 
 
 It is found native in Sweden, France, and the Hartz ; but 
 generally occurs as a sulphur et. 
 
 Process. It may be obtained by heating the native sul- 
 phuret in a covered crucible, with half its weight of iron- 
 filings; the sulphur unites with the iron, and the metal ap- 
 pears in the bottom of the crucible. Procured in this way. 
 it is not absolutely pure. and. for chemical purposes, it should 
 be procured by heating the oxide with an equal weight of 
 cream of tartar. 
 
 Properties. A brittle metal, of a white color : fuses at 
 610", and, on cooling, has a lamellated texture, and often 
 yields crystals ; burns with great brilliancy when placed on 
 ignited charcoal, under a current of oxygen gas. 
 
 Compounds of Antimony. 
 
 Sesquioxide of Antimony (2Sb-{-30. 153.2) is obtained 
 by subjecting antimony in a covered crucible to a white heat, 
 and then exposing it to the air ; a white vapor arises, and 
 condenses in fine crystals of silver jphiteness. 
 
 It is the only oxide whi : 3 regular salts. It is the 
 
 base of emdic tartar, the tartrate of antimony and po- 
 
 tassa. The test of antimony in solution is the hydrosulphuric 
 acid, which yields an orange-colored precipitate. 
 
 Antimonious Acid 2Sb-J-40. 161.2) is generated when 
 the oxide is exposed to heat in open vessels. It is white 
 when cold, and yellowish when heated ; very infusible and 
 fixed in the fire, by which it is distinguished from the oxide : 
 insoluble in water and in acids, after being heated to redness. 
 
 Antimonic Acid (2Sb -f-50. 169. -2) may be obtained as a 
 
 white hydrate, either by digesting the metal in strong nitric 
 
 acid, or by dissolving it in nitrohydrochloric acid, concen- 
 
 ing by heat to expel excess of acid, and » the 
 
 solution into water. 
 
 It is decomposed at a red heat, and converted into anti- 
 monious acid. 
 
 Sesqulchloride of Antimony (2Sb-f- 3C1. 235.46) is generated by the 
 
 spontaneous combustion of antimony in chlorine gas. It is a sort t 
 
Uranium. 275 
 
 called butter of antimony ; easily fused, and deliquesces when ex- 
 posed to the air.* 
 
 Sesquisiilphuret of Antimony. 2Sb-f-3S. 177.5. This is the princi- 
 pal ore of the metal, and hence is generally employed in making the 
 preparations of antimony. It is of an earthy appearance, but is some- 
 times found in acicular crystals, of a red-gray color and metallic lustre ; 
 sp. gr. 4.62. It may be formed artificially by fusing together antimony 
 and sulphur. 
 
 Oxysulphnret of Antimony is composed of 2 equiv. of 2 Sb-j-3S 
 and 1 equiv. of 2Sb0 3 = 508.2. This occurs native — the red antimony 
 of mineralogists. Glass, liver, and crocus of antimony are of a similar 
 nature. 
 
 Kermes Mineral is formed by boiling the sesquisulphuret with a 
 solution of potassa or soda. On neutralizing the cold solution, a simi- 
 lar substance, the golden sulpkuret, is precipitated.! 
 
 Alloys. Printers' types are formed of 3 parts of lead, 1 
 of antimony, and a little copper. 
 
 Peictcr is an alloy of 12 parts of tin, 1 of antimony, with 
 a small addition of copper. The white metal for teapots is 
 an alloy of 100 parts of tin, 8 of antimony, 2 of bismuth, and 
 2 of copper. 
 
 URAJYIUM. Symb. U. Equiv. 217. Sp. gr. 9. 
 
 Uranium was discovered by Klaproth, in 1789. It derives 
 its name from the planet discovered the same year, (Uranus.) 
 It exists in pitch blende, and is obtained from it by heating 
 the ore to redness, and digesting its powder in pure nitric 
 acid, diluted with 3 or 4 parts of water. Its properties are 
 not well known. 
 
 Protoxide of Uranium (U -\- O. 225) is obtained by de- 
 composing the nitrate of the sesquioxide by heat. It is of a 
 dark green color, very infusible, and readily oxidized by 
 nitric acid ; used in the arts to give a black color to porce- 
 lain. 
 
 * Bichloride of antimony ; 2Sb -f- 4C1. 270.88. Perchloride of anti- 
 mony ; 2Sb -f- 5C1. 306.3. Oxychloride of antimony ; 2 equiv. of 2Sb -f- 
 3C1. and 9 equiv. of Sb0 3 = 1849.72. Bromide of antimony, composi- 
 tion unknown. 
 
 t Bisulphuret of antimony ; 2Sb -f- 4S. 193.6. P er sulphur et of anti- 
 mony ; 2Sb + 5S. 209.7. 
 
 
276 Metals. — Cerium — Bismuth. 
 
 Sesquioxide of Uranium (2U -\- 30. 45S) is of a yellow 
 color, and combines with acids and alkaline bases. 
 
 The Protochloride of Uranium, (U -f- CI. 252.42 ;) the Sesquichloride 
 of Uranium, (2U -(-3C1. 540.26,) and the Sulpkuret of Uranium, are un- 
 important compounds. — (See Turner, page 380.) 
 
 CERIUM* Symb. Ce. Equiv. 46. 
 
 Cerium was obtained, by Hisinger and Berzelius, from a 
 mineral called cerite. It exists also in the mineral called 
 allanite, as an oxide, which is very difficult to be reduced to 
 the metallic state. Vauquelin obtained a small globule, not 
 larger than a pin's head, which was not acted upon by any 
 of the simple acids, and but slowly dissolved by the nitro- 
 hydrochloric. 
 
 Compounds of Cerium. 
 
 Protoxide of Cerium (Ce-j-O. Eq. 54) is a white powder, 
 insoluble in water. The salts, which are soluble, have an 
 acid re-action. 
 
 Sesquioxide of Cerium (2Ce -J-30. 116) is obtained from eerite, and is 
 a fawn-red substance, soluble in several of the acids. 
 
 Protochloride of Cerium. Ce-4-Cl or CeCl. 46 + 35.42 = 81.42. 
 
 Sesquichloride of Cerium. 2Ce -f- 3C1 or Ce 2 Cl 3 . 92 -j- 106.26= 198.26. 
 
 Protosulphuret of Cerium. Ce-f-S or CeS. 621. — (See Turner's 
 Chemistry, p. 381.) 
 
 BISMUTH. Symb. Bi. Equiv. 71. Sp. gr. 9.822. 
 
 Native Bismuth occurs in crystals, octohedra, or cubes, 
 containing arsenic and cobalt. It is also found combined 
 with sulphur and oxygen, from which it is obtained by the 
 aid of heat and charcoal. 
 
 Properties. It is a brittle solid, generally composed of 
 
 broad plates of a reddish-white color, very fusible; melts at 
 
 470° Fahr., and forms very fine crystals by slow cooling. 
 
 Exp. For this purpose, fuse a quantity of it in a crucible, and let it 
 cool until a crust is formed ; break the crust and pour out the fluid be- 
 
 * So called from the planet Ceres, discovered about the same period 
 
 - 
 
Titanium. 277 
 
 neath ; the inner surface will be lined with beautiful crystals. Under 
 the compound blowpipe it burns with much brilliancy, producing yellow 
 fumes of protoxide. 
 
 Protoxide of Bismuth (Bi + O. 79. Sp. gr. 8.211) may 
 be formed as above. It forms salts, most of which are white ; 
 sublimes at a high temperature ; fuses at a full red heat into 
 a brown liquid. If the nitrate of the protoxide be thrown 
 into water, a white precipitate is thrown down, formerly 
 called magistery of bismuth, and pearl white, which is some- 
 times used as a paint, for improving the complexion. 
 
 Sesquioxide of Bismuth (2Bi-f-3Q. 166) is formed by fusing potassa 
 with the protoxide of bismuth. It is a brown, heavy powder, little dis- 
 posed to unite with acids, or alkalies. 
 
 Chloride of Bismuth (Bi-f-Cl. 106.42) is formed by the spontaneous 
 combustion of bismuth in chlorine gas, formerly called butter of bismuth 
 It is of a grayish-white color, and granular texture. 
 
 Bromide of Bismuth. Bi-j-Br. 71 -f- 78.4 = 149.4. 
 
 Sulphuret of Bismuth (Bi-j-S. 87.1) is found native. 
 
 TITANIUM. Symb. Ti. Equiv. 24.3. Sp. gr. 5.3. 
 
 Titanium was first noticed by Mr. Gregor, of Cornwall. 
 Klaproth gave it the name of titanium, after the Titans of 
 ancient fable. But its properties were determined by Wol- 
 laston, in 1822, who found it in the slag of an iron-smelting 
 furnace in South Wales. 
 
 Properties. Its color is red, resembling copper. It exists 
 in small cubes, which are so hard as to scratch rock-crystal, 
 and very infusible. It generally contains traces of iron. 
 The pure metal is obtained by heating the chloride with am- 
 monia in a glass tube, when it appears in the form of a deep 
 blue colored powder, which is apt to take fire, if exposed to 
 the air when warm. 
 
 Compounds of Titanium. 
 
 Oxide of Titanium (Ti -(- O. 32.3) is obtained by exposing titanic acid 
 to a strong heat in a black-lead crucible. It is of a purple color. 
 
 Titanic Acid, (Ti-j-20. 40.3,) also called peroxide of titanium, exists 
 in the minerals annta.se and rutile, from which the acid is obtained by 
 the aid of heat and hydrosulphuric acid gas.* 
 
 * For processes, see Turner's Elements. 
 
278 Metals.— Tellurium. 
 
 Properties. Titanic acid is of a white color ; very infusi- 
 ble, and when once ignited, insoluble in acids, except in the 
 hydrochloric. It is a feeble acid, resembling the silicic. If 
 it is ignited with potassa, and dissolved in hydrochloric acid^ 
 a solution of gall-nuts will produce an orange-red color, which 
 is very characteristic of titanic acid. 
 
 Bichloride of Titanium (Ti-r-2Cl. 95.14) was discovered in. 1324, by 
 Mr. George, of Leeds, by transmitting dry chlorine gas over titanium 
 at a low red heat. 
 
 Properties. A transparent, colorless liquid, which boils 
 at 21*2 . The density of its vapor is 6.015; combines with 
 water with explosive violence from the evolution of intense 
 heat ; on exposure to the atmosphere, it emits dense white 
 fumes, of a pungent odor, similar to chlorine. 
 
 Bisidphuret of Titanium. Ti + 2S. Eq. 24.3 + 32.2 = 
 56.5. 
 
 TELLURIUM. Symb. Te. Equiv. 64.2. Sp. gr. 6.115. 
 
 Tellurium is a rare metal, found only in small quantities in 
 Transylrania and Connecticut. It was first noticed by Miil- 
 ler, in 1TS2, but its existence was more fully established in 
 1T9S, by Klaproth, who called it tellurium, from telJus, the 
 earth. It is found chiefly in combination with gold and 
 silver. 
 
 Properties. It is a brittle metal, of a bright gray color ; 
 very infusible and volatile. Heated in the air, it burns with 
 a sky-blue flame, edged with green: placed upon charcoal 
 before the blowpipe, it inflames with violence, and flies en- 
 tirely off in gray smoke, having a peculiarly nauseous smell. 
 
 Compounds of Tellurium. 
 
 Tellurous Acid, (Te-f-20. 80.2,) also called oxide of tel- 
 lurium, is generated by the action of nitric acid on tellurium. 
 It is a white, granular powder, resembling in many of its 
 properties the titanic, and several other feeble acids. Its 
 aqueous solution reddens litmus paper. 
 
 The other compounds are the Tc'hiric Add, (Te-fSO. 88.2 ;) Chlo- 
 ride of Tellurium, (Te -f CI. 99.62;) Bichloride. (Te -f 2C1. 135.01:) 
 Biiulphuret, (Te-f 2S. 96.4:) Persulphuret and Hydrotelluric Acid, 
 (Te -f Ii. 65.2.) 
 
Copper, 279 
 
 COPPER. Symb.Cu. Equiv.31.6. Sp. gr. 8.895. 
 
 Copper, from cuprum, a name derived from the island 
 Cyprus, has been known from the remotest ages. 
 
 Natural History. It is found native, and in combination 
 with other substances, especially with sulphur. The copper 
 of commerce is chiefly obtained from the native sulphurets. 
 It exists in great abundance in Cornwall, and other parts of 
 Europe, in Liberia, and in America. 
 
 Schoolcraft found a mass of native copper about thirty 
 miles from Lake Superior, which weighs, by estimation, 
 2000 lbs. 
 
 Process. It may be obtained perfectly pure, by dissolving 
 the copper of commerce in hydrochloric acid, diluting the 
 solution, and immersing in it a clean plate of iron, upon 
 which the copper will be precipitated. 
 
 Properties. Copper is distinguished from all other metals, 
 except titanium, by its red color. It is very ductile and 
 malleable; melts at 1996° Fahr. ; burns before the com- 
 pound blowpipe with a beautiful green flame, and if a fused 
 globule be thrown into a glass jar, two feet high, filled with 
 water, it will pass in full ignition to the bottom, and remain 
 some time at a red heat. 
 
 Uses. Copper is one of the most useful metals, being em- 
 ployed extensively in most of the arts of life. 
 
 Compounds of Copper. 
 
 Red, or Dioxide of Copper (2Cu-f-0- 71.2) is found 
 native in octohedral crystals. 
 
 Process. It may be prepared artificially, by heating, in a 
 covered crucible, a mixture of 31.6 parts of copper-filings 
 with 39.6 of the black oxide. 
 
 Properties. It resembles copper in color; sp. gr. 6.093; 
 soluble in ammonia, and the solution is colorless, but it 
 absorbs oxygen on exposure to the air, which produces a 
 blue color, owing to the formation of the black oxide. 
 
280 Metals. — Alloys of Copper. 
 
 Black, or Protoxide of Copper. Cu-(-0. 39.6. This is the copper 
 black of mineralogists, and is formed by the spontaneous oxidation oi 
 other ores of copper. 
 
 Properties. It varies from a dark brown to a bluish-black 
 color, according to the mode of formation; combines with 
 most of the acids, and its salts have a green or blue tint. It 
 forms with ammonia a deep blue solution, which distinguishes 
 it from all other substances. The salts of the protoxide of 
 copper are mostly distinguished by their color. Metallic 
 copper is separated from the salts by a rod of iron or zinc. 
 
 Binoxide of Copper. Cu -f 20. 31.6 -f- 16= 47.6. 
 
 Dichloride of Copper (2Cu + CI. 98.62) is formed by the spontane- 
 ous combustion of copper-filings in chlorine gas. It is of various colors, 
 white, yellow, and dark brown, according to the mode of preparation ; 
 soluble in hydrochloric acid, but not in water. 
 
 Chloride of Copper ; Cu + CI. 67.02. Diniodide of Copper; 2Cu + 
 I. 63.2-1-126.3 = 189.5. Sulphuret of Copper (Cu-f-S. 47.7) is a 
 constituent of copper pyrites, in which it is combined with protosul-- 
 phuret of iron. Triphosphuret of Copper; 3Cu + P. 110.5. Subse- 
 quiphosphuret ; 3Cu + 2P. 126.2. Cyanide of Copper; Cu -J- Cy 
 57.99. Disulphocyanide of Copper; Cu-f CyS 2 . 63.2 +(26.39 + 
 32. 2) = 121.79. — (See Turner's Elements, p. 389.) 
 
 Tests. The best mode of detecting copper in mixed liquids is the 
 hydrosulphuric acid. The sulphuret, after being collected, and heated 
 to redness in order to char organic matter, should be placed on a piece 
 of porcelain, and be digested in a few drops of nitric acid ; sulphate of 
 the protoxide of copper is formed, which, when evaporated to dryness, 
 strikes the characteristic blue tint on the addition of ammonia. — T. 
 
 Alloys. The alloys of copper are very important and use- 
 ful substances. 
 
 Brass is an alloy of copper and zinc. The best brass 
 consists of four parts of copper to one of zinc. Tutenag 
 contains in addition a little iron. Tombac, Dutch Gold, Si- 
 milor, Prince Rupert's Metal, and Pinchbeck, contain more 
 copper than brass. Bell-metal and Bronze are alloys of cop- 
 per and tin. The best proportion for bell-metal is 3 parts 
 of copper to 1 of tin; for bronze, 8 to 12 of tin to 100 of 
 copper. In these alloys, according to Dalton, the elements 
 combine in definite proportions. 
 
 Poisonous Properties of Copper. Copper vessels used for 
 culinary purposes should be coated with tin, as the oxide is 
 poisonous. This is done by making the surface of the copper 
 bright, rubbing over a little sal-ammoniac to prevent oxidation, 
 and then heating the vessel and rubbing it with rosin and tin. 
 
Lead, 281 
 
 LEAD. Symb. Pb. Equiv. 103-6. Sp. gr. 11.352. 
 
 Lead was well Known to the ancients. It is rarely found 
 native, but its ores are abundant, the most important of which 
 is the sulphuret or galena, from which the pure metal is 
 chiefly obtained.* Berzelius obtained the metal perfectly 
 pure by heating the pure nitrate of lead, mixed with charcoal, 
 in a Hessian crucible. 
 
 Properties. The properties of lead are generally well 
 known. It is of a bluish-white color, soft, malleable, and 
 ductile; fuses at 612°, and by slow cooling, crystallizes in 
 octohedra. The proper solvent of lead is nitric acid. 
 
 Compounds of Lead, 
 
 Protoxide of Lead (Pb + O. 111.6. Sp. gr. 9.4214) is 
 
 prepared by heating the metal to a high temperature, and col- 
 lecting the gray film which forms on the surface. This is 
 exposed to heat in open vessels, until it acquires a uniform 
 yellow color, and constitutes the massicot, and when partially 
 fused, the litharge of commerce. This is always mixed with 
 the red oxide ; it is obtained perfectly pure by adding ammo- 
 nia in excess to the nitrate in solution, washing the precipi* 
 tate in cold water, and, when dry, heating it to redness for an 
 hour in a platinum crucible. 
 
 Properties. Its color is red when hot, but acquires a rich 
 lemon-yellow when cold ; fuses at a bright red heat, and, after 
 fusion, has a highly-foliated texture ; insoluble in water ; unites 
 with acids, and forms the base for all the salts of lead. 
 
 It is precipitated from its solutions by pure alkalies as a 
 
 * Process. The ore. in the state of coarse powder, is heated in a 
 reverberatory furnace, when part of it is oxidized, yielding sulphate of 
 protoxide of lead, sulphuric acid which is evolved, and free oxide of 
 lead. These oxidized portions then re-act on sulphuret of lead, by the 
 re-action of 2 equivalents of oxide of lead, and 1 of the sulphuret ; 
 3 equivalents of oxide of lead and 1 of sulphuric acid result, 
 while 1 equivalent of the sulphuret and 1 of the sulphate mutually 
 decompose each other, giving rise to 2 equivalents of sulphurous acid, 
 and 2 of metallic lead. The lead of commerce commonly contains 
 silver, iron, and copper. — T= 
 
282 Metals. — Lead 
 
 white hydrate, which is re-dissolved by potassa in excess , as 
 a white carbonate, which is the well-known pigment white 
 lead, by alkaline carbonates ; as a white sulphate, by soluble 
 sulphates; as a dark brown sulphuret by hydrosulphuric acid , 
 and as a yellow iodide of lead, by hydriodic acid, or iodide 
 of potassium. — T. 
 
 Metallic Lead is separated from the salts of the protoxide 
 by iron or zinc. 
 
 Exp. In a solution of 1 part of acetate of lead in 24 parts of water. 
 contained in a glass bottle, suspend a piece of zinc by a thread. The 
 lead will be deposited upon the zinc in a form resembling a tree — a 
 peculiar appearance, called arbor Saturni. 
 
 Uses. Protoxide of lead enters into the composition of 
 flint-glass, and is employed for glazing earthen- ware and por- 
 celain. 
 
 Peroxide of Lead (Pb -4- 20. 119.6) is formed by the action of nitric 
 acid upon the red oxide, or minium of commerce. It is of a puce color, 
 insoluble in water, and resolved by strong oxygen acids into a salt of 
 the protoxide and oxygen gas. 
 
 Red Oxide of Lead (3 Pb-f- 40. 342.8) is prepared by 
 heating lead in the air nearly to the point of fusion, by which 
 it is oxidized. It is then exposed to a temperature of 600° 
 or 700°, while a current of air passes across its surface. It 
 slowly absorbs oxygen, and is converted into the minium of 
 commerce. It is employed as a pigment, and in the manu- 
 facture of flint-glass, but does not unite with acids and form 
 salts. 
 
 Chloride of Lead (Pb4-Cl. 139.02) is obtained by adding hydro- 
 chloric acid to a solution of acetate or nitrate of lead. It is sometimes 
 called horn lead ; dissolved in hot water, it appears, on cooling, in 
 small, acicular, anhvdrous crvstals, of a white color. 
 
 Iodide of Lead; Pb-f-1. 229.9. Bromide of Lead; Pb + Br. 182. 
 Fluoride of Lead ; Pb 4- F. 122.23. Sulphuret of Lead ; Pb + S. 11 9.7. 
 Phnsphuret of Lead and Carburet of Lead, composition uncertain. Cy- 
 anide of Lead; Pb -(- Cy. 129.99. — (See Turner's Elements, p. 393.) 
 
 The salts of lead are generally poisonous, of which the 
 carbonate is the most virulent. 
 
 Alloys of Lead. Common pewter is an alloy of 20 parts 
 of lead and 80 of tin. Fine solder consists of 1 part of lead 
 and 2 of tin, and is employed for tinning copper. Coarse 
 solder contains one fourth of tin, and is used by plumbers. 
 Pot metal is an alloy of lead and copper. 
 
Mercury. 283 
 
 Sect. 3. Metals, the Oxides of which are reduced 
 to the metallic state by a red heat. 
 
 MERCURY, or QUICKSILVER. 
 
 Symb. Hg. Equiv. 101,26 Sp. gr. 13.568. 
 
 Mercury was well known to the ancients. Its principal 
 ore is the sulphuret or native cinnabar, from which it is 
 separated by distillation with quick lime, or iron-filings. 
 
 Properties. Mercury is the only metal which retains its 
 liquid form at common temperatures. It is of a tin-white 
 color, and strong metallic lustre ; boils at 662° Fahr., and 
 congeals at 40° below zero, in which state it is malleable, 
 and has an increased specific gravity 15.612. It is not tar* 
 nished by exposure to cold, moist air, unless it contain other 
 metals. It is sometimes adulterated with an alloy of lead and 
 bismuth, which renders it less fluid and volatile, leaving a 
 residuum when boiled in a silver spoon. 
 
 Mercury is not acted upon by any of the acids except the 
 sulphuric and nitric. 
 
 It is used for collecting those gases which are absorbed by 
 water; also for barometers, thermometers, and for forming 
 connections in voltaic circles. 
 
 Compounds of Mercury. 
 
 Dioxide of Mercury (Hg^O. 210.52) is prepared by 
 mixing calomel with pure potassa in excess in a mortar, and 
 stirring it briskly to effect a rapid decomposition. The pro- 
 toxide is then washed in cold water, and left to dry in a dark 
 place. 
 
 Properties. It is a black powder, insoluble in water, com- 
 bining with acids, and bui feebly with alkalies. The alkalies 
 precipitate it from the solution of its salts, as a black protox- 
 ide. The best test of its presence is the hydrosulphuric 
 acid, by which is thrown down a black disulphuret. 
 
284 Metals. — Mercury. 
 
 Protoxide of Mercury (Hg O. 109.26) is commonly 
 known by the name of red precipitate* 
 
 Process. Protoxide of mercury may be prepared by dissolving mer- 
 cury in nitric acid, and exposing the nitrate thus formed to a tempera- 
 ture just sufficient to expel the whole of the nitric acid. It may also be 
 formed by exposing mercury in a matrass, with a long tube, to the 
 agency of heat and air, for the space of three or four weeks. 
 
 Properties. It exists in shining, crystalline scales, nearly 
 black when hot, and red when cold ; slightly soluble in 
 water. The solution has an acrid, metallic taste, and is poi- 
 sonous. 
 
 This oxide is separated from all acids by the carbonated 
 fixed alkalies, and is reduced to the metallic state by copper. 
 
 Dichloride of Mercury (Hg2-J- CI. 237.94) is common- 
 ly called calomel, and was first mentioned in the seventeenth 
 century, by Crollius. 
 
 Process. It may be obtained by bringing chlorine gas in contact 
 with mercury, but it is more commonly prepared by sublimation. This 
 is done by mixing 1 eOjUiv. of the chloride with 1 equiv. cf mercury, 
 until the metallic globules entirely disappear, and then subliming. 
 To purify it from corrosive sublimate, which is always mixed with it, 
 when first prepared, it must be reduced to powder, and w T ell washed; 
 when it will be fitted for chemical or medical purposes. The Di- 
 chloride is also found native, and called horn quicksilver. 
 
 Properties. When obtained by this process, calomel ex- 
 ists in semi-transparent, crystalline cakes, of a yellow color 
 when warm, but white when cold ; sublimes a little below 
 a red heat, and a part of it is resolved into mercury, and 
 the chloride. It is insoluble in water, and is decomposed 
 by the pure alkalies. 
 
 Used extensively for medical purposes; acts powerfully 
 upon the glandular system. 
 
 Chloride of Mercury (Hg-f- CI. 136.68) is formed by heating mer- 
 cury in chlorine gas. During the process, the metal burns with a pale 
 red flame. It is prepared for medical purposes by subliming a mixture 
 of sulphate of the protoxide of mercury with chloride of sodium, or 
 sea-salt. 
 
 Properties. Chloride of mercury, commonly called cor- 
 rosive sublimate, is a most virulent poison. It is white, semi- 
 transparent, and crystalline in its texture: taste acrid and 
 nauseous; more soluble in alcohol than in water ; sp. gr. 5.2. 
 It sublimes in the form of a dense, white vapor, when heated, 
 
 * This is the hydrargyri oxidum rubrum of the pharmacopolist. 
 
Compounds of Mercury. 285 
 
 powerfully affecting the mouth and nose ; soluble in hydro- 
 chloric, nitric, and sulphuric acids, and is decomposed by 
 the alkalies, and several of the metals.* 
 
 Tests. Place a drop of the suspected liquid on polished gold, and 
 touch the moistened surface with the point of a penknife ; the part 
 touched will instantly become white, owing to the formation of an 
 amalgam of gold. 
 
 Some animal and vegetable substances convert the bichloride into 
 calomel ; the best is albumen, made by mixing the white of an egg in 
 water ; hence the white of an egg is an antidote to poisoning by cor 
 rosive sublimate. 
 
 Disulphuret of Mercury. Hg2-j-S. 226.62.* 
 
 Sulphuret of Mercury (Hg-f-S. 117.36) maybe formed by fusing 
 sulphur with six times its weight of mercury, and subliming in close 
 vessels. 
 
 Properties. When thus obtained, it has a red color, and 
 is known by the name of factitious cinnabar. When reduced 
 to powder, its tint is greatly improved, and constitutes the 
 well known pigment, vermilion. The native cinnabar is a 
 sulphuret^ and is the principal ore of mercury. 
 
 Ethiops Mineral is a mixture of sulphur and the SuJ- 
 phuret, and may be formed by triturating equal parts of sul- 
 phur and mercury, until the globules of mercury disappear. 
 
 Dicyanide of Mercury (Hg2 -{- Cy. 236.91 ) is prepared by boiling a 
 solution of Prussian blue with an equal weight of peroxide of mercury 
 in powder, until the blue color of the pigment entirely disappears. 
 The solution, on evaporation^ yields quadrangular prisms of dicyanide 
 of mercury. It is colorless, inodorous, and highly poisonous. 
 
 Amalgams. Mercury combines with mo^t of the metals, 
 and forms a class of compounds called amalgams. An 
 amalgam of one part of potassium and seventy of mercury 
 is hard and brittle ; on adding mercury to the liquid alloy 
 of potassium and sodium, solidification and combustion 
 ensue. Two parts of mercury, one of bismuth, and one of 
 lead form a liquid amalgam, from which cubic crystals of 
 bismuth are slowly formed. The combination of mercury 
 with those metals which are not easily oxidized, enables 
 them to combine with oxygen ; hence gold and silver, in 
 combination with mercury, are easily oxidized by heat and 
 air. With tin, it forms an amalgam for coating mirrors. 
 
 * By considering the equivalent of mercury at 101.26, the names of its 
 compounds, in order to conform to the nomenclature, are changed in the 
 the text : dioxide for p?-0ioxide, protoxide for oinoxide, disulphuret for 
 protosulphuret, &c. 
 
286 Metals. — Silver. 
 
 SILVER* Symb. Ag. Equiv. 103. Sp. gr. 10.51. 
 
 Silver has been known from the earliest ages. It is found 
 native, and in combination with other substances. The 
 native silver occurs in octohedral or cubic crystals, seldom 
 perfectly pure ; it is generally found in primitive formations. 
 Peru and Mexico contain the richest mines of native silver 
 which are known. 
 
 Preparation. Pure silver may be obtained from standard 
 silver, by dissolving it in nitric acid and introducing a clean 
 piece of copper. The metal will be precipitated upon the 
 copper ; this is then to be washed in pure water, and di- 
 gested in ammonia to remove the copper. A better pro- 
 cess is to decompose the chloride of silver by carbonate of 
 potassa. 
 
 Silver is often obtained from the argentiferous sulphuret 
 of lead, by a process called cupellation.i Some of the ores 
 are also reduced by amalgamation with mercury, and the 
 mercury expelled by heat. 
 
 Properties. Silver has the clearest white color of all the 
 metals. Its lustre, when polished, is surpassed only by pol- 
 ished steel ; so malleable that it may be extended into leaves 
 less than a ten thousandth of an inch in thickness, and so 
 ductile that it may be drawn into wire finer than the human 
 hair. It fuses at 1873° Fahr., and appears extremely brilliant. 
 
 * Lat. argentum. 
 
 t This process is conducted in the following manner : —The lead is 
 kept at a red heat, in a flat furnace, with a draught of air playing on 
 its surface. The lead is thus rapidly oxidized, while the silver is un- 
 affected. As fast as the oxide is formed, it melts and runs off through 
 an aperture in the sides of the furnace; so that, in the end. the lead is 
 all removed. The button of silver which remains is then melted in a 
 small furnace resting on a porous earthen dish made with bone ashes, 
 called a cupel, the porosity of ichich is so great that it absorbs any por- 
 tions of litharge ichich. may remain on the silver. The cupel is prepared 
 by driving pounded bone ashes into a small brass mould by means of 
 a pestle. It should then be removed and dried on paper. The cupel 
 is then placed in a muffle, which is made of clay, arched above, and 
 closed on all sides except the front. The whole is then placed in a 
 cupelling furnace, which has an opening in one of its sides to receive 
 the muffle. This is a very important process, and much used by re- 
 finers and assayers, in the analysis of alloyed silver. 
 
Compounds of Silver k 287 
 
 It is not oxidized by air or moisture, but is tarnished by 
 sulphurous vapors, which act slowly upon it; it burns with 
 a fine green light, and throws off fumes of oxide when ex- 
 posed to the action of voltaic currents. None of the pure 
 acids act upon it but the sulphuric and nitric; the latter is 
 its proper solvent, with which it forms the nitrate whichj 
 after fusion, is the lunar caustic. 
 
 Use. Silver is one of the precious metals, and is used as 
 a coin, and for various purposes of art. 
 
 Oxide of Silver (Ag-f-O or AgO. 116) is best formed by 
 mixing a solution of pure baryta with the nitrate dissolved 
 in water ; it is of a brown color, insoluble in water, and 
 easily reduced by a red heat. 
 
 Fulminating Silver is a compound of oxide of silver and ammonia. 
 
 Process. Precipitate nitrate of silver by lime water ; and, after wash* 
 ing and drying the precipitate, put it into a vessel of pure ammonia 
 fur twelve hours; a black powder will be thrown down, which, when 
 carefully dried, explodes violently by the gentlest heat, or by slight 
 friction. Great care should be taken in its preparation, and it should 
 be preserved in small quantities in paper boxes. 
 
 By heating the solution, a more dangerous compound is formed. 
 
 A compound similar to the above, but less dangerous, is formed by 
 dissolving silver in nitric acid, and adding to the solution successive 
 portions of alcohol. This substance is used in the preparation of small 
 balls called torpedoes. 
 
 Chloride of Silver (Ag -\- CI. 143.42) is the horn silver 
 of mineralogists. 
 
 Process. It is formed by mixing hydrochloric acid with 
 a solution of oxide of silver. When first precipitated, it is 
 white, but becomes almost black by exposure to the solar 
 rays; insoluble in water, but very soluble in ammonia, by 
 which it is usually distinguished from other chlorides. It is 
 often employed in analysis as the means of ascertaining the 
 amount of chlorine present in various compounds. 
 
 Iodide of Silver (Ag-f-I. 234.3) is a greenish-yellow substance. 
 
 Sulphur et of Silver. Ag + S. 124.1. This is the silver glance of 
 mineralogists. Silver has a strong affinity for sulphur. On passing a 
 current of hydrosulphuric acid gas through a solution of lunar caustic, 
 a. dark brown precipitate subsides, which is a sulphuret of silver. 
 
 Cyanide of Silver (Ag-f-Cy. 134.39) is a white, curdy substance. 
 
 Alloys of Silver. Silver is alloyed with most of the metals. 
 With steel, it forms an alloy used in cutlery ; with copper, 
 
288 Metals. — Gold. 
 
 it forms the silver plate and coin, # which is the most useful 
 of its alloys ; with mercury, it forms an amalgam, sometimes 
 employed for plating copper. Thermometer scales and 
 clock dials are usually silvered by an alloy of chloride of 
 silver, chalk, and pearlashes. 
 
 GOLD A Symb. Au. Equiv. 199.2. Sp. gr. 19.257. 
 
 Gold was known to the ancients, and has always been 
 highly valued, as the most precious of the metals. 
 
 Natural History. Gold occurs native, alloyed with a little 
 silver or copper. It crystallizes in cubes and octohedra; it 
 is found in large quantities in alluvial soils, and in the beds 
 of certain rivers, especially on the western coasts of Africa 
 and Peru, in Brazil and Mexico, in Europe and the United 
 States. J 
 
 Process. Gold is generally separated by amalgamation 
 and cupellation ; but the best mode is to fuse the gold with 
 silver, so that the latter shall constitute J of the mass ; nitric 
 acid will dissolve the silver, and leave the gold. This process 
 is called quartation. 
 
 To obtain gold perfectly pure, dissolve standard gold in 
 nitrohydrochloric acid ; evaporate the solution to dryness, 
 re-dissolve it in distilled water, filter, and add to the solu- 
 tion sulphate of the protoxide of iron; a black powder falls, 
 which, when washed in dilute hydrochloric acid and distilled 
 water j yields^ on fusion, a button of pure gold. 
 
 Properties. Gold is distinguished from all other metals 
 by its yellow color; it exceeds all others in ductility and 
 malleability; it may be beaten into leaves not exceeding 
 sWo o o °f an mc h m thickness ; it is very flexible and soft ; 
 fuses at 2016° Daniell, and appears of a brilliant green color. 
 
 * The standard silver of Great Britain contains 11 -^ of pure silver, 
 and £$. of copper ; that of the United States, 1 part by weight of 
 copper, and 9 of silver. The dollar weighs 412^- grs., and the dime 
 41^ grs. 
 
 t Lat. aurum. 
 
 X The gold from all the mines in the United States, in 1836, amounted 
 to 467,000 dollars, 148,100 dollars of which were from North Carolina. 
 
Compounds of Gold. 289 
 
 It is not easily oxidized, even in the state of fusion ; but, on 
 subjecting a fine wire to an electric discharge, a purple 
 powder is produced, which is probably an oxide; it is readily 
 dissolved by nitrohydrochloric acid. 
 
 Protoxide of Gold (Au-\-Q. 207.3) is formed by adding 
 a cold solution of potassa to the protochloride; a precipitate 
 falls, of a green color, which changes spontaneously into me- 
 tallic gold and teroxide. 
 
 Binozide of Gold (Au-f-2Q. 215.2) is formed by the combustion of 
 gold. 
 
 Teroxide of Gold (Au + 30. 223.2) is the only well- 
 known oxide of gold. 
 
 Process. Dissolve 1 part of gold in the usual way, render it quite 
 neutral by evaporation, and re-dissolve in 12 parts of water; to 
 the solution add 1 part of the carbonate of potassa, dissolved in 
 twice its weight of water, and digest at about 170° ; carbonic acid 
 gradually escapes, and the hydrated teroxide, of a brownish-red 
 color, subsides. After being Well Washed, it is dissolved in colorless 
 nitric acid of sp. gr. 1.4, and the solution decomposed by admixture 
 with water. 
 
 The hydrated teroxide is thus obtained quite pure, and is rendered 
 anhydrous by a temperature of 212° Fahr. — T. 
 
 Properties. The hydrate is yellow, but the anhydrous 
 teroxide is nearly black, insoluble in water, and completely 
 decomposed by solar light, or a red heat. With alkalies it 
 acts the part of a weak acid, and was called by Pelletier 
 auric acid. When the teroxide is kept in ammonia for the 
 space of a day, a detonating compound of a deep olive color 
 is formed. It is composed of 1 equiv. of gold, 2 of nitro- 
 gen, 6 of hydrogen, and 3 of oxygen. 
 
 The Fulminating Gold is a similar compound. 
 
 Process. Add pure liquid ammonia to the dilute chloride. 
 The precipitate which is formed will be re-dissolved if too 
 much alkali is used; filter the liquid, and wash the sediment 
 several times in warm water ; dry it by exposure to the air, 
 and preserve it in small paper boxes. 
 
 Exp. Hold, on the point of a knife, a small portion of the powder 
 over the flame of a spirit lamp, and it will detonate violently. 
 
 Exp. Place two or three grains on a sheet of copper, and explode it; 
 it will force a hole through the copper ; a spark from the electrical 
 machine, or from a flint, will not^affect it; but the slightest friction will 
 cause it to explode; hence the danger of forming it, or of putting it up 
 in large quantities. 
 
 13 
 
290 Metals. — Gold. 
 
 Protochloride of Gold. An + CI. 234.62. 
 
 Terchloride of Gold (Au + SCI. 305.46) is obtained by 
 concentrating a solution of gold, in ruby-red crystals. This 
 is the compound from which pure gold is obtained, and also 
 most of the preparations of gold. 
 
 Exp. When a strong aqueous solution of the terehloFide is shaken 
 with an equal volume of ether, two fluids result, the lighter of which 
 is an ethereal solution of gold. 
 
 Exp. When a piece of charcoal is immersed in the aqueous solution'; 
 and exposed to the solar rays, it is covered with metallic gold. 
 
 Exp. Ribbons are gilded by moistening them in this solution, and 
 exposing them to a current of hydrogen gas. 
 
 Exp. Add the protochloride of tin to a dilute aqueous solution of 
 gold, and a purple-colored precipitate, the purple of Cassius, is thrown 
 down. On fusing this powder with sand and borax, it forms a purple 
 enamel, which is used for giving a pink color to porcelain.* 
 
 Alloys of Gold. Gold forms alloys with most of the 
 metals. With tin it forms a whitish brittle alloy. On 
 this account the old chemists called tin diabolus metal- 
 lorum. 
 
 With lead, it forms a very brittle alloy. Even the fumes 
 of lead destroy the ductility of gold. With copper, it forms 
 the alloy used for standard gold ; which is perfectly malleable 
 and ductile, h rider than pure gold, and resists wear better 
 than any other alloy, except that of silver; sp. gr. 17.15T. 
 The standard gold of the United States is an alloy of 1 part 
 of an alloy of copper and silver, and 9 parts of pure gold. 
 The British "sovereign" is 22 carats fine, that is, 22 parts 
 of pure gold, and 2 of copper and silver. 
 
 Water-Gilding. Mercury and gold combine, and form an 
 amalgam much employed in gilding. It is applied to the 
 surface of silver, and the mercury driven off by heat. 
 
 Porcelain is gilded with gold porcdcr, obtained by de- 
 composing the chloride of gold; applied with a pencil, 
 and burnished after exposure to the heat of a porcelain fur- 
 nace. 
 
 * Iodides of gold are formed by the action of iodide of potassium on 
 the terchloride of gold. Protiodide of gold I; Au-f-I 325.5. TerioduLe 
 of gold; Au 4- 37.. 578.1 . TersvJphuret of gold ; Au -\- 3S. 247.5. 
 
Platinum, 291 
 
 PLATLXUM. Symb. PI. Equiv. 98.8. Sp. gr. 21.25. 
 
 Platinum is a very rare metal. It occurs native in Brazil) 
 Peru, and other countries of South America, in rounded or 
 flattened grains, mingled with other metals. It is found in 
 larger quantities in the Ural Mountains. 
 
 Properties. Platinum is the most dense of the metals, of 
 a white color, resembling silver. It is malleable, and so duc- 
 tile that it may be drawn into wire not exceeding To %o- of 
 an inch in diameter. It is soft, and easily welded, conduct- 
 ing caloric with less facility than many other metals. It is 
 not attacked by any of the pure acids. Its solvent is chlo- 
 rine, or nitrohydrochloric acid. It is fused before the com- 
 pound blowpipe, and by voltaic electricity. 
 
 Spongy Platinum* has the remarkable property of causing 
 oxygen and hydrogen gases to combine. Platinum foil will 
 produce similar effects. This is due to the attraction of the 
 gases for the platinum, and the repulsive power of the gases 
 themselves. They are thus so condensed upon the surface 
 as to bring the particles of the gases within the sphere of 
 each other's attraction. 
 
 E.rp. Let a jet of hydrogen and oxygen upon a piece of spongy 
 platinum ; the gas will soon be inflamed. 
 
 Protoxide of Platinum (PI -|- O. 10G.8) is prepared by digesting pro- 
 tochloricie of platinum in a solution of pure potassa. 
 
 Binoxide of Platinum (Pl-f-20 or PIO 2 . 114.8) is prepared with diffi- 
 culty. According to Berzelius, it should be prepared by exactly de 
 composing sulphate of binoxide of platinum with nitrate of baryta, and 
 adding pure soda to the filtered solution, so as to precipitate about 
 half of tbe oxide, which falls as a bulky hydrate, of a yellowish-brown 
 color. 
 
 Sesquioxide of Platinum. 2P1-J-30. 221.6- This oxide, of a gray 
 color, is prepaied by beating fulminating platinum with nitrous acid. 
 
 Protpcldoride of Platinum (PI -f- CI. 134.22) is formed when the 
 bichloride is heated to 450°; half of its chloride is expelled, and the 
 protoehloride. of a greenish-grav color, remains. 
 
 Bichloride of Platinum. PI +201. 169.G4. This chloride is obtained 
 by evaporating the solution of platinum in nitrohydrochloric acid to 
 dryness, at a very gentle heat, when it remains as a red hydrate, 
 which becomes brown when its water is expelled. — (See Turner, 
 page 408.) 
 
 * The sponge is prepared by adding ammonia to a solution of the 
 chloride, and heating the precipitate to drive off the ammonia and 
 
 chlorine. 
 
293 Metals. — Platinum. 
 
 Protiodide of Platinum. Fl + 1. 225.1. 
 
 Biniodide of Platinum (PI -)- 21. 351.4) is prepared by the action of 
 iodide of potassium on a rather dilute solution of bichloride of platinum. 
 It is a black powder, tasteless, inodorous, and insoluble in water. 
 
 Protosulphuret of Platinum (PI -f~ S. 114.9) is prepared by heating 
 the ammoniacal chloride with half its weight of sulphur, until all the 
 sal-ammoniac and excess of sulphur are expelled. 
 
 Bisulphuret of Platinum (P1 + 2S. 131) is prepared by dropping a 
 solution of bichloride of platinum into a solution of sulphuret of po- 
 tassium. 
 
 Fulminating Platinum may be prepared by the action of 
 ammonia in excess on the sulphate of protoxide of platinum. 
 It explodes at 420° with a very loud report, but does not 
 explode by percussion. 
 
 Palladium, Rhodium, Osmium, and Iridium, are found 
 associated with platinum, but exist in small quantities. 
 
 Palladium (Pd. 53.3. Sp. gr. 11.5) was discovered by 
 Wollaston, and resembles platinum in color and lustre. 
 
 Rhodium (R. 52.2. Sp. gr. 11) was also discovered by 
 Wollaston. It is, when fused, of a white color, hard, and 
 extremely brittle. It attracts oxygen at a red heat, and a 
 mixture of peroxide and protoxide of rhodium is formed, 
 not acted upon by any of the acids, unless alloyed with other 
 metals. 
 
 Osmium (Os. 99.7. Sp. gr. 7 to 10) was discovered by 
 Tennant, in 1S03. It is a black powder, which acquires 
 metallic lustre by friction. When heated in the open air, it 
 takes fire, and is readily oxidized and dissolved by fuming 
 nitric acid. 
 
 Osmic Acid (Os-j-40. 137.7) is formed by the oxidation 
 of osmium by acids, by combustion, or by fusion with nitre 
 or alkalies. Its vapor is very acrid, exciting cough, irritating 
 the eyes, and producing a copious flow of saliva.* 
 
 Iridium (Ir. 93.8. Sp. gr. 15.3629) was discovered by 
 Tennant, in 1803, and about the same time by Descotils, of 
 France. It is the most infusible of all metals, very brittle, 
 and when polished resembles platinum. 
 
 * Several met .Is have lately been added. Erbium and Terbium, found 
 in connection with Yttria by Mosander, Petopium and Niobium, discov- 
 ered by Rose # in Columbite, and Norium in Zircon by Svanberg : but aa 
 yet they are very rare and but little known. 
 
Salts. 293 
 
 Latanium (La) is a metal recently discovered by Mosander. 
 It is prepared by calcining the nitrate of cerium, mixed with 
 nitrate of latanium. 
 
 CHAPTER III. 
 Ciass III. Salts, or Ternary Compounds. 
 
 Salts comprise a very extensive class of compounds, in 
 whieh acids combine with oxides, or with other compounds 
 having similar properties. The oxide which combines with 
 the acid, is termed a base, or salifiable base. 
 
 The substances hitherto described are either simple bodies, 
 or, with a few exceptions, compounds of two simple elements, 
 and are hence called binary compounds. 
 
 Salts, on the other hand, are composed of three or more 
 simple bodies, and are hence termed ternary compounds. 
 As salts, under favorable circumstances, readily assume regu- 
 lar crystalline forms, it seems proper, before proceeding to 
 describe them, to present the subject of crystallization in 
 general. 
 
 Section 1. Crystallization. 
 
 Most bodies, under favorable circumstances, may be made 
 to assume the form of a regular geometrical solid. The 
 process by which such a body is produced is called crystal- 
 lization ; the solid is termed a crystal; and the science, the 
 object of which is to study the form of crystals, is cry sial- 
 ography. The condition, by which this process is peculiarly 
 favored, is the slow and gradual change of a fluid into a 
 solid, the arrangement of the particles being at the same time 
 undisturbed by motion. This is exemplified during the slow 
 cooling of a fused mass of sulphur or bismuth, or the spon- 
 
294 
 
 Salts. — Cry sialography. 
 
 taneous evaporation of a saline solution. The numerous crys- 
 tals found in the mineral kingdom are due to the same cause. 
 
 The surfaces which limit the figure of crystals are called 
 planes or faces. The lines formed by the junction of two 
 planes are called edges % and the angle formed by two such 
 edges is a plane angle ; a solid angle is the point formed by 
 the meeting of at least three planes. — T. 
 
 The forms of crystals are exceedingly diversified ; they 
 may be divided into primary and secondary forms. 
 
 The primary forms are fifteen in number, and may be 
 distributed as follows : — 1. Prisms ; 2. Octohedrons ; 3. Do- 
 decahedrons. 
 
 I. The prisms have either a six-sided base, or a four-sided 
 base. 
 
 (1.) Right Prisms. 
 
 The bases are either right * or oblique, 
 and the prisms are named according to 
 their bases. 
 
 1. The Hexahedron, or Cube, (Fig. 
 95,) is a figure bounded by six square 
 faces, and all the angles of its edges are 
 equal to 90 degrees. 
 
 . 2. The Right Square Prism (Fig. 96) 
 differs from the cube in having its four lat- 
 eral planes c, c, c, c, rectangles, and the ter- 
 minal planes a a squares. 
 
 3. The Right Rectangular Prism (Fig. 
 98) differs from the former in having the 
 terminal planes a, a, rectangular instead of 
 square. 
 
 4. The Right Rhombic 
 Prism (Fig. 97) differs 
 from the two preceding 
 only in its terminal planes 
 a, b, being rhombs. 
 
 5. The Right Rhom- 
 boidal Prism (Fig. 98) 
 
 * The term right denotes that the lateral and terminal planes are 
 inclined to eachother at a right angle. It is used in opposition to 
 
 
 Fig. 95. 
 
 \ 
 
 i\ 
 
 
 i 
 
 \ 
 
 \ 
 
 Fig. 96. 
 
 A * 
 
 / 
 
 e\ c c 
 
 c 
 
 .'' CO 
 
 / 
 
 Fig. 97, 
 
 Fig. 98. 
 
Cry sialography. 
 
 295 
 
 differs from the preceding form in the terminal planes cc 
 being rhomboids. 
 
 6. The Regular Hexagonal Prism ^ig» 99. 
 
 (Fig. 99) is bounded by six perpendicu- 
 lar or lateral planes, and two horizontal 
 or terminal planes, a, b, which are at right 
 angles to them. 
 
 Fisr. 101. 
 
 (2.) Oblique Prisms. 
 
 7. The Rhombohedron 
 (Fig. 100) is bounded by 
 six rhombie faces, of the 
 same size and form. 
 
 8. The Oblique Rhombic 
 Prisms (Fig. 101) have the 
 terminal planes a, a, rhombs, 
 with the lateral planes forming oblique angles with them. 
 
 9. Oblique Rectangular Prism differs from the preceding 
 in having the terminal planes rectangles. 
 
 10. Oblique RJwmboidal Prism (Fig. 
 102) differs from the two preceding forms 
 in the terminal planes a, a, being rhom- 
 boids. 
 
 11. The Octohedrons are also named from 
 their bases. The base of the octohedron 
 is a section passing through four angles. 
 
 11. Regular Octohe- 
 dron (Fig. 103) has a Fig. 103* 
 square base, a a a a, and y 
 is contained under eight 
 equilateral triangles — 
 hence all its plane an- 
 gles are equal to 60 de- ^ 
 grees. This figure is a 
 regular solid of geom- 
 etry. 
 
 12. Square Octohe- 
 dron (Fig. 104) has a 
 
 square base J a a a a. and is bounded by eight faces, which are 
 isosceles triangles. The base is always a square, the only 
 part of the figure which is constant. 
 
 oblique, which signifies that the sides are not perpendicular, but form 
 an oblique angle with the terminal planes. — T. 
 
296 
 
 Cry sialography. 
 
 13. Rectangular Ociohcdrm (Fig. 
 105) has a rectangular base, a a a a, and 
 is bounded by eight isosceles triangles, 
 four of which are different from the other 
 four. 
 
 14. Rhombic Octohedron (Fig. 106) 
 has a rhombic base, aaaa % and is con- 
 tained under eight similar scalene trian- 
 gles, but all its dimensions are variable. 
 
 III. Dodecahedrons. 
 
 15. There is but one pri- 
 mary dodecahedron, called 
 the rhombic dodecahedron, 
 (Fig. 107,) and is limited 
 by twelve similar rhombic 
 faces; the faces incline to 
 each other at an angle of 
 120 degrees * 
 
 Fig. 107, 
 
 Secondary Forms. 
 
 The secondary forms of crystals are very numerous, 
 amounting to millions. The forms of a single mineral calca- 
 reous spar have been found to be nearly a thousand ; but each 
 of the secondary forms may be reduced to one or more of 
 the primary, by a process called cleavage. This process is 
 usually performed with a sharp instrument, by removing thin 
 laminae from the faces, edges, or angles of the crystal. The 
 surfaces exposed by splitting or cleaving a crystal, are 
 termed the faces of cleavage, and the direction in which it 
 may be cleaved is called the direction of cleavage. Some 
 crystals are cleavable in one direction, and some in two, three, 
 four, or more directions. 
 
 Those which cleave in more than two directions may, by 
 the removal of layers parallel to the planes in their cleavage, 
 
 * The instrument used for measuring the angles, at which the planes 
 of crystals meet or incline to each other, are called goniometers. — See 
 Dana's Mineralogy, p. 32, New Haven. 1837. 
 
Theories of the constitution of Salts. 297 
 
 be made to assume regular primary forms, whatever be their 
 figure previous to cleavage. 
 
 It was formerly supposed that each substance always had 
 the same primary form ; but the discovery was made by 
 Mitscherlich, in 1819, that identity of composition did not 
 always indicate identity of crystalline form. 
 
 To this new branch of science the term isomorphism 
 (from laog, equal, and f-ioQcp^ form) is applied.* 
 
 The phenomena of crystallization are ascribed to cohesive 
 attraction, or, more properly, to crystalogenic attraction. 
 
 The crystallization of salts is most readily effected by dis- 
 solving them in water, and evaporating the solution. 
 
 Exp. Introduce into a large matrass a pound and a half of Glauber s 
 salts, (sulphate of soda,) with a pound of water, and boil the mixture 
 until all the salt is dissolved ; cork it tight, as the heat is removed, and 
 let it cool. On taking out the stopper, the salt will suddenly crystal- 
 lize, and the whole will become nearly solid. 
 
 The water enters into the crystal in definite proportions, 
 and is called the water of crystallization. The quantity of 
 combined water is very variable in different crystals; such 
 salts, when heated, dissolve, if soluble, in their own water 
 of crystallization, undergoing what is termed watery fusion • 
 some salts, when exposed to the air, lose their water of crys- 
 tallization, and crumble down into a fine powder; this is 
 termed efflorescence: others absorb water from the atmos- 
 phere, and are said to deliquesce. 
 
 Some salts enclose mechanically within their texture parti- 
 cles of water, by the expansion of which, when heated, they 
 burst with a crackling noise; this is called decrepitation. 
 
 Theories of the constitution of Salts. 
 
 1. The old and commonly received definition of a salt, is a 
 substance formed by the union of two ^'elementary com- 
 pounds. Thus one series of salts are formed by the union 
 of oxides with oxides ; another by a combination "of chlorides 
 with chlorides, sulphurets with sulphurets, &c. That is, 
 compounds belonging to the same series unite with each other 
 to form salts, and when compounds of different series are 
 
 ~1 * See Turner, 5th ed. p. 429. 
 
298 Chemistry, 
 
 mixed together they do not unite, but generally decompose 
 each other ; thus when sulphuric acid is poured upon chlo- 
 ride of sodium {common salt) the chloride is decomposed, and 
 sulphate of soda and hydrochloric acid are formed. 
 
 II. By some chemists the salts are divided into two classes. 
 The first class includes those bodies constituted as above, and 
 the second class such as are formed by the union of a simple 
 body of the chlorine family with a metal, such as we have 
 described as the chlorides, bromides, iodides, &c, of metals. 
 And regarding hydrogen as a metal, the hydracids, hydro- 
 chloric, hydriodic, hydrobromic are not acids, but salts ; and 
 the fact that when the hydracids are brought in contact with 
 a metal, the metal is substituted for their hydrogen, would 
 seem to be a good reason for placing them in the same class 
 of compounds. If these views are correct, many of the oxy- 
 gen acids are really salts, in which case the water is the 
 oxygen base ; thus liquid sulphuric acid is a sulphate of 
 water. (S0 3 + HO.) Nitric acid is a nitrate of water. 
 (N0 5 .HO+3HO.) 
 
 III. A third theory of the constitution of salts would reduce 
 them all to binary compounds. That is, one of the elements 
 is what has been termed a compound radical, a compound like 
 cyanogen acting in combination like a simple element. For 
 example, when sulphuric acid is poured on zinc, sulphate of 
 zinc is formed, and hydrogen evolved. The change in this 
 case is explained by supposing that the hydrous sulphuric acid 
 (SO 3 . HO) has the composition, SO*H, and that the zinc Zn 
 takes the place of the hydrogen, and there results the salt, 
 having the constitution S0 4 -f-Zn. The SO 4 is called the 
 compound radical. This change, it will be seen, is precisely 
 similar to that which takes place when hydrochloric acid 
 (HC1) is poured on zinc, chloride of zinc (Cl-f-Zn) is formed, 
 and hydrogen escapes. 
 
 When oxygen acids act upon metallic oxides, as liquid nitric 
 acid upon potassa, we may explain the change by consider. 
 
Theories of the Constitution of Salts. 299 
 
 ing the acid to be composed of N0 6 + H, and the potassa of 
 KO. NO s combines with K to form the nitrate of potassa, 
 and the hydrogen of the acid and oxygen of the oxide unite 
 and form' water. In this way we may explain the formation 
 of all the salts. The principal objection to the theory is 
 found in the necessity of introducing a large number of these 
 compound radicals which have never been isolated. They 
 are, with a few exceptions, as cyanogen, purely hypothetical 
 bodies ; but an argument is adduced for the existence of such 
 radicals from the action of voltaic electricity in decomposing 
 binary compounds, as the iodides, chlorides, &c, compared 
 with its action upon what have been supposed to be ternary 
 compounds, or oxygen salts. It requires the same quantity 
 of electricity to decompose a binary compound ; but in the 
 case of sulphate of soda, for example, if the water and the 
 salt are both decomposed, which was supposed to be the case 
 on the old theory, it ought to require twice the quantity of 
 electricity, but it requires no more than to decompose water 
 alone. If we consider the sulphate of soda to be composed 
 of S0 4 +Na, this effect is easily explained. The current 
 separates the SO 4 from the Na, and as the sodium (Na) ar- 
 arrives at the negative electrode, it decomposes an equiv. of 
 water forming NaO and H, which escapes ; the SO 4 also, on 
 arriving at the opposite electrode, decomposes water with the 
 formation of HSO 4 , while O escapes ; the decomposition of the 
 water being a secondary action not due directly to the agency 
 of the current. 
 
 Another argument in support of the existence of such 
 radicals is, that many of the acids, as nitric acid, have never 
 been obtained free from the elements of water. Such a sub- 
 stance as NO 5 has never been isolated, but NO B HO, and 
 therefore N0 6 + H may be its constitution. NO 6 would be a 
 compound radical. Such a view cannot be objected to as an 
 hypothesis ; but if it be made the basis of a system, there 
 are certainly very strong reasons against it. 
 
300 Chemistry. 
 
 Salts are divided into neutral, acid, and basic. 
 
 1. A neutral salt consists generally of one equiv. of acid 
 united to one equiv. of base, or the number of atoms of acid 
 is equal to the number of atoms of oxygen in the base. 
 
 2. The acid salts are of two kinds. 1st. Those in which 
 water is present, in which case they are really double salts,, 
 water being one of the bases ; thus bisulphate of potash is a 
 sulphate of potash and a sulphate of wat&r= SO 3 . KO-}-S0 3 HO. 
 And 2dly. Those salts which do not contain water. These 
 are the true acid salts, in which case the acid is in excess 
 two or three equiv. of acid to one of base ; thus the chromates 
 of potash (Cro 3 +KO, 2Cro 3 +KO and 3Cro 3 +KO) are good 
 examples of acid salts. 
 
 3. TJie oasic salts have, on the contrary, two or more equiv. 
 of base to one of acid. Thus, the neutral nitrate of copper 
 has the formula N0 5 .CuO-h3HO, but the basic nitrate NO 6 
 HO-f-3CuO, in which case there are three equiv. of base, 
 which take the place of three equiv. of water in the neutral 
 nitrate. On this principle several basic salts may be formed 
 by substituting the oxide of the metal for the oxide of hydro- 
 gen. Sulphuric acid and oxide of zinc form such a series. 
 Thus, 
 
 S0 3 +ZnO+7HO. SO*+6ZnO+2HO. 
 
 S0 3 -f4ZnO-f-4HO. SO s +8ZnO. 
 
 There are several neutral salts, however, which are bibasic 
 and tribasic, as in the case of the three phosphates of silver 
 and some others. (See Kane's Chemistry.) 
 
 4. Double salts. The double salts are composed of two 
 simple salts. They generally consist of two acids and one 
 base, or of two bases and one acid. In a few cases two bases 
 and two acids are united. 
 
 5. There are several families of salts formed by the union 
 of sulphurets with sulphurets, chlorides, iodides, cyanides, 
 &c. with chlorides, iodides, cyanides, &c. These salts are 
 similar in constitution to the oxygen salts. For example, 
 
Oxy- Salts. 301 
 
 one sulphuret performs the office of an acid, and another of a 
 base ; thus the sulphuret of arsenic is a sulphur acid, and 
 sulphuret of potassium, the sulphur base. These two sub- 
 stances combine and form arsenio-sulphuret of potassium ; 
 such salts are termed sulphur salts. 
 
 When chlorides, iodides, &c, combine with each other, 
 they form a similar order, called the haloid salts ; of which 
 there are several families. 
 
 The chlorides, iodides, &c, sometimes combine with me- 
 tallic oxides and form a family of salts, called oxy-chlorides, 
 &c. 
 
 The hydro-salts are composed of hydracids, with ammonia 
 and phosphuret of hydrogen. This order is discarded by 
 many chemists. (See hydro-salts.) 
 
 For a more detailed account of the several theories men- 
 tioned above, on the nature, constitution, and classification 
 of the salts, the student is referred to Kane's Chemistry ; 
 also to the works of Fownes, Graham, and others. 
 
 If the theory of compound radicals be admitted in organic 
 chemistry, as it generally is, there seems no good reason for 
 rejecting it in the constitution of salts. But some chemists, 
 among whom is M. Gerhardt, explain the various reactions 
 of organic compounds in such a way as to dispense with 
 these hypothetical compound radicals ; and until the doctrine 
 is fully admitted in organic chemistry, it seems the safest 
 course to adopt the common theory in regard to the constitu- 
 tion of inorganic salts. In as much as the properties of salts 
 are not altered by any theory respecting their nature, we 
 have concluded to retain the old division of oxy-salts, hydro- 
 salts, sulphur salts, and Haloid salts. 
 
 Section 2. 
 ORDER I.— OXY-SALTS. 
 
 This order includes no compound the acid or base of 
 which does not contain oxygen. All the powerful alkaline 
 
302 .>_-..':• _ -;^ •.:::■; 
 
 bases, except ammonia, are protoxides of ax elcctro-pttsitire 
 mctaL If M represent an equivalent of any metal, M-J-O 
 or MO 
 
 ich the metal is capable of forming ; a single equir. 
 
 of acid neutralizes MO, forming a neutral salt. Thus, if 
 
 ->f saSphoric and nitric acids be represented bj 
 
 SO 3 and ~ ill the neutral sulphates and nitrates of the 
 
 ie will be indicated by MO + SO 3 and MO — 
 hence it may be inferred, that, in each family of salts, there 
 is a constant ratio in the oxygen of the base and that of 
 the acid ;. that for sulphates is as 1 to 3, and the nitrates 
 as 1 to 5. If the base be a binoxide, the same relation 
 ed. 
 e sometimes combine with each other, forming dembk 
 ■ 
 bases and : :r of two different acids and two diner- 
 
 em bases were formerly called triple salts. 
 
 7 Dnned by the same acid, combined 
 
 e many properties in common, and 
 - fed in the same family. 
 
 1. ScUTBLATKa. 
 
 Many of the sulphates occur motive: of which, th 
 lime and baryta are the most abundant. 
 formed by the action of sulphuric aci< 
 
 -^- : : :; : : : . '. = 
 a solubility in wale:, i n i i re all < 
 
 : arbonaceous matter with the aid of heat. 
 
 n t ' z - y : ;;e : : \. : r . : — 
 
 sulphates are salts. The 
 
 fouowi - r ire the mqpt importam : — 
 
 ..-:: :/ P. :::■:. \\ 
 
Sulphates. — Potassa — Soda. 303 
 
 was formerly called sal de duobus. It may be prepared by 
 neutralizing carbonate of potassa with sulphuric acid. 
 
 Properties. Taste saline and bitter. Its crystals belong 
 to the right prismatic system, and contain no water; soluble 
 in 10 times their weight of water at 60°, and in 5 of boiling 
 water. 
 
 Bisulphate of Potassa. KO + 2S0 3 . 127.35; with 1 
 equiv. of water, 136.35. This salt is prepared by heating 
 the sulphate, with half its weight of sulphuric acid, in a 
 platinum crucible. 
 
 Properties. It has a sour taste, and reddens litmus 
 paper;* is more soluble than the sulphates, and its crystals 
 belong to the same order. It is used for cleaning coin, and 
 other works in metal. 
 
 Sulphate of Soda (NaO-f SO 3 . 71.4; in crystals, with 10 
 equiv. of water, 161.4) is well known as Glauber's salts. 
 It is found in the earth, and in the water of many springs. 
 It is easily formed by saturating SO 3 with carbonate of 
 soda. 
 
 Properties. Taste bitter, cooling, and saline. Its crys- 
 tals belong to the right prismatic system ; effloresces on 
 exposure to the air, and undergoes watery fusion when 
 heated. 12 parts of the salt require 100 of water at 32° 
 to dissolve them. Used in pharmacy, and in the manufac- 
 ture of glass. 
 
 Bisulphate of Soda. NaO + 2S0 3 . 111.5; with 4 equiv. of water, 
 147.5. 
 
 Sulphate of Litha (LO-j-SO 3 54.45; in crystals, with 1 equiv. of 
 water, 63.45) has a saline taste, very soluble and fusible, and crystal- 
 lizes in flat prisms. 
 
 Sulphate of Ammonia (BPN-f-SO 3 . 57.25; in crystals, with 2 equiv. 
 of water, 75.25) sometimes occurs native in volcanoes, and near cer- 
 tain small lakes in Tuscany. It may be prepared by neutralizing 
 sulphuric acid with carbonate of ammonia. It is contained in soot 
 from coal. 
 
 Properties. It crystallizes in long, flattened, six-sided 
 prisms, soluble in 2 parts of water at 60°, and in an equal 
 weight of boiling water ; effloresces in warm, dry air, losing 
 
 * Unglazed paper, moistened in an infusion oi litmus, and dried. 
 
304 Salts. — Sulphates. 
 
 1 equiv. of water; yields its water of crystallization by 
 heat, fuses, and is decomposed, yielding nitrogen, water, 
 and sulphate of ammonia. 
 
 It is the source of the hydrochlorate of ammonia, which is 
 obtained by a mixture of common salt and sulphate of ammonia by 
 sublimation. 
 
 Sulphate of Baryta (BaO-f-SO 3 . 116.8. Sp. gr. 4.4) 
 occurs native in great abundance, and is known by the 
 name of heavy-spar. 
 
 Properties. Insoluble in water, and is precipitated by 
 adding sulphuric acid to any soluble salt of baryta. So 
 delicate is baryta as a test of SO 3 , that 1 part of sulphate 
 of soda in 400,000 of water is detected by it. It fuses at 
 a high temperature into an opaque, white enamel. 
 
 Uses. It is employed in the manufacture of jasper ware, and for f- 
 paint under the name of 'permanent white* (See Baryta, page 227./ 
 
 Sulphate of Strontia (SrO-j-SO 3 . 91.9) occurs native \i 
 beautiful crystals in Sicily, and also on Strontian Island 
 Lake Erie. 
 
 Properties. It has a blue tint, and is called celestine 
 sometimes it is colorless and transparent ; nearly insoluble 
 requiring 4000 parts of cold, and 3340 of hot water to 
 dissolve it. Heated with charcoal, its acid is decomposed 
 and sulphuret of strontium is formed. 
 
 Sulphate of Lime (CaO-f-SO 3 . 68.6; with 2 equiv. of 
 water, 86.6) occurs in nature in large quantities. Ever} 
 variety of gypsum is the sulphate combined with 2 equiv. 
 of water ; such as plaster of Paris, sdcnite, — which is a 
 crystallized variety, — alabaster, a white, compact varie- 
 ty, used in statuary, — and anhydrite, which contains no 
 water. The salt may be formed by mixing, in solution, a 
 salt of lime with any soluble sulphate. 
 
 Properties. Crystals of anhydrite belong to the right, and 
 of gypsum to the oblique prismatic systems. It is nearly 
 tasteless, soluble in 500 parts of cold, and 450 of boilino- 
 
 * It is the best paint for marking phials and jars in the laboratory 
 It raajjrtje prepared by mixing the powder with oil and lampblack. 
 
Sulphates, 305 
 
 water ; hence it is generally found in spring and river vi ater, 
 and especially in those waters called hard. Baryta will de- 
 tect the sulphuric acid, and oxalic acid the lime. Heated to 
 212° in vacuo, it parts with 1 equiv. of water, and at 300° 
 the whole ; in this state it is used as a cement. By mixing 
 it with a certain portion of water, it hardens rapidly, and be- 
 comes dry and solid ; on this account it is much used for 
 taking impressions, for stereotype plates, and for casts, busts, 
 and a great variety of purposes in the arts. It is used in 
 agriculture as a mineral manure, and is highly useful to 
 most soils. 
 
 Sulphate of Magnesia (MgO + SO s HO. 69.8 ; in crystals, 
 with 6 equiv. of water, = 123.8) was procured from the 
 springs of Epsom, England, and hence called Epsom salt. 
 It is found native, and constitutes the bitter salt and hair 
 salt of mineralogists. Sometimes it is found incrusting the 
 damp walls of cellars and new buildings. Many saline 
 springs contain it. 
 
 Process. But it is generally obtained from sea-water, and 
 exists in the bittern which is left after the crystallization of 
 common salt. It is obtained by decomposing the hydro- 
 chlorate of magnesia contained in it with SO 3 . It may also 
 be formed from the carbonate by adding sulphuric acid. 
 
 Properties. It has a saline, bitter, and nauseous taste. 
 Its crystals are small, quadrangular prisms,* slightly efflores- 
 cent in dry air, soluble in an equal weight of water at 60°, 
 and |- of their weight of boiling water. They undergo watery 
 fusion when heated, and are partially decomposed at a white 
 heat. 
 
 Sulphate of Alumina. 2A10 3 -(- SO 3 . 91.5 ; in crystals, with 9 equiv. 
 of water, 172.5. 
 
 Tcrsulphate of Alumina. 2A10 3 -f- 3S0 3 . 171.7; in crystals, with 18 
 equiv. of water, 333.7. 
 
 The Hydrated Disulphate is called Aluminiie. 
 
 Sulphate of Protoxide of Manganese. MnO -f S0 3 HO. 84.8. 
 
 Sulphate of Protoxide of Iron. FeO + S0 3 HO. 85.1; in 
 crystals, with 5 equiv. of water, eq. 139.1. This is known 
 
 * The larger crystals are generally right rhombic prisms. 
 
306 Salts. — Sulphates. 
 
 by the name of green vitriol, or copperas. It is prepared on 
 a large scale for the arts, by exposing the native protosulphu- 
 ret of iron to air and moisture ; the iron is converted into 
 an oxide, and the sulphur into SO 3 ; they then combine and 
 form the sulphate. It may also be formed by the action of 
 SO 3 on the iron. 
 
 Properties. Its taste is strongly styptic and inky. When 
 pure, it does not redden the vegetable blue colors. Its crys- 
 tals have a blue tint, and belong to the oblique prismatic 
 system ; soluble in 2 parts of cold, and in f its weight of 
 boiling water. It is used in the manufacture of fuming sul- 
 phuric acid and in dyeing. 
 
 Tersulphate of the Sequioxide. Fe 2 3 + 3S0 3 . 200.3. 
 
 Disulphate of the Sequioxide. 2Fe 2 3 + SO 3 . 200.1. 
 
 Sulphate of the Protoxide of Zinc, (ZnO -{- S0 3 HO. 89.4 ; 
 with 6 equiv. of water = 143.4,) commonly called white vitriol, 
 is formed by the action of dilute sulphuric acid on zinc. It 
 is prepared in the arts by roasting the native sulphuret of 
 zinc. 
 
 Properties. It crystallizes, by spontaneous evaporation, in 
 transparent, flattened, four-sided prisms, referable to a right 
 rhombic prism, and isomorphous with Epsom salt. Taste 
 strongly styptic, and, although a neutral salt, reddens vegeta- 
 ble blue colors; soluble in'2J parts of cold, and a less quan- 
 tity of boiling water. 
 
 Use. A powerful emetic, and poisonous if given in large 
 doses. 
 
 Sulphate of Protoxide of Nickel (NiO + S0 3 HO. 86.6) 
 crystallizes from its solution in pure water, in right rhombic 
 prisms, and, like most of the salts of nickel, is of a green 
 color. 
 
 Sulphate of Protoxide of Cobalt (CO + SO s HO. 86.6) is 
 formed by digesting dilute SO 3 with oxide of cobalt. On 
 evaporation, it appears in the form of red crystals. 
 
 Tersulphate of the Sequioxide of Chromium. Cr 2 3 4- 3 
 SO 3 . 200.3. 
 
Sulphates. 307 
 
 Sulphates of the Oxide of Copper. 
 
 The Disulphate (2CuO + SO 3 . 119.3) has not been ob- 
 tained in a separate state. 
 
 The Sulphate, or Blue Vitriol* (CnO + S0 3 HO. 88.7; in 
 crystals, with 4 equiv. of water, ]24.7) is formed by roasting 
 the native sulphuret. or by dissolving the protoxide in dilute 
 sulphuric acid, and crystallizing by evaporation. 
 
 Properties. The crystals are of a blue color, and yield 4 
 equiv. of water at 212°, and the whole at 430° Fahr., when 
 it becomes a white powder. 
 
 When ammonia is dropped into a solution of the sulphate, 
 it forms a dark blue solution, from which, when concentrated, 
 crystals are deposited by the addition of alcohol. This is the 
 ammoniarct of copper of the U. S. Phar. 
 
 Sulphate of the Oxides of Mercury. 
 
 The Sulphate of Dioxide Hg*0 + SO 3 . 250.62) is formed 
 when 2 parts of mercury are heated with 3 of strong sul- 
 phuric acid, so as to produce effervescence. If a strong heat 
 is employed, the 
 
 Sulphate (HgO -f SO 3 . 149.36 ) results, both being an- 
 hydrous. When this sulphate (the salt employed for 
 making corrosive sublimate) is thrown into hot water, a yel- 
 low salt, the 
 
 Trisidphate, ( 3HgO + SO 3 . 671.66,) called turpeth min~ 
 eral, is generated. 
 
 Sulphate of Oxide of Silver (AgO + SO 3 . 156.1) is depos- 
 ited when sulphate of soda is mixed with nitrate of silver, 
 and also by boiling silver with its weight of sulphuric acid. 
 
 Properties. It is white, and easily fused ; soluble in 80 
 times its weight of hot water, and deposits small, needle* 
 shaped crystals on cooling. It forms with ammonia a double 
 salt, consisting of 1 equiv. of oxide of silver, 1 of acid, 
 and 2 of ammonia. It crystallizes in rectangular prisms, 
 isomorphous with the double chromate and seleniate of oxide 
 of silver and ammonia. 
 
 * Great use is now made of this substance for exciting electricity in 
 galvanic batteries. 
 
308 Salts.— Sulphates. 
 
 Nitrosulphuric Acid, consisting of 1 part of nitric dis- 
 solved in 10 of sulphuric acid, dissolves silver, but scarcely 
 acts upon copper, lead, or iron, unless diluted with water ; 
 hence its use in separating silver from old plated articles. 
 
 Double Sulphates. 
 
 Sulphate of Soda and Lime (NaOSO 3 -4- CaOSO 3 . 140) is the Glauber- 
 ite of mineralogists, and occurs in the salt-mines of New Castle. 
 
 Sulphate of Potassa and Magnesia (KOSO 3 -f-MgOSO 3 ) is formed 
 by mixing solutions of the two salts. 
 
 Sulphate of Potassa and Alumina. KOS0 3 + A1 2 3 . 3S0 3 . 
 258.95, do. with 24 equiv. of water == 474.95. This salt, 
 the common alum, is prepared by roasting and lixiviating cer- 
 tain clays, containing iron pyrites, and adding to the lyes a 
 quantity of sulphate of potassa. It is obtained in Italy from 
 alum-stone. Alum is also found in volcanic countries, pro- 
 duced by the action of sulphurous vapors on rocks containing 
 feldspar. 
 
 Properties. It has a sweetish, astringent taste; is soluble 
 in 5 parts of water at 60°, and crystallizes in octohedrons. 
 Ignited with charcoal, it forms Homberg's Pyrophorus. 
 
 Exp. Take 3 parts of lampblack, 4 of calcined alum, and 8 of pearl- 
 ashes; mix them thoroughly, and heat them in an iron tube to a bright 
 cherry-red, for one hour; on removal from the fire, the tube must be 
 carefully stopped. This substance, when exposed to the air and 
 breathed upon, ignites with slight explosions. The essential part is 
 probably sulphur et of potassium, in minute divisions. 
 
 Use. Alum is of great use in the arts, especially in dye- 
 ing and calico-printing, because of its attraction for coloring 
 matter. 
 
 Ammonia Alum has the same form, appearance, and taste. 
 
 Soda Alum is also similar, except that it contains 26 equiv. 
 of water. 
 
 Iron Alum is formed by mixing sulphate of potassa with 
 tersulphate of sesquioxide of iron; it resembles common 
 alum in form, color, taste, and composition. 
 
 Chrome Alums. The tersulphate of sesquioxide of chro- 
 mium forms double salts, with the sulphate of potassa and 
 ammonia, very similar to the preceding. 
 
Sulphites — Nitrates. 309 
 
 Manganese Alum is formed by mixing a solution of ter- 
 sulphate of sesquioxide of manganese with sulphate of po- 
 tassa. These salts all crystallize in the octohedral system, 
 and are similar in composition, one oxide being substituted 
 for another, to form the different varieties. 
 
 2. Sulfates. 
 
 The salts of sulphurous acid have not hitherto been mi- 
 nutely examined ; the sulphites of potassa, soda, and ammo- 
 nia, are made by neutralizing those alkalies with sulphurous 
 acid, and are soluble in water j but most sulphites are spar- 
 ingly soluble, if at all ; they are decomposed by the stronger 
 acids. — (See Turner, 5th edit. p. 443.) 
 
 3. Nitrates. 
 
 The nitrates may be prepared by the action of nitric acid 
 on metals, on the salifiable bases, or on carbonates. As 
 nitric acid forms soluble salts with all alkaline bases, the 
 acids of the nitrates cannot be precipitated by any re- 
 agent. — T. 
 
 The nitrates are all decomposed by a high temperature, 
 and by the agency of heat and combustible matter ; hence 
 they are much employed as oxidizing agents. The process 
 of oxidation by nitre, is called deflagration, which is gener- 
 ally performed by mixing the inflammable body with an equal 
 weight of the nitrate, and projecting the mixture, in small 
 portions, into a red-hot crucible. All the neutral nitrates of 
 the fixed alkalies and alkaline earths, together with most of 
 the neutral nitrates of the common metals, are composed of 
 1 equiv. of nitric acid, and 1 of the protoxide ; hence the 
 oxygen of the base is to that of the acid, as 1 to 5 ; the 
 general formula is MO -j-NO 5 . 
 
 Nitrate of Potassa (KO + NO 5 . 101.3) is an abundant 
 natural product; it is obtained from the East Indies by 
 lixiviating certain soils ; in Germany and in France, it is pro- 
 duced in what are termed nitre-beds. 
 
310 Salts. — Nitrates, 
 
 The French process consists in lixiviating old plaster rub- 
 bish. Nitre also exudes from new walls. Some caTerns in 
 Kentucky afford nitrate of lime, from which nitre is obtained 
 by adding carbonate of potassa ; it is also found under old 
 buildings, and is commonly called nitre and saitpt 
 
 Properties. Colorless ; has a saline and cooling taste : 
 soluble in its own weight of boiling water : crystallizes in 
 six-sided prisms without any water of crystallization ; and 
 fuses at 616°. 
 
 Fulminating Powder is formed of 3 parts of nitre, 2 of dry 
 subcarbonate of potassa, and 1 of sulphur. 
 
 Erp. Heat a small quantity in the flame of a spirit lamp, and it will 
 explode with considerable viok 
 
 Uses. Used in chemistry as an oxidizing agent, and in 
 the formation of nitric acid. In the East Indies, it is em- 
 ployed for cooling mixtures ; one ounce of nitre to five of 
 water, reduces the temperature 15°. From its anti-septic 
 properties, it is employed for preserving animal substances. 
 
 In the arts, it is extensively employed in the manufacture 
 of gunpowder, which consists of nitre, sulphur, and charcoal. 
 In agriculture, it is used as a manure. 
 
 Nitrate of Soda, (NaO-}-N0 5 . 85.45,) called by the old 
 writers cubic nitre, occurs in the soils of India, and in 
 Peru : it is analogous, in chemical properties, to the pr-: 
 ding : mixed with charcoal, it burns more slowly than nitre. 
 
 Nitrate of Ammonia (H s N-j-N0 5 . 71.3) is formed 
 neutralizing dilute nitric acid by carbonate of ammonia, and 
 evaporating the solution. It is decomposed by heat, and 
 yields the exhilarating gas or protoxide of niirogc 
 
 Nitrate of Baryta (BaO-j- NO 5 . 130.85) is easily pre- 
 pared by digesting the native carbonate in nitr; 
 diluted with S or 10 parts of water ; on evaporation, it 
 crystallizes in transparent, anhydrous octohedrons : soluble 
 in 12 parts of water at 60°, and 3 or 4 of boiling water. 
 This salt is used as a re-agent, for preparing pure baryta, 
 and in pyrotcchny, to impart a green color to flame.* 
 
 * The green fire is composed of 13 par e of 
 
 baryta. 5 chlorate of potassa, 2 of arsenic, and 3 of charcoal. 
 
Nitrates. 311 
 
 Nitrate of Sirontia (SrO + NO 5 . 105.95; in prisms, 
 with 5 oquiv. of water, — 150.95) is prepared from the carbo- 
 nate of strontia, in the same manner as the preceding, and 
 has similar properties ; it is used for the redjire employed at 
 theatres.* 
 
 Nitrate of Lime (CaO + NO 5 . 82.65) is found in old 
 plaster and mortar ; very soluble and deliquescent; crystal- 
 lizes in hydrated prisms. 
 
 The NitraU of Magnesia (MgO + NO 5 . 74.85) has simi- 
 lar properties. 
 
 Nitrate of Protoxide of Copper (CuO -f NO 5 . 93.75) is 
 formed by the action of nitric acid on copper ; its crystals 
 are prisms containing 7 equiv. of water, of a deep blue color, 
 soluble in water and alcohol, and deliquescent. 
 
 Exp. Spread a drachm of this salt on a piece of tin foil, moisten it 
 with water, fold it, and lay it on a plate ; sufficient heat will often be 
 evolved to ignite the metal. 
 
 Nitrate of Protoxide of Lead (PbO + NO 5 . 165.75) may 
 be formed by digesting litharge in dilute nitric acid ; it crys- 
 tallizes in anhydrous octohedrons, and has an acid re-action. 
 
 Dinitrate of Protoxide of Lead. 2PbO -f NO 5 . 223.2 -j- 
 54.15 = 277.35. 
 
 Nitrate, of the Black Oxide of Mercury (Hg 2 + N0 6 . 
 264.67; in crystals, with 2 equiv. of Aq = 282.67) is formed 
 by dissolving mercury in cold dilute nitric acid. If there is 
 an excess of acid, the solution by evaporation yields clear 
 transparent rhombic crystals. By allowing the solution to 
 stand, small cunary yellow crystals form, having the compo- 
 sition of 2HgO+NO*-f- HO. 
 
 Nitrate of the Red Oxide of Mercury (2HgO + N0 6 -f-2HO 
 = 290.67) is formed by heating mercury with nitric acid in 
 excess. On cooling it deposits rhomboidal crystals, deliques- 
 cent and very soluble. When the solution is diluted it is 
 decomposed, and a basic nitrate of a bright cunary color is 
 precipitated, sy mb. 3HgO. -f-N0 5 HO. If this powder is boiled 
 in a large quantity of water, still another salt is formed, hav- 
 ing the formula 6HgO-fN0 5 . 
 ^Nitrate of Oxide 'of Silver (AgO-f-NO 5 . 170.15) may be 
 
 * Bed fire consists of 40 parts of nitrate of strontia, 13 sulphur, 5 
 chlorate of potassa, and 4 sulphuret of antimony, with a Tittle powdered 
 charcoal. 
 
312 Salts. — Nitrates. 
 
 formed by dissolving silver in nitric acid, diluted with 3 
 parts of water ; if the silver contain copper, it will give a 
 greenish hue to the solution ; if it contain gold, it will appear 
 in the form of a black powder. The solution should be per- 
 fectly clear and colorless.* 
 
 Properties. The solution by evaporation deposits trans- 
 parent, tabular crystals ; it is caustic, and tinges animal sub- 
 stances of a deep yellow, which becomes, by exposure to 
 light, deep purple or black, and is indelible. 
 
 Heated in a silver crucible to 426°, it fuses, and when 
 cast into small cylinders, forms the lunar caustic of phar- 
 macy. This, when pure, is white and transparent ; but the 
 common lunar caustic is dark and opaque, owing to the 
 decomposition of the nitrate, by raising the temperature too 
 high in its preparation, and also in consequence of copper 
 and gold, which are often contained in it ; it is soluble in its 
 own weight of cold, and in half its weight of boiling water. 
 
 It is decomposed by light, leaving a black stain upon the 
 skin or on paper, (see p. 68;) hence it is a very delicate test 
 of animal matter, also of chlorine and hydrochloric acid, 
 which latter causes a white precipitate, the chloride of silver. 
 
 It is also decomposed by sulphur, phosphorus, charcoal, 
 hydrogen, and several of the metals. 
 
 Exp Place a few grains of this salt, with a little sulphur, and also 
 with phosphorus, upon an anvil ; when struck sharply with a hammer, 
 the former will detonate, and the latter explode violently. 
 
 Exp. Dip a piece of silk into a solution of this salt, and, while moist, 
 pass over it hydrogen gas ; it will at first turn black, and then become 
 iridescent, from the reduction of the metal. 
 
 Exp. Immerse in a solution of this salt a stick of phosphorus ; it will 
 soon become beautifully incTusted with the metal. 
 
 Exp. Immerse a slip of ivory in a dilute solution of the salt, till the 
 ivory has acquired a bright yellow stain ; remove it to a tumbler of dis- 
 tilled water, and expose it to the direct rays of the sun for two hours, 
 
 * One of the best solvents of silver may be formed by dissolving 1 
 part of nitre in 10 by weight of concentrated sulphuric acid. When 
 this compound is heated to between 100° and 200° Fahr., it will dis- 
 solve about one sixth of its weight of silver without acting in the least 
 upon any copper, gold, lead, or iron, with which the silver may be 
 combined ; hence it is very useful to detach silver from old plate. To 
 recover the silver from the solution, add common salt, and then de- 
 compose the chloride thus formed by carbonate of soda. 
 
Nitrates — Chlorates. 313 
 
 when it will become black, but, on rubbing it, the surface will become 
 bright, resembling pure silver. 
 
 Nitrate of Silver is the principal ingredient in indelible 
 ink, and in those compounds which are used for changing 
 the color of the hair. 
 
 In all these cases, the effect depends upon the reduction of 
 a part of the silver to the metallic state. 
 
 4. Nitrites, 
 According to Turner, very little is known of these salts. 
 
 5. Chlorates* 
 
 The salts of chloric acid are very analogous to those of 
 nitric acid. They are all soluble in water, and are dis- 
 tinguished by the action of strong hydrochloric and sulphuric 
 acids, the former disengaging chlorine, and protoxide of chlo- 
 rine, and the latter chlorous acid,, 
 
 The chlorates are mostly composed of 1 equiv. of protoxide 
 and 1 of acid ; hence the oxygen of the base is to that of the 
 acid, as 1 to o i of Mo -[* CIO 5 . 
 
 None of the chlorates are found native, and those of baryta 
 and potassa are the only ones which require particular notice. 
 
 Chlorate of Potassa (RO + CIO 5 . 122.57) may be formed 
 by transmitting chlorine gas through a concentrated solution 
 of pure potassa, until the alkali is completely neutralized ; the 
 results are chloride of potassium and chlorate of potassa.* 
 
 Properties. " Chlorate of potassa generally occurs in four 
 and six-sided crystalline scales; colorless, and of a pearly 
 lustre; soluble in 16 times its weight of water at 60°, and in 
 2£ of boiling water. It is anhydrous, and fuses at 400° or 
 500° ; by increase of temperature, it yields pure oxygen gas, 
 
 It acts very energetically upon many imflammable bodies. 
 
 Exp. Put. 2 grains of the salt into a mortar, with 1 grain of 
 sulphur. Mix them accurately, and then strike the collected mass 
 
 * For other processes, see Turner's Chemistry. 
 14 
 
314 Salts. — Chlorates. 
 
 forcibly with the pestle ; a loud detonation will ensue. Charcoal will 
 produce a similar effect; or, 
 
 Exp. Instead of the sulphur, add a grain of phosphorus, and the 
 detonation will be much louder.* 
 
 Many of the stronger acids decompose this scdt. 
 
 Exp. Mix 2 parts of sugar with 1 of chlorate of potassa, and pour 
 upon it a few drops of sulphuric acid; the decomposition will be at- 
 tended by a sudden inflammation. 
 
 Exp. Put 2 parts of this salt with 1 of phosphorus into a wine- 
 glass filled with warm water, and then pour, by means of the dropping- 
 tube, strong sulphuric or nitric acids directly upon the salt; the phos- 
 phorus will ignite under the water, owing to the development of oxy- 
 gen from the decomposition of the salt. 
 
 Uses. It is employed in the preparation of percussion 
 powder, in which this salt is substituted for nitre. 
 
 Matches are also made by first dipping them in melted sul- 
 phur, and then in a composition of chlorate of potassa, sugar, 
 gum arabic, and vermilion. 
 
 Lucifer Matches have a similar composition. 
 
 An attempt was made in 17S3 to substitute chlorate of 
 potassa for nitre, in the manufacture of gunpowder; but, 
 as might have been expected, on triturating the mixture, 
 it exploded with violence, and destroyed several of the 
 operators. 
 
 A few grains of this salt, put into water with a few 
 drops of hydrochloric acid, form a convenient bleaching 
 liquor. 
 
 Chlorate of Baryta (BaO + CIO 5 . 152.12) is prepared by 
 digesting for a few minutes a concentrated solution of chlorate 
 of potassa, with a slight excess of silicated hydrofluoric acid ; 
 the alkali is precipitated in the form of an insoluble, double 
 hydrofluate of silica and potassa, while chloric acid remains 
 in the solution. The liquid, after filtration, is neutralized 
 by carbonate of baryta, which throws down the excess of 
 silicated hydrofluoric acid, and chlorate of baryta remains 
 in solution. 
 
 Properties. It yields, on evaporation, crystals in the form 
 of four-sided prisms, has a pungent taste, is soluble in 4 times 
 its weight of cold, and in a smaller quantity of warm water. 
 It. is employed for forming chlorous acid. 
 
 * The hands should be covered with gloves, and the mortar turned 
 from the face. 
 
Per chlorates — Iodates* 815 
 
 6. Perchlorates. 
 
 The neutral protosalts of perchloric acid consist of 1 
 equiv. of acid and base, as is expressed by the formula 
 MO -\- CIO 7 . Most of the salts are deliquescent, very solu- 
 ble in water, and soluble in alcohol. When heated to red- 
 ness, they yield oxygen gas and metallic chlorides ; and they 
 are distinguished from the chlorates by not acquiring a yellow 
 tint, on the addition of hydrochloric acid. — T. 
 
 The salts are formed by neutralizing the base with per* 
 chloric acid, excepting perchlorate of potassa, which is 
 formed from the chlorate by heat and sulphuric acid. 
 
 7. Chlorites. 
 
 The. alkaline chlorites are formed by transmitting a current 
 of chlorous acid gas into a solution of the pure alkalies ; they 
 are remarkable for their bleaching and oxidizing properties. 
 
 8. Hypochlorites. 
 
 These salts may be formed by the action of chlorine gas on 
 the alkaline bases ; the most important of these is the hypo- 
 chlorite of lime, which is well known as a bleaching powder. 
 
 9. Iodates^ 
 
 The salts of iodic acid are very similar in character to 
 those of chloric acid ; in all the neutral protiodates, the oxy- 
 gen of the base and acid is in the ratio of 1 to 5 ; the 
 iodates are easily recognized by the action of de-oxidizing 
 agents. Thus the sulphurous, phosphorous, hydrochloric 
 and hydriodic acids deprive the iodic acid in the salt of 
 its oxygen, and set the iodine at liberty. None of the 
 iodates are found native ; they are all insoluble, or sparingly 
 soluble in water, excepting the iodates of the alkalies. 
 
 IodaU K of Potassa (KO-J-IO 5 . 21345) may be obtained 
 
31 6 Salts. — Phosphates. 
 
 by adding iodine to a concentrated, hot solution of pure 
 potassa, until the alkali is completely neutralized. All the 
 insoluble iodates may be procured from this salt ; thus the 
 iodate of baryta may be formed by mixing chloride of 
 barium with a solution of iodate of potassa. 
 
 10. The Bromates are very similar to the chlorates and 
 iodates. 
 
 11. Phosphates. 
 
 There are three acids of phosphorus which are isomeric — 
 the phosphoric, pyrophosphoric, and mctaphosphoric ; hence 
 it becomes necessary to have three corresponding families of 
 salts. 
 
 I. Phosphates. All the neutral protophosphates are solu- 
 ble in water, and redden litmus paper, on which account they 
 are called superphosphates. 
 
 The Triphosphates, except those of the pure alkalies, are 
 sparingly soluble, or insoluble in water, but are all dissolved 
 by nitric or phosphoric acids. The phosphates and diphos- 
 phates are changed by heat into pyrophosphates and meta- 
 phosphates ; the phosphates of the pure alkalies are but par- 
 tially decomposed by heat and combustible matter, and those 
 of baryta, strontia, and lime, undergo no change ; but most of 
 **the phosphates of the second class of metals are resolved into 
 hosphurets by those agents. 
 
 The insoluble phosphates are decomposed when boiled 
 with a strong solution of carbonate of potassa, or soda. 
 
 Triphosphate of Potassa (3KO + P 2 5 . 212.85) is formed 
 by adding caustic potassa in excess to a solution of phos- 1 
 phoric acid. 
 
 Diphosphate of Potassa (VK03H.O + P 2 05. 165.7) is pre- ■ 
 pared by neutralizing the superphosphate of lime obtained 
 from bones, with carbonate of potassa. 
 
 Phosphate of Potassa (K0.2HO + P 2 5 . 136.55) is formed 
 by adding phosphoric acid to carbonate of potassa, until the 
 liquid ceases to give a precipitate with chloride of barium, 
 and then setting aside to crystallize. 
 
Phosphates. 317 
 
 Triphosphate of Soda. 3NaO + P 2 5 . 165.3 ; in crystals, 
 with 24 equiv. of water, = 381.3. This salt is prepared by 
 adding pure soda to a solution of the succeeding compound, 
 until the liquid feels soapy to the fingers; the solution is then 
 evaporated until a pellicle forms; on cooling, the crystals 
 which are deposited, are quickly re-dissolved in water, and are 
 crystallized. 
 
 Properties. Triphosphate of soda crystallizes in colorless, 
 six-sided, slender prisms, which have an alkaline taste and re- 
 action ; soluble in five times their weight of water at 69°, and 
 in still less of hot water; the crystals undergo watery fusion 
 at 170°, but are not decomposed at a red heat. The feeblest 
 acid deprives the salt of £ of its soda. 
 
 Triphosphate of Soda and Basic Water. 2NaO.HO + 
 P-O 5 . 143 ; in crystals, with 24 equiv. of water. = 359. This 
 salt is the most common of the phosphates, being manufac- 
 tured on a large scale, by neutralizing, with carbonate of 
 soda, the acid phosphate of lime, which is procured by the 
 action of sulphuric acid on burned bones. 
 
 Properties. It crystallizes in oblique rhombic prisms, 
 hence called rhombic phosphate ; its crystals are always alka- 
 line to test paper ; effloresce in the air ; soluble in four times 
 their weight of cold, and twice their weight of warm water. 
 
 Acid Triphosphate of Soda and Basic Water (NaO,2HO 
 -f- P 2 5 . 120.7 ; in crystals, with 2 eq. water, = 13S.7) is com- 
 monly called the Diphosphate of soda, and may be formed by 
 adding phosphoric acid to a solution of carbonate of soda, 
 until it ceases to give a precipitate with chloride of barium. 
 When the solution is concentrated, it yields two different 
 kinds of crystals without varying its composition. 
 
 Phosphate of Soda and Ammonia (NaO.H 3 N-f-P20 5 . 
 119.85, with 10 eq. water =: 209.85) is easily prepared by 
 mixing 1 equiv. of hydrochlorate of ammonia, and 2 equiv. 
 of the rhombic phosphate of soda ; each being previously 
 dissolved in a small quantity of boiling water. 
 
 It is known as microcosmic salt, and is much employed as 
 a flux in experiments with the blowpipe ; when heated, it 
 parts with its water and ammonia. 
 
318 Salts . — Phosphates. 
 
 Diphosphate of Ammonia (2H 3 N -|- P 2 5 . 105.7; in crys- 
 tals, with 3 equiv. water. — 132.7) is prepared by adding am- 
 monia to phosphoric acid until a precipitate is formed ; the 
 primary form of the crystals is an oblique rhombic prism. 
 
 Phosphate of Ammonia (H 3 N-f-P 2 Q 5 . 88.55; in crystals, 
 with 3 equiv. water, =: 115.55) is formed in the same manner 
 as the phosphate of potassa, crystallizes in octohedrons with 
 a square base, and in right square prisms. 
 
 Bone Phosphate of Lime (8CaO -f 3P 2 5 . 442.2) exists 
 in bones after calcination, and falls as a gelatinous precipitate, 
 on pouring chloride of calcium into a solution of rhombic 
 phosphate of soda. 
 
 Triphosphate of Lime (3CaO -\- P 2 O s . 156.9) occurs in the 
 mineral called apatite. 
 
 Diphosphate of Lime, (2CaO -\-V 2 5 -\- 1 eq. basic water, 
 = 137.4,) commonly called neutral phosphate, falls as a granu- 
 lar precipitate, when the rhombic phosphate of soda is added, 
 drop by drop, to chloride of calcium in excess. 
 
 Phosphate of Lime (CaO-f- l'-0 5 -)-2 eq. basic water, = 
 117.9) is commonly called the diphosphate, from its acid re- 
 action, and may be formed by dissolving either of the pre- 
 ceding salts in a slight excess of phosphoric acid ; it exists in 
 urine. 
 
 Diphosphate of Magnesia. 2MgO + P 2 05. 112.8. 
 
 Triphosphate of Magnesia. 3MgO + P 2 5 . 133.5. 
 
 Phosphate of Ammonia and Magnesia (2MgO -}- 2H 3 N -j- 
 10HO-|-P 2 O 5 . 237.1) subsides as a pulverulent, granular 
 precipitate from neutral alkaline solutions, containing phos- 
 phoric acid, ammonia, and magnesia ; it constitutes a variety 
 of urinary concretions. 
 
 Triphosphate of Oxide of Silver is formed when the 
 rhombic phosphate of soda is mixed in solution with nitrate 
 of silver ; it is a yellow powder when dry ; on exposure to 
 light, it is speedily blackened. 
 
 II. Pyrophosphates. The only salts of this family which 
 have been studied, are those of soda and oxide of silver. 
 They are thus constituted : — *- 
 
Arseniates. 319 
 
 Dipyrophosphate of Soda. 2NaO + ?*0K 62.6 + 71 .4 = 134. 
 
 Dtpyrophosphote hi crystals, with 10 eq. water, 90 = 224. 
 
 Mid Dipyrophosphate of Soda and Basic Water. NaO.HO + P 2 G 5 a 
 1117. 
 
 Pyrophosphate of Soda. NaO.P 2 5 . 31 .3 -f- 71 .4 = 1 02.7. 
 
 Dipyrophosphate of Oxide of Silver. 2AgO + P 2 5 . 232 + 71.4 = 
 303.4. 
 
 III. MetaplwspJiates. The only salts of this family yet 
 examined are those of soda, baryta, and oxide of silver. 
 
 Metaphosphate of Soda,. NaO.P 2 5 , 1 eq. Na, 31.5 + leq. P 2 5 , 71.4 
 = 102.7. 
 
 Metaphosphate of Baryta. BaO.P 2 5 , 1 eq. BaO, 767 + leq. P 2 5 , 
 71.4 = 143.1. 
 
 Metaphosphate of Silver. AgO.P 2 5 , 1 eq. AgO, 116 + 1 eq. P 2 5 , 
 71.4 = 187.4. 
 
 Sub-meta phosphate of Silver. 3AgO +2P 2 0\ 3 eq. AgO, 348+2 eq. 
 P 2 5 , 142.8 = 490,8. 
 
 12. Arseniates. 
 
 Arsenic acid resembles the phosphoric in composition, 
 and in many of its properties. The oxygen of the oxide and 
 acid in their salts is as 1 to 5 ; salts of 2 equiv. of basic 
 water are soluble in water, redden litmus paper, and are 
 usually considered bisalts ; those with 1 equiv. of basic 
 water, in which the oxygen of the base and acid is as 2 to 
 5, are commonly called neutral arseniates; those without 
 water are described as subarseniates. This acid has a strong 
 tendency to form trisalts; some of the arseniates bear a red 
 heat without decomposition, but all are decomposed when 
 thus heated with charcoal, metallic arsenic being set at 
 liberty. 
 
 The soluble arseniates are easily recognized by the tests 
 for arsenic. (See p. 266.) 
 
 The insoluble arseniates are tested by boiling them in a 
 strong solution of the fixed alkaline carbonates, by which 
 they are deprived of their acid; the acid may then be de- 
 tected in the usual way. 
 
 The following are the principal arseniates : — - 
 
 Trinrseniate of Soda. 3NaO + As 2 5 , 3 eq. NaO, 93.7+1 eq. 
 As 2 0*, 115.4 = 209.3. 
 
 Do. in crystals with 1 eq. water 21G = 425.3. 
 
220 Salts. — Arsenites. 
 
 Diarseniate of Soda and Basic Water. 2NaO -f HO 4- As 2 5 , eq. 187. 
 
 Mid Arsemale of Soda and Basic Water. JN T aO + 2HO -J- As 2 Oaq. =. 
 164.7. 
 
 TriarseniaU of Poiassa. 3KO 4- As 2 O s , 3 eq. KO, 141.45 4-1 en 
 As 2 O s , 115.4 = 256.85. 
 
 Diarseniate of Potdssa. 2KO + As 2 5 , 2 ea. KO, 94.34-1 eo 
 As 2 5 , 115.4 = 209.7. *'.■■. 
 
 Arseniate of Potassa. KO. As 2 5 , 1 eq. KO, 47.154-1 eq. As 2 5 , 
 115.4 = 162.55. H 
 
 Diarseniate of Ammonia. 2H 2 N 4- As 2 © 5 2eq. NH 3 , 34.34-1 eq. 
 As 2 5 , 115.4 = 149.7. - 
 
 Arseniatc of Ammonia. NH 3 As 2 5 , 1 eq. NH 3 , 17.55 4-1 eq. 
 As 2 5 , 115.4 = 132.55. . 
 
 Triarseniate of Baryta. 3Ba0 4-As 2 5 , 3 eq. BaO, 230.14-1 eq. 
 As 2 5 , 115.4=345.5. ? H 
 
 Diarseniate of Baryta. 2Ba0 4-As 2 Q 5 , 2 eq. BaO. 153.4 4-1 eq. 
 As 2 5 , 115.4 = 268.8. " 
 
 Arseniate of By rata. BaO 4- As s O% 1 eq. BaO, 76.7 4- 1 eq. As'-O 5 , 
 115.4 = 192.1. T* 
 
 Triarseniate of Lime. 3Ca0 4-As 2 5 , 3 eq. CaO, 85.54-1 eq. 
 As 2 5 , 115.4 = 200.9. ^ 
 
 Diarseniate of Lime. 2CaO 4- As 2 5 , 2 eq. CaO. 57 4- 1 eq. As 2 5 
 115.4 = 172.4. > -. 
 
 Arseniate of Lime. CaO 4- As 2 5 , 1 eq. CaO, 28.54-1 eq. As 9 5 , 
 115.4 = 143.9. 
 
 Triarseniate of Lead. 3PbO -4- As 2 5 , 3 eq. PbO, 334.8 4-1 eq. 
 As 2 5 , 115.4 = 450.2. 
 
 Diarseniate of Lead. 2Pb0 4-As 2 G 5 . 2 eq. PbO, 223.2 4-1 eq. 
 As 2 5 , 115.4 = 338.6. 
 
 Triarseniate of Ox-Silver. 2Aa0 4-As 2 Q 5 , 3 eq. AcjO, 348 4-1 cq. 
 As 2 0% 115.4 = 463.4, ' 
 
 13. Arsenites. 
 
 The arsenites of potassa, soda, and ammonia, may be 
 prepared by acting with those alkalies on arsenious acid. 
 
 They are very soluble in water, and have an acid re-action. 
 
 Most of the other arsenites are insoluble or sparingly solu- 
 ble in water, but are dissolved by an excess of arsenious, 
 nitric, and most other acids, with which their bases do not 
 form insoluble compounds. 
 
 They are all decomposed when heated in close vessels. 
 
 The soluble salts, if neutral, are characterized by forming 
 a yellow arseniate of oxide of silver, when mixed with nitrate 
 of silver, and a green arsenite of protoxide of copper — - 
 Schcek's green — with sulphate of copper. 
 
 The arsenite of potassa is the active principle in Foicler's 
 arsenical solution. 
 
Chromates — Borates 321 
 
 14. Chromates. 
 
 The chromates may generally be known by their yellow 
 or red color. They may be known chemically by the green 
 solution of chloride of chromium, formed by boiling any 
 chromate with hydrochloric acid mixed with alcohol. They 
 are all decomposed by heat and combustible matter. 
 
 Chromate of Potassa (KO + CrO 3 . 99.15) is formed by 
 heating to redness the native oxide of chromium and iron 
 {chromate of iron) with nitrate of potassa, when chromic acid 
 is generated, and unites with the alkali of the nitre. 
 
 Properties. Taste cool, bitter, and disagreeable, soluble 
 in boiling water, and insoluble in alcohol. 
 
 Bichromate of Potassa (KO + 2Cr0 3 . 151.15) is of great 
 importance in dyeing. It is prepared by acidulating the 
 neutral chromate with sulphuric, or, still better, with acetic 
 acid, and allowing the solution to crystallize by spontaneous 
 evaporation. 
 
 Properties. When slowly formed, four-sided rhombic 
 prisms are deposited, which are anhydrous, and of a rich 
 red color ; soluble in 10 times their weight of water at 60° 
 and the solution reddens litmus. 
 
 The insoluble chromates, such as those of baryta, zinc, 
 lead, mercury, and silver, are prepared by mixing the soluble 
 salts of those bases with a solution of chromate of potassa. 
 
 Chromate of Lead. PbO + CrO 3 . 103.6. This is the 
 yellow chromate, and is extensively used as a pigment. 
 Chromate of oxide of zinc may be used for the same purpose. 
 
 15. Borates. 
 
 The boracic is a feeble acid, and neutralizes imperfectly ; 
 hence the borates, such as soda, potassa, and ammonia, have 
 an alkaline re-action ; hence, also, the more powerful acids 
 separate the alkali from boracic acid, although, at a red heat, 
 boracic acid, owing to its fixed nature, decomposes every salt 
 whose acid is volatile. The borates of the' alkalies are solu- 
 14* 
 
322 Salts. — Carbonates. 
 
 ble in water, but most of the other borates are sparingly 
 soluble ; they are not decomposed by heat, though remark- 
 able for their fusibility. They are distinguished by the 
 following character : — 
 
 By digesting any borate in an excess of strong sulphuric 
 acid, evaporating to dryness, and boiling the residue in 
 strong alcohol, the solution will burn with a green flame. 
 
 Biborate of Soda, (2BO* + Na0. 191.1; in crystals, with 
 10 equiv. of water, = 101.01.) commonly called borax, oc- 
 curs native in certain lakes in Thibet. It is imported from 
 India under the name of tincal, which, after purification 
 constitutes the refined borax of commerce. 
 
 Properties. It crystallizes in hexahedral prisms. The 
 crystals are efflorescent : when heated, they lose their water 
 of crystallization, fuse, and form, on cooling, a crystalline 
 mass, called glass of borax. 
 
 Boreix is much used as a flux for welding iron and steel. 
 
 Boracitc is a biborate of magnesia. 
 
 A new biborate of soda has been lately described; better 
 as a flux, for the use of jewellers, than the preceding. 
 
 16. Carbonate^. 
 
 The carbonates are distinguished from all other salts, by 
 being decomposed with effervescence, owing to the escape 
 of carbonic acid gas, by nearly all acids, 
 
 All the carbonates, except those of potassa, soda, and lithia, 
 are decomposed by heat ; and all, except those of potassa, 
 soda, and ammonia, are of sparing solubility in pure water; 
 but all are soluble in excess of carbonic acid. Several of 
 them occur native. 
 
 Carbonate of Potassa (KO-f-CO 2 . 69.27) is procured by 
 lixiviating the ashes of land plants, and boiling the lye — a 
 process which is performed on a large scale in Russia, and 
 in this country. This is the impure carbonate of commerce, 
 known by the names potash and pcarlash, and is of great utili- 
 ty in the arts, especially in the manufacture of soap and glass. 
 As thus prepai ed, it always contains other compounds, such 
 
Carbonates. 323 
 
 as sulphate of potassa, and chloride of potassium. For 
 chemical purposes, it is obtained by heating cream of tartar 
 to redness, when the acid is decomposed, and a pure car- 
 bonate of potassa mixed with charcoal remains. The char- 
 coal is removed by solution in water, and evaporation. 
 
 Properties. Taste strongly alkaline, and slightly caustic; 
 changes the vegetable purple colors to green ; soluble in less 
 than an equal weight of water at 60° ; deliquesces on ex- 
 posure to the air; is insoluble in pure alcohol, and fuses at 
 a full red heat, but undergoes no other change. 
 
 Bicarbonate of Potassa (KO-|-2C0 9 . 91.39; in crystals, 
 with 1 equiv. water, ==: 100.39) is made by transmitting a 
 current of carbonic acid gas through a solution of the car- 
 bonate. This salt is milder than the carbonate, into which 
 it is converted by a low red heat. It does not deliquesce on 
 exposure, and requires four times its weight of water at 60° 
 for solution. 
 
 Carbonate of Soda {NoO +CO\ 53.42; in crystals, with 
 10 equiv. water, — 143.42) was formerly obtained from the 
 ashes of several species of sea-weed, but it is now obtained 
 from common salt, (chloride of sodium.) The salt being first 
 converted into sulphate of soda by the action of sulphuric acid 
 and heat, is acted upon by chalk heated with small coal. The 
 fused mass is called black ash, and from it the pure carbonate 
 is obtained by dissolving in boiling water and crystallizing. 
 
 Properties. Crystallizes in rhombic prisms ; effloresces, 
 and dissolves in its water of crystallization when heated, and 
 becomes anhydrous byjjontinued heat ; soluble in about 2 
 parts of cold, and in less than its weight of boiling water. 
 
 Bicarbonate of Soda (NaO+2C0 3 . 75.54; in crystals, 
 with 1 equiv. water, = 84.54) is formed by the same process 
 as the bicarbonate of potassa, and. like that salt, is much 
 milder than the carbonate. 
 
 Sesquicarbonate of Soda (2NaO + 3C0 2 . 4HO. 164.96) 
 is found native in Africa, on the banks of soda lakes, and is 
 called trona. 
 
 Carbonate of Ammonia (H 3 N+C0 2 . 39.27) is obtained 
 by mixing dry carbonic acid over mercury, with twice its 
 volume of ammoniacal gas. It is a dry, white powder, and 
 
324 Salts. — Carbonates. 
 
 has an alkaline re-action ; its odor is pungent, resembling 
 ammonia. 
 
 Bicarbonate of Ammonia (H 3 N.2HO + 2C0 2 . 79.39) is 
 obtained by transmitting a current of carbonic acid gas 
 through a solution of carbonate of ammonia, and evaporating 
 the-solution by gentle heat. It is deposited in right rhom- 
 bic prisms ; inodorous, and nearly tasteless. 
 
 Sesquicarbonate of Ammonia (2H 3 N.2H0 2 + 3C0 2 . 
 118.06) is prepared by heating 1 part of hydrochlorate of 
 ammonia, mixed with 1J of carbonate of lime, carefully 
 dried. 
 
 The chloride of calcium remains in the retort, and this 
 salt is sublimed; it is hard, compact, translucent, of a crys- 
 talline texture, and ammoniacal odor. 
 
 Carbonate of Baryta (BaO -j- CO 2 . 98.82) occurs native 
 in the mineral Witherite. It may be prepared by mixing a 
 soluble salt of baryta with any of the alkaline carbonates. 
 
 Properties. This salt is anhydrous, very insoluble, and 
 highly poisonous. 
 
 Carbonate of Strontia (SrO-f CO 2 . 73.92) is known by 
 the name of strontianite ; it may be prepared in the same 
 manner as carbonate of baryta ; it is soluble in excess of 
 carbonic acid. 
 
 Carbonate of Lime (Ca + CO 2 . 50.62) is a very abundant 
 natural production, occurring under a great variety of forms, 
 such as limestone, marble, chalk, Iceland spar, etc. ; often 
 in regular crystals. Carbonic acid and lime have a strong 
 affinity for each other ; and hence moist lime, or lime in so- 
 lution, when exposed to the air, absorbs the acid contained 
 in the atmosphere, and carbonate of lime is formed. It is 
 sparingly soluble in water, but soluble in excess of carbonic 
 acid; the crust formed on the top of lime water is car- 
 bonate of lime. 
 
 Carbonate of Magnesia (MgO -\- CO 2 . 42.82; in crystals, 
 with 3 equiv. of water, = 69.82) is found native in the mine- 
 ral called magnesite, which is nearly pure anhydrous car- 
 bonate of magnesia. It is obtained in minute, transparent, 
 
Carbonates 325 
 
 hexagonal prisms, when a solution of the bicarbonate evapo- 
 rates slowly in an open vessel ; the crystals lose their water, 
 and become opaque by a very gentle heat, and even in dry 
 air, at 60°. They are decomposed by water. 
 
 A Carbonate of Magnesia, consisting of 4 equiv. of water, 
 3 of acid, and 4 of magnesia, falls as a white powder when 
 carbonate of potassa is added to a hot solution of sulphate 
 of magnesia; this salt is very insoluble, requiring 9000 parts 
 of hot water for solution. 
 
 Carbonate of Protoxide of Iron (FeO-f CO 9 . 58.12) is a 
 very abundant natural production, occurring either in masses, 
 or in rhombohedrons. It exists also in most of the cha- 
 lybeate mineral waters. It may be formed by mixing an 
 alkaline carbonate with sulphate of protoxide of iron. It 
 acts as a tonic upon the animal system. 
 
 Bicarbonate of Protoxide of Copper (2CuO + Co 2 . 101.32) 
 is found native as a hydrate, in the mineral called malachite, 
 of a beautiful green color. 
 
 It may be obtained by precipitation from a hot solution of 
 sulphate of protoxide of copper, by carbonate of soda or po- 
 tassa ; this is the mineral green of painters. 
 
 When the hydrate is boiled for a long time in water, it 
 loses both carbonic acid and combined water, and the color 
 changes to a brown. 
 
 The blue copper ore, and the blue pigment called verditer* 
 have a similar composition. 
 
 Carbonate of Protoxide of Lead (PbO + CCH 133.72) is 
 the ivliite lead of painters. It occurs native in white pris- 
 matic crystals. As an article of commerce, it is prepared 
 from the subacetate by a current of carbonic acid ; also by 
 
 * Refiners 1 Verditer, made by silver refiners, is composed of 3 equiv. 
 of oxide and 4 of carbonic acid. 
 
 A very good verditer is formed by adding a quantity of lime to ni 
 trate of copper sufficient to throw down the oxide. The green precip- 
 itate must be washed, and nearly dried upon a strainer. If it is then 
 mixed with 10 per cent, of fresh lime, the color Vvill become blue. It 
 must now be dried, and is then fit for use. 
 
326 Salts. — Double Carbonates — Silicates . 
 
 exposing metallic lead in minute division to air and moisture, 
 or by the action of the vapor of vinegar on thin sheets of 
 lead. 
 
 Bicarbonate of Peroxide of Mercury, 2HgO--j-CO;, 
 458.12. When a solution of the nitrate of peroxide o* 
 mercury is decomposed by carbonate of soda, this salt falls 
 as an ochre-yellow precipitate. 
 
 17. Double Carbonates. 
 
 The most remarkable of these salts is the double carbonate 
 of lime and magnesia, (MgO.CO-j-CaO.COo. 93.44,) form- 
 ing the minerals called dolomite, bitter spar, and pearl spar. 
 
 The rock called magnesian limestone is an impure variety 
 of dolomite. 
 
 Barytocalcite is a double carbonate of baryta and lime. 
 CaO.CO^ + BaO.COl 149.44. 
 
 Carbonate of Soda, fused with the carbonate of baryta, 
 strontia, or lime, in the ratio of their equiv., yields crystal- 
 line, definite compounds. In the same manner, also, sulphate 
 of soda, heated with the above carbonates, yields double 
 salts, which are very similar, 
 
 18. Silicates. 
 
 Silicic Acid is one of the most powerful acids. The salts 
 which it forms, although very numerous and important com- 
 pounds, have not hitherto been fully investigated. The sili- 
 cates are remarkable for their great variety of composition ; 
 they are composed of from 1 equiv. of base and 6 of silicic 
 acid to 1 of acid and 3 of base. Those most frequently met 
 with are, — 
 
 1. Simple Silicates, or those composed of 1 equiv. of base 
 and 1 of silicic acid. These are a very numerous class of 
 natural compounds, as, silicate of manganese, zinc, glucina, 
 cerium, zirconia, iron, &c. 
 
 2. Bisilicates, in which 2 equiv. of silicic acid are com- 
 
Silicates. 327 
 
 bined with 1 of base. There are many native compounds 
 of tms order : tabular spar is a bisilicate of lime ; bottle 
 glass is another example. 
 
 3. Trisilicatcs, in which 3 equiv. of silicic acid are united 
 to 1 of base. The most important of the trisilicates is plas 
 tic clay, which is a trisilicate of alumina. 
 
 4. Quadrisilicates, which are principally artificial com- 
 pounds, among which are crown glass, French window glass, 
 flint glass, and enamel. 
 
 In addition, it should be remarked, that there are a very 
 great number of simple minerals, which are composed as 
 above, or by the union of silicic acid with other acids and 
 with bases. In fact, the greater portion of the crust of the 
 globe is composed of silicates. The soils, rocks, and 
 mountains, are but masses of silicates. 
 
 The silicates are all fusible before the compound blow- 
 pipe, and all, except those of magnesia and alumina, in a 
 forge fire. Those of 2 or more bases are most easily fused; 
 and those of fusible bases are more easily melted than those 
 whose bases are more refractory. 
 
 In the separation of the metals from their ores, such mat- 
 ters are added as will form with the earthy parts of the ores 
 fusible silicates. These float like glass on the surface of the 
 reduced metal, and are easily removed. 
 
 All kinds of glass are formed by heating siliceous sand 
 with alkaline carbonates. When heat is applied, the alkali 
 melts, and the sand (silicic acid) combines with the alkali, 
 while the carbonic acid escapes in the form of a gas, causing 
 the mass to sweil to twice its former bulk. When the car- 
 bonic acid all escapes, the mass subsides, and is called frit. 
 This is then put into a refractory vessel, and placed in a 
 furnace, where it is heated until it is melted and becomes 
 glass. (See page 221.) 
 
 The silicates are all insoluble, excepting those of potassa 
 aiid soda. Those compounds formed by the union of 1 or 
 2 equiv. of silicic acid are more soluble than those of 3 or 
 4. The double silicates of these alkalies, that is, the union 
 
328 Salts,— Hydro-Salts. 
 
 of another acid or base, renders the compounds still less 
 soluble. 
 
 The silicate of alumina and soda, which is combined with 
 sulphuret of sodium in lapis lazuli is used by painters, under 
 the name of ultramarine, and is a very important compound. 
 
 The silicates are the most important chemical com- 
 pounds ; forming, as they do, almost the entire mass of the 
 soil in every country, their influence upon vegetation is con- 
 stant and universal. To the agriculturist they are com- 
 pounds of great interest, and should be made the subjects 
 of intense study. 
 
 Section 3. 
 
 ORDER II. — HYDRO-SALTS. 
 
 This order includes those salts the acid or base of which 
 contains hydrogen. The salts formerly called muriates or 
 hydrochlorates of metallic oxides, are now generally de- 
 scribed as chlorides of those metals, and also the salts of 
 hydriodic and most other hydracids. The only salts which 
 are included in this order are formed by the hydracids with 
 ammonia and phosphureted hydrogen. 
 
 Hydroclihrate of Ammonia. JPN + HCL. 53.57. This 
 is the sal ammoniac of commerce, and was formerly imported 
 from Egypt, where it was prepared from the soot of camels' 
 dung by sublimation; but it is now formed by several pro- 
 cesses. The most usual is to decompose the sulphate of am- 
 monia* bv the chloride of sodium or magnesium. 
 
 It occurs native, in masses and in crystals, in the vicinity 
 of volcanoes. 
 
 Process. It mav be produced directly, by introducing 
 liquid ammonia into one retort, (see Fig. 54, p. 113,) and 
 HCL into the other, and apply heat. As the two gases pass 
 
 * This sulphate is obtained by digesting with gypsum the impure 
 carbonate of ammonia, procured from the destructive distillation of 
 bones and other animal substances, so as to form an insoluble carbonate 
 of lime and a soluble sulphate of ammonia. 
 
Hydro-Salts 329 
 
 into the receiver, a white cloud appears, which is hydrochlo- 
 rate of ammonia in fine powder. 
 
 Properties. This salt has a pungent, saline taste, and is 
 insoluble in water and in alcohol ; it sublimes at a tempera- 
 ture below that of ignition, without fusion or decomposi- 
 tion. 
 
 Uses. Used in the arts for a variety of purposes, in tin- 
 ning copper, to prevent oxidation, and by dyers. 
 
 When dissolved in nitric acid, it forms the aqua regia, 
 which is employed for dissolving gold, instead of nitro- 
 hydrochloric acid. 
 
 Hydriodate of Ammonia (H 3 N.HI. 144.45) is a white powder, very 
 soluble and deliquescent. 
 
 Hydrobromats of Ammonia (H 3 N.HBr. 96.55) is a white anhy- 
 drous salt. 
 
 Hydrojluate of Ammonia. H 3 N.HI. 36.83. See Turner, 5th edit, 
 p. 469. 
 
 Hydro sulphate of Ammonia (H 3 N-j-HS. 34.25) is 
 formed by heating a mixture of 1 part of sulphur, 2 of sal- 
 ammoniac, and 2 of unslacked lime. It is used as a re- 
 agent, and for this purpose it is formed by saturating a 
 solution of ammonia with hydrosulphuric acid. 
 
 Hydrocyanate of Ammonia. H 3 N -f- HC 2 N. 44.54. 
 
 Hydrosulphocyanate of Ammonia, H 3 N-j-HCyS 2 . 76.74. 
 
 Trifiuoborate of Ammonia. 3H 3 N + BF 3 . 1 18.39. 
 
 Difuoborate of Ammonia. 2H 3 N + BF 3 . 101.24 
 
 Fluoborate of Ammonia. H 3 N + BF 3 . 84.09. 
 
 Fluosilicate of Ammonia, H 3 N + SiF. 43.33. 
 
 Carbosulphate of Ammonia. H 3 N + CS 2 . 55.47.* 
 
 Salts of Phosphureted Hydrogen. 
 
 Phosphureted Hydrogen resembles ammonia in composi- 
 tion, and in some of its properties; it is a feeble alkaline 
 base, and combines with some of the hydr acids. The salt 
 
 * See Turner, 5th edit. p. 469, 
 
330 Salts. — Sulphur-Salts. 
 
 best known is the hydriodate of phosphureted hydrogen, 
 which is composed of 127.3 parts or 1 eq. acid, and 34.4 
 parts or 1 eq. base, and crystallizes in cubes. 
 
 Section 4. 
 
 ORDER III. — SULPHUR-SALTS. 
 
 The sulphur-salts are double sulphurets, just as the oxy- 
 salts are double oxides. 
 
 The sulphur-salts, with two metals, are so constituted, that 
 if the sulphur in each were replaced by an equivalent quan- 
 tity of oxygen, it would form an oxy-salt. 
 
 The close analogy between the two orders of salts appears 
 a^so from the fact, that hydrosulphuric and hydrosulphocy- 
 anic acids unite ooth with ammonia and sulphur bases. 
 
 The principal sulphur bases are the protosulphurets of 
 potassium, sodium, lithium, barium, strontium, calcium, 
 magnesium, and the hydrosulphate of ammonia ; and the 
 sulphur acids are the sulphurets of arsenic, antimony, tung- 
 sten, molybdenum, tellurium, tin, and gold, together with 
 hydrosulphuric acid, bisulphuret of carbon, and sulphuret of 
 selenium. 
 
 The sulphur-salts are divided into families which contain 
 the same sulphur acid : the generic name of each family is 
 formed from the sulphur acid terminated with sulphuret ; 
 thus the salts which contain persulphuret of arsenic or 
 hydrosulphuric acid, as the sulphur acid, are termed arsenio- 
 sulpKurets and hydro sulphurets, and a salt composed of those 
 sulphur acids, with sulphuret of potassium, is termed crstnio- 
 sulphuret, and hydro sulphuret of sulphuret of potassium, or 
 simply hydrosulphuret of potassium* 
 
 * Dr. Hare lias adopted a method of naming the sulphur-salts, 
 founded on the nomenclature of the oxy-salts. He calls the electro- 
 negative sulphuret an acid, and forms its name by changing the termi- 
 nation of the element with which the sulphur i,s combined into ic, and 
 
Sulphur ets. 331 
 
 1. Hydro-sulphurets. 
 
 The salts of this family have hydrosulphuric acid for their 
 electro-negative ingredient ; most of them are soluble in 
 water, are decomposed by exposure to the air and by acids. 
 
 Hydro-sulphur ct of Potassium. KS-j-HS. 72.35, 
 
 The anhydrous salt may be obtained by heating to low 
 redness anhydrous carbonate of potassa in a tubulated retort, 
 through which a current of hydrosulphuric acid is transmit- 
 ted. It forms, when cold, a white, crystalline solid. The 
 hydrous salt has an acrid, alkaline, and bitter taste. 
 
 Hydro-sulphur et of Sodium. NaS -j- HS. 5G.5. 
 
 Hy dro- sulphur <et of Lithium. LS -f- HS. 43.2. 
 
 Hydro-sulphuret of Barium (BaS -|- HS. 101.9) is formed 
 by the action of hydrosulphuric acid on a solution of baryta, 
 excluded from the air. It crystallizes in four-sided prisms, 
 and is very soluble. 
 
 Hydro-sulphuret of Strontium. SrS -|- HS. Eq. 77. 
 
 Hydro-sulphuret of Calcium. CaS + HS. Eq. 53.7. 
 
 Hydro-sulphuret of Magnesium. MgS -|- HS. Eq. 45.9. 
 
 2. Hydro-sulphocyanides. 
 
 The acid of these salts is the hydrosulphocyanuric acid. 
 
 Hydro-sulpho cyanide of Potassium (KS-|~HCyS 2 . 114.84) 
 is a white, crystalline solid, soluble in water and in alcohol. 
 
 Hydro-sulpliocyanide of Hydrosulphate of Ammonia 
 (H 3 N + HS) + (HCyS 2 . 93.84) exists in long, brilliant crys« 
 tals, of a lemon-yellow color. 
 
 3. Carbo-sulphurets. 
 
 The acid of this family is the bisulphuret of carbon. 
 
 Carbo-sulphuret of Potassium (KS + CS 2 . 93.57) is pre- 
 pared by agitating bisulphuret of carbon with a strong alco- 
 holic solution of protosulphuret of potassium. The liquid, 
 when set at rest, separates into three layers, the lowest of 
 which is the carbo-sulphuret of potassium. On evaporation, 
 
 prefixing sulph or sulpJto. Thus, persulphuret of arsenic he calls sulph- 
 arsenic acid, and its sulphur salts, sulpharseniates. Hydrosulphuric acid 
 he denominates sutyhydric acid, and its salts sulphydrates ; so of the rest, 
 
332 Salts. — Molybdo-sulphurets. 
 
 a deliquescent, yellow, crystalline salt is deposited, sparingly 
 soluble in alcohol. 
 
 The Carbo-sidphuret of Sodium (NaS + CS 2 . 77.72) and 
 the Carbo-sulphurct of Lithium (LS + CS 2 . 64.42) are simi- 
 lar to the preceding. 
 
 Carbo-sulphurtt of the Hydrosulphate of Ammonia (H 3 N. 
 HS-j-CS 2 . 72.57) is a very volatile salt, and must be kept 
 in bottles tightly corked. Exposed to the air, it absorbs 
 water and becomes red.* 
 
 4. Arsenio-sulphurets. 
 
 Each of the three sulphurets of arsenic is capable of acting 
 as a sulphur acid ; giving rise to three distinct families of 
 sulphur salts, arsmiG-protosulphurets, arsenio-sesquisulphurcts, 
 and arscnio-persulphurets. The persulphuret of arsenic is 
 the most powerful of these acids. The arsenio-persulphurets 
 of the alkalies and alkaline earths, are very soluble in water, 
 have a lemon-yellow color when anhydrous, but colorless 
 when combined with water of crystallization, or in solution; 
 but those of the second class of metals are generally in- 
 soluble. 
 
 5. MOLYBDO-SULPHURETS. 
 
 The acid in this family is the tersulphuret of molybdenum. 
 The most remarkable of these salts is 
 
 Molybdo-sulphuret of Potassium, (KS -f- MoS 3 . 151.25,) 
 which is formed by decomposing a solution of molybdate of 
 potassa with hydrosulphuric acid ; on evaporation, beautiful 
 crystals with four and eight sides are deposited. Berzelius de- 
 scribes this compound as the most beautiful which chemistry 
 can produce. The crystals, by transmitted light, are ruby- 
 red, and their surfaces, while moist, and also the solution 
 which yields them, shine like the wings of certain insects, 
 with a metallic lustre, of a rich green tint. 
 
 * The carbo-svlphuret of barium, (BaS -f- CS 2 . 123.12.) the carbo-sul- 
 phurct of strontium, (SrS-f-CS 2 . 93.22,) and the carbo-suJphurct of calcium, 
 (CaS -f- CS 2 . 74 92,) may be obtained by acting on bisulphuret of car- 
 bon with a solution of the protosulphurets of these metals. The solu- 
 tions are orange or brown, and the crystals, when dry, are of a citron- 
 yellow color. Carbo-sulphuret of magnesium. MgS + CS 2 . 67.12. 
 
Haloid Salts. 333 
 
 6. Antimonio-sulphureits. 
 
 The acid of this family is the sesquisulphuret of antimony, 
 and the only salt examined is the antimonio-sulphuret of po- 
 tassium, which may be formed by mixing 2 parts of car- 
 bonate of potassa, 4 of sesquisulphuret of antimony, and 1 of 
 sulphur, and fusing the mixture. 
 
 7. TlINGSTO-SULPHURETS. 
 
 The best known of this family is potassium. When a 
 solution of tungstate of potassa is decomposed by hydrosul- 
 phuric acid, and the solution evaporates, anhydrous, quadri- 
 lateral, flat prisms are deposited, of a pale-red color, which is 
 the tungstosulphuret of potassium. This salt unites with 
 tungstate of potassa as a double salt. 
 
 Section 5. 
 
 ORDER IV. — HALOID SALTS. 
 
 This order includes substances composed, like the pre- 
 ceding salts, of bi-elementary compounds, one or both of 
 which are analogous to sea-salt in composition. The haloid 
 acids belong generally to the electro-negative, and the haloid 
 bases to the electro-positive metals. 
 
 The following are the principal groups or families : — 
 
 1. Hydrar go-chlorides. The haloid acid is the bichloride 
 of mercury ; they are obtained by mixing their ingredients in 
 the ratio of combination, and setting aside the solution to 
 crystallize. 
 
 2. Auro-chlorides. The acid in this family is the ter- 
 chloride of gold ; they are prepared like the preceding ; most 
 of them have an orange, or a yellow, color. 
 
 3. Platino-chlorides. The haloid acids in this family are 
 the protochloride and bichloride of platinum. 
 
 4. Palladio-cMorides are salts in which the chlorides of 
 palladium act as haloid acids, combining with many of the 
 metallic chlorides. 
 
334 Salts. — Haloid Salts. 
 
 5. Rhodio-chlorides are formed by the action of sesqui- 
 chloride of rhodium on the chlorides of potassium and so* 
 dium. 
 
 6. The Chlorides of Iridium and Osmium are the haloid 
 acids of the iridio-chlorides and the osmio-chlorides. 
 
 7. Oxy -chlorides. This family embraces a large number 
 of compounds, in which a metallic oxide is united with a 
 chloride, generally of the same metal, but often of other 
 metals. These salts are commonly termed submuriates, on 
 the supposition that they consist of hydrochloric acid, com- 
 bined with two or more equivalents of an oxide* 
 
 Oxy- chlorides of Iron. When the crystallized protochloride of iron is 
 strongly heated in close vessels, a deep green oxy-chloride, in scaly 
 crystals, is formed. 
 
 Oxy-chloride of Copper constitutes the paint called Brunsicick green, 
 and is prepared by exposing metallic copper to hydrochloric acid. This 
 is the compound formed by the action of sea- water on the copper of 
 vessels. 
 
 Oxy-chloride of Lead may be formed by adding pure ammonia to a 
 hot solution of chloride of lead; another oxy-chloride — the pigment 
 called patent yellow — is prepared by the action of moist sea-salt on 
 litharge. 
 
 8. Chlorides with Ammonia. The perchlorides of tin and 
 some other metals absorb ammonia at common temperatures, 
 and most of the other chlorides absorb it when gently heated ; 
 but most of these compounds lose their ammonia, on exposure 
 to the air, and nearly all, by heat. 
 
 9. Chlorides with Phosphuretcd Hydrogen. These are 
 very similar to those with ammonia, and are not of sufficient 
 importance to be inserted in this place. 
 
 10. Double Iodides. These compounds have not yet been 
 closely studied, but the iodides probably form with each other 
 an extensive family of salts. 
 
 The most important are the 
 
 Platino-biniodide of Potassium, prepared by digesting an excess of 
 biniodide of platinum in a concentrated solution of iodide of potassium, 
 and the Platino-biniodide of Hydrogen, which is prepared by acting on 
 biniodide of platinum with a cold dilute solution of hydriodic acid. 
 
 11. Oxy-iodides. The best known of this family are 
 those formed by the oxide and iodide of lead. 
 
 The double bromides have not yet been studied. 
 
Organic Chemisiry. 335 
 
 12. Double Fluorides. There are several extensive fami- 
 lies of these salts, in which the fluorides of boron, silicon, 
 
 I titanium, and other electro-negative metals, are the acids, 
 1 and the fluorides of the electro-positive metals are the bases. 
 
 13. Double Cyanides and Ferro-cyanides. The double 
 i cyanides constitute a large and important family of salts, 
 
 I of which the principal are the ferro-cyanides, ferro-sesqui- 
 J cyanides, zinco-cyanides, cobalto-cyanides, nicco-cyanides, 
 ! and cupro-cyanides, in which the proto-cyanide of iron, 
 j sesqui-cyanide of iron, cyanide of zinc, cobalt, nickel, and 
 
 copper, are the electro-negative cyanides. (See Turner's 
 
 Elements, p. 487.) 
 
 CHAPTER IV. 
 
 ORGANIC CHEMISTRY. 
 
 Organic chemistry treats of those substances which are of 
 animal or vegetable origin, and which are therefore called 
 organic. Organic bodies differ from inorganic compounds in 
 several particulars. 
 
 1. Of the fifty-seven or fifty-eight simple substances, only 
 four, carbon, hydrogen, oxygen, and nitrogen, enter in any con- 
 siderable quantities into the composition of organic compounds. 
 In addition to these four elements, which are called organic, 
 a few other constituents are found, as iron, silicon, potassium, 
 sulphur, phosphorus, &c, but these substances exist in small 
 quantities. 
 
 2. Organic compounds differ from inorganic in the greater 
 number of atoms of which they are composed. Thus olive 
 oil contains 270 simple atoms, spermacetti 458, and albu- 
 men 883, hence their composition is much more complex than 
 inorganic compound.-. 
 
 3. A third characteristic of organic substances is the fa- 
 cility with which they may be decomposed, and especially in 
 
336 Organic Chemistry. 
 
 being, without exception, decomposed by a red heat, and often 
 by a lower temperature ; if heated in the open air, they are 
 converted chiefly into water and carbonic acid. 
 
 4. With a few exceptions, organic bodies cannot be formed 
 artificially, by the direct union of their elements. They are 
 formed under the influence of vitality. There are, however, 
 three classes into which they may be divided in respect to 
 their origin. 
 
 The first class includes those bodies which are the elements 
 of an organized and living being. They are formed under 
 the influence of life, and, while connected with the animal or 
 plant, do not obey the ordinary laws of affinity ; such are 
 the animal and vegetable tissues, the blood, &c. They are 
 organized, rather than organic bodies, and yield to affinity 
 only when life is extinct. Their composition cannot be ef- 
 fected by any chemical reactions, or explained by any chemi- 
 cal formula. They are the products of life. 
 
 The second class includes such substances as organized 
 bodies secrete, or as are produced from the elements which 
 nourish organized bodies ; such are sugar, starch, albumen, 
 oils, resins, gums, &c. 
 
 The third class includes those bodies which are formed 
 from the decomposition of the two preceding classes, and are 
 very numerous. 
 
 Many of the second and third classes of compounds may 
 be formed artificially by ordinary affinity, or by a force 
 called catalitic. The third class resemble, in many respects, 
 inorganic compounds, but are distinguished from them still 
 by their greater complexity of composition. 
 
 Catalitic force. Organic compounds manifest a strong ten- 
 dency to decomposition, when exposed to the air or to the in- 
 fluence of chemical agents. The more complex bodies are 
 thereby easily reduced to those more simple. Thus, when 
 yeast is added to sugar, the latter is converted into carbonic 
 acid and alcohol. The yeast acts by its presence, and is 
 called the catalitic agent. This agent, must be in a state of 
 
Analysis of Organic Compounds. 337 
 
 decomposition in order to induce a similar state in the other 
 body. The law of catalysis is, that molecules in motion im- 
 part their motion to the molecules of other bodies with which 
 they are brought in contact. 
 
 Analysis of Organic Compounds. 
 
 The elementary analysis of an organic compound is effected 
 by burning the substance with oxide of copper. This oxide 
 readily yields its oxygen to the carbon and hydrogen of the 
 substance, forming carbonic acid with the former, and water 
 with the latter. These new compounds are collected, and 
 from their weight may be known the weight of the carbon 
 md of the hydrogen. 
 
 The loss of oxygen in the oxide of copper is also noted, 
 and compared with the quantity in the carbonic acid and 
 water. The excess of the latter over the former, is the 
 amount derived from the substance under examination ; and, 
 if there be no such excess, it is inferred that there was none 
 in the substance. 
 
 Although this process is very simple, it requires a special 
 apparatus, and many specific directions to insure accurate 
 results. The following is a general description of the appa- 
 ratus. For more minute details the student is referred to 
 larger works, and such as treat of analytical processes, such 
 as those of Liebig, Rose and others. 
 
 The apparatus consists of a glass tube, free from lead, 14 
 inches in length, and half an inch in diameter, drawn to a 
 
 Fig. 108. 
 
 15 
 
338 
 
 Organic Chemistry. 
 
 point, and sealed at one (extremity, a, Fig. 108, and open 
 at the other. This tube is then filled three-fourths full 
 of pure oxide of copper that has just been ignited m a 
 crucible, intimately mixed with a few grains of the body to 
 be examined, (suppose it to be sugar,) in a porcelain mortar, 
 a little pure oxide being first put into the sealed end. The 
 tube is then filled within one inch of its open end with pure 
 oxide. By this process the mixture will absorb some mois- 
 ture from the air, which must be expelled. To abstract this 
 moisture, a small tube filled with dry chloride of calcium is 
 inserted through a cork in the open extremity of the com- 
 bustion tube c, while the other end of the small tube is con- 
 nected with an exhausting syringe b. The tube containing 
 the mixture is then placed in sand heated to 250°, and the 
 air exhausted, and allowed to pass in several times, when all 
 the moisture will be taken out of the mixture and absorbed 
 by the chloride.. The tube is then placed in a furnace made 
 of sheet-iron, (B, Fig. 109,) and the open extremity of it con- 
 nected with a tube A, containing fragments of dry chloride of 
 calcium, for the purpose of condensing the water generated 
 by the combustion. Connected with A, by a piece of India- 
 rubber tube, is a glass instrument, D, consisting of 5 bulbs, 
 connected together as in Fig. 109, the 3 lower a nearly filled 
 with caustic potassa in solution, the weight of which must be 
 accurately determined. To ascertain whether all the joints 
 are tight, a few bubbles of air are drawn through the open 
 end of the potash tube, and if the liquid remains raised a lit- 
 tle above the level on the other side, everything is prepared 
 for the next stage of the process, which is to heat the tube to 
 redness, with ignited charcoal, h, first near to A, and then ex- 
 tend it slowly towards the other extremity by means of a 
 screen which is made to slide along, as in Fig. After the 
 
 Fig. 109, 
 
Analysis of Organic Compounds. 339 
 
 combustion is completed, the combustion tube is broken off, 
 and the products are weighed. The water will be in the 
 tube A, and is determined by the increase of the weight of 
 the chloride ; by this the quantity of hydrogen in the sub- 
 stance is found. The carbon is in the form of carbonic acid, 
 united to the potassa a, and the amount of it is easily deter- 
 mined. By this process the quantity of hydrogen and car- 
 bon are very accurately ascertained. 
 
 Some organic substances, as volatile liquids, are prepa- 
 red for combustion in a different 
 manner. A bulb, b, with a nar~ Fi s* 110J 
 
 row neck, Fig. 110, is carefully 
 weighed, then filled with the li- 
 quid and hermetically sealed, and 
 weighed again, to determine the 
 quantity of liquid. The end, a, 
 is then broken off and inserted in 
 the combustion tube, which is filled 
 with oxide of copper, and arranged 
 as in Fig. 109. By heating the 
 bulb, the liquid is volatilized, and 
 passing through the oxide of cop- 
 per, is decomposed, The products are collected, and the 
 composition determined, in the same manner as in the pre- 
 ceding analysis. 
 
 In the analysis of bodies, such as fats, containing much 
 hydrogen, chromate of lead is used instead of oxide of cop- 
 per. To ascertain the quantity of nitrogen present, the sub- 
 stance is heated with excess of carbonate of potassa, when all 
 the nitrogen will be given off in the form of ammonia, and 
 the amount thus accurately ascertained. 
 
 To determine the quantity of chlorine, the vapor is passed 
 over quicklime heated to redness, chloride of calcium is 
 formed, and this is decomposed by nitrate of silver. From 
 the weight of the chloride of silver, the quantity of chlorine 
 is easily deduced. Some other substances are found in 
 organic bodies, in small quantities, such as sulphur and 
 metallic oxides* 
 
340 Organic Chemistry* 
 
 Constitution and Classification of Organic bodies* 
 
 1. Theory of Compound Radicals. In inorganic cher. 
 
 simple elements, as we ha T f seen, are united two and two, 
 
 or in a binary arrangement : thus Jxygen and sulphur unite 
 
 to form SO 3 . ren and potassium unite to form potassa, and 
 
 then sulphuric acid and potassa unite to form sulphate of 
 
 \ssa. (S0 3 -j-rIO) the acid being regarded as negative and 
 the alkali as positive. It has been supposed that this binary 
 arrangement applies to organic compounds, but as these are 
 composed often of several simple elements, it is necessary to 
 regard the compound of two or more elements as possessing 
 the properties of a simple body. Thus cyanogen, composed 
 of NC, performs, in its various combinations, the part of an 
 dement. So when crystallized oxalate of ammonia, repre- 
 sented by the formula NH HO.C.O 2 , is distilled, a white 
 tasteless powder is obtained, which has the composition XH 2 . 
 0*0", or it is oxalate of ammonia deprived of 3 equivalents 
 of water ; it is called oxamide. On heating this in contact 
 with potassa, it takes up 3 atoms of water, and is converted 
 into oxalate of ammonia; benGe it is inferred that there 
 isfcs a compound of 1 equiv. of X. and 2 equiv. of H — XH 3 . 
 This body has never been isolated, but has been supposed to 
 act as a simple element, and has been called amide or ammi- 
 dogen ; symbol. Ad. This body combines with potassium, 
 and forms potassamid: NH*K 3 and also with several other 
 bodies. 
 
 In the same manner, by experiments upon the oil of bitter 
 almonds, it is inferred that benzoic acid (C I4 H s .O a HQ) has a 
 base, which has been called benzoyl, symb. E: having the 
 formula which also performs the part in composi- 
 
 tion of an element, and constitutes the base of a large class 
 c: :■:.-.:; :ur. is. 
 
 Ether also is supposed to have a base, (C 4 H S ) which is 
 capable of combining with C ing rise to sulphuric, 
 
Theory of Substitutions. 341 
 
 chloric, and bromic ethers. All such bodies performing in 
 composition the part of an element, are called compound radi- 
 cals. Such radicals are supposed to exist in a large number of 
 compounds, and have been made the basis of the classification 
 of those bodies. They are, however, with a few exceptions, 
 as cyanogen, mellone, and kakodyle, purely hypothetical bodies, 
 that is, have never been isolated from their compounds. 
 These hypothetical compounds are not supposed to exist in 
 all organic bodies, and it is as yet impossible to make them 
 the basis of a general classification. With regard to those 
 bodies which are supposed to contain these compound radi- 
 cals, some chemists, as M. Gerhardt, have explained their 
 formation, and the changes which they pass through, on a 
 theory which entirely dispenses with them. They can be 
 of no use, unless it be to give us a clearer idea of the changes 
 which take place in organic compounds ; and if those 
 changes are equally well explained on any theory which is 
 capable of demonstration., it would seem to be introducing 
 numerous hypotheses which can be of no possible service, in. 
 stead of a simple statement of facts. But, as it is desirable 
 to present the subject of chemistry in its present state, we 
 have concluded to describe those bodies which are supposed 
 to contain such compound radicals, in one group, or as one 
 class. Should M. Gerhardt's theory be received by chem- 
 ists, it will not only render the doctrine of compound radicals 
 unnecessary, but will probably require some changes in 
 nomenclature, changes which he has made in his work. (See 
 Gerhardt's Precis de Chimie Organique.) 
 
 2. Theory of Substitutions. When oxygen, chlorine, bro- 
 mine, and iodine, unite with various compounds, the latter 
 give out hydrogen, and the process is termed dehydrogeniz- 
 ing. Thus, when dry chlorine gas is passed into pure oil of 
 bitter almonds, (C u H0 2 +H,) it loses its atom of hydrogen, 
 and an atom of chlorine is substituted, and the compound 
 consists of C M H 5 2 +C1, a chloride of benzoyl. This and 
 
342 • Organic Chemistry, 
 
 other analogous facts have been generalized by Dumas, and 
 the following general conclusions made : — 
 
 (1.) That when a body is subjected to the dehydrogenizing 
 action of O, CI, Br, and I, it gains one of the latter for each 
 atom it loses of hydrogen. 
 
 (2.) But if the body contain water, it loses its hydrogen 
 without any substitution. If, after this, hydrogen is ex- 
 tracted, the substitution proceeds as before. 
 
 (3.) The fundamental radical and its derivatives will be 
 neutral or alkaline, whatever be the portion of oxygen, hy- 
 drogen, &c, entering into it. But when the oxygen, bro- 
 mine, &c, enter into combination with this radical they ren- 
 der it acid. 
 
 3. Pyracids. — Theory. When several of the vegetable 
 acids are distilled, they undergo decomposition, and new 
 acids are generated, which are called by the term pyracids. 
 Tartaric acid becomes pyrotartaric acid ; gallic, pyrogallic ; 
 and so of several others. The difference in composition 
 seems to be that a quantity of water is expelled by the heat. 
 
 Section I. Amylaceous and Saccharine Substances. 
 
 Starch, C 12 H 10 O 10 . Starch exists abundantly in the vege- 
 table kingdom. It is a principal constituent of most kinds of 
 grain, potatoes, and other farinaceous substances. It is ob- 
 tained from potatoes by scraping them and washing in cold 
 water, when the gluten, which is the other principal constitu- 
 ent, remains in the hand, and the starch is mechanically dif- 
 fused through the water. The water is then allowed to 
 stand, and the starch subsides, while the saccharine and mu- 
 cilaginous matters remain in solution. When made from 
 the dough of wheat flour,, and the water containing the soluble 
 and insoluble parts of the flour is allowed to ferment, acetic 
 acid is formed, which dissolves the gluten and facilitates the 
 separation of the starch. Starch exists in the vegetable or- 
 gans in small granules, surrounded by sacks, which are 
 
Starch. — Diastase. 343 
 
 broken by the process of grating or grinding, and the starch 
 is thus separated. 
 
 Properties. A white powder, soluble in hot water, forming 
 a semitransparent jelly, but nearly insoluble in cold water. 
 Its uses are well known. 
 
 Starch is easily converted into sugar. In the germination 
 of seeds, and in the malting of barley and other grains, this 
 change takes place. If starch is boiled for a considerable 
 time in water which contains one-twelfth of its weight of sul- 
 phuric acid, it is converted into a kind of sugar, like that ob- 
 tained from grapes. Arrow-root, prepared from the root of a 
 plant, is a very pure starch. Sago, prepared from the pith 
 of an East India palm tree, and tapioca and cassava, also 
 from the root of a plant, are essentially the same. Inulin is 
 a variety of starch found in the roots of the inula helenium, 
 dahlia, and in certain lichens. It is a fine white tasteless pow- 
 der, having the formula C 24 H 21 21 , (Parnell.) Lichen starch 
 exists in several species of lichens. The cetraria Islandica 
 (Iceland moss) yields a very pure variety of starch, which is 
 used to form blanc mange. It forms a white opaque jelly. 
 Starch forms compounds with chlorine, bromine, and iodine. 
 
 Gelatinous starch, or amidin, is formed by rubbing the 
 grains of starch with sand in a mortar. The coats of the 
 starch granules are broken, and form a grayish white pow- 
 der. By adding cold water, the mass expands into a trans- 
 parent jelly. Mucilaginous starch, or dextrine, is formed by 
 the action of acids, alkalies, diastase, and heat upon gelatinous 
 starch. It is a white glutinous substance, resembling gum. 
 
 Diastase is formed by the malting of grain. It is found in 
 grain, the seeds of plants, and in the tubers of potatoes after 
 germination. It is prepared by adding water to freshly 
 malted barley and subjecting it to pressure. A viscid liquid 
 is obtained, which, by heat and the action of alcohol, yields 
 diastase. It is a white substance, remarkable for its property 
 of converting starch into sugar. It is this substance which, 
 
344 Organic Chemistry. 
 
 in the fermentation of grain, converts the starch into sugar, 
 and then the yeast which is added changes the sugar into 
 alcohol and carbonic acid. 
 
 Gluten. Gluten exists with starch in most kinds of grain. 
 It is obtained from wiieat flour by washing out the starch and 
 soluble matter, and boiling the remainder in alcohol. On 
 adding water and distilling off the spirit, gluten is deposited. 
 
 Properties. Gluten is without taste, very tenacious, elas- 
 tic, and insoluble in water. It ferments when kept warm and 
 moist. The tenacity of common paste is owing to the gluten 
 which it contains. 
 
 The rising of bread is caused by the fermentation of glu- 
 ten, the tenacity of which retains the bubbles of carbonic acid 
 gas, which are generated in the process. Gluten consists 
 mostly of vegetable albumen and Jibrine, which may be ob- 
 tained by the action of alcohol on the gluten of wheat and of 
 other grains. 
 
 Gum. Under this name are included all those vegetable 
 principles which form, when dissolved in water, an adhesive 
 viscid liquid, called mucilage, and which yield an acid, 
 called mucic acid, when boiled with 4 times their weight of 
 nitric acid. Gum is insoluble in ether and alcohol, and is 
 precipitated by them from its aqueous solution, as an opaque 
 white substance ; but in acids and alkalies, it is more soluble 
 than in pure water. 
 
 Gum Arabic is the most common variety of gum. It is 
 obtained from several species of acacia or mimosa, in Africa 
 and Arabia. It has the composition C 12 H"0". 
 
 Gum Senegal differs in no important respect from gum Ara- 
 bic. The gum of the peach, plum and cherry-tree, although 
 identical in composition with gum arabic, differs in being in- 
 soluble in cold water ; after being boiled, however, it assumes 
 the characteristics of that gum. 
 
 Gum Tragacanth differs from gum Arabic in containing a 
 large portion of bassoric, starch, and water. It is tougher 
 
Lignin. — Xyloidine. 345 
 
 than common gum. Gum tragacanth is therefore a very- 
 useful ingredient in paste. The jelly of fruits is distinct from 
 gum in some properties, but is nearly allied in others. These 
 substances have the composition C 12 !! 1 ^ 11 . 
 
 Lignin. Lignin, or woody fibre, constitutes the fibrous 
 structure of plants, and is the most abundant principle in 
 them. The common kinds of wood contain about 90 per 
 cent, of lignin. Lignin is insoluble in alcohol and water; 
 with caustic alkalies, and acids, it is much changed. With 
 sulphuric acid it is changed into gum, and on boiling, is fur- 
 ther changed into a sugar, like sugar of grapes. Straw, 
 bark, and linen, may be converted in the same way into 
 sugar. The lignin of lint, linen cloth, hemp, and straw, has 
 the formula C 36 H 24 20 (Pay en.) Lignin combines with the 
 sulphate of copper, acetate of iron, chloride of mercury, and 
 is preserved thereby from the dry rot. The wood of trees, 
 as soon as they are cut down, will imbibe these salts in solu- 
 tion, become impregnated with them, and rendered almost 
 impenetrable to the ordinary agents of decay. 
 
 Xyloidine, Gun-cotton (C 12 H 8 N 2 1S ) is formed by the action 
 of nitric acid on starch or woody fibre. To prepare gun- 
 cotton, common cotton is carded to separate the fibres, and 
 then immersed in a mixture of equal quantities of strong 
 nitric and sulphuric acids for about 5 minutes. It is re- 
 moved from the acid, washed in a large quantity of pure 
 water, and then dried slowly under 212° F. It is then pre- 
 pared for use. 
 
 Properties. This substance, which has of late become so 
 celebrated, does not differ in nppearance from cotton, but 
 possesses greater explosive qualities than gunpowder, ignites 
 at a lower temperature, 380°, and is therefore more danger- 
 ous to use, especially as it often explodes by sudden compres- 
 sion, as when struck with a hammer. When ignited, it is 
 wholly converted into gases and vapors. The products are 
 water or steam, carbonic acid and carbonic oxide gases. 
 15* 
 
346 Organic Chemistry. 
 
 It has been used with good results in blasting rocks, and 
 for the same purposes as gunpowder. Owing to the compara- 
 tive harmlessness of the products of its combination, its use 
 in deep mines would be preferable to that of gunpowder. 
 
 Action of Oxygen on Woody Fibre, or Lignin. When any- 
 organic body is kept from the air, or from moisture, it will 
 rarely decay. If wood is exposed to dry oxygen alone, it is 
 acted upon but slightly, if at all, but when exposed to air 
 and moisture, it suffers successive changes, which have been 
 called by Liebig eremacausis, or decay. The oxygen of the 
 air combines with the carbon of the wood to form carbonic 
 acid, while the oxygen and hydrogen of the woody fibre unite 
 and form water ; but as two equivalents of water are formed 
 for one of carbonic acid, the residue, after each change, con- 
 tains a greater quantity of carbon than the wood itself, while 
 its hydrogen and oxygen remain in the same relative propor- 
 tions. The process is a slow combustion. The final result, 
 however, is not carbon, but a pulverulent brown substance, 
 described as humus, humic acid, geine, ulmine, ulmic acid. 
 But when vegetable matter is suffered to decay under wa- 
 ter, or away from the oxygen of the air, the products are 
 carbonic acid, from the elements of the wood, carburet of 
 hydrogen, tar and other matters rich in hydrogen. The final 
 result in this instance is peat, lignite, and coal ; and it is in 
 this way that we may account for the formation of the vast 
 beds of coal which are laid up in the rocky strata of the 
 earth. This process is sometimes called putrefactive fer- 
 mentation. When wood is subjected to destructive distilla- 
 tion, a variety of compounds are formed, the more important 
 of which are described in other parts of the work. 
 
 Sugar. C 18 H"O n . Sugar is found in most ripe fruits, but 
 more abundantly in the sap of the maple-tree, in the sugar- 
 beet, and in the sugar-cane ; from the latter it is obtained by 
 evaporating the juice at a moderate ebullition, until the syrup 
 is sufficiently thick for the sugar to crystallize on cooling. 
 
Cane Sugar. — Grape Sugar. 347 
 
 During this operation, lime-water is added to neutralize the 
 acid present, and to remove impurities which rise with the 
 ! lime in a scum to the surface ; it is next drawn off into shal- 
 ; low coolers, in which it becomes a soft solid. Lastly, it is 
 1 put into barrels with holes in the bottom, through which the 
 I molasses gradually runs out, leaving raw or brown sugar. 
 \ Raw sugar is purified by boiling it with the white of eggs or 
 I bullock's blood and lime-water ; it is then received into coni- 
 I cal vessels, and in cooling assumes the form of loaf sugar. 
 
 When two pieces of loaf sugar are rubbed together in the 
 ! dark, phosphorescence is observed ; it is obtained in large 
 crystals by fixing threads in a sirup, which evaporates grad- 
 ually in a warm room : in this state it is called rock-candy. 
 Sugar does not deliquesce when exposed to the air, except 
 when impure, as raw sugar. It is soluble in an equal weight 
 of cold water, and is much more soluble in warm water; it 
 is soluble in four times its weight of boiling alcohol, from 
 which solution fine crystals are obtained. The vegetable 
 acids diminish the tendency of sugar to crystallize, as in 
 molasses. 
 
 By the action of sulphuric acid, starch and common wood 
 may be converted into sugar. By the action of heat on cane- 
 sugar, a brown substance is produced called caramel, C 12 H 9 
 O 9 ; it is used for coloring spirits. Sugar combines with 
 baryta, lime, oxide of lead, &c, forming unimportant com- 
 pounds. 
 
 Grape Sugar (C i2 H 14 14 ) exists in the juice of fruits, in 
 honey, and in diabetic urine. It may be obtained from the 
 juice of the sweet grape by adding chalk, clarifying with the 
 white of an egg, evaporating, and setting aside to crystallize. 
 But the process by which it is manufactured as an article of 
 commerce, is to boil starch with from tV to ^ of its weight of 
 sulphuric acid, diluted with 4 parts of water, for 36 hours, 
 adding chalk to separate the acid, and crystallizing. 
 
 Properties. Grape sugar, as thus obtained, is white and 
 
348 Organic Chemistry. 
 
 granular, rather less sweet than cane sugar, and less soluble 
 in cold water, but more soluble in alcohol, from which it may 
 be obtained in transparent cubic crystals. 
 
 By the action of acids upon grape sugar, as the sulphuric, 
 a new compound is formed, the sulpho -saccharic acid. The 
 same acid decomposes cane sugar. But alkalies, such as lime 
 and baryta, scarcely affect cane sugar, while they decompose 
 grape sugar into formic, glucic, and melassic acids. 
 
 Saccharic Acid (C 12 H 10 O 16 ) is formed by the action of 
 dilute nitric acid on cane or grape sugar. It is soluble and 
 sharply acid. It is remarkable for the variety of its com- 
 pounds, as the saccharate of potassa, ammonia, lead, zinc, 
 and silver. The latter salt, when gently heated under wa- 
 ter, is decomposed, and a metallic coat of silver is formed 
 upon the sides of the vessel, resembling a mirror. 
 
 Sugar of Milk, Lactine (C" 4 H B4 24 , or C 24 H 19 19 +5HO) 
 exists only in the whey of milk, from which it may be obtained 
 by evaporation, purifying the product with animal charcoal, 
 and recrystallizing. It appears in the form of semi-transpa- 
 rent quadrangular prisms, soluble in 6 parts of cold, and in 
 2£ parts of hot water. This solution has a much sweeter 
 taste than the crystals themselves. It is insoluble in alco- 
 hol and ether. By the action of mineral acids it is converted 
 into grape sugar. With the oxide of lead it forms two com- 
 pounds, C"H 19 19 -r-5PbO, and C 24 H I9 O i9 +10PbO. 
 
 Mucic Acid (C :2 H p 14 . 2HO) is formed by the action of 4 
 parts strong nitric acid, 1 of water heated with 1 part of sugar 
 of milk. A part of the lactine is converted into oxalic acid, 
 and the mucic acid is deposited, on cooling, as a white crystal- 
 line powder. Taste feebly acid, soluble in 6 parts of boiling 
 water, and insoluble in alcohol. It is bibasic, combining with 
 alkalies and metallic oxides, and forming two classes of salts. 
 By the dry distillation of this acid, jpyromucic acid is formed, 
 C l0 H 3 O 5 HO, 6 equiv. of water and 2 equiv. of carbonic acid 
 
Fermentation. 349 
 
 being separated, mucic ether (2C 4 H 6 0+C 12 H 8 0) crystallizes 
 in quadrangular colorless prisms. 
 
 Honey consists of two kinds of sugar, one of which, when 
 separated, crystallizes, and the other is uncrystallizable. Be- 
 sides sugar, it contains gum, and probably an acid ; when 
 diluted with water, honey undergoes the vinous fermentation. 
 Common sugar requires the addition of yeast for this change. 
 
 Manna is the concrete juice of several species of ash, and 
 owes its sweetness, not to sugar, but to a distinct principle 
 called mannite, having the formula C 6 H 7 0°. 
 
 Liquorice owes its sweetness to a saccharine principle 
 which is quite distinct from sugar. 
 
 Fermentation of Sugar, Starch, <ftc. 
 
 Many vegetable substances, when exposed to warmth and 
 moisture, undergo spontaneous changes, and the process is 
 called fermentation. It is most commonly observed in sub- 
 stances containing gluten, starch, gum, or sugar. In diffe- 
 rent stages of the process, sugar, alcohol, and acetic acid 
 are formed, and finally, there is a total dissolution of the sub- 
 stance. These stages of the process are called the saccharine, 
 vinous, acetous, and viscous fermentations. 
 
 Saccharine Fermentation. Starch only is subject to this 
 kind of fermentation. The quantity of sugar produced equals 
 in weight half of the starch employed. The ripening of 
 fruits has been regarded as a kind of saccharine fermenta- 
 tion, in which the acid of the green fruit is converted into 
 • sugar ; this change is caused by heat, not by the vitality of 
 the plant. 
 
 Vinous Fermentation. When sugar with water, and yeast 
 or some other ferment, is exposed to a warm temperature, 
 the sugar is converted into carbonic acid gas and alcohol, in 
 nearly equal weights of each. As starch is convertible into 
 sugar by fermentation, if the process be continued under the 
 above conditions, it will be converted into alcohol and car- 
 
850 Organic Chemistry. 
 
 bonic acid. All vegetable bodies contain some substances 
 which act as a ferment, and therefore, by the addition of 
 moisture and regulation of the temperature, various kinds of 
 grain containing starch, and of ripe fruits containing sugar, 
 will undergo the vinous fermentation. Thus cider is formed 
 from apples, and beer from grain. To obtain ardent spirits, 
 the fermented liquor is heated, and the alcohol passes over by 
 distillation. 
 
 In the fermentation of bread, the saccharine matter of the 
 flour is resolved, into alcohol and carbonic acid gas. The 
 latter causes the dough to rise, and the former is entirely ex- 
 pelled by the heat of baking. A company in London was 
 formed for collecting the spirit emitted by the baking of 
 bread. If the fermentation of dough be continued, it under- 
 goes the change next described, and becomes sour. 
 
 Acetous Fermentation. Any liquid which has undergone 
 the vinous fermentation, or pure alcohol with water and 
 yeast, exposed to the air in a warm place, undergoes a 
 change, in which oxygen is taken from the air, and carbonic 
 acid thrown off. In place of alcohol, acetic acid is found in 
 the liquor. Thus cider becomes sour by age, if exposed to 
 the air, and at length is converted into vinegar. In France, 
 wine is converted into vinegar, and in England, an infusion 
 of malt. 
 
 Acetic acid is often formed in the spontaneous decomposi- 
 tion of vegetable substances without sugar. In these cases, 
 the process is quite different from the acetous fermentation, 
 properly so called. 
 
 Viscous Fermentation. This kind of transformation takes 
 place in several bodies containing azotized albuminous sub- 
 stances at certain stages of decomposition. Milk or cheese 
 curd mixed with sugar, when the temperature is raised from 
 95° to 114°, undergo a change which renders the liquid viscid 
 with the formation of mannite and lactic acid. A similar 
 change takes place when the juices of beets and carrots are 
 
Compound Radicals. 351 
 
 subjected to a high temperature and allowed to ferment; also 
 ! many animal substances, in the early stages of decay, give 
 I rise to similar products. 
 
 Theory of Fermentation. The changes above described 
 are explained by the fact, that when any body is in a state 
 | of decomposition, it has a tendency to induce changes in bodies 
 with which it is in contact by the force of catalysis, see p. 300. 
 This principle is extended by Liebig to matters of contagion, 
 miasm, &c. Thus when any body in the atmosphere, or in 
 contact with the living system, is in a state of decomposition, 
 it induces a morbid action in the parts exposed, which, unless 
 resisted by counteracting forces, extends its influence through- 
 out the body ; hence the danger of dissection in anatomical 
 rooms ; a slight cut upon the hand with a knife used upon 
 a subject which has passed to a certain state of putrefactive 
 change, will often excite a morbid action through the whole 
 body, and death is not unfrequently the result. 
 
 Section II. Compound Radicals, or substances supposed to 
 contain Compound Radicals, 
 
 I. Alcohol, C^HXXHO. Alcohol is always the product of 
 fermentation. It does not exist readily formed in any living 
 vegetable. It was discovered in the thirteenth century by 
 the Arabians. 
 
 Process. It is obtained from the fermentation of various 
 grains and acidulous fruits by the process of distillation. As 
 thus obtained, it is about one-half water, constituting various 
 kinds of ardent spirits, from which pure alcohol is obtained 
 by a second distillation, and the addition of dry carbonate of 
 potassa to remove any remaining water. (See page 59.) 
 
 Properties. Pure alcohol has a sp. gr. of .79, boils at 
 173° F., is highly combustible, burning with a pale blue but 
 hot flame. No smoke is produced in its combustion, and 
 hence it is of great utility in the laboratory, using it instead 
 of oil to heat various kinds of apparatus. Although exposed 
 to a temperature of — "176°, pure alcohol has not been frozen. 
 
352 Organic Chemistry. 
 
 Alcohol combines with water in every proportion. With an 
 equal quantity of water, it constitutes spirit of the first proof ) 
 sp. gr. about .92. The density will vary with the quantity 
 of water. Its solvent properties are nearly equal to those of 
 water, for which it has a strong affinity. 
 
 Uses. As a solvent, alcohol is highly useful. Many vege- 
 table principles not soluble in water are freely so in alcohol, as 
 camphor, and many of the resins. Both mineral and vegeta- 
 ble alkalies are soluble, but the other metallic oxides are 
 insoluble. Proof spirit is also useful in cabinets of natural 
 history, for the preservation of specimens of fishes, reptiles, 
 or any other animals. Its uses in the arts are numerous and 
 well known. 
 
 Relation to Animals. Alcohol acts upon the animal system 
 as a poison. "When taken into the stomach, it has the prop- 
 erty of passing into the circulation undigested. It irritates 
 all the organs with which it comes in contact, and produces 
 the most serious effects both upon the body and the mind. 
 The stronger wines contain from 13 to 25 per cent., and the 
 weaker from 12 to 17 per cent, of alcohol. Beers, and all 
 fermented liquors, contain more or less of alcohol. The in- 
 toxicating effect of wines is not so great as that of ardent 
 spirits, which may be due to the chemical combination of al- 
 cohol in them with mucilaginous and saccharine matters. 
 And yet most wines are more injurious to the system than 
 ardent spirits, because of the acetate of lead and other poison- 
 ous matters which are often added in their preparation. 
 
 Alcohol is supposed to contain a radical called cihy 7 e, hav- 
 ing the formula C 4 H 5 , and symbol E. On this theory it is 
 called hydrated oxide of cthyle, EO-f-HO. The several com- 
 pounds in which this radical is supposed to exist are called 
 the ethyle series of compounds . 
 
 Ether, Sulphuric Ether, Oxide of Ethyle, OH 5 0. 
 
 Process. Ether may be formed from alcohol bv several 
 processes. The easiest process, and the one always em- 
 
Ethers. 353 
 
 ployed in the manufacture of this substance, is to boil in a 
 glass flask about 5 parts of alcohol to 8 of sulphuric acid, al- 
 .cohol being gradually added, so as to preserve the liquid at 
 the same level. The alcohol is decomposed into ether and 
 water, which distil over through a tube, and are condensed 
 in a receiver surrounded by ice-cold water. The ether floats 
 on the top of the water, and is purified by a second distillation. 
 
 Properties. Ether is a volatile transparent liquid sp. gr. 
 .725, as commonly sold, .74, boils at 96°, at the common pres- 
 sure; invacuo at — 40° F., and evaporates rapidly at the ordin- 
 ary temperature, producing a very intense cold. Its vapor 
 is highly inflammable, and explosive when mixed with oxygen 
 gas. When the vapor of ether is inhaled for a little time, it 
 produces exhilarating effects, similar to the exhilarating gas. 
 It possesses the property of rendering the system insensible 
 to pain, hence it has been used much of late when surgical 
 or dental operations are to be performed. 
 
 Uses. Ether is sparingly soluble in water. It is used in 
 medicine as a stimulant, and also applied externally to reduce 
 the temperature in cases of inflammation. Ether combines 
 with several acids, forming a series of salts. 
 
 Hydrochloric Ether. Chloride of Ethyle (C 4 H 5 C1) is formed 
 by the action of hydrochloric acid on alcohol. It is a color- 
 less, highly volatile liquid, sp. gr. .874, boils at 52° F., neu- 
 tral to test paper, and soluble in 24 parts of water. 
 
 Hydrobromic Ether. Bromide of Ethyle (C 4 H 5 Br) is 
 formed by mixing one part of bromine, four of alcohol, and 
 one-eighth part of phosphorus, and distilling. A volatile 
 transparent liquid comes over, rather denser than water, 
 
 Hydriodic Ether. Iodide of Ethyle (C 4 H 5 I) is obtained by 
 distilling alcohol with hydriodic acid. It is a colorless liquid. 
 
 Sulphurei of Ethyle (C 4 H 5 S) is formed by passing the va- 
 por of hydrochloric ether through the proto-sulphuret of 
 potassium. It is a colorless liquid, disagreeable odor, boiling 
 at 163°.4 F. 
 
 There is also a Usulphuret (C*H5S ? .) 
 
354 Organic Chemistry. 
 
 Theory. It will be perceived that all these compounds are formed by 
 substituting an equiv. of CI. Br. &c. for O.HO in the alcohol, although 
 there may be more complex changes in some of these processes than the^ 
 simple substitution of one substance for the other. 
 
 Mercaptan (C 4 H b S + HS) was discovered by Zeise, and 
 may be formed by passing the vapor of hydrochloric ether 
 through a strong solution of potassa saturated with sulphuret 
 of hydrogen, and condensing the product in a cool receiver. 
 
 Properties. It is a colorless liquid, with a penetrating 
 garlic odor, boils at 100 9 . 
 
 This substance acts with great power on several of the 
 metallic oxides, and forms a singular class of compounds — 
 the mercaptides. 
 
 Nitric Ether. Nitrate of Oxide of Ethyle, C 4 H 5 O.N0 5 . By 
 the action of nitric acid on alcohol, nitrous acid and some 
 other bodies are formed*; but if a small quantity of the ni- 
 trate of urea is added, the nitric acid takes the place of the 
 elements of one equiv, of werter in the alcohol, and forms 
 nitric ether, which distils over as a highly inflammable vapor, 
 and condenses into a colorless liquid. Taste sweetish and 
 agreeable, sp. gr. 1.112, boils at 185° F. 
 
 Hyponitrous Ether. Hyponitrite of Oxide of Ethyle (O 
 H 5 0,NO ? ) is formed by the action of nitric acid on alcohol, 
 but nitrous acid is also formed, which decomposes the ether. 
 By pouring nitric acid on starch, hyponitrous acid is formed. 
 If this acid is then passed through dilute alcohol, the acid 
 takes the place of one equiv. of water, and hyponitrous ether 
 distils over, and is condensed as a pale yellow liquid, having* 
 the fragrant odor of apples, sp, gr. ,93, boils at 62° F. 
 
 The sweet spirits of nitre used in medicine is prepared by 
 distilling alcohol and nitric acid, and passing the vapor of the 
 product through alcohol to absorb it. 
 
 Carbonic Ether. Carhonate of the Oxide of Ethyle (C 4 H 5 
 O.CO 2 ) is prepared by dropping pieces of potassium into j 
 oxalic ether, until the evolution of gas ceases, and distilling 
 a mixture of the brown paste thus formed with water, car- 
 
Ethers, 355 
 
 bonic ether distils over with the water, and is found floating 
 on its surface in the receiver, as a colorless liquid ; odor aro- 
 matic, taste burning, boils at 259° F. 
 
 Boracic Ether (C*H 5 O.B0 8 ) is obtained by the action of 
 chloride of boron on alcohol, as a limpid liquid. Taste burn- 
 ing, boils at 246°. sp. gr. .885. By the same process, a vari- 
 ous solid compound is formed, having the formula C 4 H 5 . 
 2BO\ 
 
 Silicic Ethers. Silicate of the Oxide of Ethyle. Two ethers 
 are formed by the action of the chloride of silicon upon alco- 
 hol, similar in constitution to the preceding compounds. Both 
 are volatile liquids, odorous, with a hot burning taste. 
 
 Oxalic Ether. Oxalate of the Oxide of Ethyle (C 4 H 5 O.C 3 
 O 3 ) may be obtained by distilling a mixture of 4 parts of bin- 
 oxalate of potassa, 5 parts of sulphuric acid, and 4 parts of 
 strong alcohol, nearly to dryness, and collecting the products 
 in a receiver, kept warm to dissipate any common ether formed 
 in the process. The impure ether is separated by water and 
 re-distilled. It is an oily liquid, colorless, having a very 
 pleasant aromatic odor, sp. gr. 1.09, boils at 363° F. De- 
 composed by caustic, alkalies, and converted, by a solution of 
 ammonia, into oxamide and alcohol. 
 
 Acetic Ether (C 4 H 5 O.C 4 H 3 3 ) is prepared by heating a 
 mixture of 3 parts of acetate of potassa, 3 of alcohol, and 2 
 of sulphuric acid. The distilled product is purified by a lit- 
 tle chalk, then with fused chloride of calcium, water being 
 added to separate the alcohol. It is a liquid, limpid, and of a 
 very fragrant odor, sp. gr. .89, boils at 165° F. It is decom, 
 posed by alkalies. 
 
 Formic Ether (C 4 H 6 O.C ? H0 3 ) is formed by distilling 7 
 parts of dry formate of soda, 10 of sulphuric acid, and 6 of 
 alcohol. The ether is separated from the products by mag- 
 nesia and chloride of calcium. It requires several days to 
 complete the process. It is a colorless liquid, with an arc 
 matic odor, sp. gr. .915, boils at 133°. 
 
356 Organic Chemistry. 
 
 (Enanihic Ether (C 4 H 5 O.C 14 H 13 2 ) is obtained in the proJ 
 cess of distilling certain wines, as an oily thin liquid of a pe-: 
 culiarly powerful odor of wine. It appears to be formed by 
 the action of an acid called cenanthic, which is generated in 
 the process of fermentation. It is this ether which gives the 
 peculiar aroma to wines. 
 
 Benzoic Ether (C 4 H 5 0+C 14 H 5 3 ) is an oily liquid, obtained 
 by the distillation of a mixture of 4 parts of alcohol, 2 of ben- 
 zoic, and 1 of hydrochloric acids. 
 
 Theory. In the above compounds one equivalent of the acid is substi- 
 tuted for the elements of an equivalent of water (HO) in the alcohol. 
 
 Sulphovinic Acid (C 4 H 5 0. 2S0 3 + HO) is prepared by 
 mixing equal weights of sulphuric acid and alcohol, heating 
 the mixture to the boiling point, and after being allowed to 
 cool, adding a quantity of water, and sufficient chalk to ren- 
 der it neutral. The whole is then filtered, and the solution 
 evaporated by the heat of a water bath, filtered again, and 
 crystallized. By this process we obtain sulphovinate of 
 lime in colorless transparent crystals. Efflorescent in dry 
 air, and soluble in water. By substituting carb. of baryta 
 for chalk, a similar salt of baryta is formed, and from this 
 sulphovinic acid may be obtained by adding dilute sulphuric 
 acid, to precipitate the baryta, and evaporating in vacuo. It 
 is a syrup-like liquid, sour to the taste, and easily decom- 
 posed. When the temperature is raised above 32G° it yields 
 water and olefient gas. 
 
 Phosphovinic Acid (C 4 H 5 0. P0 5 +2HO) is obtained in a 
 similar manner with the above, using phosphoric acid instead 
 of sulphuric. It resembles the preceding substance in its 
 properties, uniting with bases, and forming a class of salts. 
 
 Heavy Oil of Wine. This substance is obtained as a yel- 
 lowish oily liquid, when 2£ parts of sulphuric acid and 1 
 part of alcohol are distilled. After being purified, it is 
 heavier than water, nearly insoluble in that liquid, solu- 
 ble in alcohol and ether. In contact with boiling water, it is 
 
Products of the Oxidation of Alcohol, dtc. 357 
 
 converted into sulphovinic acid, and an oily liquid, — the 
 
 sweet oil of wine. When this latter substance is left to cool, 
 
 it deposits white tasteless crystals of a substance called ether- 
 
 ine, and there remains a yellowish oily liquid, lighter than 
 
 water, called etherole. These substances are isomeric with 
 
 olefiat gas, C 4 H\ 
 
 Tluory. The above acid compounds are formed in the usual manner 
 by substitution, but differ from the preceding in possessing acid properties. 
 
 II. Products of the Oxidation of Alcohol and Ether. 
 
 When alcohol and ether are acted upon by nitric acid and 
 other oxidizing agents, a series of compounds are formed, 
 which have been supposed to contain a new radical — Acetyle, 
 C 4 H 3 =Ac. 
 
 Aldehyde (C 4 H 3 O.HO) is prepared by several processes, 
 by passing the vapor of ether, or of alcohol, through a red hot 
 tube, and by distilling sulphuric acid 6 parts, 4 of alcohol, 4 
 of water, and 6 of oxide of manganese. 
 
 Properties. It is a colorless liquid, with a suffocating 
 ethereal odor, sp. gr. .79, boils at 7 2°F., soluble and neutral, 
 but becomes acid on exposure to the air, and unites with bases 
 to form salts. When kept for a long time, two new isomeric 
 bodies are formed, eladehyde and metaldehyde. Aldehyde is 
 similar in constitution to alcohol. 
 
 Aldehydic Acid. Acetous Acid (C 4 H 3 2 .HO) is obtained 
 by passing sulphuret of hydrogen through a solution of aide- 
 hydate of silver. It is also formed by the slow combustion 
 of ether. 
 
 Exp. Put a few drops of aldehyde into a little water in a test tube, then 
 add nitrate of silver and ammonia to precipitate the oxide of silver. If. 
 now the tube be heated by a spirit lamp, the silver will be deposited on 
 the surface, giving it the appearance of a mirror. 
 
 Acetic Acid. Vinegar. C 4 H 3 3 .HO. This acid exists 
 in the sap of many plants, and is generated in large quantities 
 by the acetous fermentation. It is the acid of common vine- 
 gar. To obtain acetic acid in a pure state, saturate distilled 
 vinegar with a metallic oxide, as of copper or lead, and distil 
 
858 Organic Chemistry. 
 
 the compound. Distilled vinegar is mostly acetic acid. It 
 may also be obtained in a concentrated state by distilling dry 
 acetate of soda with sulphuric acid, and subjecting the prod- 
 ucts to cold, the pure acid crystallizes out in the solid state. 
 
 Pyroligneous Acid consists of acetic acid mixed with tar and. 
 a volatile oil, and is obtained by the dry distillation of wood. 
 Alcoholic spirits^ by the aid of ferment, are converted into 
 acetic acid. 
 
 Properties. Acetic acid is solid below 60° F., but contains 
 one equiv. of water, which appears to be essential to its 
 constitution. The liquid acid is transparent, has a fragrant 
 and refreshing odor, and sharp acid taste, sp. gr. 1.065, boils 
 at 248°, soluble in water, alcohol and ether, and highly cor- 
 rosive to the animal organs. It forms a numerous class of 
 salts, all soluble in water. 
 
 Uses. The uses of vinegar^are well known. The pure 
 acid is much used in analytical processes, and the crude acid 
 for forming several compounds used in the arts, as white 
 lead. i 
 
 Acetate of Potassa (C 4 H ? 3 .KO) is formed by decomposing 
 the carbonate of potassa with acetic acid. It is a white de- 
 liquescent salt, much used in medicine. 
 
 Acetate of Ammonia. Spirit of Mindereus is a medical 
 preparation, formed by the direct union of ammonia with the 
 acid when they are brought in contact. It is a very soluble 
 and volatile solid* 
 
 Neutral Acetate of Lead — Sugar of Lead. C 4 H 3 3 .3HO 
 PbO. This substance, commonly known under the name 
 of sugar of lead, may be prepared by dissolving the carbonate 
 of lead, (white lead) or litharge, in distilled vinegar. It is 
 obtained as a white crystalline salt, of a sweetish astringent 
 t ate, and is highly poisonous. It is used in medicine, and 
 by dyers and calico printers for the preparation of acetate of 
 alumina and of iron. 
 
 Tri-acetate of Lead (C 4 H s 3 . 3PbO) is prepared by mixing 
 
 
Acetates of Lead and Copper. 359 
 
 1 parts of litharge with a solution of 6 parts of sugar of lead. 
 The salt crystallizes from the solution in long slender needles, 
 very soluble in water, with an alkaline reaction. It is used 
 in medicine under the name of Goulard's extract of lead* 
 This salt contains 3 equiv. of the oxide of lead, two of which, 
 on exposing the salt to the air or carbonic acid, combine with 
 
 2 equiv. of the acid, and form the well known paint white 
 lead, while the other equiv. of oxide remains in combination, 
 forming the neutral acetate. 
 
 In the manufacture of white lead, the tri-aceiate performs 
 an essential part. Plates of lead are exposed to the influence 
 of acetic acid, water, air, and carbonic acid. The oxygen of 
 the air forms a film of oxide on the plates, which combines 
 with the acetic acid, forming the neutral acetate ; this latter 
 substance acts on the oxide of lead, and forms the tri-acetate. 
 This is decomposed by the carbonic acid into white lead, and 
 the neutral acetate, which again unites with more oxide, 
 formed by the oxygen of the air, reproducing the tri-ace- 
 tate, which is again decomposed by the carbonic acid. The 
 process once begun by a, small quantity of acetic acid, will 
 continue to produce white lead from the pure lead, until the 
 metal is all exhausted. 
 
 Acetates of Copper. Of these three or four are known. 
 The neutral acetate (C 4 H 3 3 .CuO + HO) is formed by dis- 
 solving verdigris in hot acetic acid, and crystallizing from 
 the filtered solution. It forms beautiful crystals of a dark 
 green color, soluble in water and alcohol. Verdigris is a 
 variable mixture of the several acetates of copper, and is pre- 
 pared in France by covering copper plates with the refuse 
 of grapes after the wine has been extracted. A better arti- 
 cle is prepared in England by covering copper plates with 
 cloths soaked in pyroligneous acid. 
 
 Acetate of Alumina (3C 4 H 3 3 +A1 2 3 ) is much employed 
 by calico printers as a mordant for fixing colors. It is pre- 
 pared for this purpose by mixing acetate of lead and alum 
 
880 Organic Chemistry. 
 
 (sulphate of alumina and potassa) in solution, and filtering. 
 Gum is put into the filtered liquid to thicken it, and then it 
 is applied to the cloth by a stamp. A moderate degree of 
 heat drives off the acetic acid and the alumina unites with the 
 dye. Acetate of iron is also used for the same purpose. 
 Acetate of zinc is sometimes applied externally as a remedy. 
 Several other acetates are known, most of which are of little 
 importance 
 
 Acetone, Pyracetic Spirit (C 3 H 3 0) is obtained by decompos- 
 ing acetic acid, or metallic acetates, by heat. It is a color- 
 less volatile liquid, very inflammable, burning with a bright 
 flame, sp. gr. .792, boils at 132° F. When this substance is 
 distilled with half its volume of Nordhausen sulphuric acid, 
 another inflammable liquid is obtained, (C 3 H 2 ) and by the 
 action of perchloride of phosphorus on acetone, an oily liquid 
 separates, (C 6 H 5 C1.) 
 
 III. Kakodyle and its Compounds. 
 
 Kakodyle, C 4 H 6 As=Kd. This substance is considered as 
 one of the compound radicals, one of the few which have 
 been proved to have an existence. It was discovered by 
 M. Bunsen. It is a colorless liquid, crystallizing on ex- 
 posure to cold, odor offensive 3 resembling arseniuret of hydro- 
 gen, takes fire in the air and in chlorine gas. It is very 
 poisonous. Kakodyle forms a large class of compounds, in 
 which it performs the part of a simple metal. 
 
 Protoxide of Kakodyle- ^Alkarsine, C 4 H 6 AsO. This sub- 
 stance has been long known as Cadet's fuming liquid. Pre- 
 pared by heating equal weights of dry acetate of potassa and 
 arsenious acid to redness in a glass retort, and condensing the' 
 products in a receiver surrounded with ice. 
 
 Properties. A colorless ethereal liquid, very offensive odor, 
 sp. gr. 1.462, boils at 300° F. ; subjected to cold, 9° F., it 
 crystallizes in silky scales. Takes fire in the air, after 
 emitting a dense white smoke, and explodes in contact with 
 
Kakodyle and its Compounds, 361 
 
 nitric acid. Its vapor attacks the eyes and mucous surfaces 
 of the nose, even in small quantities. Inhaled, it is highly 
 poisonous and destructive of life. 
 
 Kakodylic Acid. Alkargene (C 4 H 6 As0 3 , or KdO 3 ) is formed 
 by slowly oxydizing kakodyle, or its oxide, by means of add- 
 ing oxide of mercury to kakodyle covered with water. The 
 acid crystallizes from this solution in oblique rhombic prisms, 
 permanent in dry air, deliquescent when exposed to moisture ; 
 very soluble in water and alcohol ; combines with oxides and 
 forms salts. It is distinguished from the other compounds of 
 kakodyle by not being poisonous^ 
 
 Chloride of Kakodyle (C 4 H 6 AsCl=^KdCl) is formed by 
 distilling hydrochloric acid With an alcoholic solution of oxide 
 of kakodyle previously mixed with a dilute solution of corro- 
 sive sublimate. It is a colorless liquid of a very offensive 
 odor, and highly poisonous. 
 
 Iodide of Kakodyle (Kdl) is prepared by distilling hydrio- 
 dic acid with oxide of kakodyle; It is a yellowish liquid — 
 very offensive odor. Kakodyle also unites with bromine and 
 fluorine, forming similar compounds, 
 
 Sulphuret of Kakodyle (KdS) is a thin colorless liquid, fe- 
 tid odor, and spontaneously combustible in air or oxygen gas. 
 It dissolves sulphur, and produces a persulphuret of kakodyle, 
 (KdS 3 ) which is one of the sulphur acids capable of uniting 
 with sulphurets of gold, copper, bismuth, lead, and antimony 
 and thus of forming an interesting class of double salts. 
 
 Cyanide of Kakodyle (KdNC 2 ) is prepared by distilling the 
 oxide of kakodyle with strong hydrocyanic acid. It is liquid 
 above 91° F., below that point it crystallizes in four-sided 
 prisms of a beautiful diamond lustre. Its vapor is poisonous 
 in the highest degree ; a few grains will so affect the atmos- 
 phere of the room as to produce numbness in the hands 
 and feet, vertigo, unconsciousness, and even death, if long 
 lespired. 
 
 16 
 
862 Organic Chemistry. 
 
 IV. Products of the Dry Distillation of Wood. 
 
 When wood is subjected to destructive distillation, at a red 
 heat, several substances are formed, the most important of 
 "which are tar and pyroxylic, or wood spirit, which is an alco- 
 hol of a series of compounds, containing, as it is supposed, a 
 new radical methyle, C 2 H 3 = Me, 
 
 Methylic Ether. Oxide of Methyle (C 2 H 3 0=MeO) is pre- 
 pared by distilling a mixture of 1 part of wood spirit with 4 
 of sulphuric acid, and transmitting the gas through milk of 
 lime, and then through pure water, which dissolves the ether. 
 From this liquid the gas is obtained by boiling it, and col- 
 lecting over mercury. 
 
 Properties. A colorless gas, of an ethereal odor, combusti- 
 ble, soluble in water and sulphuric acid. It acts as a base, 
 and unites with the strongest acids to form a class of salts. 
 
 Pyroxylic Spirit, Wood Spirit, Hydrate of Oxide of Me- 
 thyle. C 2 H 3 0+HO=MeO+HO. 
 
 Process. When the impure acetic acid obtained by the 
 distillation of wood is saturated with quick-lime and distilled, 
 impure wood spirit first comes over, which is purified by re- 
 peated distillation with chloride of calcium and water. It 
 exists also in oil of winter-green. 
 
 Properties. A volatile colorless liquid, disagreeable odor, 
 pungent taste, burns with a pale blue flame, soluble in wa- 
 ter, alcohol, and ether, sp.gr. .798, boils at 151.7° F. It 
 dissolves, by the aid of heat, sulphur and phosphorus in small 
 quantities. Its solvent properties resemble alcohol. 
 
 Uses. It is used in the arts to dissolve resins, in the man- 
 ufacture of spirit varnishes. In medicine, it has been used 
 for affections of the lungs, under the name of icood naptha ; 
 but its medicinal virtues are not generally acknowledged. 
 
 Chloride of Methyle (C 2 H 3 Cl = MeCl) is obtained by the 
 action of 2 parts of common salt, 3 of sulphuric acid, and 1 
 of wood spirit. The chlorine of the salt displaces the oxygen 
 and water in the wood spirit, and gives rise to a colorless gas 
 of an ethereal odor and sweet taste, sp.gr. 1.731. 
 
Metliyle Series of Compounds* 363 
 
 Iodide of Methyle (C 2 H 8 I = MeI) has been obtained as a 
 colorless liquid, slightly inflammable, sp. gr. 2.24 
 
 Fluoride of Methyle (MeF) is obtained as a colorless gas, 
 and 
 
 Cyanide of Metliyle (MeCy) as an ethereal liquid. 
 
 Sulphuret of Methyle (MeS) is a limpid liquid of very offen- 
 sive odor. 
 
 Theory. It will be seen that the above compounds are formed by dis- 
 placing O-pHO from wood spirit by CI. I..F.S., &c, or perhaps hydrogen 
 from one of the bodies unites with the oxygen of the oxide of methyle to 
 form water, and these simple bodies unite directly with the methyle, dis- 
 placing only HO from the wood spirit. 
 
 Sulphate of Oxide of Methyle (C 2 H 3 0+S0 3 -=MeOS0 3 ) is 
 easily prepared by distilling 1 part of wood spirit with 8 or 
 10 of sulphuric acid. A colorless oily liquid distils over into 
 the receiver, which is purified by caustic baryta. It has an 
 alliaceous odor, sp.gr. 1.324, boils at 370° F., insoluble in 
 water, decomposed by boiling water into sulpho-methylic acid 
 and wood spirit* 
 
 Nitrate of Oxide of Methyle (MeO.+NO & ) is formed by 
 pouring 1 part of wood spirit, and 2 of sulphuric acid, on 
 1 part of nitrate of potash, in a glass retort, and collecting 
 the products in a receiver. This is purified by repeated dis- 
 tillations with water and chloride of calcium. The pure ni- 
 ^ trate is an ethereal colorless liquid, sp. gr. 1.182, boils at 150°, 
 and burns with a yellow flame. Its vapor is very dense, and 
 when heated above 300° explodes with great violence ; de- 
 composed by caustic potash into nitre and wood spirit. 
 
 Oxalate of Oxide of Methyle (MeO.C 2 3 ) is obtained in 
 the form of a spirituous liquid, by distilling equal weights of 
 oxalic acid, wood spirit, and sulphuric acid, and condensing 
 the products in a receiver. This, when exposed to the 
 air, yields rhombic crystalline plates, colorless, with the 
 odor of oxalic ether; melts at 124°, and boils at 322°, solu- 
 ble in alcohol and water. The latter substance decomposes 
 it into oxalic acid and wood spirit. 
 
364 Organic Chemistry. 
 
 Acetate of Oxide of Methyle (MeO.C 4 H 3 3 ) is prepared by 
 distilling 1 part of aGetic acid, 1 of sulphuric acid, and 2 of 
 wood spirit. It resembles acetic ether, and is isomeric with 
 formic ether. 
 
 Sidpho-metliylic Acid> Me0.2S0 3 -f-HO. This acid is ob- 
 tained by adding sulphuric acid to sulpho-methyliate of baryta, 
 It is a sour sirupy liquid, which may be made to deposit aci- 
 cular crystals. Soluble in water and alcohol, easily decom- 
 posed by heat. It unites with metallic bases to form salts. 
 
 Theory. In the preceding compounds, the acids unite with the oxiJe 
 of methyle, displacing HO from wood spirit. 
 
 V. Formic Acid (C 2 H0 3 -r-HO) is a secretion from the red 
 ant, from which it derives its name. It may be formed by 
 the action of platinum black on wood spirit, and by trans- 
 mitting dry sulphuret of hydrogen through a solution of for- 
 mate of lead. 
 
 Properties. It is a colorless liquid, powerfully acid, odor 
 exceedingly penetrating, sp. gr. 1/235, boils at 212°, and 
 crystallizes in large brilliant plates when cooled below 32° F. 
 Its vapor burns with a bluish flame. The pure acid blisters 
 the skin. Decomposed by sulphuric acid, with the escape 
 of carbonic oxide, unites with oxides, and forms a class of salts 
 which resemble those of acetic acid, but which are distin- 
 guished from acetates by precipitating the oxide of silver or 
 mercury from their combinations. 
 
 Formic acid is supposed to have a radical (C 2 H, symb. Fo.) 
 called Formyle, with which O.Cl.Br.L, &c, unite to form a 
 series of compounds. This base is derived from methyle by 
 removing 2 equiv. of hydrogen. 
 
 Formates. Formic acid unites with soda, \ormmg formate 
 of soda, a crystalline solid, very soluble, and easily decom- 
 posed by sulphuric acid, with escape of carbonic acid. 
 
 Formate of Potassa is not easily crystallized. 
 
 Formate of Ammonia is easily decomposed by heat into hy- 
 drocyanic acid and water. There are also formates of baryta, 
 
Potato Oil 365 
 
 stronta, lime, magnesia, lead, cobalt, and several other metal, 
 lie oxides. Formate of copper crystallizes in beautiful, blue, 
 rhombic prisms. Formates of mercury and silver are easily 
 decomposed by a gentle heat, the metal being precipitated 
 with escape of carbonic acid. 
 
 Chloroform Perchloride of Formyle (C 2 HC1 3 ) is best ob- 
 tained by distilling a mixture of 1 part of alcohol or wood 
 spirit, 3 of chloride of lime, and 24 of water, in a large vessel. 
 A heavy otf collects in the receiver, which, when rectified, 
 is a thin colorless liquid, of an agreeable ethereal odor and 
 sweetish taste, sp. gr. 1.48, boils at 141° F. Dissolved in 
 alcohol, it is used in medicine under the name of chloric ether. 
 By the action of chlorine, we obtain C 2 C1 4 , oi bichloride of 
 carbon. Its vapor when respired renders the system insensible. 
 
 Bromoform, Perbromide of Formyle (C 2 HBr) is prepared 
 in the same manner with the preceding, using bromine in- 
 stead of chlorine. It is a heavy volatile liquid. 
 
 Iodoform (C 2 HF) is also formed in the same manner. It is 
 a yellow crystalline solid. Both of these compounds are de- 
 composed by a solution of potash in alcohol. 
 
 VI. Potato Oil—Amylic Alcohol, C ,0 H ai O.HO. This 
 substance distils over with the potato brandy in the manu- 
 facture of the latter article, as an acrid volatile oil. In its 
 constitution it is similar to alcohol, and has been supposed to 
 be a hydrated oxide of a new radical, amyle, C 10 H n . symb, 
 Ayl. This hypothetical radical unites with O.Cl.Br, I and S, 
 forming a series of compounds similar to acetyle, &c. 
 
 Chloride of Amyle (C 10 H n .Cl) is prepared by distilling 
 equiv. weights of potato oil and perchloride of phosphorus. 
 It is a liquid of an agreeable aromatic odor, insoluble and 
 neutral ; burns with a flame tinged with green, boils at 215°, 
 By the action of chlorine exposed to sunshine, another com- 
 pound is formed, chloruret of chloride of amyle, (C 10 H 3 C1 9 ) the 
 chlorine replacing a portion of the hydrogen, 
 
366 Organic Chemistry. 
 
 Bromide of Ample (C 10 H 13 Br) and the Iodide of Amyh 
 (C 10 H n I) are volatile liquids, somewhat similar in theif 
 properties. 
 
 Sulphamylic Acid (C 10 H n O+SO 3 HO) may be obtained by 
 precipitating it from its combination with oxide of barium, by 
 ms-ans of dilute sulphuric acid. It has an acrid bitter taste, 
 and forms salts with metallic oxides. 
 
 VII. Valerianic Acid (C 10 H 3 O 3 .HO) exists in. the root of 
 the Valeriana officinalis, from which it may be obtained by 
 distillation. It is also prepared by heating potato oil with 
 quicklime and hydrate of potassa. The valerianate of potassa 
 thus formed is distilled with dilute sulphuric acid. 
 
 Properties. A colorless oil, sharp acid taste, odor of vale, 
 rian root, burns with a bright smoky light, sp. gr. .937, boils 
 at 374°. 
 
 Uses. Used in medicine, in the form of valerianate of 
 zinc. The medicinal qualities of the valerian root are due 
 to the presence of this acid. 
 
 Valerianic acid is supposed to contain a base radical called 
 valeryle, (C 10 H 9 , symb. VI) which forms a series of com- 
 pounds analogous to the other hypothetical radicals. 
 
 VIII. Oil of Bitter Almonds and its Products. 
 
 This, oil is supposed to contain a compound radical called 
 Benzoyle, C 14 H 5 2 Bz, which unites with O.Cl.Br.I.S, &c, 
 and forms a series of compounds. 
 
 Bitter Almond Oil is considered a Hydruret of Benzoyle, 
 C 14 H 5 2 +H=BzN. This compound is obtained by digest- 
 ing in water, for some hours, crushed bitter almonds, and dis- 
 tilling. An oily liquid passes over, containing the pure oil, 
 mixed with hydrocyanic acid and some other substances. 
 This is purified by adding protochloride of iron, hydrate of 
 lime, and distilling again. 
 
 Properties. A colorless liquid, odor very fragrant, taste 
 
Benzoic Acid. — Chloride of Benzoyle. 367 
 
 pungent, sp. gr. 1.073, boils at 356° F. The vapor burns 
 with a bright smoky flame. The crude oil is poisonous, but 
 when perfectly pure it is not injurious. 
 
 Uses. Extensively used by perfumers, for giving an agree- 
 able flavor to puddings,, custards, &c. Exposed to the air, 
 2 equiv. of oxygen combine with it, and form 
 
 Benzoic Acid, C 14 H 5 Q 3 .HO, which also exists in a fra- 
 grant resin, obtained from a species of the Iaurus (laurus 
 benzoin) in the balsam of Peru, and in several other vegeta- 
 ble substances. 
 
 Properties. Benzoic acid crystallizes in soft white scales, 
 flexible, transparent, and of a pearly lustre, or in hexagonal 
 needles; is slightly biting, but of a sweetish taste, producing 
 sensation in the throat. When warmed, it is slightly fra- 
 grant. Fuses at 248°, and sublimes a little above, and boils 
 at 462° F. 
 
 Exp. Suspend a smalt branch of a shrub in a tall glass without a bot- 
 tom ; ptaee a small quantity of tbe acid upon a plate of metal ; place the 
 jar over the pLite, at the same time applying the heat of a lamp to evapo- 
 rate the aeid, and the branch will soon be covered with delicate white 
 crystals. 
 
 Benzoic aeid combines with metallic bases, and forms a 
 large but unimportant class of compounds, the Benzoates — 
 1 equiv. of acid to 1 of base. 
 
 Chloride of Benzoyle (C 14 H 5 2 .Cl=BzC!) is prepared by 
 
 passing chlorine gas through bitter almond oil, and heating 
 
 the yeilow liquid thus formed to expell excess of chlorine. 
 
 Theory. One equiv. of chlorine takes the place of one equiv. of hy- 
 drogen, by simple substitution. 
 
 Properties. A colorless liquid, odor penetrating and dis- 
 agreeable, sp. gr. 1.106, boils at 383°. Its vapor burns with 
 a greenish tint. Slowly decomposed by cold water into ben- 
 zoic and hydrochloric acids ; by alcohol into HO and benzo- 
 ate of ether. With alkalies it yields a benzoate and a chlo- 
 ride. By distilling this substance with metallic bromides, 
 iodides, sulphurets, &c, compounds are formed similar to the 
 
368 Organic Chemistry. 
 
 chlorides. By passing dry ammoniacal gas through chloride 
 of benzoyle, a white solid is formed, called 
 Benzamide, C ls H 5 O s .NH 2 = BzNH\ 
 
 Theory. CI unites with one equiv. of H of the NH J , leaving NH 2 in 
 combination. 
 
 This substance is purified by solution in water, from 
 which pure benzamide crystallizes in right rhomboidal prisms 
 or plates, of a pearly lustre. Fuses at 239° ; decomposed 
 by acids and alkalies, if water be present, into ammonia and 
 benzoic acid. 
 
 Benzole (C 12 H 6 ) was discovered by Faraday, and called bi- 
 carburet of hydrogen. It may be obtained by heating 1 part 
 of benzoic acid with 3 of slacked lime. It is a limpid liquid, 
 with an agreeable ethereal odor; sp.gr. .85, boils at 187° F. 
 insoluble in water, but soluble in alcohol and ether. When 
 decomposed by acids, it forms several compounds, as sulpho- 
 benzole, C 12 H 5 S0 2 , mtro-benzole, C 12 H 5 N0 4 . An. equivalent 
 of hydrogen unites with one equiv. of oxygen in the above 
 acids to form water, and SO 3 and NO* remain in combination 
 with the benzole. Br. and CI. and I. and N, unite with ben- 
 zole, and form unimportant compounds. 
 
 Benzoine (C u H 6 2 ) is obtained by mixing equal quantities 
 of bitter almond oil and an alcoholic solution of potassa. By 
 repeated crystallization, it is obtained in colorless prisms, 
 without odor or taste. It is isomeric with the oil of bitter 
 almonds. 
 
 Benzile (C 14 H 5 2 ) is obtained by passing ehlorine gas 
 through benzoine in a state of fusion. It is a yellowish 
 crystalline solid, inodorous and tasteless. This substance 
 has the composition assigned to the hypothetical radical ben- 
 zoyls, and has been supposed to be an isomeric modification 
 of it. It would seem preferable to make it the radical of the 
 series ; but the series of compounds it forms, by the action 
 of other bodies, does not seem to favor such a view. The ben- 
 zoyle series of compounds are very numerous — only the most 
 
Amydaline. Salicene. 369 
 
 important have been described. The two following sub- 
 stances are also obtained from bitter almonds, and are virtu- 
 ally related to this series. 
 
 Amygdaline (C 40 NH 27 O 22 ) exists also in the seed of the 
 peach and cherry-laurel. It is obtained by the action of boil- 
 ing alcohol upon the almond cake, or substance which remains 
 when bitter almonds are pressed to obtain the oil. It crystal- 
 lizes in large transparent prisms, having a silky lustre. By 
 the action of alkalies it yields 
 
 Amygdalic Acid, (C*°H aG 2 \HO) which has a very agree- 
 able acid taste, capable of forming a class of salts, the amyg- 
 dalates, of which little is known. 
 
 Synaptase, or Emulcine, is another singular body, consti- 
 tuting the white portion of both sweet and bitter almonds. It 
 is very soluble in water, of uncertain composition. 
 
 Hippuric Acid (C 18 NH 8 5 .HO) is formed from benzoic acid 
 in a very singular manner. When benzoic acid is taken into 
 the stomach, the urine formed will contain hippuric acid in 
 quantities greater than that of the benzoic acid swallowed. 
 It also exists in the urine of the horse and cow. When pure, 
 it is in the form of beautiful white crystals, of a slightly bit- 
 ter taste. By a high temperature it is converted into benzoic 
 acid and benzoate of ammonia. When the urine of the horse 
 is left to putrefy, its hippuric acid is converted wholly into 
 benzoic acid. 
 
 IX. Salicene (C 4a H 29 22 ) is a peculiar bitter principle 
 which exists in the leaves and bark of the willow, poplar, 
 and some other trees. It may be prepared by heating the 
 bark with boiling water, and digesting the evaporated liquid 
 with oxide of lead, and then precipitating the lead by sulphu- 
 ret of hydrogen. On evaporation, salicene crystallizes, and 
 is purified by animal charcoal. 
 
 Properties. Salicene appears in the form of small silky 
 needles, having an intensely bitter taste. On heating, it is 
 16* 
 
370 Organic Chemistry. 
 
 decomposed, and burns with a bright flame. Soluble in wa- 
 ter and alcohol. 
 
 Uses. Used extensively in medicine as a tonic. By dis- 
 tilling salicene with sulphuric acid and bichromate of potassa, 
 a yellow sweet-scented oil is produced, which is found to be 
 identical with the volatile oil from the flowers of the common 
 meadow-sweet, (spirea ulmaria) and is called 
 
 Hydrosalicylic Acid, and Salicid of Hydrogen, C 14 H 5 4 .H. 
 This substance is supposed to contain a new compound radi- 
 cal, Salicyle, (C 14 H 5 4 — Sa) which forms a series of com- 
 pounds analogous to benzoyle. Hydrosalicylic acid is an oily 
 liquid, fragrant odor, and burning taste; sp. gr. 1.173, boils 
 at 380°, soluble in water, reddens litimus, and gives a vio- 
 let color to the pure salts of iron ; soluble in alcohol and 
 ether. 
 
 Salicylic Acid (C 14 H 5 4 .0) is prepared by heating bydru- 
 ret of salicyle with solid hydrate of potassa in excess, dis- 
 solving the fused mass in water and adding a little hydrochlo- 
 ric acid. The acid crystallizes from the solution in small 
 white crystals, sparingly soluble in water, and very soluble 
 in alcohol and ether. It exists in oil of winter-green, and 
 may be obtained from it by heating it with a solution of 
 potassa, and adding hydrochloric acid to separate the potassa. 
 It somewhat resembles benzoic acid. 
 
 Chloride of Salicyle (C 44 H 5 4 ) is obtained by action of 
 chlorine gas on salicylic acid, the CI taking the place of the 
 oxygen. It crystallizes in tabular crystals of a pearly 
 lustre ; odor disagreeable, taste hot and pungent. It com- 
 bines with metallic oxides, such as potassa, baryta, &c. 
 Bromine and iodine also displace one equiv. of oxygen from 
 salicylic acid, and form compounds analogous to the corres- 
 ponding compounds of benzoyle. 
 
 Phloridzine (C 42 H 23 18 . 6HO) exists in the bark of the root 
 of the apple, pear, plum, and cherry-tree, and may be ob- 
 tained from the bark by the action of boiling alcohol. It re- 
 
Oil of Cinnamon. 371 
 
 sembles salicine. Forms fine silky needle-shaped crystals, 
 having a bitter astringent taste. It is used as a febrifuge. 
 
 X. Oil of Cinnamon (C ie H 6 2 H) is obtained from cinna- 
 mon bark by soaking it in a saturated solution of salt, and 
 distilling. It is a heavy oily liquid, with the well known 
 cinnamon odor and taste. This oil is supposed to be a hy- 
 druret of a new radical called cinnamyle, C 18 H 8 2 , symb. Ci. 
 
 Cinnaminic Acid (C ie H 8 3 .HO) is formed by exposing oil 
 of cinnamon to the air or to oxygen gas. It is a white crys- 
 talline substance, resembling benzoic acid, and forms a simi- 
 lar class of salts. Heated with sulphuric acid and bichro- 
 mate of potassa, it is converted into benzoic acid. It exists 
 also in the balsam of Tolu, from which it may be obtained 
 by boiling this substance with an equal weight of hydrate of 
 lime, and a large quantity of water. Oil of cinnamon and 
 chlorine give rise to compounds of little importance. This 
 oil is obtained from China and Ceylon ; the former is much 
 the best ; both are impure. They may be purified by 
 adding cold strong nitric acid, and decomposing the solid 
 matter thus formed with water. 
 
 XI. Oxide of Carbon, (Oxalyle,) C 2 2 . Oxide of carbon 
 has already been described as carbonic oxide, page 172. To 
 make it correspond to the termination which has been given 
 to the compound radicals, it has received the name oxalyle, 
 derived from oxalic acid. 
 
 Oxalic Acid (C 2 3 HO) was discovered by Seheele, in 1776, 
 and is found in several plants, among which is common sor- 
 rel, the sour taste of which is caused by the presence of ox- 
 alic acid ; it is obtained also by the action of nitric acid on 
 sugar. Many other organic substances, as starch, gum, most 
 of the other vegetable acids also, wool, silk, &c., are con- 
 verted into oxalic acid by the action of nitric acid. 
 
 Properties. Oxalic acid is sold in small, slender crystals, 
 
ST 2 Organic Chemistry. 
 
 and much resembles Epsom salts, for which it is sometimes 
 mistaken with fatal consequences. But, although a power- 
 ful poison, it may be tasted without danger, when its strong 
 acidity will easily distinguish it ; if taken by accident, pow- 
 dered cbalk in water or magnesia should be administered. 
 
 Oxalates of Potassa. There are three of these compounds, 
 one of which, the Unoxalale. HO C : 0\ KG I -2Aq.) 
 is often sold under the name of essential salt of lemons, 
 for removing' the stains of ircn-rust from linen ; a solu- 
 tion of oxalic acid will answer the same purpose. Quad- 
 roxalatt of potassa is sold for the preceding, and is formed 
 by dissolving the binoxalate in hydrochloric acid, and crys- 
 tallizing. In this way the salt is manufactured on a large 
 scale. 
 
 Oxalate of Lime (CaO .C - — : Aq.) exists in several spe- 
 cies of lichen, and, when recently precipitated, is a snow- 
 white flocculent powder. This salt may be distinguished 
 from most other precipitates by its being insoluble in water, 
 ammonia, and acetic acid, but soluble in nitric and hydro- 
 chloric acids. On this account, lime may be detected in 
 solutions from which all other metallic oxides have been 
 separated: thus these oxalates are used to separate lime from 
 magnesia. Lime may also be used to detect oxalic acid. 
 
 XII. Cyanogen, symb. XO 2 . or Cy. equiv. -26.39. Cyanogen 
 
 has already been noticed, (page 196.) It is easily obtained by 
 
 heating in a glass retort the cyanide of potassium. A black 
 
 substance remains in the retort, identical in composition with 
 
 i cyanogen, which has been called Para-cyanogen. 
 
 Properties. Cyanogen is a colorless gas, wkh a strong 
 pungent odor, and burning with a beautiful purple flame. It 
 is characterized by the property of entering into combination 
 with other boc simple substance. It is one of the 
 
 compound radicals. Its compounds, which have been de- 
 
Cyanic Acid. — Urea. 373 
 
 scribed as cyanurets, are now generally classed with the ides, 
 thus, cyanide of potassium, for cyanuret of potassium, &c. 
 
 Cyanic Acid (CyO, HO=43.39) is formed by dissolving 
 cyanogen gas in a solution of caustic potash. It is a trans- 
 parent, highly volatile liquid, of a pungent odor, strongly 
 affecting the eyes. It passes, soon after its formation, with 
 the evolution of heat, into a substance called cyamelide, (C a 
 O 2 , NH, Liebig.) 
 
 Cyanate of Ammonia (C 2 2 N 3 H 4 ) is formed by ming- 
 ling dry ammonia with the vapor of cyanic acid. It is a 
 white crystalline salt, which, when heated, loses a little am- 
 monia, and is converted into 
 
 Urea. This substance exists as an animal product in 
 urine, and was the first organic body which was formed arti- 
 ficially. It may be obtained by evaporating fresh urine to a 
 sirup, and acting upon it with strong nitric acid, decompos- 
 ing the compound thus formed by an alkali, and purifying 
 the urea with alcohol. It has the formula C 2 2 2NH 2 =Ur. 
 
 Properties. Urea crystallizes in flattened four-sided prisms. 
 It has a cooling taste like nitre, somewhat acrid and bitter, so- 
 luble in its own weight of cold water. It fuses at 248°. Ex- 
 posed to dry air, it is permanent, but deliquesces in damp 
 air. It is a feeble base, uniting with acids. The nitrate of 
 urea and the oxalate are the most important. The lactate 
 of urea is the form it assumes in human urine, and the hip- 
 puriate of urea in the urine of the cow. 
 
 Fulminic Acid (Cy 2 2 ,2HO=86.78) was noticed page 196, 
 as isomeric with cyanic acid. The proportion of its elements 
 are the same ; but it possesses quite different properties. It 
 has never been separated from its salts, in consequence of its 
 undergoing decomposition the moment it is liberated. 
 
 It forms two classes of salts, one containing 2 equivalents 
 of base as the fulminate of silver, (Cy 2 2 ,2 AgO) and the other 
 containing two bases as the fulminate of oxide of silver and 
 potassium Cy 2 2 AgO.KO. 
 
374 Organic Chemistry. 
 
 All the salts of this acid are characterized by the property 
 of exploding when heated or struck with any solid body. 
 
 The fulminate of silver and the fulminate of mercury are 
 used for percussion caps, torpedoes, 6cc. The former is the 
 most dangerous to experiment with. 
 
 It is easily formed by dissolving silver in dilute nitric 
 
 acid, and adding pure alcohol to check the violence of the 
 
 action. The process may be conducted in a glass tumbler. 
 
 The white precipitate which is formed, must be poured on a 
 
 filter, and allowed slowly to dry. It should then be placed 
 
 in small paper boxes, and kept undisturbed in a cool place. 
 
 Mercury may be used instead of the silver, and preserved 
 
 in the same way. 
 
 Exp. Take a small quantity of this salt on the point of a knife, place 
 it in sand or small pebbles, and roll the whole up into paper balls. These, 
 when thrown against the floor, will explode with a sharp report. The ex- 
 plosion is due to the decomposition of the salt : the solid being suddenly 
 resolved into the state of a gas. 
 
 Cyanuric Acid (Cy 3 3 .3HO) may be formed by several 
 processes, (see p. 196.) One of the best is to dissolve 
 Melam in sulphuric acid, add 30 parts of water, and boil the 
 whole, adding water for 4 or 5 days till the liquid does not 
 give a white precipitate with ammonia. The liquid on cool- 
 ing deposits crystals of cyanuric acid, which maybe purified 
 by re-crystallization. This acid is tribasic, forming three 
 classes of salts, which are distinguished by the fact, that one, 
 two. and three equivalents of water are displaced by some 
 other base : thus, the 
 
 Acid has the formula, Cy s O E .3HO. 
 
 Cyan urate of Potassa, Cy J ! .K02HO. 
 
 Cyanurate of Binox, silver, Cy s 3 ,2AgO.HO. 
 
 Cyanurate of Terox, silver, Cy s O\3AcO, 
 This acid differs in other respecis, also, from the two pre- 
 ceding, and particularly in a greater permanence of compo- 
 sition. Cyanogen unites with chlorine, iodine, and bromine, 
 forming unimportant compounds. (See page 197.) 
 
 Hydrocifanic Acid, Prussic Acid, CyH. This remarkable 
 
Compounds of Cyanogen. 375 
 
 substance has been described (page 197) as one of the most 
 virulent of poisons. It is used in medicine for diseases of 
 the chest and lungs. It is easily decomposed by exposure to 
 light, and should be kept in the dark. 
 
 As this substance is sometimes used for poisoning, it is de- 
 sirable to be able to detect it. 
 
 The most delicate test is the following — 
 
 1. Take the suspected liquid as the contents of the stom- 
 ach, mix it with one-sixth of its bulk of sulphuric acid, and 
 distil it. Add now to the distilled liquid a few drops of proto- 
 sulphate of iron, and a slight excess of caustic potash to 
 precipitate the oxide of iron. 
 
 2. Take the alkaline liquid, and after exposing it to the 
 air, to allow the peroxide of iron to form, add sufficient 
 hydrochloric acid, to render it acid, when there will be formed 
 the well known substance, prusssian blue-*—& sure test of the 
 presence of hydrocyanic acid. 
 
 Cyanogen unites with sulphur, forming several compounds. 
 
 The compound described as bisulphuret of cyanogen, 
 (page 208,) is supposed to be a substance composed of 
 a hypothetical radical sulphocyanogen with sulphocyanic 
 acid, and water. The radical has the formula, Cy2S, or 
 Csy. 
 
 Hydrosulphocyanic Acid, (S ? CyH.) is described, p. 208. 
 
 Su/phocyanide of Potassium, (CyS 2 K,) is formed by fu- 
 sing 17 parts of dry carb. of potash, 32 of sulphur, and 46 of 
 dry ferrocyanide of potassium in an iron retort. The mix- 
 ture is stirred gently until bubbles of gas cease to escape, and 
 the vessel has attained a dull red heat. By washing in water, 
 the salt is dissolved, and by evaporation, crystallizes in long 
 colorless prisms, having a sharp saline taste. 
 
 Cyanide of Potassium (CyK) is described page 233. 
 
 Cyanogen also unites with zinc, cobalt, iron, mercury, pal- 
 ladium, silver, and gold, forming cyanides of these metals, some 
 of which have already received attention, in other parts of 
 
376 Organic Chemistry. 
 
 the work. With iron, cyanogen forms one of the hypotheti- 
 cal radicals called 
 
 Ferrocyanogen. (Cfy.) which is supposed to unite with hy- 
 drogen to form 
 
 Hydro-Ferrocyanic Acid, Cy 3 Fe.H 2 . This acid is formed 
 by the action of 1 part of hydrochloric acid on 4 parts of a 
 saturated solution of ferrocyanide of potassium, and then di- 
 gesting the mixture with 2£ parts, dry measure, of pure ether, 
 a white crystalline body rises to the surface with the ether, 
 which, when purified with ether, and dried, is pure ferrocy- 
 anic acid. 
 
 Properties. This acid in solution has a powerfully acid 
 taste, and decomposes readily alkaline carbonates. It unites 
 with bases forming ferrocyanides. 
 
 Ferrocyanide of Potassium (C 6 X 3 Fe.K0.3HO) is manufac- 
 tured on a large scale under the name of yellow prussiate of 
 potash. 
 
 Process. Impure carbonate of potash, iron filings, and dry 
 refuse animal matter, are put into a large iron vessel, excluded 
 from the air, and fused at a red heat. By this process, cya- 
 nide of potassium is generated, and is dissolved out with hot 
 water ; the cyanide is thus converted by the oxide or the 
 sulphuret of iron into the ferrocyanide of potassium. When 
 this filtered solution is evaporated, crystals are formed, which, 
 by resolution and evaporation, yield large yellow crystals, sol- 
 uble in 4 parts of cold and in 2 of boiling water. It has a 
 mild saline taste, and may be taken with impunity. 
 
 Ferrocyanide of potassium is a valuable chemical reagent. 
 When mixed with slightly acid or neutral salts of the metals, 
 as of copper, lead, and iron, the potassium of the base is dis- 
 placed by these metals, and forms compounds of characteristic 
 colors. With any salt of the peroxide of iron, it forms ordi- 
 nary Prussian blue, or 
 
 Ferrocyanide of Iron. Cy 9 Fe 7 . This salt is well known 
 as a beautiful blue pigment ; dissolved in oxalic acid, it con- 
 stitutes blue ink. 
 
 By passing chlorine ga6 through a solution of ferrocyanide 
 
Mellone and its Compounds, 377 
 
 of potassium, a persalt of iron is precipitated, and the solu- 
 tion, by evaporation, yields beautiful dark red prismatic crys- 
 tals of ferridcyanide of potassium, which is supposed to con- 
 tain a radical called ferridcyanogen. Cy 6 Fe 2 or Cfdy, 
 
 Cyanogen unites with cobalt and platinum, forming a se- 
 ries of salts, having each a hypothetical radical, Cobaltocy- 
 anogen, (Cy 6 Co 2 =Chy) and platinocyanogen (Cy 2 Pt.=Cpy.) 
 
 XIII. Mellone. C 6 N 4 =M1. 
 
 When chlorine acts on sulphocyanide of potassium in so- 
 lution, a yellow substance is precipitated, which has been 
 called Metasulplwcyanogen C ,8 N 6 S ia H 3 (Parnell.) 
 
 By heating this substance, several substances are driven 
 off, such as sulphuret of carbon, sulphur and water, and 
 there remains a yellow powder, which has the composition 
 C 6 N 4 , and has received the name of mellon or mellone. 
 
 It is insoluble, and is decomposed by a bright red heat 
 into 3 vols, of cyanogen and one of nitrogen. It is one of 
 the salt radicals combining with hydrogen, potassium, &c. 
 
 Hydromellonic Acid (C 6 N 4 H or M1H) is formed by the ac- 
 tion of hydrochloric acid on a hot solution of mellonide of 
 potassium. On cooling, a white powder subsides, having 
 strongly marked acid properties. 
 
 Mellonide of Potassium (C 6 N 4 K or M1K) is formed by de- 
 composing acetate of potash with hydromellonic acid, and 
 washing the crystals thus formed with alcohol. The sulpho- 
 cyanide is dissolved, and the mellonide of potassium remains, 
 forming with water small needle-shaped crystals of a bitter 
 taste. 
 
 Melam (C 12 N n H 2 ) is formed by decomposing sulphocya- 
 nide of ammonia by heat. It is a grayish- white powder. 
 
 Melamine (C C N 6 H 8 ) is formed by boiling melam in a so- 
 lution of 1 part of hydrate of potash and 20 of water, until 
 the turbid liquor becomes perfectly clear. On cooling, mel- 
 amine is deposited in transparent colorless or slightly yellow 
 
378 Organic Chemistry. 
 
 crystals of the form of rhomboidal octahedrons. It forms 
 salts with dilute acids. 
 
 Ammeline (C 6 N 5 H 6 2 ) remains in the solution when mela- 
 mine crystallizes, combined with potash, and is obtained by 
 the action of acetic acid, and then by dilute nitric acid, form- 
 ing nitrate of ammeline ; the ammeline is then precipitated 
 by carbonate of ammonia. It forms very brilliant silky nee- ' 
 dies, and unites with the more powerful acids to form salts. 
 
 Ammelide (C 12 N 9 H 9 5 ) is produced where melam, mela- 
 mine, or ammeline, are decomposed by concentrated acids. 
 It is a white powder, insoluble excepting in strong alkalies i 
 or acids. i 
 
 XIV. Uric Acid (Lithic Acid) C 10 N 4 H 4 O° exists in the 
 urine of all carniferous animals. Guano, which exists in 
 such abundance on many small islands, near the coast of 
 Peru and Chili, and which is so extensively used as manure, 
 is mostly urate of ammonia. It results from the decomposi- 
 tion of the excrements of aquatic birds. Urinary calculi are 
 often composed of it. Uric acid may be prepared from the 
 excrements of serpents, as that of the boa constrictor, by dis- 
 solving them in caustic potash, and decomposing the urate 
 of potassa thus formed with hydrochloric acid. It crystal- 
 lizes in thin silky scales of brilliant whiteness, inodorous and 
 nearly insoluble in cold water. It unites with the alkalies 
 and alkaline earths, forming sparingly soluble salts, Uric 
 acid is supposed to be composed of a salt radical called Urile 
 ==Ur, which radical contains the elements of cyanogen and 
 oxide of carbon (2Cy.4CO or C 8 N 2 4 ) by adding 1 eq. of 
 urea (C 2 2 N 2 H 5 ) to this, it will give the formula of uric acid 
 (C i0 N 4 O 6 H 4 .) By the action of oxidizing substances upon 
 uric acid, a very remarkable class of compounds are formed. 
 By^boiling this acid with peroxide of lead, a new compound 
 is formed, called 
 
 Allontoin. C*N 2 H 3 3 . This substance is found in the 
 
Alloxan. — Murexide, 379 
 
 allontoic fluid of the cow, and may be obtained in brilliant 
 colorless prisms, by evaporating this fluid to one quarter of 
 its bulk. (See Graham's Chemistry.) By adding uric acid 
 gradually to nitric acid, sp. gr. 1.35, another compound, 
 
 Alloxan (C 8 N 2 O 10 H 4 ) is formed, This substance crystal* 
 lizes in large octohedrons with a rhombic base, very soluble 
 in water, reddens vegetable blues and gives a purple stain to 
 the skin. By the action of alkalies it forms alloxanic acid 
 (ON 2 HO\) 
 
 Alloxantin (C 8 N 2 H 5 10 ) is still another product of the de, 
 composition of uric acid by nitric acid. It is also formed by 
 the action of sulphuret of hydrogen on alloxan. It crystal* 
 lizes in obtuse four-sided prisms, which become red in am- 
 moniacal air, and acquire a green metallic lustre. Allox- 
 antin is decomposed into several compounds by the action of 
 sulphuret of hydrogen. 
 
 Murexide (C 2 N 5 H 6 8 ) is formed by " evaporating a solu* 
 tion of uric acid in dilute nitric acid, until the solution ac- 
 quires a flesh-red color." After cooling to 110°, ammonia is 
 added, the whole diluted with half its bulk of water and 
 cooled. 
 
 Properties. Murexide forms crystals which are of a gar, 
 net-red color, by transmitted light. By heating this sub* 
 stance in caustic potash till the blue color disappears, and 
 adding an excess of dilute sulphuric acid, 
 
 Murexan (C°N 2 H 4 5 ) is formed, called also -purpuric acid. 
 It crystallizes in plates which have a very brilliant silky 
 lustre. Murexan resembles uramile, and possibly may be 
 identical with it. 
 
 We have given the most important of the cyanogen series 
 of compounds. For more extended details, the student is 
 referred to Graham's Chemistry, 
 
380 Organic Chemistry. 
 
 
 Section III. Organic Acids. 
 
 Organic Acids are, for the most part, less liable to spon- 
 taneous decomposition than other organic substances, although 
 none of them can exist at the temperature of a red heat ; 
 they all contain carbon and oxygen, most of them hydrogen ; 
 generally they have more oxygen than would be sufficient 
 to form water by combination of their hydrogen, but a few- 
 have these elements in the same ratio as in water. 
 
 Malic Acid. C 8 H 4 8 ,2HO. This acid is contained in 
 grapes, currants, gooseberries, oranges, apples, and in most 
 of the acidulous fruits. It is also obtained by the action of 
 nitric acid on \ of its weight of sugar ; it forms salts with 
 metallic oxides, called malates. 
 
 Citric Acid. C 18 H 5 O n ,3HO. This acid is also found in 
 many acidulous fruits, especially in limes and lemons, from 
 which it is usually obtained. It has an agreeable flavor, and 
 is an excellent substitute for lemons ; it is used in the prep- 
 aration of lemon syrup, in which, however, tartaric acid is 
 largely employed, being much less expensive, but of very 
 inferior flavor. 
 
 Aconitic Acid, (C 4 H 2 3 ,HO,) is formed by heating citric 
 acid to a temperature of about 300°. It is also obtained 
 from Aconitum napellus and Equisetum jtuviatale. It. forms 
 small confined crystals, soluble in alcohol, and by the action 
 of dry hydrochloric acid upon its alcoholic solution, forms 
 Aconitic Ether. When rapidly distilled it forms two iso- 
 meric bodies, itaconic and citraconic acids. 
 
 Tartaric Acid. C 8 H 4 O 10 ,2HO. This acid also exists in 
 acidulous fruits, usually in combination with lime or potassa. 
 Tartaric acid is used with the bicarbonate of soda for an 
 effervescing drink ; it forms numerous salts, many of which 
 are double. 
 
 Bitartrate of Potassa. In an impure form, this is known 
 by the name of crude tartar, and is found incrusted on the 
 
Tartar Emetic— Tannic Acid. 381 
 
 sides of wine casks, colored by the wine ; when purified it 
 is white, and is known by the name of cream of tartar. It 
 is used for the preparation of tartaric acidj and as a med- 
 icine. 
 
 Tartrate of Antimony and Potassa* This compound is 
 sold under the name of tartar emetic, and is prepared by boil- 
 ing sesquioxide of antimony with cream of tartar. It is neu- 
 tralized by vegetable astringents, as tea or Peruvian bark^ 
 which may therefore be used as an antidote, in case of taking 
 a too powerful dose. It is a white solid, slightly efflores- 
 cent, and is composed, according to Philips, of 1 atom of 
 bitartrate of potassa, 3 sesquioxide of antimony, and 3 of 
 water. 
 
 Tartrate of Potassa and Soda is prepared by saturating 
 an excess of acid in tartar, with carbonate of soda. It has 
 long been used in pharmacy under the name of Pochette Salt 
 and Sel de Seignette. It consists of 1 atom of tartrate of 
 potassa, 1 atom of tartrate of soda, and 10 atoms of water. 
 By the action of heat, tartaric acid loses successive portions 
 of water, and two new acids are formed, the 
 
 Tartrelic and Tartralic Acids, and when subjected to de- 
 tructive distillation, it yields two other acids, the 
 
 Liquid Pyrotartaric. C 6 H 3 O s ,HO. And 
 
 Solid Pyrotartaric. C 6 H 3 3 HO. 
 
 Paratartaric or Racemic Acid, (C 4 H 2 5 HO,) exists in cer- 
 tain wines, or in the cream of tartar which is found in them. 
 It is a more powerful acid than tartaric, and forms a class of 
 salts, similar in composition to the salts of tartaric acid. Its 
 decomposition by heat, produces also several new acids. 
 
 Tannic Acid, or Tannin. C 16 H 8 12 . This substance ex- 
 ists in gall-nuts, (the excrescences of several species of the 
 oak,) in the bark of most trees, in tea, and in most vegetable 
 astringents, and is the cause of their astringency. With 
 gelatin or glue, it forms an insoluble compound, which is the 
 basis of leather. Hence leather is prepared by soaking 
 
882 Organic Chemistry. 
 
 skins in water, which contains ground bark, the tannic acid 
 
 of which is taken in solution by the water. 
 
 Exp. To a strong solution of gelatin (common glue answers well 
 enough) add a strong infusion of gall-nuts ; a white precipitate will be 
 formed, and may be collected upon a glass rod and pressed together, 
 forming a strong extensible mass, resembling new leather. When exposed 
 to the oxygen of the air, it is gradually converted into gallic acid. 
 
 Gallic Acid. C 7 H 3 5 . This acid also exists in gall-nuts 
 and in the bark of trees, but is more abundantly obtained by 
 the oxidation of the tannic acid of gall-nuts. Common ink 
 owes its color to the compounds of tannic and gallic acids 
 with the sesquioxide of iron, and may be extemporaneously 
 prepared by adding to an infusion of gall-nuts a solution of 
 copperas, which has been exposed to the air.* 
 
 Some of the most important of the remaining organic 
 acids are the following : — 
 
 Mellitic Acid, (C 4 3 .HO,) is contained in the rare sub- 
 stance called honey-stone. It exists as a white, slightl} 
 crystalline powder, soluble in alcohol ; and, by boiling the 
 solution, there seems to be formed an acid — mellitate of ether. 
 It forms salts called mellitates. 
 
 Croconic Acid (C 6 4 ) is a yellow, easily crystallized solid, 
 soluble in water and in alcohol. All its salts are yellow. 
 
 Lactic Acid, (C c H 5 5 ,) so called from being first noticed in 
 sour milk, was discovered by Scheele, in 1780. It has since 
 been found in several vegetable bodies when left to sponta- 
 neous fermentation. It is colorless, without smell, but ex- 
 cessively sour. lis salts are termed lactates. 
 
 Kinic Acid (C 14 !! 11 © 11 .HO) exists in cinchona bark, in 
 combination with lime, quinia, and cinchonia. 
 
 * A very good ink may be formed thus : Take 8 oz. of bruised galls, 
 4 oz. sulphate of iron, 3 oz. gum arabic, and 1 oz. of sugar candy. Boil 
 the galls in 6 qts. of water until but 3 qts. remain; strain, and add the 
 other ingredients, stirring the whole till dissolved. 
 
 Ink may be kept from moulding by keeping a few cloves in the bottle. 
 Common writing ink is much more permanent, if Indian ink — which is 
 lampblack made into a cake with isinglass — is dissolved in it, 1 oz. to 3 
 qts. of ink. 
 
Succinic, Oleic, Crenic Acids. 383 
 
 Meconic Acid (C 14 HO n .3HO) is found in the poppy, in 
 combination with morphia, and crystallizes in white, trans- 
 parent scales. 
 
 Pyromeconic Acid. C 10 H 3 O 6 .HO, 
 
 Comenic Acid (C 12 H 2 3 .2HO) is obtained from the meconic 
 by boiling its aqueous solution. 
 
 Pyrogattic Acid (C 6 H 3 3 ) is obtained by heating gallic 
 acid to 419°. 
 
 Metagallic Acid (C 12 H 3 3 ) is formed by heating gallic acid 
 (o 480°. 
 
 Ellagic Acid (CTPO 4 ) is very similar to the preceding. 
 
 Succinic Acid (C 4 H 3 3 HO) exists in amber, and is obtained 
 by the aid of heat. It is obtained in three states:-— 1. Com- 
 bined with an atom of water, which, when pure, is the crys- 
 tallized acid of the shops. 2. With •£ an atom of water, pro- 
 duced by keeping the crystallized acid for a long time be- 
 tween the temperatures of 260° and 284°. 3. Anhydrous- 
 The compounds which this acid forms with bases are termed 
 succinates. 
 
 Moroxylic Acid is found, in combination with lime, on the 
 bark of the white mulberry. 
 
 Oleic Acid (C 44 H 39 4 ) is obtained from the soap made from 
 linseed oil and potassa. It burns like the fixed oils, and forms 
 salts, or soaps, called oleates. When olive oil is mixed with 
 half its weight of concentrated sulphuric acid, three acids are 
 formed, one of which has been called sulplw-oleic ; and this, 
 when decomposed, affords hydro-oleic acid. 
 
 Crenic Acid (108) was discovered by Berzelius, in 1832, 
 in the water of Porla well, in Sweden. It is inodorous, a 
 sharp, followed by an astringent taste, yellow and transpa- 
 rent ; very soluble in water and in alcohol. When the solu- 
 tion is exposed to the air, apocrenic acid is formed. Its salts 
 are termed cremates, and resemble extracts in appearance, 
 but are incapable of crystallizing. 
 
 Apocrenic Acid (132) was obtained by digesting the ochre 
 
SS4 Organic Chemistry. 
 
 of Porla well with potassa, and precipitating the acid by means 
 of acetate of copper. The apocrenate of copper falls, from 
 which the acid is separated by the action of bydrosulphuric 
 acid, absolute alcohol, and potassa. It is a brown substance, 
 resembling a vegetable extract. Crenic and apocrenic acids 
 have been detected in many waters, and in the vegetable 
 mould of soils. 
 
 Section IV. Vegetable Alkalies. 
 
 The existence of vegetable alkalies was not known until the 
 present century, and very little attention was given to them until 
 1316. They all contain nitrogen, and unite with acids to form 
 salts, in which state they are found in the vegetable kingdom. 
 These salts exactly resemble those of metallic oxides. They 
 possess other properties, which proves their alkaline character. 
 
 The method of preparation is nearly the same for all of 
 these alkalies : the substance which contains one of them is 
 steeped in a large quantity of water, which dissolves the sak 
 that contains it ; the solution is boiled for a short time with 
 lime or magnesia, and the vegetable alkali is set free in an 
 insoluble state, and may be collected on a filter with the lime ; 
 if then boiled in alcohol with powdered charcoal, it is dis- 
 solved by the former, and purified by the latter : then, by 
 filtering while hot, it is separated from the charcoal, and the 
 lime with which it was mixed ; it is deposited from the alco- 
 hol on cooling, by evaporation. 
 
 Morphia. C S4 H :: NO : = 2S4. This alkali is the narcotic 
 principle of opium, in which it is combined with sulphuric 
 and meconic acids, and is associated with several other vege- 
 table alkalies, and with gummy, resinous, and coloring mat- 
 ters. Opium contains about nine and a half per cent, of mor- 
 phia ; when pure, it is very insoluble in water, and conse- 
 quently but little poisonous ; but when in the state of a salt, 
 as in opium, it is a very powerful poison : one half a grain in 
 solution will produce alarming effects on the animal system. 
 
Vegetable Alkalies. 385 
 
 When opium has been administered as a poison, the presence 
 of its morphia may be detected by a process too elaborate to 
 be inserted here. A skilful chemist will detect a single grain 
 of morphia in 700 grains of water. Some of the salts of mor- 
 phia are useful as medicines ; of which the hydrochhrate and 
 acetate are the principal. 
 
 Narcotina (C 4S H 24 N0 1B ) was discovered by Desrone, ill 
 1803, and is obtained from opium; it is a white substance, 
 and may be taken into the human stomach without sensible 
 effects, but it is speedily fatal to dogs. 
 
 Cinchmiia (C 20 H 12 NO) and Quinia, (C 20 H 12 NO 2 ==162.) 
 These two alkalies were detected by Pelletier and Caventou, 
 in 1820, in Peruvian bark, and impart to it its value as a med- 
 icine. Cinchonia is found in the pale bark ; quinia, with a 
 little cinchonia, in the yellow bark ; and both in the red bark. 
 Cinchonia is insoluble in cold water, and nearly so in hot 
 water ; in boiling alcohol it is freely dissolved, and the solu- 
 tion has an intensely bitter taste ; some of its salts are solu- 
 ble in water. 
 
 Quinia, or Quinine, is also almost insoluble in water, but 
 with alcohol forms an intensely bitter solution. 
 
 Quinia forms several salts, one of which, the sulphate, is 
 manufactured in large quantity for medical purposes, and is 
 commonly sold by the name of quinine. It is soluble in al- 
 cohol, or slightly in pure water, and freely if the water is 
 slightly acidulated by sulphuric acid ; the solution, although 
 containing but a minute portion of quinia, is intensely bitter. 
 
 On account of its high value, sulphate of quinia is often 
 adulterated with gum, starch, sugar, magnesia, and various 
 other substances ; gum and starch are insoluble in alcohol, 
 and may be detected by dissolving the suspected quinia in 
 boiling alcohol. Sugar may be detected by adding pearlash 
 to the solution in Water, when the quinia will be thrown 
 down, and the sweet taste may be perceived ; magnesia will 
 be left after burning a portion of the adulterated article. 
 
 17 
 
386 Organic Chemistry. 
 
 Strychnia (C 44 H 23 N 2 Q 4 ) was discovered in 1818, by Pelle- 
 tier and Caventou. This remarkable alkali is found in the 
 nux vomica and in the upas-tree. It is freely soluble in alco- 
 hol, and but slightly so in water ; although nearly insoluble 
 in the latter, the minute portion which is taken up, commu- 
 nicates to the water the most intense bitterness ; a single 
 grain of strychnia will render eight gallons of water bitter. 
 It is one of the most virulent poisons yet discovered ; half a 
 grain in the throat of a rabbit occasioned death in live min- 
 utes. Its action is always accompanied by symptoms of 
 locked-jaw. 
 
 Emetia. This alkali constitutes 16 per cent, of ipecac- 
 uanha, and appears to be the sole cause of its emetic prop- 
 erties. 
 
 Sanguinaria is a peculiar alkali, discovered, by Mr. Dana, 
 in the blood root, (sanguinaria Canadensis.) Its salts have a 
 red color. 
 
 Nicotina is the peculiar principle of tobacco ; it is a viru- 
 lent poison. 
 
 Codeia, (C'H^NO*) discovered in 1832, by Robiquet, in 
 the hydrochlorate of morphia. When taken into the stomach 
 in doses of from 4 to 6 grains, it produces an excitement sim- 
 ilar to intoxication, followed by depression, nausea, and vom- 
 iting. 
 
 Brucia (C 44 H 25 N 2 7 ) resembles strychnia, and may be 
 procured from the nux vomica. It is intensely bitter, less 
 poisonous than strychnia, but similar in its effects. 
 
 Conia (C 12 H 14 NO) is the active principle of conium-macu- 
 latum, or hemlock, and is the most virulent poison known, 
 with the exception of hydrocyanic acid. 
 
 Parilla, or Parillina, exists in the common sarsaparilla of 
 commerce. Its color is white, taste sharp and bitter, and, 
 when swallowed to the extent of 13 grains, produces nausea, 
 vomiting, diminishes the rapidity of the circulation, and acts 
 as a sudorific. 
 
Fixed Oils, — Glycerine. 387 
 
 Section V. Oils and Fats. 
 
 The oils are divided into fixed and volatile oils. The for- 
 mer are not much affected by a heat which does not decom- 
 pose them, while the latter rapidly pass away in vapor. The 
 greasy stain of the former on paper, or any other surface, is 
 permanent ; that of the latter soon disappears. 
 
 1. Fixed Oils. The fixed oils are usually obtained from 
 seeds; as the almond, linseed, and poppy-seed. Olive oil, 
 however, is extracted from the pulp around the stone. The 
 density of these oils is less than water, varying from .9 to 
 .96. They are solid at a low temperature. They burn 
 with a clear, white light. By exposure to the air, they be- 
 come rancid, and at length viscid. In this change, oxygen 
 is absorbed ; and the oil itself probably undergoes some 
 change, although it has been supposed that rancidity was 
 caused by the acidification of some mucilage present. By 
 heating the oil in open vessels, it acquires the property of 
 drying rapidly ; in which process much oxygen is absorbed, 
 and carbonic acid and hydrogen given off. Drying oils are 
 used for paint, and, when mixed with lampblack, constitute 
 printers' ink. Drying oils sometimes absorb oxygen so 
 rapidly as to set fire to combustibles. Spontaneous com- 
 bustion often occurs where cotton has been moistened with 
 them. 
 
 By means of mucilage or sugar, the fixed oils may be 
 permanently suspended in water. Such a mixture is called 
 an 'emulsion. With ammonia, they form a soapy liquid 
 called volatile liniment, which is a direct compound of oil 
 and the alkali. The fixed alkalies have a similar action m 
 the cold, but, when heated, soap is generated. When acted 
 upon by alkalies, with the aid of heat, they are separated 
 into acids, which combine with the alkalies to form soaps, 
 and into another compound, called 
 
 Glycerine. C 8 H 7 5 ,HO. This substance is easily formed 
 
388 Organic Chemistry: 
 
 by heating a mixture of olive, or some other oil, oxide of 
 lead, and water ; an insoluble soap of lead is formed, and a 
 sweetish substance is separated by the water, which appears 
 to act as the base of the oil, the acid of which combines with 
 the lead. The solution is acted upon by sulphuret of hydro- 
 gen, with the addition of animal charcoal, filtered and evap- 
 orated in vacuo. 
 
 Properties. When pure, glycerine is a viscid liquid, sp. 
 gr. 1.27, very sweet taste, soluble in water, volatizes in part 
 when exposed to heat, and is converted by the action of nitric 
 acid into oxalic acid. It forms a compound acid with sul- 
 phuric acid, the Sulpho-gly eerie acid, C 8 H 7 5 ,2S0 3 . 
 
 When glycerine is heated with any body having a strong 
 affinity for water, a new compound is formed having the 
 peculiar pungent odor of burnt fat, called Acroleine, C 6 H 4 2 . 
 Glycerine is combined with several acids, giving rise to 
 Stearine, Margarine, and Oleine. 
 
 Stearine exists in tallow, from which it may be separated 
 by means of hot ether. It is a white crystalline solid. By 
 the action of caustic alkalies, 
 
 Stearic Acid (C 68 H 66 Q 5 ,2HO) is separated from the gly- 
 cerine. This acid is insoluble in water, but very soluble in 
 alcohol and ether, fuses at 167°, and possesses distinct acid 
 properties. It unites with the alkalies, and forms soaps, all 
 soluble in water; while the stearates of the metallic oxides 
 are insoluble. 
 
 Margarine exists, also> in many fats, and is obtained by 
 evaporating the ethereal solution, and absorbing the oil with 
 blotting-paper. It differs but slightly from stearine, and 
 when acted upon by alkalies, it yields glycerine, and 
 
 Margaric Acid, (C 68 H 6e 6 ,2HO,) a substance very anal- 
 ogous to stearic acid, containing only one eq. of oxygen less, 
 and forming similar salts, the margarates ; melts at 140°, and 
 when digested with nitric acid it yields suberic and succinic 
 acids, and several other products. 
 
Palm Oil. — Olive Oil. 389 
 
 Oleine is a white combustible liquid, lighter than water, 
 obtained from olive oil by means of cold, which causes the 
 margarine to crystallize. By the action of alkalies it also 
 yields glycerine, and 
 
 Oleic Acid. C 36 H 33 3 ,HO. This acid is obtained from the 
 soap made of linseed oil and potassa. It is combustible, and 
 resembles oleine in its properties, rapidly absorbing oxygen 
 from the air, and uniting with alkalies and forming soaps. 
 When heated it is decomposed into 
 
 Sebacic Acid. C 10 H 8 O 3 ,HO. 
 
 Palm Oil, which is used extensively in the" manufacture 
 of yellow soap, is obtained by boiling and pressing the 
 fruits of the elais guianensis, growing in Africa. It is of the 
 consistency of butter, has an orange-red color, with an aro- 
 matic odor. It is a mixture of oleine and palmatine. The 
 soap formed by this oil with alkalies, when decomposed, is 
 found to contain a new acid, called 
 
 Palmitic, (C 32 H 31 3 ,HO,) which is similar to the margaric 
 acid in appearance, and fuses at the same temperature, 140°. 
 
 Cocoa Oil, which is extracted from the kernel of the cocoa- 
 nut, is a white substance, consisting of oleine and a solid fatty 
 matter used for making candles. By the action of alkalies 
 we obtain a peculiar fatty acid, the 
 
 Cocinic Acid. C 37 H 26 3 . 
 
 Olive Oil is extracted from the fruit of the common olive, 
 (Olea Europea,) and is used as an article of luxury. When 
 mixed with nitrous acid, it yields a fatty crystalline body 
 called Elaidine, and this body by saponification gives rise to 
 Elaidic Acid, C 72 H 66 5 . 
 
 Croton Oil is obtained from the croton tiglium of the East 
 Indies, and possesses powerful purgative properties. It is 
 used in medicine. 
 
 Train Oil is obtained from the blubber of the right whale, 
 and is much inferior for lights to spermaceti. 
 
 Spermaceti is obtained from the blubber of the sperm 
 
390 Organic Chemi 
 
 whale, and from a large cavity in the head, from which 
 twelve or fifteen barrels of liquid oil are sometimes dipped 
 out. This substance is strained through stout bags, which 
 are subjected to a strong pressure. The solid which remains 
 is spermaceti, of which candles are manufactured, and the 
 liquid is the spermaceti oil. As the oil is more liquid in hot 
 weather, summer strained oil contains more spermaceti, and 
 a given quantity will therefore produce more light, and burn 
 less freely than icinter strained oil ; the latter is usually pre- 
 ferred, as giving a clearer light, and as being less affected by 
 cold, but it is much less economical. 
 
 Hog's Lard and Suet are well-known substances, differing 
 much in respect to their point of fusion. A very- good oil 
 has been obtained from hog's lard, by pressing it in strong 
 bags. It is nearly equal, for giving a white clear light, to 
 sperm oil. 
 
 Soaps. When any of the animal or vegetable oils or fats 
 are boiled with a solution of potassa or soda, they are con- 
 verted into oleic, margaric, or stearic acids, and another 
 principle, glycerine : the acids unite with the alkalies and 
 form soaps. All the various kinds of soap have a similar 
 constitution. Soft soaps are formed from fat and potassa ; 
 hard soaps contain soda as their base. They are soluble in 
 water, and are extensively used in the arts and in culinary 
 operations ; but when lime, oxide of lead, and many other 
 metallic compounds, are mixed in solutions of soap, the acids 
 combine in preference with these oxide, and form insoluble 
 compounds : hence, hard water, containing salts of lime, cur. 
 dies soap. 
 
 Butter consists of a solid crystalline fat, an oil, a yellow 
 coloring matter, and a little caseine, which latter substance " 
 does not belong to its constitution. The oil is a mixture of 
 oleine, and a fatty substance, butyrine. which by the action 
 of alkalies, forms soaps; and these, when decomposed, are 
 found to contain three acids, butyric, capric, and caproic acids. 
 
Volatile or Essential Oils. 391 
 
 Butyric Acid (C 8 H 7 0, s HO) has a sour taste, and an odor re- 
 sembling rancid butter. It is a colorless, oily liquid, sp. gr. 
 .976, soluble in water, and has lately been formed by the 
 fermentation of starch. The other acids are very similar to 
 butyrie, but are less soluble in water, • 
 
 Wax. The various kinds of wax, such as bees-wax, 
 myrtle-wax, and eowtree-wax, are regarded as similar in 
 composition with fats, and are classed by some chemists with 
 them. 
 
 Ambergris, found floating on the surface of the ocean, is 
 supposed to be a concretion formed in the stomach of the 
 sperm whale. 
 
 2. Volatile or Essential Oils. The flavor of aromatic 
 plants is owing to the presence .of volatile oils, which are 
 obtained by distillation. Water must be added to the plants 
 to keep them from burning, Some^ however, are obtained 
 by expressing the rinds of certain fruits, such as the orange, 
 lemon, bergamot Although usually of an agreeable odor, 
 those oils have an unpleasant, acrid taste ; but, when diluted, 
 some of them have an agreeable taste. They are but slight- 
 ly soluble in water, and are freely dissolved in. alcohol. 
 Such solutions are commonly sold under the name of es* 
 sences. Like the fixed oils, they burn with a clear, white 
 light. They have the property of dissolving ' sulphur, and 
 the solution is called balsam of sulphur. 
 
 A few of these oils — as the oil of turpentine, of lemons, 
 and of eopaiva— contain only carbon and hydrogen ; others 
 contain oxygen also. A few contain one or more additional 
 elements, as sulphur and nitrogen, 
 
 The principal volatile oils are, oil of turpentine, lemons, anise, juniper, 
 camomile, caraway, lavender, peppermint, rosemary, camphor, cinnamon, 
 cloves, sassafras, mustard and bitter almonds. 
 
 Common Spirits of Turpentine consists of resin dissolved 
 in the oil of turpentine — which last may be obtained by. dis- 
 tillation. 
 
392 Organic Chemistry. 
 
 Camphor is a volatile oil, solid at common temperatures. 
 On account of its toughness, it is pulverized with difficulty, 
 unless a few drops of alcohol is added. It is insoluble in 
 water, but is freely soluble in alcohol. Artificial camphor 
 may be formed by passing a current of hydrochloric acid gas 
 through oil of turpentine or oil of lemons. Camphor is very 
 offensive to insects, which are prevented from devouring cab- 
 inets of natural history, collections of birds, insects, etc., by 
 placing pieces of camphor in the cases. 
 
 Resins. Resins are the concrete juices of plants, solid, 
 brittle, and without taste -> they are good non-conductors of 
 electricity, and, by friction, become negatively electrified; 
 they are easily melted, and burn with a yellow flame and 
 dense smoke. They are soluble in alcohol, ether, and the 
 essential oils, but are quite insoluble in water. 
 
 Common Resin is procured by heating turpentine ; the vol- 
 atile oil is expelled, and resin remains. It is a mixture of 
 pinic acid (C 20 H 15 O 2 ) and sylvic acid (C 4ft H 30 O\) 
 
 Turpentine is the juice of several speeies of pine-trees. 
 Other resins are : copal, lac, mastic, and dragon's Hood. 
 
 Copal is the most important, and is used for varnish. In- 
 dian ink is a solution of borax, lac, and lampblack. 
 
 The uses of resin are various. Dissolved in oil or alcohol, 
 and diluted with spirits of turpentine, they form various kinds 
 of varnish. Sealing-wax is made of lac, turpentine, and com- 
 mon resin. It is colored red with cinnabar or red lead, or 
 black with lampblack. 
 
 The soot, which is procured from the combustion of res- 
 inous wood, turpentine, or resin, is lampblack. When tur- 
 pentine is extracted by heat, it is partially changed, and be- 
 comes tar. When tar is thickened by boiling, it becomes 
 pitch. 
 
 Amber is a fossil substance, consisting of a peculiar bitu- 
 minous matter and resin ; it often contains insects. 
 
 Balsams are the juices of some kinds of trees. Some are 
 
Gum Resins. — Wax. 393 
 
 solid, others are liquid. They are composed of resin and 
 benzoic acid. 
 
 Gum Resins are the hardened juices of certain plants, con- 
 sisting of resin, gum, and volatile oil. Their proper solvent, 
 therefore, is a mixture of alcohol and water, or common spir- 
 its. They are numerous, and many of them are valuable 
 medicines ; among them are aloes, assafoetida, galbanum, gam- 
 boge, myrrh, and giiaiacum. 
 
 Caoutchouc, or India rubber, is obtained from four species 
 of trees, two of which grow in South America, and two in 
 the East Indies. It is usually black, but when not darkened 
 by smoke, is of a whitish color. It burns with a bright flame ; 
 is insoluble in water or alcohol. It is soluble in ether, the 
 essential oils, etc. If a bag of it be soaked in ether, it will 
 become soft and gelatinous before dissolving, and in that 
 state may be blown out into a very large and thin bag. The 
 most useful solvent of caoutchouc is a dark, volatile liquid, 
 obtained by the careful distillation of caoutchouc itself ; about 
 four-fifths of the solid pass over in this liquid form. 
 
 Wax. Wax is found in the pollen or dust of flowers, on 
 some leaves as a kind of varnish, and especially on the ber- 
 ries of the wax plant, (myrica cerifera.) As bees deposit wax, 
 when fed only on sugar, beeswax is an animal product. Wax 
 is insoluble in water, and is sparingly dissolved by alcohol 
 and ether. It is composed of two principles, cerine and 
 myricine. 
 
 Creosote. This substance exists in tar, and in pyroligne- 
 ous acid. It is a colorless, oily liquid, with an odor like 
 smoked meat. It has a burning taste, followed by sweetness. 
 Its most remarkable property is that of preserving meat. The 
 antiseptic properties of smoke, and crude pyroligneous acid, 
 appear to be owing to this substance. It is soluble in 80 
 parts of water, and freely in alcohol. Insects and fish are 
 killed by the aqueous solution. It is said to be useful as a 
 cure for toothache, ulcers, etc. 
 
 17* 
 
394 Organic Chemistry. 
 
 Section VI. Coloring Matters. 
 
 The most common colors in the vegetable kingdom are 
 green, yellow, blue, and red. The greater part of the infinite 
 diversity of colors consists of different shades or mixtures of 
 these. The coloring matter of plants is usually diffused 
 through other proximate principles. All vegetable colors 
 are destroyed by chlorine, and usually changed by acids or 
 alkalies. 
 
 Lakes are insoluble compounds of coloring matter with 
 alumina, or oxide of iron or of tin. 
 
 Process. Dissolve alum in a colored solution, and, on add- 
 ing an alkali, (as potassa,) alumina will be precipitated ; and, 
 at the moment of separation from the alum, will combine with 
 the coloring matter. 
 
 In dyeing, some colors have a sufficient affinity for the 
 fibre of the cloth to remain fast on a mere immersion of it. 
 In many cases, however, this is not sufficient, and the color 
 would be removed by washing. A third substance is intro- 
 duced, which, having an affinity both for the coloring matter 
 and the cloth, fixes the former permanently to the latter. 
 This third substance is called the mordant or basis : those 
 which are in common use are, alumina in alum, oxide of 
 iron in copperas, and chloride of tin, which is converted into 
 the oxide. All the colors of dyed stuffs are produced from 
 the four — blue, red, yellow, and black. 
 
 Blue Dyes. Indigo is the most important of these, and is 
 obtained from several species of a genus of plants which are 
 cultivated in America and Asia. The plants are fermented 
 and beaten in water, at the bottom of which the indigo sub- 
 sides. Common indigo contains, in addition to its peculiar 
 blue, a red and a brown coloring matter, with some gluten. 
 Pure indigo sublimes at 550° Fahr., and condenses in acic- 
 ular crystals. It is insoluble in water, and but slightly solu- 
 
Indigo. — Isatine. 395 
 
 ble in boiling alcohol ; it is soluble in sulphuric acid. If in- 
 digo be put into a tube with three times its weight of green 
 vitriol, and an equal quantity of slacked lime, with water, the 
 protoxide of iron will be precipitated by the lime from the 
 green vitriol, and the indigo will be de-oxidized by it, and 
 become yellow. Dyers dip their cotton cloth into it in this 
 condition, and by exposure to air the cloth becomes perma- 
 nently blue. 
 
 Pure Indigo is composed of C^IPNO 12 , but when exposed 
 to deoxidizing agents as above, it is reduced, and becomes 
 white, having the formula C Ifi H 5 N0 2 ,H. 
 
 When indigo is heated with dilute chromic acid, or SO 3 , 
 and bichromate of potassa, it forms a yellow solution, which, 
 on evaporation, deposits orange-red crystals of 
 
 Isatine, (C^IPNO 4 ,) containing two additional equiv. of 
 oxygen. By the action of alkalies, isatine takes up the ele- 
 ments of water, and forms 
 
 Isatinic Acid, (C 16 H 6 N0 5 ,) and this acid by the action of 
 chlorine, forms two peculiar substances, called chlorisatine, 
 (C 16 H 4 N0*C1,) and bichlorisatine. (C 16 H 3 N0 4 C1 2 .) And by 
 the continued action of chlorine on these latter substances, a 
 volatile substance in crystalline scales, of a brown-yellow 
 color, is formed, called Chloranile, (C 6 C1 2 2 ,) which by the 
 action of potash, gives rise to chloride of potassium, and 
 Chloranilate of potash. From this latter substance Chlora- 
 nilic Acid (COo 3 ) may be obtained, as a reddish powder. 
 
 By transmitting sulphuret of hydrogen through an alcoholic 
 solution of chlorisatine, a white compound is formed, called 
 CMorisatyde. 
 
 By the continued action of nitric acid, upon indigo, anilic, 
 or indigotic acid, (C 14 H 4 N0 9 ,) and carbazotic or picric acid, 
 (C 12 H 2 N 3 13 ,) are formed. The former forms colorless crys- 
 tals, of a bitter taste, and the latter, yellow, brilliant prisms, 
 of a very bitter taste. The picrates explode when heated. 
 
 Many other compounds are derived from indigo. Sulphu- 
 
396 Organic Chemistry. 
 
 ric acid dissolves indigo with the formation of two acids. 
 The sulphindigotic add is the most important, because it is 
 the substance used for coloring Saxon blue. 
 
 E-:i B-,-:s. T::e .:::r. >::::: ::.::. -: :. .-" ::i- ::': ir." :'"r5. :-.'.": 
 cochineal, lac, archil, madder. Brazil-wood, and logwood. 
 
 Cochineal is obtained from an insect, which feeds upon 
 the leaves of several species of the cactus, and derives : 
 oring matter from its food. 
 
 It is very soluble in water, and is fixed on cloth, by means 
 of alumina or oxide of tin. Its natural color is crimson, 
 but when bitartrate of potassa is added to the solution, it 
 yields a rich scarlet dye. The beautiful pigment called 
 carmine, is a lake made of cochineal and alumina or oxide 
 of tin. 
 
 Archil is obtained from certain lichens, which grow in the 
 Canary Islands. From the Roccefla Tinctoria or archil 
 plant, several compounds have been obtained. 
 
 Erythrilin, (C 32 H ls O%) is a white powder. Er\ 
 (C^H^O*) which is formed into brilliant snow-white s : 
 becoming brown on exposure. Amaruthrin, (C^EPO 1 *,) and 
 several other bodies are also found. 
 
 The archil of commerce is obtained mostly from the Par- 
 melia, but. the principle most active in any of the lichens 
 is Orcein, which is of a fine red color ; with ammonia or 
 potash it gives a most splendid purple color, and various 
 lakes are formed from its combinations with alkalies and 
 metallic oxides. 
 
 Litmus is prepared from archil, and from this substance, 
 which is blue, red coloring matters are obtained. 
 
 Madder is the root of the rubia tinctorum, and contains a 
 peculiar coloring principle. 
 
 Alizarin. (C 37 H"0 1 \) It exists as a red powder, 
 may be made to form long slender needles, soluble in boiling 
 water. There are several coloring matters obtained from 
 
Nutritive Substances. 397 
 
 madder, as Madder-purple, Madder-red, Madder -orange, 
 Madder-yellow, Madder-brown. 
 
 The most beautiful reds and purples are obtained from this 
 substance, as well as those most durable — the Turkey-reds 
 and lakes. 
 
 Yellow Dyes. The principal, are quercitron bark, tumeric, 
 saffron, and fustic. Several distinct principles are found in 
 these substances, which are the coloring matters in yellow 
 dyes. 
 
 Black Dyes are prepared from the same ingredients as 
 writing-ink. Logwood contains a crystalline reddish sub- 
 stance, called Hematoxylin, which is the coloring principle of 
 black and blue-black. 
 
 Section VII. Nutritive Substances. 
 
 In addition to the substances already described, such as 
 starch, sugar, lignin, &c, there exists in vegetables a dis- 
 tinct class of bodies, containing nitrogen, and small quantities 
 of sulphur and phosphorus. They are the substances which 
 nourish animals, and form, with but slight change of prop- 
 erties, the muscles of animals. They are also found in the 
 blood and some other fluids of the animal body. These sub- 
 stances have a strong tendency to putrefaction when exposed 
 to the air. They are, Fibrine, Albumen, Legumine, Caseine, 
 Froteinc, and Gelatine. 
 
 Fibrine. Vegetable fibrine may be obtained from wheat 
 flour, by separating the starch ; the tenacious substance which 
 remains is called gluten, (see p. 344) but it is mostly vegetable 
 fibrine. 
 
 Animal fibrine is probably the same substance, somewhat 
 changed by the animal organs. It is the basis of muscle, 
 and exists in the blood, from which it may be obtained by 
 stirring freshly drawn blood with a stick ; the fibrine ad- 
 heres, and when washed, is a white substance, becoming 
 somewhat horny on drying. When subjected to the action 
 
898 Organic Chemistry. 
 
 of nitric acid, it throws off a large quantity of nitrogen ; 
 with acetic acid, it forms a jelly. 
 
 Albumen. Vegetable albumen exists in the juices of 
 plants, and in their seeds. 
 
 Animal albumen is very similar, if not identical, with it ; 
 and is found, in a solid state, in the skin, glands, and vessels 
 of animals ; and in a liquid state in the serum of the blood, 
 the fluid of dropsy, and the white of eggs. When liquid, it 
 is coagulated by heat, as in the boiling of an egg, or by 
 alcohol and the stronger acids. Corrosive sublimate is a 
 very delicate test, producing a milkiness in water which con- 
 tains -^ro P ar t of albumen. 
 
 Legumine, Vegetable Caseine, exists in the seeds of beans 
 and peas, from which it is obtained by the action of acetic 
 acid. It resembles the curd of milk. 
 
 Animal Caseine is similar to the above, and is the substance 
 known as milk curd. It is obtained from milk, in which it is 
 held in solution by an alkali, by adding dilute acids. When 
 milk sours and coagulates, lactic acid is formed from the su- 
 gar it contains, aided by caseine in a state of decomposition. 
 Rennet, a substance formed by soaking the lining membrane 
 of a calf's stomach in water, acts like caseine, and facilitates 
 the coagulation of the milk, as in the manufacture of cheese. 
 All these substances are identical in composition. They are 
 formed by the vegetable, taken into the animal organism, and 
 assimilated with but slight change of properties. 
 
 Proteine (C 4e H 30 N fi O 12 ) is obtained from either of the above 
 substances by heating them in a dilute solution of potash, 
 and adding acetic acid, a white solid is precipitated, which 
 was discovered by Mulder, and named proteine. It differs 
 from the substances from which it is derived by not contain, 
 ing. sulphate of lime and salts of soda. It appears to be 
 closely allied to albumen and fibrine, and nearly identical 
 in composition. 
 
 Gelatine. C 18 H 10 N 2 O 5 . This substance is abundant in 
 
Complex Animal Substances. 399 
 
 the solid parts of animals, in the skin, cartilages, membranes, 
 and bones. It is very soluble in boiling water, and forms a 
 bulky jelly on cooling. One part in 100 of hot water will 
 render the whole solid on cooling. The jelly is a hydrate of 
 gelatine ; and, if the water be expelled by gentle heat, it 
 may be preserved for any length of time. This is known as 
 glue, which is prepared from the ears, skins, and hoofs of 
 animals. 
 
 Isinglass is a pure variety obtained from the sounds offish. 
 It is the gelatine which forms leather by uniting with tannic 
 acid, and for this purpose the skins of animals are steeped in 
 an infusion of oak or hemlock bark, and the gelatine forms 
 an insoluble compound with the tannic acid. 
 
 Glycocoll* or Gelatine Sugar (C 4 H 4 N0 3 .HO) is formed by 
 the action of sulphuric acid on gelatine, or isinglass ; also by 
 boiling hippuric acid with sulphuric or any of the stronger 
 acids, benzoic acid and a salt of glycocoll are formed. This 
 substance is then obtained by decomposing the salt. 
 
 Properties. A crystalline solid ; taste sweet ; neutral to 
 test paper ; soluble in water ; nearly insoluble in alcohol ; 
 performs the part both of a base and of an acid, and forms a 
 large number of compounds, by uniting with acids and bases. 
 
 Section VIII. Complex Animal Substances. 
 
 Blood. Blood consists of a clear liquid, through which 
 are diffused red globular particles. The liquid portion con- 
 sists of water holding in solution fibrine, albumen, saline and 
 oily matters. When set at rest it coagulates, forming a jelly. 
 The red, or orange-red globules in the higher animals, are 
 spherical and ellipsoidal, marked with a colorless spot in 
 the centre. These globules are compound, consisting of a 
 sack, which is allied to fibrine in composition, and a coloring 
 matter which is called 
 
 Hemaiosin or Hematine. C 44 H 22 N 3 6 Fe. The iron is not, 
 
 * A very able paper on Glycocoll and its compounds, may be found in 
 Silliman's Journal, Nos. 9, 10, and 12, (1847,) by Prof. E. N. Hosford. 
 
400 Organic Chemistry. 
 
 however, essential to its constitution, as it may be separated 
 from it. It has been supposed that the scarlet color of arte- 
 rial blood was due to peroxide of iron ; but hematine is not 
 altered in color by this substance, nor is it changed by the 
 action of oxygen. 
 
 It is a brownish-red solid, and when in solution its color is 
 similar to venous blood. The color of this substance is 
 changed to that of arterial blood by the action of alkalies, so 
 that the change of color from red to scarlet, by the action of 
 the oxygen of the air, is not satisfactorily accounted for. 
 Mulder has suggested the hypothesis that the action of the 
 oxygen in the lungs upon the fibrine surrounding the blood 
 globules forms a layer of proteine, which is white, and 
 gives the scarlet tint. During the circulation, this matter is 
 taken up, and the globules appear dark again in venous blood. 
 
 Liebig ascribes the change of color which the venous 
 blood undergoes by the action of oxygen, to the peroxidation 
 of the iron in the blood. Thus venous blood contains car- 
 bonate of the protoxide of iron, which gives it the dark 
 color ; but when it meets a stream of oxygen gas in the 
 lungs, the oxygen unites with the protoxide of iron ; con- 
 verting it into the binoxide, which gives the arterial blood the L 
 scarlet color ; while the carbonic acid is expelled or cast out 
 in the atmosphere. During the circulation, the oxygen com- 
 bines with the worn-out tissues, forming carbonic acid, which 
 appears in venous blood, combined with protoxide of iron ; 
 this protocarbonate is again decomposed by oxygen. 
 
 When blood is set at rest, it does not separate into the two 
 parts above mentioned, but into a red coagulum, called the : 
 clot and the serum. The latter is a yellowish liquid. The 
 saline substances contained in the blood are carbonates, ; 
 phosphates, and sulphates of potassa and soda. It contains ' 
 also chloride of sodium, {common salt,) chloride of potassium, 
 and, as we have seen, oxide of iron. More than three-quar- 
 ters of the blood is water : coloring matter .125, and albumen 
 
780.145 
 
 785.590 
 
 2.100 
 
 3.565 
 
 133.000 
 
 119.626 
 
 . ' 65.090 
 
 69.415 
 
 2.43 
 
 4.300 
 
 1.310 
 
 2.270 
 
 .790 
 
 1.920 
 
 1.265 
 
 2.010 
 
 Animal Heat Theories. 401 
 
 .067, though the proportions vary somewhat even in the same 
 person at cP.fferent times. 
 
 The following table, by M. Le Canu, represents the com- 
 position of the blood as derived from two careful analyses : — 
 
 Water, 
 
 Fibrin, 
 
 Coloring matter, 
 
 Albumen, ..... 
 Crystalline fatty matter, 
 Oily matter, .... 
 
 Extractive matter, soluble in water and alcohol 
 Albumen combined with soda, 
 Chloride of sodium, ^| 
 
 " of potassium, . . | 
 Carbonates i f> 8.370 7.304 
 
 Phosphates > of soda and potassa, 
 Sulphates ) J 
 
 Carbonates of lime and magnesia, i 
 
 Phosphates of lime, magnesia, and iron, > . 2.100 1.414 
 
 Peroxide of iron, \ 
 Loss, 2.400 2.586 
 
 1000.000 1000.000 
 Animal Heat. There is a striking analogy between the 
 process of combustion and respiration. In both cases, oxygen 
 is consumed, and carbonic acid produced. This fact led 
 Dr. Black to infer that the heat generated in the animal sys- 
 tem was derived from the change which takes place in the 
 lungs. That the development of animal heat is dependent 
 upon respiration, is a matter of easy demonstration ; but how 
 the effect takes place, has not been satisfactorily explained, 
 In those animals which consume a small quantity of oxygen, 
 the temperature of their bodies varies with the surrounding 
 medium, and are called cold-blooded ; but in those that con- 
 sume a larger quantity of oxygen, the temperature is nearly 
 uniform, whatever be the temperature of the medium. They 
 are hence called warm-blooded. The temperature of the 
 same animal varies often, according as the respiration is 
 sluggish or rapid. 
 
 To account for animal heat, Dr, Crawford proposed the 
 first consistent theory, which is founded on the supposition 
 that the blood, when purified by the oxygen of the air, haa 
 
402 Organic Chemistry. 
 
 its capacity increased for caloric ; and hence the heat pro- 
 duced in the lungs by the consumption of the oxygen, enters 
 into an insensible state in the arterial blood. As this blood 
 circulates through the system and enters the veins, it loses its 
 capacity, and gives out its caloric. But Dr. Davy denies that 
 there is any difference between the capacity of venous and 
 arterial blood. If, however, we suppose that the oxygen does 
 not combine with the carbon in the lungs, but in the course 
 of circulation, there would be heat developed in all parts of 
 the system ; and this view would account for the facts, irre- 
 spective of the different capacities of the two kinds of blood. 
 
 MM. Dumas and Boussingault have proposed a theory 
 which is received with much favor by chemists. They sup- 
 pose that the oxygen of the air on entering the blood, con- 
 verts its soluble matters into lactic acid, which unites with 
 soda, forming lactate of soda. The oxygen converts the lac- 
 tate into carbonate of soda. A new portion of lactic acid de- 
 composes this salt and liberates the carbonic acid, which 
 appears in the venous blood. In this case there is a true 
 combustion—the combination of oxygen with carbon. But 
 whatever view be adopted of the action of oxygen in pro- 
 ducing animal heat, there can be no doubt but that the union 
 of the oxygen of the air with the worn-out tissues of the body, 
 and with substances taken as food, which are rich in hydro- 
 gen, as oils, fats, &c, are sufficient to account for the 
 heat which is generated in the animal system. The action 
 of oxygen is to burn up the system, 1st, by uniting with those 
 particles which have served their purpose in the animal 
 economy, and must be removed, and their places supplied 
 with others endowed with a higher degree of vitality, and 
 2dly, by combining with that portion of the food which is in- 
 tended for respiration, and not for nutrition. 
 
 Water and carbonic acid are the products of this combus- 
 tion, and are not only expelled through the lungs, but ex- 
 haled from all parts of the body. 
 
Gastric Juice. — Bile, 403 
 
 Saliva. This liquid contains only seven parts of solid 
 matter in a thousand. It contains chloride of potassium, 
 sulphate, phosphate, acetate and carbonate of potassa, with 
 some other salts, and an animal substance called ptyaline. 
 It forms a soft, pulpy mass with the food in mastication, pre, 
 paring it for more easy digestion. 
 
 Gastric Juice. This fluid taken from an empty stomach 
 has a saline taste, and is neutral. But when any substance 
 enters the stomach, acid is secreted. Both hydrochloric and 
 acetic acids are formed. All nutritious substances are dis* 
 solved by this juice, and converted into a pulpy mass called 
 chyle. It does not act on living substances, or the stomach 
 itself would be dissolved, as sometimes is the fact after death. 
 Its solvent power is due to the acids, which are greatly aided 
 by the temperature of the stomach. By taking magnesia, the 
 acids are neutralized, and the digestive power suspended for 
 the time. The gastric juice consists mostly of pepsin. 
 
 Bile. The bile is a yellow or greenish, nauseous liquid, 
 of which •£ are water, and the remainder a peculiar bitter 
 principle called bilin, with resin, and several salts. The bile 
 stimulates the intestinal canal, and assists in converting the 
 chyme into chyle. 
 
 The bilin is translucent, colorless, and inodorous, with a bit* 
 ter and somewhat sweetish taste. In the resinous portion, a 
 white earthy substance has been obtained, called dyslysin. 
 
 Taurin (C 4 H 7 N0 10 ) is another substance, which has been 
 derived from the bile. It is a crystalline solid, neutral and 
 of a weak taste. Several acids have also been obtained from 
 bile : cholic acid, which crystallizes in fine needles, and has 
 a sharp sweet taste ;fellinic acid, which is a white, inodorous, 
 and bitter solid, fusing at 212° ; cholinic acid, also, a whitish 
 substance, insoluble in water, but soluble in alcohol ; bileverdin, 
 a greenish-brown mass without taste, soluble in alkalies, and 
 
 Cholesterin (C 37 H 32 0.) which is also a constituent of the 
 brain and nerves. It is a crystalline substance, and is found 
 
404 Organic Chemistry. 
 
 in the greatest abundance in gall stones, which are solid con- 
 cretions in the gall bladder. 
 
 Chyle. This is a white fluid resembling milk. It contains 
 %bt>ut 90 per cent, of water ; of the other constituents, albu- 
 men is most abundant. 
 
 Milk. This liquid is well known to consist of cream, 
 curd, and whey. 100 parts of cream, of specific gravity 
 1.0244, contain only 4.5 parts of butter ; of the remainder, 
 92 are whey, and 3.5 curd. The coagulation in sour milk is 
 produced by the generation of lactic acid, which, in common 
 with acids generally, separates the curd from the whey. 
 The same effect is caused by rennet prepared from a calf s 
 stomach, which is impregnated with the gastric juice, and 
 therefore contains acid. Milk is of course curdled when 
 taken into the stomach. 
 
 Lymph is a peculiar, limpid, transparent liquid, which 
 moistens the cellular membrane, and collects abundantly in 
 some dropsical affections. It consists chiefly of water, with 
 hydrochlorate of soda and albumen. 
 
 The humors of the eye contain more than 80 per cent, of 
 water ; the other ingredients are albumen, muriate and ace- 
 tate of soda, pure soda, and an animal matter like curd, 
 which gives it a milky appearance. 
 
 The tears contain pure soda, chloride of sodium, and phos- 
 phate of soda, with water, and an animal matter analogous to 
 albumen. 
 
 Mucus is a fluid secreted by the mucous surfaces, as the 
 nose. 
 
 Pus is a liquid matter secreted by an inflamed and ulce- 
 rated surface. Its characteristic ingredient resembles al- 
 bumen! 
 
 Sweat is the vapor which constantly passes off from the 
 skin, and consists mostly of water, mixed with a little muriate 
 of soda, and free acetic acid, and perhaps formic acid. 
 
 Urine differs from most animal fluids in serving no ulterior 
 
 1 
 
Urinary Calculi* 405 
 
 purpose in the animal Economy. It is an excretion consisting 
 of substances which would prove injurious to life and health. 
 The urine is separated by the kidneys from the blood, and 
 consists of a great variety of substances, such as water and 
 urea, which are the principal, uric acid, lactic acid, lactate 
 of ammonia, mucus, sulphates of potassa and of soda, phos- 
 phates of soda and of ammonia, muriates of soda and of am- 
 monia, earthy matters with a trace of fluate of lime, and sili- 
 ceous earth. 
 
 Urinary Calculi are solid concretions found in the urinary 
 organs. The following are some of the varieties: — 
 
 Xanthic Oxide (C 5 N 2 H 2 2 ) is among the most rare of these 
 calculi, it is of a light-brown color, and may be known by 
 its solubility in caustic potassa, from which it is precipitated 
 by carbonic acid. 
 
 Cystic Oxide (C 6 NH 6 4 S 2 ) is also rare ; color yellowish- 
 white and brilliant waxy-lustre. It may be known by being 
 soluble in caustic potassa, from which acetic acid separates 
 it in the form of hexagonal plates. 
 
 Mulberry Calculus, (Oxalate of Lime,) Bone Earth Cal- 
 culus, (Phosphate cf Lime,) and Ammoniaco-Magnesian Phos- 
 phate Calculus, are more common, and may be known by 
 vj^y simple tests. Calculi are more commonly formed of uric 
 acid and nitrate of ammonia. 
 
 Eggs. The shell of an egg is about -fa, the white -^, and 
 the yolk -^ of the whole. The shell consists chiefly of car- 
 bonate of lime ; and the white, of albumen, with a little sul- 
 phur. The yolk contains phosphorus, which supplies phos- 
 phoric acid for forming the bones of the chicken. 
 
 Bones. Bones contain about i of animal matter, \ of phos- 
 phate of lime, tV of carbonate of lime, with a little fluoride 
 of calcium, and some other salts. Teeth have the same com- 
 position, but the enamel contains 78 per cent, of phosphate 
 of lime. The shells of crustaceous animals, as lobsters and 
 crabs, consist of carbonate and phosphate of lime, with ani- 
 
406 Organic Chemistry, 
 
 mal matter; but the shells of molluscous animals, or true 
 shells, as of the oyster, snail, etc., consist almost entirely of 
 carbonate of lime and animal matter. 
 
 .Horn differs from bone in containing only a trace of earth. 
 The composition of the nails, hoofs, and cuticle of animals is 
 similar to horn. 
 
 Tendons are composed almost wholly of gelatin. 
 
 The true skin has nearly the same composition. Mem- 
 branes and ligaments contain in addition some substance 
 which is insoluble in water, and is similar to coagulated al- 
 bumen. 
 
 Hair contains a peculiar animal substance, insoluble in 
 water at 212°, but soluble in a solution of potassa. It also 
 contains an oil, which gives the peculiar color of the hair, 
 sulphur, upon which the nitrate of oxide of silver acts in stain- 
 ing it, together with silica, iron, manganese, and carbonate 
 and phosphate of lime. 
 
 Wool and feathers are similar in composition to hair. 
 
 Silk is covered with a peculiar varnish, which amounts to 
 about 23 per cent. 
 
 Muscle, The lean flesh of animals consists essentially of 
 fibrin, with numerous other ingredients, such as albumen, 
 gelatin, a peculiar extractive matter called osmazome, fsfy 
 and salts. 
 
 Brain and Nerves. The brain consists of 7 parts of albu- 
 men, 5 parts of fatty matter, and 80 parts of water. The 
 fatty portions contain two peculiar acids. 
 
 Cerebric Acid, which appears in white crystalline grains, 
 soluble in boiling alcohol, and swells up like starch in con- 
 tact with boiling water, without being soluble. It is com- 
 bustible, fusing at a high temperature. 
 
 Oleophosphoric Acid is separated from the preceding by the 
 action of ether. It is a viscid substance, forming soaps with 
 alkalies. Cholesterin, olein and margarine, are also found 
 
Growth and Nourishment of Plants and Animals. 407 
 
 [ 
 
 i| in the brain, with lime, phosphorus and soda. The nerves 
 
 have a similar constitution. 
 
 Section IX. Growth and Nourishment of Plants and An« 
 imals. 
 
 Germination refers to the process by which a new plant 
 originates from the seed. The seed consists of two parts. 
 The germ, which is endowed with the vital principle, and the 
 cotyledons, or seed-lobes, which furnish nourishment to the 
 plant before it can derive it from the earth. The germ is 
 composed of the radicle, or that part which descends into the 
 ground, and forms the root, and the plumula, which rises into 
 the air, and forms the stem of the plant. 
 
 The three conditions necessary to the germination of the 
 plant, are moisture, a certain temperature, and oxygen gas. 
 Dry seeds will not germinate, or, if moist, germination will 
 not take place at 32°, nor at the temperature of boiling water, 
 which deprives the germ of its vitality. The most favorable 
 temperature is from 60° to 80°, varying with the nature of 
 the plant. Air is also necessary to germination ; for if seeds 
 are buried deep, excluded from the air, they will never pass 
 through this process. 
 
 In the malting of barley, the process of germination may 
 be accurately studied. The malting is done by exposing the 
 grain to moisture, warmth, and air, until it begins to germi- 
 nate, and then drying it in a kiln, where the temperature 
 ranges from 100° to 160°, or more. The chemical changes 
 which take place in this process, are the following : The 
 hordein, an insoluble substance, is converted into starch, 
 gum, and sugar, which are soluble and very nutritive sub- 
 stances, easily absorbed by the radicle of the plant ; at the 
 same time, oxygen gas is consumed, and carbonic acid gas 
 is given off. 
 
 Growth of Plants. There are many points of resemblance 
 
408 Organic Chemistry. 
 
 between the growth of plants and of animals ; and also many 
 points in which they differ. The plant absorbs carbonic 
 acid, and yields oxygen, but the animal absorbs oxygen, and 
 yields carbonic acid. The absorption of the acid by the 
 plant is the natural mode of obtaining food. The oxygen it 
 gives out is an excretion resulting from the assimilation of 
 the carbon, but the absorption of oxygen by animals is for a 
 very different purpose. It is to purify the system, by burn* 
 ing up particles which can no longer retain their vitality, 
 and to keep the animal warm. 
 
 The growth of plants proceeds by continued or annual ad- 
 ditions, which ever remain a portion of the trunk, but the 
 growth of animals proceeds in a very different manner ; the 
 matter of their bodies is continually changing. 
 
 Plants are nourished mostly by inorganic substances, while 
 animals must have organized structures for their support. 
 
 Food of Plants. The food of plants has beep a subject 
 of much controversy. The elementary substances, oxygen, 
 carbon, hydrogen, nitrogen, and a few metallic salts, are the 
 only constituents of plants and of animals, and it would seem 
 to be an easy matter to point out the source, and the mode 
 in which they are assimilated or combined to form vegetable 
 or animal bodies. But there is still some difference of opin- 
 ion on the subject. 
 
 Source of Carbon. Carbon is the most abundant constitu- 
 ent of plants. 
 
 Whence do plants obtain it ? 
 
 There can be no doubt but that a large quantity of this 
 substance is derived from the carbonic acid of the atmos- 
 phere ; for it is a well-settled doctrine among vegetable phvs- 
 iologists, that the leaves and green parts of plants absorb car- 
 bonic acid during the day, and by the aid of solar light, de- 
 compose it — -assimilating the carbon, and yielding back the 
 oxygen to the air. Carbonic acid is also generated by the 
 decomposition of vegetable matter in the soil, and absorbed by 
 
Source of the Organic Constituents of Plants. 409 
 
 the water with which it enters the roots of plants, ascends 
 to the leaves, where it is decomposed by the action of light. 
 
 So large a portion of the carbon of plants is derived from 
 the carbonic acid of the atmosphere, that a distinguished 
 chemist (Liebeg) has attempted to prove that carbonic acid 
 is the only source of carbon. It is admitted by all chemists 
 and vegetable physiologists that carbonic acid is the principal 
 source, but other substances rich in carbon, such as the con- 
 stituents of vegetable mould, which have been described un- 
 der the names of humus, humic acid, geine, ulmin, may also 
 furnish to plants a portion of their carbon. 
 
 It will be readily seen that previous to the formation of 
 coal beds, the quantity of carbonic acid in the atmosphere 
 must have been much greater than at present — -for we find 
 that coal originated from living vegetables-— and these veg- 
 etables obtained their carbon mostly from the atmosphere. 
 1 he quantity of carbonic acid in the atmosphere is easily es- 
 timated, and the quantity of coal or carbon which it is cat- ■ 
 pable of yielding, in the form of wood, &c. The quantity 
 of coal stored up in rocks can also be estimated with some 
 degree of accuracy ; and from those estimates, it is supposed 
 that the atmosphere once contained at least five times as 
 much carbonic acid at it does at the present time ; and, hence, 
 we may account for the absence of air-breathing animals in 
 early geological times; Air-breathing animals make their 
 appearance on the earth's surface immediately after the coal 
 beds were deposited, and not before* If our atmosphere 
 contained five times its present quantity of carbonic acid, 
 it would prove injurious to animal life, perhaps, wholly de- 
 structive of it. 
 
 Source of Oxygen and Hydrogen. There can be but little 
 doubt but that water yields both oxygen and hydrogen to 
 plants, in fact, woody fibre contains oxygen and hydrogen in 
 the same proportion as in water. A certain quantity of car- 
 bon united to the elements of water would form woody fibre ; 
 
 18 
 
410 Organic Chemistry. 
 
 but in some compounds hydrogen, and in others, oxygen, is 
 in excess. 
 
 Hydrogen may be derived from ammonia, (NH a ,) and both 
 oxygen and hydrogen from vegetable mould. 
 
 Source of Nitrogen. Nitrogen is derived from ammonia, 
 which exists in the atmosphere and in all fermenting manures. 
 Nitrogen may also be obtained from nitre and from vegetable 
 mould. 
 
 The unorganized portions are all derived from the earth, 
 absorbed through the roots, and with water, introduced 
 into the circulation. Out of these simple elemental sub- 
 stances, vegetables manufacture all their peculiar principles. 
 The nutritious matters pass first to the leaves, which seem to 
 be the great organs of digestion and respiration ; from the 
 leaves the matter descends between the bark and wood in 
 exogens, and passing through several transformations, de- 
 posits a layer of new wood, which forms a ring of annual 
 growth. The conditions of the growth of plants, and the 
 means by which their products may be increased, belong to 
 the science of Agricultural Chemistry. To the numerous 
 works on that subject, the student is referred for full infor- 
 mation. 
 
 Nourishment of Animals. Animals originate in a different 
 manner from plants — the one from a seed, the other from an 
 egg ; and yet the composition of animal bodies is identical 
 with that of vegetables ; for, although animals are endowed 
 with a higher degree of vitality than vegetables, they have 
 not the power of forming any portion of an animal tissue, or 
 any other animal substance, out of inorganic matter — they 
 merely assimilate the substances which vegetables form. 
 There is nothing in animal bodies which is not found in veg- 
 etables. The process of growth, however, is much more 
 complicated, the nutritive matters taken from vegetables are 
 assir^p**^ and made a part of animal bodies, after having | 
 
Nourishment of Animals. 411 
 
 passed through the process of digestion and purification by 
 the action of oxygen. 
 
 The crude material passes through a process of purifica- 
 tion, by which the nutritious matters are appropriated to the 
 sustenance and service of the various organs. All substances, 
 which are strictly nutritious, contain nitrogen ; hence, oils, 
 fats, sugars, &c, are not strictly nutritious, and will not sup- 
 port life for a long time. All the animal tissues and organs 
 contain nitrogen. That portion of their food which does not 
 contain nitrogen, is used for the purposes of respiration. One 
 object of respiration is to produce heat. It is easy to see, 
 why it is that those animals which inhabit cold climates re- 
 quire a larger quantity of food for respiration, than those 
 that live near the equator ; why more of such food is re- 
 quired in winter than in summer ? why those animals that 
 pass into a torpid state during the winter, lay up large quan- 
 tities of fat in the autumn, to be consumed in keeping their 
 bodies at a temperature at which life can be maintained dur- 
 ing the winter. An animal, during its torpid state, has a 
 very sluggish respiration — yet sufficient oxygen enters the 
 lungs to combine with the fat, to consume it, so that in the 
 spring, they come out of their sleep, very much emaciated. 
 In fact, an animal is like a furnace in one respect, it uses up 
 fuel in the form of non-azotized food, and the worn-out tis- 
 sues of the body, converting them into carbonic acid, water, 
 and ammonia. 
 
 By the process of respiration, the oxygen of the atmos- 
 phere is consumed, and its place supplied by an equivalent 
 volume of carbonic acid. 
 
 The process of respiration is not the only source of car- 
 bonic acid ; the process of combustion, also generates carbonic 
 acid in large quantities; the decomposition of vegetable mat- 
 ter is still another source — to this may be added a large 
 quantity thrown into the atmosphere from changes going on 
 among the rocks. 
 
412 
 
 Analytical Che 
 
 "Why is not the atmosphere wholly converted into carbonic 
 acid 1 Simply because this acid is absorbed by vegetables, 
 its carbon assimilated, and its oxygen sent back to the at- 
 mosphere, as pure as at first, again to enter the animal 
 organs, and to become the means of supplying to plants the 
 carbon they need for their growth. This most intimate and 
 beautiful relation of the vegetable and animal kingdoms, fur- 
 nishes one, out of numberless illustrations of the Divine 
 wisdom, which cannot fail to excite the admiration of every 
 observer. 
 
 CHAPTER VI. 
 
 ANALYTICAL CHEMISTRY. 
 
 It is the object of analytical chemistry to point out the 
 method of separating compound bodies into their simple 
 elements. As the subject is extensive, a few things only 
 will be inserted here, in order to give the student an idea of 
 the nature of the process. 
 
 Sect. 1. Analysis of Mixed Gases. 
 
 Fig. 102. 
 
 I. Gaseous Mixtures containing Oxygen. 
 The best process by which oxygen gas may 
 be withdrawn from gaseous mixtures, is by 
 means of hydrogen gas. In case of the air, 
 a given portion is taken, and rather more 
 hydrogen added than is sufficient to com- 
 bine with the oxygen. The mixture is then 
 introduced into a strong glass tube, or eudi- 
 ometer, (Fig. 102,) over water or mercury, 
 and exploded by the electric spark. The 
 total diminution in volume, divided by three, 
 will crive the quantity of oxygen present. 
 Instead of exploding the gases, they may be 
 made to combine slowly, by introducing into the mixture 
 platinum sponge. 
 
Analysis of Minerals. 413 
 
 2. Gaseous Mixtures containing Nitrogen. As the air 
 contains only oxygen and nitrogen, when other substances 
 are withdrawn, if its oxygen is determined, the quantity of 
 its nitrogen may be easily known. The only mode of ascer- 
 taining the quantity of nitrogen in any mixture, is to with- 
 draw the other gases from it. 
 
 3. Gaseous Mixtures containing Carbonic Acid. When 
 carbonic is the only acid gas present, as is the case with air 
 and organic compounds, the process consists merely in ab- 
 sorbing this gas by lime water, or a solution of caustic potassa. 
 
 4. Gaseous Mixtures containing Hydrogen and other In- 
 flammable Bodies. The quantity of hydrogen, when mixed 
 with nitrogen, oxygen, or atmospheric air, is ascertained by 
 adding a portion of oxygen, and exploding the mixture. The 
 quantity of other inflammable bodies, such as carbonic oxide, 
 light carbureted hydrogen, or olefiant gas mixed with nitro- 
 gen, is determined by adding a sufficient quantity of oxygen, 
 and detonating the mixture. The diminution of volume in- 
 dicates the quantity of hydrogen contained in the mixture, 
 and by withdrawing the carbonic acid, the quantity of car- 
 bon may be known. 
 
 Sect. 2. Analysis op Minerals. 
 
 In order to analyze any mineral compound, the first object 
 is to bring the body into a state of solution. This is effected, 
 generally, by water or acids; but in cases where the sub- 
 stance is not dissolved by these, it is made into a paste, with 
 three or four times its weight of fused borax, potassa, soda, 
 baryta, or their carbonates, and subjected to a strong heat, 
 in a platinum or silver crucible. By this means, the alkali 
 combines with one or more of the constituents of the' min- 
 eral, and then it is in a state to be acted upon by acids. 
 
 L Analysis of Minerals soluble in Acids with Effervescence. 
 
 Reduce the mineral to a fine powder, and boil it for two hours in 
 the acid which holds it in solution, diluted with five or six times its 
 bulk of water. This solution may contain lime, baryta, magnesia, 
 Btrontia, alumina, and oxides of metals. 
 
 1. Add to a small portion of the liquor, diluted with 20 parts of water, 
 
414 
 
 Analytical Chemistry. 
 
 sulphate of soda, and if a precipitate appear, baryta, or strontia f or 
 both, are present. Nitric acid, diluted with an equal weight of water, 
 will dissolve the strontia, if present, in the separated precipitate, but 
 will not act upon the baryta. 
 
 2. Add to a portion of the liquid, ferrocyanate of potassa, and if 
 metallic oxides are present, a precipitate will be thrown down, the 
 color of which will probably show the kind of metal. 
 
 3. Carbonate of potassa will precipitate the lime, magnesia, and 
 alumina, from which the alumina may be dissolved by a solution of 
 potassa, and precipitated again by dilute hydrochloric acid. 
 
 Having precipitated the alumina, dilute hydrochloric acid will re- 
 dissolve what remains, from which oxalate of ammonia will precipitate 
 the Urns. 
 
 Add to the remaining liquid, in successive portions, carbonate of 
 ammonia and phosphate of soda, and magnesia, if present, will be pre- 
 cipitated. 
 
 II. Analysis of Minerals which are insoluble in Acids. 
 Heat a mixture of 1 part of the mineral to 3 of fused borax, for three 
 hours, in a platinum crucible ; dissolve the contents by digesting the 
 whole in hydrochloric acid, for several hours; add carbonate of am- 
 monia, and the whole will be precipitated; filter and wash the precipi- 
 tate, to separate the borax, and re-dissolve in hydrochloric acid. If any 
 matter remain, it is silica. The solution may then be tested as in the 
 former case. 
 
 III. Analysis of Minerals containing Carbonate of Lime, Silica, 
 Oxide of Iron, and Magnesia. 
 
 1. Reduce the mineral to a fine powder, and weigh out a given por- 
 tion, as 1000 grs. ; dry the powder just up ta.browning paper; the loss 
 of weight is water. 
 
 2. Having put the powder into a flask, 
 to which a cork with a bent tube is at- 
 tached, (Fig. 103,) pour upon it water, and 
 then hydrochloric acid, quickly inserting 
 the stopper, and placing the tube in a ves- 
 sel of baryta water ; carbonic acid will 
 escape through the tube into the solution 
 of baryta, and form carbonate of baryta, 
 which will be in fine powder. Filter and 
 dry the residue ; the weight will give the 
 quantity of carbonic acid, 22 parts of acid 
 being combined with 78 of baryta. 
 
 3. Dilute the liquor in the flask with 
 water, throw it upon a filter, and wash : 
 the insoluble matter is silica. 
 
 4. The washings of the filter contain a solution of the oxide and lime. 
 Precipitate the oxide with excess of ammonia; filter, wash, dry, and 
 weigh; from this the iron may be estimated, as the oxide will contain 
 12 parts of oxygen, 9 of water, and 28 of iron. Oxalate of ammonia will 
 precipitate the lime from the remaining liquor, which being filtered, 
 washed, and burned in a crucible, lime only will remain. The magnesia, 
 which is still in solution, may be precipitated by carbonate of ammonia 
 in excess, and by adding phosphate of soda; filter, dry, and weigh ; 100 
 parts will contain 40 of pure magnesia. 
 
 The Compounds of Silica, Mumina t and Iron, are decomposed by al- 
 
 Fig. 112. 
 
Analysis of Metallic ures. 415 
 
 kaline carbonates, at a red heat. For further processes, see Turner's 
 Chemistry, or Rose's Analytical Chemistry. 
 
 IV. Tests of Metallic Ores. 
 
 1 . Ores of Antimony are first dissolved in nitrohydrochloric acid, which 
 takes up all the sulphur. The oxide of antimony is then precipitated 
 by simply adding water. 
 
 2. Ores of Lead are dissolved in nitric acid, with the exception of 
 the sulphur, which may be separated by a filter ; add to the solution 
 carbonate of soda, and carbonate of lead will be thrown down. The 
 silver, if present., will also be precipitated, and may be separated from 
 the carbonate of lead by liquid ammonia, which holes it in solution. 
 
 3. Ores of Mercury are mixed with iron-filings or lime, and exposed, 
 in an iron retort, to a strong heat; when the mercury will distil over. 
 
 4. Ores of Zinc may be boiled in nitric acid to dryness, and the pro- 
 cess repeated. If iron is present, it will be pero.xidated, and dilute 
 nitric acid will dissolve out the zinc ; filter the solution, and add liquid 
 ammonia in excess; the lead, if present, will be precipitated, and the 
 zinc will remain in solution. The oxide of zinc is obtained by boiling 
 this solution to dryness. 
 
 5. Ores of Tin. As these ores usually contain silica, they must be 
 first treated like an earthy mineral not soluble in acids. The tin will 
 be detected by forming a purple solution with the chloride of gold. 
 
 6. Ores of Iron. The peroxide of iron is first rendered soluble by 
 heating it for an hour with one eighth of its weight of powdered char- 
 coal. The black oxide is soluble in dilute hydrochloric acid. If phos- 
 phate of iron is present, it may be detected by adding to the hydrochloric 
 solution 10 parts of water, (which has been boiled, to separate the air,) 
 
 ^placing it in a bottle corked tight, and set aside for 6 or 8 days, when 
 the phosphate of iron will be precipitated. The filtered solution may 
 contain oxides of iron, manganese, and zinc, all of which are thrown 
 down by carbonate of soda. The oxide of zinc may then be separated 
 .y ammonia, and the oxide of manganese by acetic acid. The oxide 
 of iron will then remain, and, after being ignited, will contain 72 per 
 ent. of the pure metal. 
 
 7. Ores of Copper are boiled dry with five times their weight of sul- 
 pnuric acid. The sulphate of copper which is formed is dissolved by 
 water, and the metallic copper precipitated by a plate of clean iron. 
 
 8. Ores of Silver are dissolved by nitric acid. Immerse in the solu- 
 tion a plate of polished copper, and the silver will be precipitated upon 
 it, if no-lead is present. Common salt will throw down the chloride 
 of silver. 
 
 9. Ores of Gold and Platinum are dissolved in nitrohydrochloric 
 acia ; the solution is then evaporated until nitrous acid fumes cease to 
 appear, and the odor of chlorine is perceptible ; the product is dissolved 
 in water, and a solution of hydrochlorate of tin added, when a purple 
 precipitate will be thrown down, if gold is present. If platinum is in 
 the mixture, it may be precipitated by hydrochlorate Gf ammonia. 
 
 When the solution contains gold with other metals, the sulphate of 
 the protoxide of iron precipitates the gold with the palladium, mercury, 
 and silver, if present. As silver is most frequently present, common 
 ealt should be added previous to the sulphate of iron, to precipitate it. 
 
 Earthy Sulphates. The sulphate of lime is easily analyzed by boil- 
 ing it for fifteen or twenty minutes in a solution of twice its weight of 
 carbonate of soda. The carbonate of lime and sulphate of soda are 
 
416 Analytical Chemistry. 
 
 formed by double decomposition. The sulphate of soda is then de- 
 composed by chloride of barium, and the carbonate of lime analyzed in 
 the usual way.* 
 
 Sect. 3. Analysis of Mineral Waters. 
 
 The purest water is obtained by distillation. Rain watery 
 or that from fresh fallen snow, is next in purity. 
 
 Well and spring water contain some salts, which are de- 
 rived from the soil through which the rain water passes : 
 hence the purity of water will depend upon the nature of the 
 soils. If it is filtered through primitive strata, such as gran- 
 ite, it will contain few salts, hut if through secondary soils, 
 such as limestone and gypsum, it becomes impregnated with 
 various other substances, and is mineralized. Lime renders 
 it hard. 
 
 The different kinds of mineral water are acidulous, alka- 
 line, chalybeate, sulphureted, saline, and siliceous springs. 
 
 1. In acidulous springs, of which those of Saratoga and 
 Seltzer are examples, the acidity is due to the carbonic acid 
 with which their waters are impregrfated ; they frequently 
 contain protoxide of iron, carbonates of lime, magnesia, and 
 other saline compounds. The carbonic acid is easily expelled 
 by heat, and may be collected over mercury. 
 
 2. Alkaline springs are very rare ; they generally contain 
 a free or carbonated alkali. 
 
 3. Chalybeate springs. These waters are characterized by 
 styptic, inky taste, and by striking a black color with infu- 
 sion of gall-nuts. The iron is either combined with hydro- 
 chloric and sulphuric acids, or exists in the form of proto- 
 carbonate, held in solution by free carbonic acid. On 
 exposure to the air, the protoxide is oxidized, and the hy- 
 drated peroxide subsides as an ochreous deposit, which is 
 commonly found in the vicinity of chalybeate springs. — T. 
 
 4. Saline springs owe their properties to saline compounds, 
 such as sulphates and carbonates of lime, magnesia, and so- 
 da, and the chlorides of calcium, magnesium, and sodium. 
 
 In the analysis of saline springs, the first object is to ascer- 
 tain the nature of the ingredients. Hydrochloric acid is 
 detected by nitrate of oxide of silver, sulphuric acid by chlo- 
 ride of barium; and if an alkaline carbonate be present, the 
 precipitates will contain a carbonate of oxide of silver, or of 
 baryta. Lime and magnesia may be detected, the former by 
 
 * For other sulphates, see Turner, p. 241. 
 
Test Tubes. 
 
 417 
 
 oxalate of ammonia, and the latter by phosphate of ammonia 
 Potassa is known by the action of chloride of platinum. To 
 detect soda, the water should be evaporated to dryness, the 
 deliquescent salts removed by alcohol, and the matter insolu- 
 ble in that menstruum taken up by a small quantity of water, 
 and allowed to crystallize by spontaneous evaporation. The 
 salt of soda may then be recognized by the rich yellow color 
 which it -communicates to flame. If the presence of hydri- 
 odic acid be suspected, the solution is brought to dryness, the 
 soluble parts dissolved in two or three drachms of a cold so- 
 lution of starch, and strong sulphuric acid slowly added. — T. 
 
 Sulphur eted springs are characterized by their odor, and 
 by the brown precipitate, which a salt of lead or silver occa- 
 sions. This is owing to the hydrosulphuric acid gas which 
 they contain. The quantity of gas is ascertained by boiling 
 the water, which expels it. 
 
 To detect Hydrosu'phuric Acid. Take a flask, Fig. 113. 
 
 with a tube bent twice at right angles, one end 
 of which dips into a solution of acetate of lead. 
 (Fig. 104.) Introduce the water into the flask, 
 and apply heat until it boils. The gas will be 
 driven off, and decompose the acetate, forming a 
 sulphuret of lead ; filter, dry, and weigh. 16.1 
 parts will be sulphur, and 103.6 parts lead. T *g- 
 part of the weight of the sulphur, added to its 
 weight, will give the weight of the hydrosulphu- 
 ric acid 
 
 W the water, after being boiled, yields a black 
 precipitate, with acetate of lead, acetic acid must be added, and the 
 liquor boiled, and the gas passed through the acetate, as before. 
 
 The mode of estimating the solid matter held in solution in mineral 
 waters is simply to boil the whole to dryness, and weigh the residue. 
 The different kinds of matter are then detected in the usual way for 
 analyzing other solid bodies. 
 
 Test Tubes. For 
 
 the purpose of test- 
 ing substances in 
 solution, test tubes 
 (Fig. 105) are very 
 convenient. They 
 are glass tubes, from 
 3 to 12 inches in 
 length, and from % 
 to 1 inch in diame- 
 ter, open at one end, 
 while the closed end 
 is so made that the 
 --mid may be heat- 
 
 Fisr. 114 
 
418 
 
 Analytical Chemistry. 
 
 ed as in a retort. A small quantity of any solution may be 
 examined in them with great facility, and they are especially 
 convenient to form precipitates. These tubes may be placed 
 upon a frame, as in the figure, and answer often the threefold 
 purpose of retort, receiver, and test tube. 
 
 Filtration. . When a solution has been prepared for exam- 
 ination, it ought to be perfectly clear. If it appears muddy, 
 it must be subjected to filtration ; that is, it must be passed 
 through a paper filter, by which means it is separated from 
 solid matters, which make it appear opaque. As this opera- 
 tion frequently occurs in chemical analysis, and in various 
 manipulations, it is important to understand the mode of per- 
 forming it. 
 
 The filtering paper should contain no glazing or sizing, 
 and should be folded in the following form : — 
 
 1. Take a square piece of paper, and fold it like a sheet of 
 paper, that is, so as to bring two corners together ; then fold 
 it so as to bring four corners together ; cut off the corners, 
 and by opening the folds it will have the form of an inverted 
 cone, and may be placed in a funnel. 
 
 2. But for filtering rapidly, 
 the filter may be folded in the 
 following form : — Fold the pa- 
 per in two, as before ; then (Fig. 
 106) fold 10 upon 2, then 10 
 upon 6, then 1 10 upon 1 8, 
 then 2 upon 8. then 2 upon 6, 
 2 upon 4, and 10 upon 4 : this will produce 
 7 folds, all on one side of the paper. Make, 
 now, folds between each of these, so as to 
 raise ribs on the opposite side of the paper. 
 Cut out the projecting corners, to give the 
 whole acircularshape ; open it, and form it into 
 a cup. (Fig 107.) 
 
\ 
 
 Filtration. 
 
 419 
 
 Fig. 117. 
 
 The filter may then be placed 
 in the funnel c, (Fig. 108,) and 
 supported by a lamp-stand or a 
 wood-stand, made for the pur- 
 pose ; or it may be placed in the 
 top of a tall jar. The liquid to 
 be filtered is then put into it, and 
 a vessel placed beneath to con- 
 tain the liquid as it slowly passes 
 through the paper. By this pro- 
 cess, the solid and liquid parts 
 are separated, and either may 
 be examined in their separate 
 state.* 
 
 If it is desired to estimate the quantity of solid matter, the 
 filter must be weighed previous to placing it in the funnel ; 
 and the solid matter, after being washed, by directing a fine 
 stream of water upon it, until the water comes through taste- 
 less, is dried and weighed : the difference of weight shows 
 the quantity of solid matter. 
 
 Supports of filters and vessels may be 
 of iron wire, made into the form of a tri- 
 angle. (Fig. 109.) Take three pieces of 
 iron or copper wire, and twist the ends as 
 in the figure, leaving a triangular aperture : 
 this may be placed upon the tops of jars 
 and other vessels, or upon the rings of the 
 lamp-stand, to support crucibles, evapo- 
 rating dishes, retorts, filters, &,c. 
 
 Fig* 118. 
 
 * For chemical manipulation, and blowpipe analysis, the student is 
 referred to Griffin's Chemical Recreations. 
 
APPENDIX 
 
 TVolIaston's Synoptic Scale of Chemical Equivalents* — 
 The scale consists of a movable slider, with a series of 
 numbers upon it, from 10 to 3*20, on each side of which, and 
 on the fixed part of the scale, are set down the names of va- 
 rious chemical substances. 
 
 The scale is founded on the constancy of composition in 
 chemical compounds, the equivalent power of the quantities 
 that enter into combinations, and the properties of a logo- 
 metric scale of numbers. 
 
 The numbers are so arranged, that at equal intervals they 
 bear the same proportion to each other. The student wiH 
 easily observe and understand this, by measuring a few dis- 
 tances upon the scale, with a pair of compasses, or even a 
 piece of paper. If his paper extend from 10 to 20, it will 
 also extend from 20 to 40, or from 55 to 110, or from 160 to 
 320. Whatever number is at the upper edge of the paper 
 will be double at the lower. If any other distance be taken, 
 the same effect will be observed. If, for instance, the paper 
 extends from 10 to 14, then any other two numbers found at 
 its upper and lower edge will be in the same proportion as 
 these two numbers 10 and 14." Thus, make the upper num- 
 ber 100, and the lower number will be 140. 
 
 Now, supposing that the paper were cut of such a width 
 that, one of its edges being applied upon the scale to the num- 
 ber representing the equivalent of one body, the other should 
 coincide with the number of the equivalent of a second body ; 
 then, upon moving trie paper, wherever it was placed over the 
 numbers, those at its upper and lower edges would still rep- 
 resent the corresponding proportional quantities of the two 
 bodies as accurately as at first, because the numbers at equal 
 
 * The paper, by its author, describing the scale, is inserted in the 
 Philosophical Transactions for 1814 
 
Appendix. 421 
 
 distances on the scale are proportional to each other. Thus, 
 suppose the upper edge were made to coincide with 40 and 
 the lower with 78, then the upper edge might be called sul- 
 phuric acid, and the lower baryta; and this width once as- 
 certained, the paper, wherever applied upon the scale, would 
 show at its lower edge the quantity of baryta necessary to 
 combine with the quantity of sulphuric acid indicated by its 
 upper edge. 
 
 It is evidently of no consequence whether the paper be 
 moved up and down over the scale, or the line of numbers 
 be moved higher and lower, to bring its different parts to the 
 edges of the paper. And supposing the piece of paper just 
 described to be pasted upon the side of the scale, then, by 
 moving the latter, any of the numbers might be made to coin- 
 cide with the upper or lower edge at pleasure, and conse- 
 quently the quantity of sulphuric acid necessary to combine 
 with any quantity of baryta, and vice versa, ascertained by 
 mere adjustment and inspection of the scale. Or if, instead 
 of referring to the separate piece of paper, marks were to be 
 made on the side of the scale at 40 and 78, and named sul- 
 phuric acid and baryta, the same object would be attained, 
 and the same method of inquiry rendered available. 
 
 Other substances are to be put down upon the scale ex- 
 actly in the same manner. Thus, the scale being adjusted 
 until the number 40 coincides with the sulphuric acid already 
 marked, then sulphate of baryta is to be written at 1 18, and 
 thus its place is ascertained ; nitrate of baryta at 132 ; soda 
 at 32 ; sulphate of soda at 72; and a similar process is to be 
 adopted with every substance, the number of which has been 
 ascertained by experiment. The instrument, which in this 
 state merely represents the actual numbers supplied by exper- 
 iment, will faithfully preserve the proportions thus set down, 
 whatever the variation of the position of the slider may be. 
 It is therefore competent to change all the numerical expres- 
 sions to any degree required, the knowledge of one only being 
 sufficient, first by adjustment, and then by inspection, to lead 
 to the rest. 
 
 A few illustrations of the powers and uses of this scale 
 will be sufficient to make the student perfect master of its 
 nature and applications. Suppose that, in analyzing a mineral 
 water, the sulphates in a pint of it have been decomposed by 
 the addition of muriate of baryta, and the resulting sulphate 
 of baryta washed, dried, and weighed; from its quantity may 
 
422 Appendix. 
 
 oe dedueed the exact quantity of sulphuric acid previously 
 existing in the mineral water. Thus, if the sulphate of baryta 
 amount to 43.4 grains, the slider is to be moved until that 
 number is opposite to the sulphate of baryta, and then at sul- 
 phuric acid will be found the quantity required, namely, 14.7 
 grains. In the same manner the scale will give information 
 of the quantity of any substance contained in a given weight of 
 any of its compounds ; these having previously been deduced 
 from experiment, and accurately set down on the table in the 
 manner just explained. 
 
 If it be desired to know how much of one substance must 
 be used in an experiment to act upon the other, it is evident 
 that the equivalent must be taken, and this may be learned 
 from the scale. Suppose that a pound of sulphate of baryta 
 has been mixed with charcoal, and well heated, to convert it 
 into a sulphuret, and that by the addition of nitric acid it is 
 to be converted into nitrate of baryta. The quantity of acid 
 which will probably be required may be learned by bringing 
 100 to sulphate of baryta, and then by looking for the num- 
 ber opposite nitric acid ; it will be found to be 46. But this 
 represents the quantity of dry acid ; casting the eye therefore 
 lower down, upon liquid nitric acid of a specific gravity of 
 1.50, it will be found that 61 lbs., or a little more, is the 
 equivalent for 100 lbs., and consequently that 61 hundredth 
 parts, or somewhat above y 6 ^ of a pound of such acid, will 
 be sufficient for the pound of sulphate of baryta operated 
 with. 
 
 If a certain weight of carbonate of baryta be required in 
 that moist and finely-divided state in which it is obtained by 
 precipitation, and in which it cannot be weighed, the accu- 
 racy of the quantity may be insured by taking the equivalent 
 of dry muriate, or nitrate of baryta, precipitating it by an ex- 
 cess of carbonate of potassa, and then washing off the salts 
 which remain in solution. Suppose 100 grains of the car- 
 bonate were required ; by bringing that number to carbonate 
 of baryta, it will be found that the quantity of dry muriate 
 necessary will be 105.8 parts, and the quantity of nitrate 
 133.4 ; and if the quantity of carbonate of potassa necessary 
 for this purpose be also required, it will be found, opposite 
 the name of that substance on the scale, to be a little less 
 than 70 parts, so that 5 or 10 parts more will insure a satis- 
 factory excess. 
 
 The second paragraph of Wollaston's description of this 
 
Appendix. 423 
 
 scale may be transcribed, as a further illustration of the 
 powers of the instrument. " If, for instance, the salt under 
 examination be the common blue vitriol, or crystallized sul- 
 phate of copper, the first obvious questions are — (1) How 
 much sulphuric acid does it contain ? (2) How much oxide 
 of copper? (3) How much water 1 He [the analytic chemist] 
 may not be satisfied with these first steps in the analysis, but 
 may desire to know further the quantities (4) of sulphur, (5) 
 of copper, (6) of oxygen, (7) of hydrogen. As means of 
 gaining this information, he naturally considers the quantity 
 of various re-agents that may be employed for discovering the 
 quantity of sulphuric acid, (8) how much baryta, (9) carbon- 
 ate of baryta, or (10) nitrate of baryta, would be requisite 
 for this purpose. (11) How much lead is to be used in the 
 form of (12) nitrate of lead; and when the precipitate of 
 (13) sulphate of baryta, or (14) sulphate of lead, are obtained, 
 it will be necessary that he should also know the proportion 
 which either of them contains of dry sulphuric acid. He 
 may also endeavor to ascertain the same point by means of 
 (15) the quantity of pure potassa, or (16) of carbonate of 
 potassa, requisite for the precipitation of the copper. He 
 might also use (17) zinc, or (18) iron, for the same purpose ; 
 and he may wish to know the quantities of (19) sulphate of 
 zinc, or (20) sulphate of iron, that will then remain in the 
 solution." 
 
 All these questions and points are answered by moving the 
 slider until the number expressing the quantity operated with, 
 coincides with sulphate of copper crystallized. 5, Water. 
 Let it, for instance, be 100 ; this being brought opposite crys- 
 tallized sulphate of copper, the information relative to all the 
 above points, except the sixth and seventh, is supplied by 
 mere inspection. The sixth may be supplied by substracting 
 (5) the quantity of copper from (2) the quantity of oxide of 
 copper, or by halving the quantity at 2 oxygen, or taking the 
 third of that at 3 oxygen. The seventh relates to the quan- 
 tity of hydrogen in the 5 water present in the salt; this quan- 
 tity of hydrogen does not come within the line of numbers, 
 but may easily be obtained by doubling the quantity of water, 
 or doubling the quantity of the salt used, which will then 
 bring 10 hydrogen into the scale, and the half of this is to be 
 taken as the quantity in 5 water, or in 100 grains of the salt. 
 Putting, therefore, 200 to sulphate of copper, 10 hydrogen, is 
 indicated as 17 parts nearly, when of course the half of this, 
 
424 Appendix. 
 
 or 5.5 parts, is the quantity in 100 grains of the crystallized 
 salt of copper. 
 
 Whenever it thus happens that the number known or the 
 number sought for is out of the scale, then some convenient 
 multiplier of the numbers may be used. The most conve- 
 
 :;:ethod is to use the tens or the hundreds as ani 
 what is the same thing, to consider for the time that decimal 
 points are inserted between the units and the tens, or between 
 the tens and the hundreds of all the numbers on the scale. 
 Thus, if it were required to ascertain how much magnesia and 
 sulphuric acid were contained in a poun I of crystallized sul- 
 phate of magnesia, no 1 exists upon the scale, and of course 
 no fractions or small parts of 1 ; but imagine decimal points 
 between the tens and the hundreds, then 10 upon the scale 
 becomes one tenth, 22 twenty-two hundredths. 100 one, 22Q 
 two and two tenths, and so on. Bringing, therefore. I 
 crystallized sulphate of magnesia, it represents the 1 pound, 
 and by inspection it will be found that it contains 16 hun- 
 dredths of a pound of magnesia, and 3*2 .j hundreds of a pound 
 ..'phuric acid. 
 
 As another illustration, suppose that the quantity of mag- 
 nesia in 58 lbs. of crystallized Epsom salt were required ; 
 upon bringing 50 opposite the name of the salt, the quantity 
 of magnesia will be found smaller than any quantity expressed 
 upon the scale ; but all that is necessary to obtain the answer 
 is, to double the quantity of the salt, and then to halve the 
 quantity of magnesia indicated : in which way it will be found 
 that the 50 lbs. contain about B lbs. : the oxide. 
 
 T -.ese > wptit :-:rJes are generally constructed of paper 
 or wood. It is almost impossible that they should be accu- 
 rate, because of the extension and contraction of the paper, 
 and the facility with which it yields to mechanical impressions, 
 and maybe stretched when in a moistened state. These scales 
 should never be considered as accurate when they first come 
 from the instrument-maker. They may be examined by a 
 pair of compasses or a piece of paper, to ascertain how nearly 
 equal intervals on the scale of numbers accord with equal 
 proportions between the numbers at the extremities of those 
 intervals, and thus the degree of error in them, and the part 
 where it exists to the greatest extent, may be observed ; but it 
 will be useless to _ bc ::h the view of finding one so accu- 
 ; to dispense with calculation in exact analytical exper- 
 iment 
 
Appendix 425 
 
 Those scales which are laid down directly upon wood, 
 though not liable to the same sources of error as the paper 
 scales, are still seldom, if ever, so accurate as to compete 
 with calculation. — W. 
 
 Cementing. 1. When vapors of watery liquors, and such 
 others as are not corrosive, are to be confined, it is sufficient 
 to surround the joining of the receiver to the retort with 
 slips of wet bladder, or of linen, or paper, covered with flour 
 paste, or mucilage of gum arabic. 
 
 2. Soft cement is made of yellow wax melted with half its 
 weight of turpentine and a little Venetian red to give it color. 
 It can be easily moulded by the fingers, and sticks well to 
 dry substances. 
 
 3. For containing the vapors of acid, or highly-corrosive 
 substances, fat lute is made use of. This is formed by beat- 
 ing perfectly dry and finely-sifted tobacco-pipe clay, with 
 painters' drying oil, in a mortar, to such a consistence that it 
 may be moulded by the hand. To use it, it is rolled into 
 cylinders of a convenient size, which are applied, by flatten- 
 ing them, to the joinings of the vessels, which must be quite 
 dry, as the least moisture prevents the lute from adhering. 
 The lute, when applied, is to be covered with slips of linen 
 spread with the lime lute ; which slips are to be fastened 
 with pack-thread. 
 
 4. When penetrating and dissolving vapors are to be con- 
 fined, the lute .to be employed is of quick lime slacked in the 
 air, and beaten into a liquid paste with white of eggs. This 
 must be applied on strips of linen ; it is very convenient, as 
 it easily dries, and becomes firm. This lute is very useful 
 for joining broken china ware. 
 
 5. For cementing stone ware to metals and wood, litharge 
 and red lead mixed and worked up with spirit of turpentine, 
 makes a good cement. It takes several days to give off the 
 turpentine and become dry and hard. 
 
 6. Cement for fastening brass necks upon glass jars, etc. : 
 — 4 parts of rosin, 1 of wax, and 1 of finely-powdered brick 
 are melted and well mixed together. It is to be put on warm, 
 but care is to be taken not to apply it so hot as to split the 
 glass. It holds very hard. 
 
 7. Mix linseed meal with water, and knead it into a stiff 
 paste. It soon hardens, and withstands the fumes of acids 
 and ammonia. It is better if made with lime water, or thin 
 glue. It is charred by a strong heat, 
 
426 Appendix 
 
 8. Thick gum water, with pipe clay and iron-filings. Mix 
 well. It becomes very hard and firm, and is fit to be used 
 where it is required to hold good a considerable time. 
 
 9. Plaster of Paris, stirred up with milk, starch water, or 
 thin glue. It hardens immediately, and is very good for 
 securing tubes in flasks, when the corks do not fit well, and 
 gases are to be prepared in them. 
 
 10. Dissolve melted India rubber in boiling linseed oil, 
 and afterwards thicken the latter with pipe clay till it forms 
 a stiff mass. The thorough incorporation of the pipe clay 
 demands a great deal of labor. This is a capital cement to 
 be used when acids are to be prepared. 
 
 11. Cement for fastening Labels upon Bottles. Soften and 
 subsequently boil glue in strong vinegar. During the boil- 
 ing, thicken it with flour. This mixture can be preserved in 
 a soft state without becoming mouldy. It should be put into 
 a glass bottle, with a wide neck and a ground stopper. When 
 it is to be used, it is taken out of the bottle on the point of a 
 spatula, warmed over the lamp, if too thick for use, and then 
 spread upon the paper. 
 
 12. Universal Cement. Curdle skim milk, press out the 
 whey, break the curd in small pieces, dry it, and grind it in a 
 coffee mill. Take ten ounces of dry curd, one ounce of fresh 
 burnt quick lime, and two scruples of camphor. Mix the 
 whole intimately, and preserve it in small, wide-mouthed 
 bottles, closely corked. When it is to be used, mix it with 
 a little water, and apply it immediately. 
 
 13. Diamond Cement for Glass or Porcelain. Dissolve 
 five or six pieces of gum mastic, as large as peas, in the 
 smallest possible quantity of alcohol. Mix this liquid with 
 two ounces of a strong solution of isinglass, (made by soften- 
 ing and dissolving isinglass in boiling brandy or rum to 
 saturation,) having previously incorporated the two ounces 
 of isinglass solution with two or three small pieces of galba- 
 num or gum ammoniac, by trituration. The mixture is to be 
 preserved in a well-closed bottle, arid is to be gently heated 
 by holding the bottle in hot water at the moment when you 
 are going to use it. — Griffin's Chem. Recreations. 
 
 Elastic Tube Making. Take a piece of the sheet rubber, 1 or 1£ 
 inches long, and a little more than three times as wide as you intend 
 the tube to be. Take a glass rod rather smaller than the intended 
 
Appendix* 
 
 427 
 
 caoutchouc tube, fold a slip of paper round the glass rod, and over it 
 the piece of caoutchouc, previously softened by warming before the 
 fire. Fold the two edges together, and cut off the double projecting 
 edges by a pair of scissors, so as to produce two parallel straight edges. 
 Put the two clean surfaces thus produced face to face, being careful not 
 to let the fingers, or any thing else, touch them. Press the two faces 
 together by the thumb nails, and finally press the seam from end to 
 end with the flat part of the thumb nail. The junction is then effected 
 and the tube complete. But if the fingers -or any dirt is allowed to 
 touch the clean cut surfaces of the rubber, they cannot be made to 
 unite by pressure. ' After you have withdrawn the glass rod and the 
 slip of paper from the rubber tube, you are to smear its inner surface 
 with flour or fine ashes, to prevent the subsequent sticking together of 
 its sides, which is otherwise liable to take place, —-.lb. 
 
 Cutting Glass. Dissolve in spirits of turpentine as much camphor 
 gum as the liquid will hold in solution by the aid of moderate heat — a 
 common file dipped into the solution and applied to glass, will cut it 
 with nearly the same facility as iron. 
 
 Specific Gi 
 
 avity of Esse? 
 
 itial and other 
 
 Oils. 
 
 Oil of Anise-seed, 
 
 . 
 
 • ♦ • • 
 
 0.9958 
 
 " " Bergamot, . 
 
 . 
 
 
 . 
 
 
 
 0.885 
 
 " " Cajeput, . 
 
 
 
 . 
 
 
 
 0.948 
 
 " " Caraway, . 
 
 . 
 
 
 . . . 
 
 
 
 0.975 
 
 " " Cassia, 
 
 
 
 . 
 
 
 
 1.071 
 
 " " Cinnamon, 
 
 
 
 . . • 
 
 
 
 1.035 
 
 " « Cloves, 
 
 , . 
 
 
 . . 
 
 
 
 1.061 
 
 « " Fennel, 
 
 
 
 • . • 
 
 
 
 0.997 
 
 " " Juniper, 
 
 . 
 
 
 • 
 
 
 
 0.911 
 
 " " Lavender, . 
 
 . 
 
 
 . 
 
 
 
 0.898 
 
 " " Lemons, 
 
 
 
 . , 
 
 
 
 0.8517 
 
 " " Nutmegs, . 
 
 . 
 
 
 • • : 
 
 
 
 0.948 
 
 « « Peppermint, 
 
 . 
 
 
 
 
 
 0.899 
 
 " " Roses, (Ottar of Roses,) 
 
 
 
 
 
 0.832 
 
 " " Rosemary, 
 
 
 
 > 
 
 0.85 
 
 Oils of Fermented Liquors. 
 
 
 Oil of Grain Spirits, 
 
 
 0.835 
 
 " " Potato Spirits, 
 
 . 
 
 
 , 
 
 
 
 0.821 
 
429 
 
 Appendix. 
 
 TABLE. 
 
 The following are the results obtained by a commission ap- 
 pointed by the Parisian Academy of Sciences to examine 
 the elastic force, of vapor* They were obtained by 
 experiment up to a pressure of 25 atmospheres, and at 
 higher pressures by calculation. 
 
 Elasticity of the vap. 
 taking atmospheric 
 press, as unity. 
 
 Temperature ac- 
 cording to Fahr. 
 
 Elasticity of the vap. 
 taking atmospheric 
 press, as unity. 
 
 Temperature ac- 
 cording to Fahr. 
 
 1 
 
 212° 
 
 13 
 
 380.66° 
 
 H 
 
 233.96 
 
 14 
 
 386.94 
 
 2 
 
 250.52 
 
 15 
 
 392.86 
 
 2J 
 
 263.84 
 
 16 
 
 398.48 
 
 3 
 
 275.18 
 
 17 
 
 403.82 
 
 3J 
 
 285.08 
 
 18 
 
 408.92 
 
 4 
 
 293.72 
 
 19 
 
 413.78 
 
 44 
 
 300.28 
 
 20 
 
 418.46 
 
 5 
 
 307.5 
 
 21 
 
 422.96 
 
 f 
 
 314.24 
 
 22 
 
 427.28 
 
 320.36 
 
 23 
 
 431.42 
 
 6J 
 
 326.26 
 
 24 
 
 435.56 
 
 7 
 
 331.70 
 
 25 
 
 439.34 
 
 n 
 
 336.86 
 
 30 
 
 457.16 
 
 8 
 
 341.78 
 
 35 
 
 472.73 
 
 9 
 
 350.78 
 
 40 
 
 486.59 
 
 10 
 
 358.88 
 
 45 
 
 491.14 
 
 11 
 
 366.85 
 
 50 
 
 510.60 
 
 12 
 
 374.00 
 
 
 
 * Brande's Jour N. S. viii. 191 
 
G LOSSARY 
 
 ... 
 
 A, 
 
 Absorption, from absorbeo, to suck up; the power or act of imbibing 
 
 a fluid. 
 Acetic Acid, from acetum, vinegar ; the acidifying principle of com- 
 mon vinegar. 
 Acicular, from acus, a needle; having sharp points like needles. 
 Action, from ayui, to move ; the effort by which one body produces, 
 
 or endeavors to produce, motion in another. 
 Adhesion, -ive, from ad, to, and hareo, to stick; the tendency which 
 
 dissimilar bodies have to adhere or stick together. 
 Aeration, from alo, the air ; the saturation of a liquid with air. 
 Aeriform, from aer^ the air, and forma, a form; having the forr.i 
 
 of air. 
 
 ostation, from or/'e, the air, and icrrij/tt, to weigh; primarily, it 
 
 denotes the science of weights suspended in the air; but, in the 
 
 M adern application of the term, it signifies the art of navigating 
 
 the air. 
 Affinity, from ad, to, and finis, a boundary; relationship; the force 
 
 which causes dissimilar particles of matter to combine together, 
 
 so as to form new matter. 
 Albumen,, -inous, from albumen, the white of an egg) an important 
 
 animal principle. The white of an egg is albumen mixed with 
 
 water. 
 Alkali, a soluble body, with a hot, caustic taste, which possesses the 
 
 power of destroying acidity ; the term is derived from kali, the 
 
 Arabic name of a plant, from the ashes of which one species is 
 
 obtained, and the article al. 
 Amalgam, from uua, together, and yaut'w, to marry ; a chemical term, 
 
 signifying the union of any metal with mercury, which is a sol- 
 vent of various metals. 
 Amorphous, from «, not, and uoqcp^, a form ; not possessing regular form. 
 Analysis, from avU, thoroughly, and Xvui, to loosen; the separation of 
 
 a whole into parts. 
 Angle, from angulus, a corner; the inclination of two straight lines 
 
 to each other, which meet together, but are not in the same 
 
 straight line. 
 Anhydrous, from «, not, and i'dwn, water; containing no water. 
 Anion, from avu, up, and siut, to go ; that which goes up; a substance 
 
 which in electrolysis passes to the anode. 
 Anode, from uvu, up, and vdbc i a way; the way which the sun rises, 
 
 the surface at which the electricity passes into a body, supposing 
 
 the currents to move in the apparent direction of the sun. 
 Antiseptic, from arri, against, and ai',no^ to make rotten; possessing 
 
 the power of preventing putrefaction 
 
430 Glossary. 
 
 Approximate, -Tvely, from ad, to, and prozimus, nearest; having 
 
 affinity with ; bordering upon. 
 Aqua. Regia, i. e., Regal Water, a mixture of nitric and muriatic 
 
 acids ; so called from its property of dissolving gold, held by the 
 
 alchemists to be the king of the metals: 
 Aq,ueo, from aqua, water; when prefixed tc a word, denotes that 
 
 water enters into the composition of the substance which it 
 
 signifies. 
 Arc, from arcus, a bow; a part of a curved line, as of a circle, 
 
 ellipse, &c. 
 Armature, from armo, to arm; a piece of soft iron applied to a load- 
 stone, or connecting the poles of a horseshoe magnet. 
 Astatic Needle, from arrraroc, balanced; a double magnetic needle, 
 
 not affected by the earth's magnetism. 
 Astronomv, from Uotqov, a star, and vouog, a law or rule; the science 
 
 which treats of the heavenly bodies, their motions, periods, *fcc, 
 
 and the causes on which they depend. 
 Athermanous, from 3, not, and diouog, heat; that through which 
 
 heat will not pass is said to be athermanous. 
 Atmosphere, -ic, from arubg, vapor, and oyaioa, a sphere; the sphere 
 
 of air which surrounds the globe. 
 Atom, -ic, from «, not, and riiivto, to cut; a minute particle, not sus- 
 ceptible of further division. 
 Attraction, -ive, from ad. to. and traho, to draw; the tendency which 
 
 bodies have to approach each other. 
 Austral, from ouster, the south; southern. 
 Axis, in geometry ; the straight line in a plane figure, about which it 
 
 revolves to produce or generate a solid; more generally, the right 
 
 line conceived to be drawn from the vertex of a figure to the 
 
 middle of the base. 
 
 B. 
 
 Barometer, -rical, from fano:, weight, and uItqoi, a measure; an 
 instrument for measuring the varying weight of the atmosphere. 
 
 Bibulous, from bibo, to drink; that which has the quality of drinking 
 in moisture. 
 
 Binary, from bis, twice ; containing two units. 
 
 Boreal, from boreas, the north; northern. 
 
 c. 
 
 Calorimeter, from calor, heat, and mr.trum, a measure ; an instrument 
 
 for measuring caloric. 
 Capillary, from capillus, a hair; resembling or having the form 
 
 of hairs. 
 Capsule, from capmla, a little chest; a small, shallow cup. 
 Carbon, from carbo, a coal ; the chemical name for charcoal. 
 Catalysis, from y.aru, thoroughly, and Ivm, to loosen; an imaginary 
 
 force, which is supposed to assist the decomposition of some bodies, 
 
 and the composition of others. 
 Cathode, from y.uru. downward, and 6do:, a way; the way which the 
 
 sun sets; the surface at which electricity passes out of a body, 
 
 supposing the current to movein the apparent direction of the sun. 
 Cation, from y.ara, down, and e»«i, to go; that which goes down; a 
 
 substance which in electrolysis passes to the cathode. 
 Caustic, from xctlw, to burn ; possessing the power of burning. 
 
Glossary. 431 
 
 Chemistry, -ical, from an Arabic word, signifying the knowledge of 
 
 the substance or constitution of bodies; the science whose object 
 
 it is to examine the constitution of bodies. 
 Circumference, -tial, from circum, around, and fero, to bear; the 
 
 line which is the boundary of a circle. 
 Cleavage, Plane of; the plane in which crystals have a tendency to 
 
 separate. 
 Cohesion, -ive, from con, together, and harco, to stick ; the relation 
 
 among the component parts of a body, by which they cling 
 
 together. 
 Combustion, from comburo, to burn; the disengagement of light and 
 
 heat which accompanies chemical combination. 
 Concave, from concavus, hollow; curved inwardly, or hollow. 
 Conduction, from con, together, and duco, to lead. The power of 
 
 transmitting caloric, without change in the relative position of the 
 
 particles of the conducting body. 
 Cone, -ical, and -ic ; a solid figure, having a circular base, and its 
 
 other extremity or vertex terminated by a point. 
 Congelation, from con, together, and gclo, to freeze; the process of 
 
 freezing. 
 Congeries, from congeries, a heap; a mass of bodies heaped up 
 
 together. 
 Constituent, from constituo, to put together; that of which any thing 
 
 consists or is made up. 
 
 > Contact^ from con, together, and tango, to touch; the relative state 
 of two things which touch one another, but do not cut. 
 Contraction, from con, together, and traho, to draw; the state of 
 .% being drawn into a narrow compass. 
 Convergent, from con, together, and vergo, to bend; tending to one 
 
 point from various parts. 
 Convection, from con, together, and veho, to carry ; the power in fluids 
 
 of transmitting heat or electricity by currents. 
 Convex, from con, together, and veho, to carry ; curved outwardly, or 
 
 protuberant. 
 Corpuscular, from corpus, a body ; composed of or relating to atoms. 
 Coruscation, from corusco, to flash or shine; a flash, or quick vibra- 
 tion of light. 
 Crucible, from crux, crucis, a cross; a little pot, such as goldsmiths 
 
 melt their gold in ; so called from having a cross impressed upon it. 
 Cryophorus, from y.Qi'oc, cold, and tptQta, to produce ; an instrument 
 
 for showing the relation between evaporation at low temperatures 
 
 and the production of cold. 
 Crystalography, from yovora?.Xog, a crystal, and yquipto, to describe; 
 
 the science which treats of crystals. 
 Crystal, -line, from y.ovoraXXog, ice; a substance having a regular 
 
 form, as rock-crystal, which resembles ice. 
 Crystallization ; the formation of crystals during the passage of 
 
 certain bodies from a fluid to a solid form. 
 Cube, -ic ; a solid figure, contained by six equal squares. 
 
 D. 
 
 Decomposition; the resolution of a compound body into its compo- 
 nent parts. 
 
 Decrement, from decresco, to grow less; the quantity by which any 
 thing decreases or becomes less. 
 
432 Glossary. 
 
 Deflagration, from defiagro, to burn : burning. 
 
 Deflection, from dc, from, and Jlecto, to bend: a turning aside out 
 of the straight ■ 
 
 Degree, from dc, down, and gradus, a step ; a quantity in measure- 
 ment — as, in geometry, the 360th part of the circumference of a 
 circle. 
 
 Deliquescence, from deiiqueo, to melt ; a gradual melting, caused by 
 the absorption of water from the atmosphere. 
 
 Density, from dcnsus, thick ; vicinity ox closeness of particles. 
 
 Dephlogisticatep ; depriTed of phlogiston, the supposed principle 
 of inflammability. 
 
 Detonation^, from deiono, to thunder: explosion, accompanied with 
 noise. 
 
 Diameter, from lu^ through, and ustq or, a measure: the line which 
 passes through the centre of a circle, or of any -other curvilinear 
 figure. 
 
 Diaphanous, from 8ia, through, and yams, to shine ; that which allows 
 a passage to tbe rays of light. 
 
 Diathermanous. from $ik, through, and -Seouoc, heat; that through 
 which heat will pass is said to be diathermanous. 
 
 Dilatation, from differo, to bear apart; tbe act of extending into 
 greater space. 
 
 Dimorphous, from He, twice, and uogcfl, a form; having two forms. 
 
 Disc, from discus, a quoit ; the apparent surface of a heavenly " 
 
 Disintegration, from dis, meaning separation, an" 
 an utter separation of particles. 
 
 Dispersion, -ite, from di, in different directions, and 
 ter ; tbe act of scattering. 
 
 Disruption, from dis, in different directions, and rumps, 
 the act of tearing asunder. 
 
 Dissection, from disseco, to cut to pieces; the act of separating into 
 piecf : 
 
 Distillation ; separation drop by drop; the process by which a fluid 
 is separated from another substance, by first being converted into 
 vapor, and afterward condensed drop by drop. 
 
 Ditellent, from divello, to tear asunder: that which causes sepa- 
 ration. 
 
 Divergent, from di, in different directions, and vergo, to bend; tend- 
 ing to various parts from one point. 
 
 Dodecahedron, from 3m£e*iz, twelve, and s$q&, a base or side: a solid 
 figure contained by twelve equal s:ie: 
 
 Dynamics, -ical. from dviapic, power; that branch of mechanical sci- 
 ence which treats of moving pov,-fr=. 11 : of the action of forces 
 on solid bodies, wnen the result of that action is motion. 
 
 K 
 
 Ebullition, from ebuilio, to boil -, the act of boiling. 
 
 Efflorescence, from effloresco, to blow, as a flower; the formation 
 of small crystals on tbe surfaces of bodies, in consequence of the 
 abstraction of moisture from them by the atmosphere. 
 
 Elasticity, -ic, from iXavvw, to push or thrust: tbe pto pe ity bodies 
 possess of resuming their original form when pressure is re- 
 
 moved. 
 
 Electrode, from TjktzTQor, electricity, and the point at 
 
 which an electric current enters or quits the body tluu n gh which 
 
Glossary. 433 
 
 Electrography, from )']\ty.TQov and yqaqxa) a method of copying 
 medals, copperplate, &c, by galvanism. 
 
 Electrolysis, -lyte, &c, from ifisxrQov, electricity, and kvu) t to 
 loosen ; the act of decomposing bodies by electricity. 
 
 Electro-magnetism ; magnetism produced by electricity. 
 
 Electrometer ; an instrument for ascertaining the quality and quan- 
 tity of electricity in electrified bodies. 
 
 Electrophorus ; an instrument for producing electricity. 
 
 Electroscope ; an instrument for exhibiting the attractive and re- 
 pulsive agencies of electricity. 
 
 Element, -ary, from elementum, an element ; that which cannot be 
 resolved into two or more parts, and contains but one kind of 
 ponderable matter. 
 
 Ellipse, from ix, deficiently, and XsLtcw, to leave ; one of the conic 
 sections, formed by the intersection of a plane and a cone, when 
 the plane makes a less angle with the base than that formed by 
 the base and the side of the cone. 
 
 Empirical, from £v, in, and nBiqao^iai, to make trial ; that which is 
 made or is done as an experiment, independently of hypothesis or 
 theory. 
 
 Empyreumatic, from iv, in, and tivq, fire ; having the taste or smell 
 of burned animal or vegetable substances. 
 
 Endosmose, from hSov, within, and tbopbg, the act of pushing; a flow- 
 ing from the outside to the inside. 
 
 Epidermis, from sitl, upon, and dtQ^ia, the skin; the exterior layer of 
 the skin. 
 
 Equilibrium, from aquus, equal, and libra, a balance ; the state of rest 
 produced by forces equally balancing one another. 
 
 Equivalent, from aquus, equal, and valeo, to be worth ; equal in 
 value. 
 
 Etiolation ; the blanching of vegetables by exclusion from light. 
 
 Evaporation, from e, out, and vapor, vapor ; the conversion of a 
 liquid into vapor. 
 
 Exosmose, from !'|a>, without, and axx/tog, the act of pushing; a flow- 
 ing from the inside to the outside. 
 
 Expansion, from expando, to open out ; the enlargement or increase 
 in the bulk of bodies, which is produced by heat. 
 
 Experience, from experior, to attempt, to try ; knowledge gained by 
 observation. 
 
 Experiment; something done in order to discover an uncertain or 
 unknown eifect. 
 
 Explosion, from ex, out, and plaudo, to utter a sound ; a sudden ex- 
 pansion of an elastic fluid, with force and a loud report. 
 
 F- 
 
 Ferruginous, from ferrum, iron; of iron. 
 
 Filter ; a strainer. 
 
 Filtration ; the process whereby liquids are strained. 
 
 Flexure, from flecio, to bend ; the act of bending; also, the bend or 
 
 curve of a line or figure. 
 Focus, -cal, from focus, a fireplace ; a point in which a number of rays 
 
 of light or heat meet, after being refracted or reflected. 
 Formula; a general theorem ; it is called algebraic, logarithmic, &c., 
 
 according to the branch of mathematics to which it relates. 
 Friction, from frico, to rub; the rubbing or grating of the surfaces of 
 19 
 
434 Glossary. 
 
 bodies upon one another ; also, the retarding force caused by this 
 rubbing of surfaces together. 
 
 G. 
 
 Galvanism, from Professor Galvani ; current electricity is sometimes 
 
 so called. 
 Galvanometer;" an instrument for measuring galvanism. 
 Gas, -eous ; a term first introduced by Van Helmont ; a permanent, 
 
 aeriform fluid. 
 Gelatinous, from gelo, to freeze ; resembling jelly. 
 Goniometer, from ywria, an angle, and uztqot, a measure ; an instru- 
 ment for measuring angles. 
 Gravitation, from gravis, heavy ; the abstract power which draws 
 
 bodies toAvards each other's centres. 
 Gravity, from gravis, heavy ; the natural tendency of bodies to fall 
 
 towards a centre. 
 Gravity, Specific ; the relative gravity of a body considered with 
 
 regard to some other body, which is assumed as a standard of 
 
 comparison. 
 
 H. 
 
 Halo, from wUoq, a crown; a luminous circle, appearing occasionally 
 around the heavenly bodies, but more especially about the sun 
 and moon. 
 
 Heliographic, from ?'/ioc r the sun, and ygofe?, to write; delineated 
 by the sun. | ■&* 
 
 Helix, from tiuwcn, to twist round ; a screw or spiral. 
 
 Hemisphere, from fjitovg, half, and cyaiQa, a sphere; tbe half of a 
 sphere, formed by a plane passing through the centre. 
 
 Hermetic Seal ; when the neck of a glass vessel or tube is heated 
 to the melting point, and then twisted with pincers until it be 
 air-tight, the vessel or tube is said to be hermetically sealed, or to 
 have received the seal of Hermes, the reputed inventor of chem- 
 istry. 
 
 Heterogeneous, from 'trsoog, different, and ytrog, kind; different in 
 nature and properties. 
 
 Homogeneous, from cuo:, alike, and yiroc y kind; alike in nature and 
 properties. 
 
 Horizontal, from ooiZTw, to bound or terminate; parallel to the hori- 
 zon. 
 
 Hydrate, from vSuq, water ; any uncrystalhzed substance which con- 
 tains water in a fixed, definite proportion. 
 
 Hydro,, when prefixed to the name of a chemical substance, denotes 
 • that hydrogen enters into the composition of the substance which 
 it signifies. 
 
 Hydrometer, from v3vm, water, and fiirgor, a measure ; an instru- 
 ment for comparing tbe density and gravity of liquids with water. 
 
 Hydrostatics, from vdog, water, and orarbc, standing ; that branch 
 of natural philosophy which treats of the pressure and equilibrium 
 of non-elastic fluids, and also of the weight, pressure, &c., of 
 solids immersed in them. 
 
 Hygrometer, from vyqog t moist, and ueroov, a measure; an instru- 
 ment for ascertaining accurately the quantity of moisture in the 
 atmosphere. 
 
 Hygroscope, from lyQoc^ moist, and axorcf n, to consider ; an instru- 
 ment for exhibiting aporoximatively the moisture of the 'atmos- 
 phere. 
 
Glossary. 435 
 
 Hypo, from into, under ; when prefixed to a word, denotes an inferior 
 quantity of some ingredient whieh enters into the composition of 
 the substance which it signifies. 
 
 Hvpothesis, -tical, from vnb, under, and ri-9-tjfii, to place ; a princi- 
 ple supposed or taken for granted in order to prove a point in 
 question. 
 
 Impinging, from impingo, to strike against ; dashing against. 
 
 Incandescent, from incandesco, to grow white ; white or glowing 
 with heat. 
 
 Incidence, from in, upon, and cado, to fall; the direction in which 
 one body falls on or strikes another ; the angle which the moving 
 body makes with the plane of the body struck, is called the " angle 
 of incidence." 
 
 Increment, from incresco, to increase; the quantity by which any 
 thing increases or becomes greater. 
 
 Induction, -ive, from in, to, and duco, to lead; the process of reason- 
 ing, by which we are led from general to particular truths. 
 
 Induction, Electrical ; the effect produced by the tendency of an 
 insulated electrified body to excite an opposite electric state in 
 neighboring bodies. 
 
 Inductometer ; an instrument for measuring electrical induction. 
 
 Inertia, from inertia, inactivity; the disposition of matter to remain in 
 its state of rest or motion, 
 
 Inflammable, from in, and flamma, a flame ; capable of burning with 
 a flame.' 
 
 Inflection, from in, to, and flecto, to bend. 
 
 Insulation, from insula, an island; when a body, containing a quan- 
 tity of free heat, or of electricity, is surrounded by non-conductors, 
 it is said to be insulated. 
 
 Integrant, from integer, whole, entire; those parts of a body which 
 are of the same nature with the whole, are called integrant. 
 
 Interstices, from inter stitium, a break or interval; the unoccupied 
 spaces between the molecules of bodies. 
 
 Iridescent, from iris, the rainbow; marked with the colors of the 
 rainbow. 
 
 Isomeric, from Xooq, equal, and /.itQog, a part; substances which con- 
 sist of the same ingredients, in the same proportion, and yet differ 
 essentially in their properties, are called isomeric. 
 
 Isomerism ; that portion of chemical science which treats of isomeric 
 substances. 
 
 J. 
 
 Juxtaposition, from juxta, near, and pono, to place ; the placing of one 
 thing close to another. 
 
 L. 
 
 Lamina, from lamina, a thin plate ; extremely thin plates, of which 
 some solid bodies are, composed. » 
 
 Lens, from lens, a bean ; properly a small glass in the form of a bean ; 
 but more generally it means a piece of glass, or other transparent 
 substance, having its two surfaces so formed that the rays of light, 
 in passing through it, have their direction changed, and are made 
 to diverge or converge, or to become parallel after diverging or 
 converging. 
 
 Levigation, from Uevis, smooth ; the art of reducing to a light powder. 
 
436 Glossary. 
 
 Liquefaction, from liquefacio, to make liquid , the process of convert 
 ing into a liquid state. * 
 
 Litmus ; a blue pigment obtained from the lichen rocella; it is a most 
 delicate test of acids, which turn it red. 
 
 Loadstone, i.e., Leadstone ; an ore of iron having magnetic properties. 
 
 M. 
 
 Magnet, from Magnesia, a town in Asia Minor ; artificial magnets are 
 
 small bars of steel or iron, which, when placed at liberty, turn one 
 
 end to the north. 
 Magnetism ; the peculiar property possessed by certain ferruginous 
 
 bodies, whereby, under certain circumstances, they attract and re- 
 pel one another according to certain laws. 
 Magneto-Electricity ; electricity produced by magnetism. 
 Malleable, from malleus, a hammer ; that which is capable of being 
 
 spread by beating. 
 Maximum, from maximus, greatest; the greatest value of a variable 
 
 quantity. 
 Mechanics, from fnjxavij, a machine; the science which treats of the 
 
 laws of the rest and motion of bodies. 
 Metallurgy, from /ufralkov, a metal, and tQyov, a work ; the art of 
 
 working metals, and separating them from their ores. 
 Mineralogy ; the science which treats of bodies not being vegetable 
 
 or animal. 
 Moiree Metallique, from moirie, a watered silk ; when tin plates are 
 
 washed over with a weak acid, the crystalline texture of the tin 
 
 becomes apparent, forming a crystalline appearance, which has been 
 
 called Moiree Metallique. 
 Molecules, -ar, a diminutive from moles, a mass; the infinitely small 
 
 material particles of which bodies are conceived to be aggregations. 
 Momentum, from moveo, to move ; the product of the numbers which 
 
 represent the quantity of matter and the velocity of a body, is 
 
 called its momentum or quantity of motion. 
 Mucilaginous ; resembling mucilage or gum. 
 Multiple, from multiplico, to render manifold ; a quantity is said to be 
 
 a multiple of another when it contains that other quantity a certain 
 
 number of times without a remainder. 
 
 N. 
 
 Nascent, from nascor, to be born ; in the moment of formation. 
 
 Negative, from nego, to deny ; quantities to which the sign of subtrac- 
 tion, or negative sign, is prefixed, are called negative quantities ; 
 this sign is also used to denote operations which are the reverse 
 of those denoted by the positive sign. 
 
 Nodes, -al, from nodus, a knot; in the doctrine of curves, a node is a 
 small oval figure made by the intersection of one branch of a curve 
 with another. 
 
 Normal, from norma, a rule ; according to rule. 
 
 Nucleus, from nucleus, a kernel ; the central parts of a body, which are 
 supposed to be firmer, and separated from the other parts, as the 
 kernel of a nut is from the shell ; also, the point about which mat- 
 ter is collected. 
 
 O. 
 
 Oblate, from ob, in front of, and latus, broad ; flattened or short- 
 ened. 
 
Glossai y. 437 
 
 Oblong, from ob, in front of, and longus, long ; greater in length than 
 in breadth. 
 
 Octohedron, -AL,from oztw, eight, and sSqcc, a side; a solid figure con- 
 tained by eight equal and equilateral triangles. 
 
 Olefiant Gas, from oleum, oil, and fio, to become ; a colorless, taste- 
 less gas, which derives its name from its property of forming an 
 oil-like liquid with chlorine. 
 
 Optics, from oizrouai, to see : that branch of natural philosophy which 
 treats of vision, and of the nature and properties of light, and of the 
 various changes it undergoes. 
 
 Organic Matter, from ogyavov, an organ ; when matter possesses or- 
 gans, or organized parts for sustaining living action, as animals and 
 plants, it is called organic. 
 
 Organization ; construction in which the parts are so disposed as to 
 be subservient to each other. 
 
 Oscillation, from oscillor, to swing; the vibration or reciprocal ascent 
 and descent of a pendulum. 
 
 Oxide ; a combination with oxygen, not being acid. • 
 
 Oxidizable ; capable of being converted into an oxide. 
 
 Oxygen, from 6$vg, acid, and yswaco, to produce ; a colorless, aeriform 
 fluid, which was formerly supposed to be the universal acidifying 
 principle. 
 
 P. 
 
 Parabola, from naqa, parallel to, and /5«AAw, to place ; one of the conic 
 sections, formed by the intersection of a plane and a cone, when the 
 plane passes parallel to the side of the cone. 
 
 Parallel ; a term applied in geometry to lines and planes, which are 
 every where equidistant from one another; straight lines, which, if 
 infinitely produced, never meet, are called parallel straight lines. 
 
 Parallelogram : a four-sided figure, of which the opposite sides are 
 parallel and equal. 
 
 Parallelopipedon ; a solid figure contained by six parallelograms, 
 the opposite sides of which are equal and parallel. 
 
 Pellicle, a diminutive from pellis, a skin or crust ; a thin crust formed 
 on the surface xjf a solution by evaporization. 
 
 Pendulum, from pendeo, to hang ; a heavy body so suspended that it 
 may vibrate, or swing backward and forward about some fixed 
 point, by the action of gravity. 
 
 Percolate, from per, through, and colo, to strain ; to strain through. 
 
 Permeate, from permeo, to pass through ; to penetrate. 
 
 Perpendicular ; the straight line which, standing upon another 
 straight line, makes the adjacent angles equal, and consequently 
 right angles, is said to be perpendicular to the line upon which it 
 stands. 
 
 Phenomenon, from tpaivo^ai, to appear; an appearance. 
 
 Philosophy, -ical, from (piktw, to love, and aoqia, wisdom; the study 
 or knowledge of nature or morality, founded on reason and expe- 
 rience, the word originally implying " a love of wisdom." 
 
 Phlogiston, from (pXiyw, to burn ; a name given by the older chemists 
 to an imaginary substance, which was considered as the principle 
 of inflammability. 
 
 Phosgene, from (pcog, light, and ytwaw, to produce ; produced by light. 
 
 Phosphorus, from qxog, light, and (ptQco, to produce; a highly inflam- 
 mable substance, obtained from calcined bones, which emits light 
 when placed in the dark. 
 
438 Glossary. 
 
 Photometer, from q£c, light, and ptroor, a measure; an instrument 
 for measuring the different intensities of light. 
 
 Physiology, -ical, from cpvoic, nature, and ?.6yoc. an account; the 
 science which treats of the structure of living beings. 
 
 Pneumatics, from Tirtvua, air; that branch of natural philosophy 
 which treats of the weight, pressure, and elasticity of aeriform fluids. 
 
 Polarity; the opposition of two equal forces in bodies, similar to that 
 which confers the tendency of magnetized bodies to point to the 
 magnetic poles. 
 
 Polarization : the communication of the above opposition of forces. 
 
 Polarized Light; light which, by reflection or refraction at a certain 
 angle, or by refraction in certain crystals, has acquired the prop- 
 erty of exhibiting opposite effects in planes at right angles to each 
 other, is said to be polarized. 
 
 Poles of a Magnet ; points in a magnet where the intensity of the 
 magnetic force is a maximum ; one of these attracts, and another 
 repels, the same pole of another magnet. 
 
 Pores, from 71600c, a passage ; the small interstices between the solid 
 particles of bodies. 
 
 Precipitation, from -prcEcipito, to fall suddenly; the separation of a 
 solid from a liquid; a triangular glass solid used for tSe separation 
 of rays of light by refraction. 
 
 Projectile, from pro, forward, and jacio, to throw; a heavy body pro- 
 jected, or cast forward into space, by any external force. 
 
 Proportion ; the relation of equality subsisting between two ratios. 
 
 Pyrometer, from ttvq, fire, and uiroov, a measure ; an instrument for 
 measuring higher degrees of temperature than can be ascertained 
 by a thermometer. 
 
 Pyroxylic Spirit, from ttvq, fire, and 6:1 c, acid ; a colorless, transpa- 
 rent spirit, obtained by the destructive distillation of wood. 
 
 Pyro ; when prefixed to a word, denotes that the substance which it 
 signifies has been formed at a high temperature. 
 
 Photography, from (pa>g, light, and y§a<j>u), to write ; writing with the 
 sun's rays. 
 
 a 
 
 Quadrant ; the fourth part of the circumference of a circle. 
 
 R. 
 
 Radiation, from radius, a ray; the shooting forth in all directions 
 
 from a centre. 
 Radical, from radix, a root; the original principle of a compound. 
 Radius ; the straight line drawn from the centre to the circumference 
 
 of a circle. 
 Rarefaction, from rams, rare, and facto, to make ; the act of causing 
 
 a substance to become less dense ; it also denominates the state of 
 
 this lessened density. 
 Ratio ; the relation which subsists between two quantities of the same 
 
 kind, the comparison being made by considering what multiple 
 
 part or parts one of them is of the other. 
 Ray ; a beam of light propagated from a radiant point. 
 Reaction ; the reciprocation of any impulse, or force impressed, made 
 
 by the body on which such impression is made. Reaction is always 
 
 equal to action. 
 Rectangle, from rectus, right, and angulus, an angle ; a four-sided plane 
 
Glossary. 439 
 
 figure, In which all the angles are right angles, and its opposite 
 
 sides equal and parallel. 
 Rectification; the process of drawing any thing off by distillation, in 
 % order to make it more pure and refined. 
 Rectilinear ; consisting of, or bounded by, straight lines. 
 Reflection, from re, back, and flecto, to bend ; the act of bending back ; 
 
 when rays of light fall on the surfaces of bodies, part of them are 
 
 thrown back or reflected. 
 Refraction, from re, back, and frango, to break; the deviation of rays 
 
 of light from their direct course, when passing through media of 
 
 different densities. 
 Refrangible ; susceptible of refraction. 
 
 Refrigeration, from re, again, and frigo, to cool; the act of cooling. 
 Repulsion, from re, back, and pello, to drive ; that property in certain 
 
 bodies whereby they mutually tend to recede and fly off from each 
 
 other. 
 Retort, from re, back, and torqueo, to twist ; a vessel with a bent neck, 
 
 which is made use of in chemical operations. 
 Rhombus ; a figure which has all its sides equal, but its angles are not 
 
 right angles. 
 Rhombohedron; a solid figure, whose sides are composed of rhombs. 
 Rhomboid ; a figure which has its opposite sides equal, but all its angles 
 
 are not equal, neither are all its angles right angles. 
 
 • S. 
 
 Salifiable Bases, from sal, salt, and fio, to become; bodies capable 
 of combining with acids to form salts. 
 
 Saturation, -ated, from satur, full ; the solution of one body in an- 
 other until the receiving body can contain no more. 
 
 Scale, from scala, a ladder ; an instrument in which a line is divided 
 into small and equal parts, and which is applied for the purpose of 
 ascertaining the relative dimensions of other lengths not so divided. 
 
 Section, from sr.co, to cut ; a cutting, or part separated from the whole. 
 
 Segment of a Circle ; any portion cut off" by a straight line. ' 
 
 Sine ; the straight line drawn from one extremity of an arc, perpen- 
 dicular to the radius which passes through the other extremity. 
 
 Solution, from solvo, to loosen ; in chemical language, any fluid that con- 
 tains another substance dissolved in and intimately mixed with it. 
 
 Solvent; any substance which will dissolve another. 
 
 Specific, from species, a particular sort or kind; that which denomi- 
 nates any property which is not general, but is confined to an in- 
 dividual or species. 
 
 Spectrum ; the colored image formed on a white surface by rays of 
 light passing through a hole, and being refracted by a glass prism. 
 
 Sphere ; the solid figure formed by the rotation of a semicircle about 
 its diameter. 
 
 Spheroid, -al ; a solid figure, formed by the revolution of an ellipse 
 about one of its axes ; hence it is sometimes called an ellipsoid ; 
 the spheroid will be oblate or prolate, according as the revolution 
 is performed about the minor or major axis of the ellipse. 
 
 Statics, -ical, from otutoc, standing; that branch of mechanical 
 science which treats of the equilibrium, pressure, weight, &c, of 
 solid bodies when at rest. 
 
 Stratum, from sterno, to strew ; a layer. 
 
 Symmetry, -ical, from avv, together, and fiirQov, a measure ; confor- 
 mity of measure. 
 
440 G..;::-.;. 
 
 Stxthesis, from ovr, together, and t'i&tjii, to place; the composition 
 of a whole from its parts ; in mathematics, die process of reasoning 
 out new principles from those already established. 
 
 Sublimation, from subtends, high ; the act of raising into Taper %f 
 means of heat, and condensing in the upper part of a vessel. 
 
 Sry c hrokous, from oiw, together, and j^Lroz , time ; performed in the 
 
 Tactile, from tango, to touch; of or relating to touch. 
 
 I - - ' :• i .■ t . •: a i ; the line which touches a circle or any other curre.but 
 
 does not cot it. 
 
 iamx, from ter, thrice; containing three units. 
 _ ::?aHiDEOjr, from thwoosc, four, and ?&>**, a base or side ; a solid 
 
 figure contained by four equal and equilateral triangles. 
 Theort, -etical, from ftc^la, a view ; a collected view of all that 
 
 is known on any subject into one. 
 Thekmo-Electmcitt ; electricity produced by heat. 
 Thiemomitik, from &teuo;, heat, and uctqot, a measure; an instru- 
 ment for measuring the degrees of heat. 
 i BKnrascans, from &£ouog 3 heat, and oxvtiia, to view ; an instrument 
 
 for exhibiting the powers of beat. 
 Ttre ; a hoop of iron used to bend and receive the felly of a wheel. 
 Torsiojj, Force of, from torqueo, to twist; a term applied by Cou- 
 
 1:~": :: irnr.r :r.e erf::: n.-ir :j i ±.:eii —-.::. r.i; :-r:; :-TTi;-.e d 
 
 to untwist itself. 
 Transparent : a term to denote the quality of a substance which not 
 
 only admits the passage of light, but also of the vision of external 
 
 Triturated, from trituro. to thrash ; reduced to powder. 
 I : cation, from truncus, cut short; the cutting off a portion of a 
 solid, as of the solid angle of a crystal. 
 
 r. 
 
 Undulation, from vnda, a wave ; a formation of waves. 
 Uniaxal, from turns, one, and axis, an axis ; having but one axis. 
 
 Vacuum, Latin ; a space empty and devoid of all matter. 
 V ■ n : l ation, from rcntus, wind; the supply of fresh air. 
 
 ; an instrument invented by Vernier ; it consists of a 
 
 movable scale, running parallel to the fixed scale of a quadrant or 
 
 other instrument, and having the effect of subdividing the divisions 
 
 of the instrument into more minute parts. 
 Vibration, from ribro, to brandish ; the regular reciprocating motion 
 
 of a body, as of a pendulum, &c.; a motion to and fro. 
 Volume, from toImmvb*, a roll ; the apparent space occupied by a body. 
 
 W. 
 
 Weight ; the pressure which a body exerts vertically downward in 
 consequence of the action of gravity. 
 
 Z. 
 
 Zero ; the numeral 0, which fills the blank between the awcewfing 
 and descending numbers in a series. 
 
INDEX. 
 
 Page 
 
 Acetate of alumina 359 
 
 ammonia 358 
 
 copper 359 
 
 iron 360 
 
 lead 358 
 
 zinc 360 
 
 potassa 358 
 
 methyle 364 
 
 Acetic ether 355 
 
 Acetone 360 
 
 Acetous fermentation 350 
 
 Acid, acetic 357 
 
 aconitic .... .... - 380 
 
 aldehy die 357 
 
 amygdalic 369 
 
 antimonic '. 274 
 
 antimonious 274 
 
 apocrenic 383 
 
 arsenic 267 
 
 arsenious 265 
 
 benzoic 367 
 
 boracic 216 
 
 bromic 153 
 
 capric 390 
 
 caproic 390 
 
 carbazotic 395 
 
 carbonic 184 
 
 cerebric 406 
 
 cholic 403 
 
 cholinic 403 
 
 chloric 147 
 
 chloranilic 395 
 
 chlorous 147 
 
 chloriodic 151 
 
 chlorocarbonic ; . . J 89 
 
 chromic * . . 269 
 
 cinnaminic 371 
 
 citric 380 
 
 cocinic 389 
 
 columbic 273 
 
 comenic 383 
 
 crenic 383 
 
 croconic 3S2 
 
 Page. 
 
 Acid, cyanic 196, 373 
 
 cyanuric 196, 374 
 
 elaidic 389 
 
 ellagic 383 
 
 fellinic 403 
 
 fluosilicic 221 
 
 fluoboric 217 
 
 formic 364 
 
 fulminic 196, 373 
 
 gallic 382 
 
 humic 346 
 
 hydriodic 164 
 
 hydrobromic. , 165 
 
 hydrochloric 1 62 
 
 hydrocyanic 137, 374 
 
 hydroferrocyanic 376 
 
 hydrofluoric 165 
 
 hydromellonic 377 
 
 hydrosalicylic 370 
 
 hydroselenic 219 
 
 hydrosulphocyanic 375 
 
 hydrosulphuric 205 
 
 hydrosulphurous 206 
 
 hydrotelluric 178 
 
 hydrothionic 107 
 
 hypochlorous 146 
 
 hyponitrous 173 
 
 hypophosphorous 210 
 
 hyposulphuric 202 
 
 hyposulphurous 200 
 
 hypuric 369 
 
 indigotic 395 
 
 iodic 151 
 
 isatinic 395 
 
 kakodylic 361 
 
 kinic 382 
 
 lactic 382 
 
 lithic 378 
 
 malic 380 
 
 margaric 388 
 
 manganic 250 
 
 meconic 383 
 
 mellitic 382 
 
442 
 
 INDEX. 
 
 Page. 
 
 Acid, metagallic 383 
 
 molybdic 272 
 
 moroxylic 383 
 
 mucic 348 
 
 muriatic 162 
 
 nitric 174 
 
 nitrohydrochloric 1 76 
 
 nitre-hydrofluoric 177 
 
 nitrous 173 
 
 nitromuriatic 176 
 
 oleic 383, 389 
 
 oleophosphoric 406 
 
 osmic 272 
 
 oxalic 371 
 
 palmitic .- 389 
 
 paracyanuric 197 
 
 paraphosphoric 212 
 
 perchloric 148 
 
 permanganic 250 
 
 periodic 151 
 
 phosphoric 212 
 
 phosphovinic ........ ... 356 
 
 Acidulous springs 416 
 
 Acid, phosphorous 211 
 
 prussic 197, 374 
 
 pyrogallic 383 
 
 pyroligneous 358 
 
 pyromucic 348 
 
 pyrophosphoric 21 2 
 
 racemic 381 
 
 sacharic 348 
 
 salecylic 370 
 
 sebacic 389 
 
 selenic 219 
 
 selenious 218 
 
 silicic 220 
 
 silicohydrofluoric 221 
 
 stearic 388 
 
 succinic 383 
 
 sulpindigotic 396 
 
 sulphoglyceric 388 
 
 sulphomethylic 364 
 
 sulphovinic 356 
 
 sulphuric 202 
 
 sulphurous. ...' 200 
 
 tannic 381 
 
 tartaric 380 
 
 tartralic 381 
 
 tartrelic 381 
 
 telluric. 278 
 
 tellurous 278 
 
 titanic 277 
 
 tungs'dc 272 
 
 uric 378 
 
 Page. 
 
 Acid, valerianic 366 
 
 vanadic 271 
 
 Affinity, chemical 1 13 
 
 disposing 155 
 
 double 114 
 
 effects of. 120 
 
 elective 113 
 
 measure of 119 
 
 simple 114 
 
 Air 168 
 
 Alabaster 304 
 
 Albumen 398 
 
 Alcohol 351 
 
 Aldehyde 357 
 
 Alkalies, metallic bases of 228 
 
 Alkaline earths 237 
 
 Alkarsine 360 
 
 Alkargene 361 
 
 Allontoin 378 
 
 Alloys of antimony 278 
 
 copper 280 
 
 lead 282 
 
 manganese 251 
 
 silver p 287 
 
 sodium and potassium . . . 235 
 
 Alloxan 379 
 
 Alloxantin , 379 
 
 Alizarin 396 
 
 Alum 308 
 
 ammonia 308 
 
 Alum stone 308 
 
 iron 308 
 
 manganese 309 
 
 Alkaline springs 416 
 
 Alumina 244 
 
 Aluminium 244 
 
 Aluminous earth 244 
 
 Amalgams 285 
 
 Amarythrin 396 
 
 Amber.... 392 
 
 Ambergris 391 
 
 Ammeline 378 
 
 Armnehde. ■, 378 
 
 Amnridogen 179 
 
 Ammonia 178 
 
 Amrrfonyjin 179 
 
 Amygdaline 369 
 
 Amylic alcohol 365 
 
 Analysis of carbonate of lime. 414 
 
 Analysis of minerals 4t3 
 
 mixed gases 412 
 
 Analysis of mineral waters. . . 416 
 
 organic compounds 337 
 
 Anhydrite 304 
 
INDEX. 
 
 443 
 
 Anthracite 181 
 
 Animal heat 401 
 
 Antimonio-sulphurets 333 
 
 Antimony 273 
 
 Aqua fortis 17-4 
 
 Archil 39G 
 
 Aerostation 157 
 
 Arrow-root 343 
 
 Arseniates 319 
 
 table of compounds ..... 320 
 
 Arsenic 264 
 
 Arsenites 320 
 
 Arsenio-sulphurets 332 
 
 Atomic theory 126 
 
 Auro-chlorides ', 333 
 
 B 
 
 Balloons 157 
 
 Balsam of sulphur 391 
 
 Balsam 392 
 
 Barium. 237 
 
 Barometer 53 
 
 Baryta 237 
 
 Bell-metal 280 
 
 Benzamide 368 
 
 Benzile 368 
 
 Benzoic ether 356 
 
 Benzole 368 
 
 Benzoine 368 
 
 Benzoyle 366 
 
 Biborate of soda 322 
 
 Bicarbonate of ammonia 324 
 
 potassa 323 
 
 soda 323 
 
 Bicarburet of nitrogen. . . 196, 372 
 
 Bichromate of potassa 321 
 
 Bichloride of cyanogen 197 
 
 molybdenum 272 
 
 platinum 291 
 
 tin 260 
 
 titanium 278 
 
 tungsten 272 
 
 Bichlorisatine 395 
 
 Bile r . . 403 
 
 Bileverdin 403 
 
 Bilin 403 
 
 Biniodide of platinum 292 
 
 tin 260 
 
 Binoxide of barium 238 
 
 columbium 273 
 
 copper 280 
 
 gold 287 
 
 hydrogen 161 
 
 mercury 287 
 
 Pag 8. 
 
 Binoxide of molybdenum 271 
 
 nitrogen 172 
 
 platinum 291 
 
 tungsten 272 
 
 tin 260 
 
 vanadium 271 
 
 Bisilicates 326 
 
 Bismuth 276 
 
 Bisulphuret of carbon 207 
 
 calcium 242 
 
 cobalt 263 
 
 iron 254 
 
 mercury 285 
 
 potassium 232 
 
 platinum 292 
 
 tin 261 
 
 selenium 219 
 
 titanium 278 
 
 Bisulphate of potassa 303 
 
 soda 303 
 
 Bitartrate of potassa 380 
 
 Bituminous coal 181 
 
 Black dyes 397 
 
 lead 181 
 
 oxide of copper 280 
 
 oxide of iron 253 
 
 Bleaching 144 
 
 powder .... . . . , 242 
 
 Block tin 259 
 
 Blood 399 
 
 Blue vitriol 307 
 
 dyes 394 
 
 Bone phosphate of lime 318 
 
 Bones 405 
 
 Boracic ether. 355 
 
 Borates 321 
 
 Borax 322 
 
 Boron 215 
 
 Brain 406 
 
 Brass 280 
 
 Bromine 151 
 
 Bromates .... 316 
 
 Bromide of carbon '. 189 
 
 Bromide of amyle 366 
 
 bismuth 277 
 
 calcium 241 
 
 barium 238 
 
 cyanogen 197 
 
 iodine 1 53 
 
 lead 282 
 
 magnesium 243 
 
 sodium 235 
 
 sulphur 205 
 
 phosphorus 213 
 
444 
 
 INDEX, 
 
 Page. 
 
 Bromide of potassium 231 
 
 selenium 219 
 
 silicon 221 
 
 zinc 257 
 
 Bromoform . . 365 
 
 Brucia 38G 
 
 Butter 390 
 
 Butyrine 390 
 
 Cadmium 257 
 
 Calatilic force 336 
 
 Calcium 240 
 
 Caloric 25 
 
 absorption of 32 
 
 conduction of 26 
 
 effects of 36 
 
 radiation of 29 
 
 reflection of 31 
 
 theories 32 
 
 Calomel 284 
 
 Camphene 192 
 
 Camphor 392 
 
 Canton's phosphorus #r 241 
 
 Calorimotor «J. 81 
 
 Caoutchouc 393 
 
 Carbon 180 
 
 Carbonates 322 
 
 ammonia 323 
 
 baryta 324 
 
 lead 325 
 
 lime. .^ 324 
 
 magnesia 324 
 
 potasssa 322 
 
 protoxide of iron 325 
 
 soda 323 
 
 strontia 324 
 
 Carbonic oxide 184 
 
 ether 344 
 
 Carbosulphurets 331 
 
 ammonia 332 
 
 barium 332 
 
 calcium 332 
 
 sulphuret of lithium 332 
 
 magnesium 332 
 
 potassium 331 
 
 sodium 332 
 
 Carburet of manganese 251 
 
 iron 255 
 
 Carmine 396 
 
 Carumel 347 
 
 Caseine 398 
 
 Cast iron 255 
 
 steel 255 j 
 
 Page. 
 
 Cassava 343 
 
 Cementing 425 
 
 Cerium 276 
 
 Chalybeate springs 416 
 
 Cholisterin 403 
 
 Charcoal ". . 181 
 
 Chloral 189 
 
 Chloranile 395 
 
 Chlorates 313 
 
 baryta 314 
 
 potassa 313 
 
 Chloride of barium 238 
 
 amyle 365 
 
 benzoyle 367 
 
 bismuth 277 
 
 bromine 153 
 
 cadmium 258 
 
 calcium 241 
 
 carbon 291 
 
 cobalt 262 
 
 copper 280 
 
 cyanogen 197 
 
 kakodyle : 361 
 
 lead 282 
 
 lime 242 
 
 lithium 236 
 
 magnesium 243 
 
 methyle 362 
 
 nikel 264 
 
 potassium 231 
 
 salicyle 379 
 
 selenium 219 
 
 silicon 221 
 
 silver 287 
 
 soda 235 
 
 sodium 234 
 
 strontium 239 
 
 tellurium 278 
 
 zinc 257 
 
 Chlorisatine , 295 
 
 Chloroform 365 
 
 Choke-damp 187 
 
 Chlorine 141 
 
 Chlorites 315 
 
 Chromates 321 
 
 lead 321 
 
 potassa 321 
 
 oxide of zinc 321 
 
 Chromium 268 
 
 Chyle... 403 
 
 Cinchonia 385 
 
 Citrine 192 
 
 Cleavage 296 
 
 faces of 292 
 
INDEX. 
 
 445 
 
 Page. 
 
 Cleavage, direction of 296 
 
 Coal gas 193 
 
 Cobalt 261 
 
 Cochineal 396 
 
 Cocoanut oil 389 
 
 Codeia 386 
 
 Cohesion 115 
 
 Coloring matters 394 
 
 Columbium 273 
 
 Combustion 142 
 
 Composition of blood 401 
 
 Compound blowpipe 160 
 
 Compound radicals 299 
 
 Conia 386 
 
 Copal 392 
 
 Copperas 294 
 
 Copper 279 
 
 Copper pyrites 280 
 
 Corrosive sublimate 284 
 
 Cream of tartar 327 
 
 Creosote 393 
 
 Croton oil 389 
 
 Crucibles 199 
 
 Crystal 293 
 
 Crystallization 293 
 
 Cry sialography 293 
 
 Cyanogen 196, 372 
 
 Cyanate of ammonia 373 
 
 Cyanide of lead 282 
 
 barium 239 
 
 kakodyle 361 
 
 manganese 251 
 
 methyle 363 
 
 nickel 264 
 
 silver 287 
 
 sodium 235 
 
 zinc 257 
 
 potassium 233, 375 
 
 Cupellation 286 
 
 Cuticle 406 
 
 Cystic oxide 405 
 
 D 
 
 Daguerreotype 69 
 
 Decrepitation 297 
 
 Definite proportions 122 
 
 Deflagration 105 
 
 Deflagrator 82 
 
 Deliquesce 297 
 
 Diamond 180 
 
 Dichloride of copper 280 
 
 mercury 284 
 
 Dicarbonate of mercury 326 
 
 Dicarburet of hydrogen 190 
 
 Page. 
 
 Dicyanide of mercury 285 
 
 Digester, Marcet's 55 
 
 Diphosphate of potassa 316 
 
 ammonia - 318 
 
 lime.... 318 
 
 magnesia 318 
 
 Diphosphuret of iron 255 
 
 Dinitrate of protoxide of lead. 31 1 
 
 Diniodide of copper 280 
 
 Dioxide of copper 279 
 
 mercury ... 283 
 
 Disulphate of protoxide of cop- 
 per 307 
 
 Disulphuret of iron 254 
 
 nickel 264 
 
 Dodecahedron 296 
 
 Dolomite 326 
 
 Double bromides 334 
 
 cyanides 335 
 
 fluorides 335 
 
 iodides 320 
 
 Ductility 223 
 
 E 
 
 Ebullition 52 
 
 Efflorescence 297 
 
 Eggs 405 
 
 Elasticity 109, 117 
 
 Electricity 73 
 
 Electrical machine 74, 75 
 
 Electro-chemical decomposi- 
 tion 91 
 
 Electrodes 89 
 
 Electrography 112 
 
 Electrometer, gold leaf 75 
 
 balance 78 
 
 Electro-magnetism 94 
 
 theory 106 
 
 Electro-magnetic multiplier. . . 95 
 
 telegraph 109 
 
 Electrophorus 78 
 
 Electrotype 104, 112 
 
 Emetia 386 
 
 Emulsion 387 
 
 Eremacausis 346 
 
 Erythrilin 396 
 
 Erythrin 396 
 
 Essences 391 
 
 Etching • 166 
 
 Etherine 192, 357 
 
 Etherole 357 
 
 Ethiop's mineral 255 
 
 Ethyle 352 
 
 Eudiometer 160 
 
446 
 
 IJJDEX. 
 
 Page. 
 
 Eupione 192 
 
 Evaporation 59 
 
 Exhilirating gas 171 
 
 F 
 
 Feathers 406 
 
 Fermentation of sugar 349 
 
 Ferro-cyanide of potassium . . . 376 
 
 iron 376 
 
 Ferrid-cvanogen 377 
 
 Fibrine 397 
 
 Filtration 418 
 
 Fire damp 194 
 
 Fixed oils 387 
 
 Flowers of zinc 306 
 
 Fluoride of barium 238 
 
 calcium 241 
 
 lead 281 
 
 lithium 236 
 
 magnesium 243 
 
 methyle 363 
 
 potassium 231 
 
 sodium 235 
 
 strontium 240 
 
 . zinc 257 
 
 Fluorine 153 
 
 Food of plants 408 
 
 Formate of ammonia 364 
 
 baryta „ 364 
 
 copper ♦ »..... 365 
 
 lime ...... 365 
 
 magnesia « 365 
 
 mercury 365 
 
 potassa 364 
 
 silver 365 
 
 strontia 365 
 
 Formic ether 355 
 
 Fowler's arsenical solution. . . 320 
 
 Freezing mixtures 50 
 
 Fulminating gold 289 
 
 platinum 292 
 
 silver 287, 374 
 
 Fusion 110 
 
 Fusion, watery 297 
 
 G 
 
 Galena 281 
 
 Galvanism 79 
 
 'theories 85 
 
 effects of 87 
 
 Gasometers 137 
 
 Gas lights 192 
 
 Gastric juice ....'. 403 
 
 Gaseous mixtures 412 
 
 Page. 
 Gaseous mixtures containing 
 
 carbonic acid 413 
 
 hydrygen 413 
 
 nitrogen 413 
 
 oxygen 413 
 
 Gelatine 398 
 
 sugar - 399 
 
 Germination 407 
 
 Glass 221 
 
 green bottle 221 
 
 crown 221 
 
 plate 221 
 
 flint 221 
 
 Glauber's salts 309 
 
 Glucina 246 
 
 Glucinium 246 
 
 Glue 399 
 
 Gluten 344 
 
 Glycerine 387 
 
 Glycocoll 399 
 
 Gold 288 
 
 powder 290 
 
 Green vitriol 305 
 
 Graphite 255 
 
 Gum 344 
 
 arabic .... 344 
 
 Senegal 344 
 
 tragacanth 345 
 
 resins 393 
 
 Gun cotton 345 
 
 Gypsum 304 
 
 H 
 
 Hair 406 
 
 Hartshorn 323 
 
 Heavy oil of wine 356 
 
 Hematoxylin 397 
 
 Hematine 399 
 
 Hexahedron 294 
 
 Homberg's oyrophorus 308 
 
 Hog's lard 350, 390 
 
 Honey 349 
 
 Hoofs , 408 
 
 Horn 406 
 
 Humus 346 
 
 Hydriodate of ammonia 328 
 
 Hydriodic ether 353 
 
 Hydro-salts 328 
 
 Hydrobromic ether 353 
 
 Hydrochlorate of ammonia . . . 328 
 
 Hydrochloric ether 352 
 
 Hydrobromate of ammonia. . . 329 
 
 Hydrofluate of ammonia 3'29 
 
 Hydrocyanate of ammonia . .. 329 
 
INDEX. 
 
 447 
 
 Page. 
 
 Hydrogen 154 
 
 Hydrargochlorides 333 
 
 Hvdrosulphocyanides 331 
 
 Hyduret of arsenic 268 
 
 potassium 232 
 
 Hygrometers G2 
 
 Hyponitrous ether 354 
 
 1 
 
 Idoform 365 
 
 Idrialine 192 
 
 Ignition 71 
 
 Indefinite proportions 122 
 
 Indelible ink 313 
 
 India rubber 393 
 
 Indigo 395 
 
 Induction ' 76 
 
 Ink 382 
 
 Insolubility 116 
 
 Iodates 315 
 
 Iodate of potassa 315 
 
 Iodide of barium 238 
 
 calcium *. 241 
 
 cadmium 258 
 
 kakodyle 361 
 
 lead 282 
 
 magnesium 243 
 
 methyle 363 
 
 silver 287 
 
 sodium 235 
 
 phosphorus 213 
 
 sulphur 205 
 
 potassium 231 
 
 strontium 240 
 
 zinc 257 
 
 Iodine 148 
 
 Iron 251 
 
 Iron pyrites 244 
 
 Iridium 292 
 
 Isatine , 395 
 
 Ising-glass 399 
 
 Isomerism 127 
 
 Isomorphism 297 
 
 Ivory-black 181 
 
 K 
 
 Kakodyle 360 
 
 Kalium 228 
 
 Kermes mineral 275 
 
 L 
 
 Lakes 394 
 
 Lactine 348 
 
 Lamp-black 181 
 
 Page. 
 
 Lapis causticus 230 
 
 Lataniuni 293 
 
 Lead 281 
 
 Legumine 398 
 
 Leyden jar 77 
 
 Light 67 
 
 reflection of 67 
 
 refraction of 67 
 
 decomposition of 68 
 
 absorption of 70 
 
 carbureted hydrogen 190 
 
 Liquefaction 49 
 
 Lignin 345 
 
 Lime 240 
 
 Lime-water 240 
 
 Liquorice 349 
 
 Litharge 281 
 
 Lithia 236 
 
 Lithium 236 
 
 Litmus 306 
 
 Loaf-sugar 347 
 
 Lucifer matches 314 
 
 Lunar caustic 312 
 
 Lymph 404 
 
 M 
 
 Madder 396 
 
 Magnesium 242 
 
 Magisetry of bismuth 277 
 
 Magnesia 243 
 
 Magnetic iron pyrites 254 
 
 Magic circle 99 
 
 Malleability 222 
 
 Magneto-electric induction . . . 105 
 
 Magneto-electric machine 105 
 
 Manganese 248 
 
 Manna 349 
 
 Margarine 388 
 
 Matches 310 
 
 Membranes 406 
 
 Metals 224 
 
 Metallic lustre 224 
 
 Metaphosphates 319 
 
 Mercury 283 
 
 Mellone 377 
 
 Mellonide of potassium , 379 
 
 Melome 377 
 
 Melomine 377 
 
 Mercapton 354 
 
 Milk 404 
 
 Microcosmic salt 317 
 
 Mineral green 352 
 
 Molasses 347 
 
 Moly bdosulphurets 33Q 
 
448 
 
 INDEX. 
 
 Page. 
 
 Molybdosulphuret of potassa. . 332 
 
 Molybdenum 271 
 
 Morphia 384 
 
 Mosaic gold 261 
 
 Mucic ether 349 
 
 Mucus ." 404 
 
 Murexide 379 
 
 Murexan 379 
 
 Muscle 406 
 
 N 
 
 Nails 406 
 
 Naphtha 192 
 
 Naphthaline i#2 
 
 Narcotina 385 
 
 Natron 233 
 
 Nickel 263 
 
 Nicotina 386 
 
 Nitre 310 
 
 Nitric ether 354 
 
 Nituret of potassium 232 
 
 Nitrates 309 
 
 Nitrate of ammonia 310 
 
 baryta 310 
 
 lime.... 311 
 
 magnesia 311 
 
 methyle 363 
 
 potassa 309 
 
 soda 310 
 
 strontia 311 
 
 protoxide of copper 311 
 
 lead 311 
 
 mercury ... 311 
 
 oxide silver 311 
 
 Nitrites 313 
 
 Nitrogen 166 
 
 Notation 134 
 
 Nomenclature 130 
 
 Nourishment of animals 410 
 
 Nux vomica 386 
 
 O 
 
 Oblique prisms 295 
 
 rhombic prisms 295 
 
 rectangular 295 
 
 rhomboidal 295 
 
 Octohedron 295 
 
 Octohedron, regular 295 
 
 square 295 
 
 rectangular 296 
 
 rhombic 296 
 
 CEnanthic ether *. . . 356 
 
 Oils 387 
 
 Oil of bitter almonds 366 
 
 Page. 
 
 Oil of cinnamon. 371 
 
 Oleine 389 
 
 Olefiant gas 190 
 
 Olive oil 389 
 
 Orcein 396 
 
 Orpiment 268 
 
 Osmium 292 
 
 Oxalate of potassa 372 
 
 of lime 372 
 
 methyle 363 
 
 Oxalic ether 355 
 
 Oxalyle 371 
 
 Oxigenation 141 
 
 Oxidation 141 
 
 Oxide of selenium 218 
 
 cadmium 258 
 
 carbon 184 
 
 methyle 362 
 
 phosphorus 210 
 
 titanium 277 
 
 silver 287 
 
 strontium 240 
 
 Oxychlorides 334 
 
 chromium 270 
 
 copper 334 
 
 iron 334 
 
 lead 334 
 
 Oxygen 136 
 
 Oxysalts 301 
 
 Oxysulphuret of antimony . . . 275 
 
 P 
 
 Palladium 292 
 
 Palladio-chlorides 333 
 
 Palm-oil 389 
 
 Paranapthaline 192 
 
 Parraffine 192 
 
 Parmelia 396 
 
 Parilla 386 
 
 Peat 181 
 
 Pearlash 323 
 
 Perbromide of phosphorus .... 213 
 
 Percussion powder 314 
 
 Perchlorates 315 
 
 Perchloride of iron 253 
 
 manganese 250 
 
 phosphorus 213 
 
 Periodide of arsenic 268 
 
 iron 254 
 
 carbon 189 
 
 Perfluoride of iron 254 
 
 manganese 251 
 
 Perphosphuret of hydrogen . . . 229 
 
 Peroxide of strontium , . 239 
 
449 
 
 Page. 
 
 Peroxide of calcium 241 
 
 manganese 249 
 
 iron 253 
 
 cobalt 262 
 
 four-three oxcobalt 262 
 
 titanium 277 
 
 tellurium 278 
 
 lead 282 
 
 Permuriate of tin 260 
 
 Persulphuret of arsenic 268 
 
 tellurium 278 
 
 Perphosphuret of iron 255 
 
 Pewter 275 
 
 Phloridzine 370 
 
 Phosphureted hydrogen . . 213, 229 
 
 Phosphorus 208 
 
 Phosphorescence • 71 
 
 Phosphates 316 
 
 Phosphate of potassa 316 
 
 soda and ammonia 317 
 
 ammonia 318 
 
 lime 318 
 
 magnesia and ammonia. . 318 
 
 Phosphuret of potassium 232 
 
 cadmium 259 
 
 calcium 242 
 
 manganese 251 
 
 barium 239 
 
 Pitch 392 
 
 Pinchbeck 280 
 
 Photometers 72 
 
 Photographic drawing 69 
 
 Platinum 291 
 
 spongy 29 1 
 
 Platinochlorides 333 
 
 Plumbago 181 
 
 Pneumatic cistern 137 
 
 Pot-metal 281 
 
 Portable gas 193 
 
 Potassa 230 
 
 hydrate 231 
 
 Potassa-fusa 231 
 
 Potassium 228 
 
 Potassamide 340 
 
 Potash and pearlash 323 
 
 Potato oil 365 
 
 Printers' types 275 
 
 Proteine 398 
 
 Protobromide of iron 254 
 
 potassium 23 1 
 
 Protochloride of iron 253 
 
 tin 260 
 
 carbon 188 
 
 manganese 250 
 
 Page. 
 Protochloride of arsenic ...... 267 
 
 cerium 276 
 
 mercury 284 
 
 gold 290 
 
 platinum 291 
 
 uranium 276 
 
 Protocyanide of iron 255 
 
 Protiodide of iron 253 
 
 cadmium 258 
 
 carbon 189 
 
 tin 260 
 
 platinum 292 
 
 Protohyduret of arsenic 268 
 
 Protophosphuret of chromium. 270 
 
 strontium . . 239 
 
 Protosulphuret of arsenic .... 268 
 
 platinum 292 
 
 mercury 285 
 
 cerium 276 
 
 cobalt 263 
 
 nickel 264 
 
 manganese 251 
 
 tin 261 
 
 iron 254 
 
 strontium 240 
 
 calcium 241 
 
 potassium 232 
 
 Protosulphocyanide of iron. . . 255 
 
 Protoxide of strontium 239 
 
 cerium 276 
 
 hydrogen 158 
 
 bismuth 277 
 
 nitrogen 171 
 
 potassium 230 
 
 gold 289 
 
 sodium 234 
 
 copper 280 
 
 lithium 236 
 
 barium 237 
 
 lead 281 
 
 calcium 240 
 
 magnesium 243 
 
 mercury 284 
 
 thorium 247 
 
 manganese 248 
 
 iron 252 
 
 platinum 291 
 
 zinc 257 
 
 tin 259 
 
 cobalt 263 
 
 nickel 263 
 
 vanadium 271 
 
 molybdenum , 271 
 
 uranium 275 
 
450 
 
 INDEX. 
 
 Prussian blue 376 
 
 Pus 404 
 
 Putrefactive fermentation 346 
 
 Pyracetic spirit 
 
 Pyrometers 
 
 of Wedgewood 46 
 
 oY Daniel 46 
 
 of Brequet 46 
 
 Pyrotechny 310 
 
 Pyrophosphates 318 
 
 of soda 319 
 
 Pyrosylic spirit 362 
 
 ft 
 
 Quadrisilicates 327 
 
 Qnadrochloride of nitrogen ... 177 
 
 Qnartation 288 
 
 duinia 355 
 
 R 
 
 Realgar 266 
 
 Red dyes 396 
 
 Red oxide of manganese 249 
 
 lead 252 
 
 Red precipitate 254 
 
 Regular hexagonal prism 295 
 
 Respiration 188 
 
 Resins 392 
 
 Revolving rectangle 97 
 
 Right prisms 294 
 
 Right square prisms 294 
 
 rectangular 294 
 
 rhombic 294 
 
 rhomboidal 294 
 
 Rhodium 292 
 
 Rhodio-chlorides 334 
 
 Rhombohedron 295 
 
 Rochelle salt 335 
 
 Rock candv 347 
 
 salt...' 234 
 
 S 
 
 Saccharine fermentation 349 
 
 Safetv lamp 195 
 
 Sago' 343 
 
 Sal-ammoniac 326 
 
 Saliva 
 
 Salifiable base 293 
 
 Salicine 
 
 Saline springs 
 
 Saltpetre...^ 310 
 
 Salts or ternary compounds 
 
 Sandarac 264 
 
 San^uinaria S?6 
 
 Page. 
 
 Saxon blue 
 
 5 :0.rtle's green 320 
 
 Sealing-wax 392 
 
 Seleniuret of ammonia 245 
 
 phosphorus 220 
 
 potassium 232 
 
 Selenium 2\7 
 
 Sesquiphosphuret of aluminium 245 
 
 cobalt 263 
 
 Sesquibromide of arsenic 268 
 
 carbonate of ammonia ... 334 
 
 carbonate of soda 393 
 
 Sesquichloride of aluminium. . 245 
 antimony 274 
 
 arsenic. 
 
 cerium 
 
 chromium 
 
 uranium 
 
 Sesquifluoride of chromium. 
 Sesquioxide of aluminium . . 
 
 antimony 
 
 bismuth 
 
 cerium 
 
 chromium . , 
 glucinium . . 
 manga.nese . 
 nickel 
 
 platinum 
 
 sodium 
 
 tin 
 
 uranium 
 
 zirconium 
 
 Sesquisulphuret of aluminium 
 
 antimony 
 
 arsenic 
 
 chromium 
 
 tin 
 
 oobah 
 
 Sesquisulphoryanide of iron.. 
 Sulphocyanide of barium 
 
 potassium 233. 
 
 Shells 
 
 Silver 
 
 Silver glance 
 
 Silex 
 
 Silicon 
 
 Silicates 
 
 Silicic ethers 
 
 Silicium 
 
 Silica 
 
 Silk 
 
 Simple silicates 
 
 Skin 
 
 270 
 276 
 270 
 
 244 
 274 
 
 271 
 269 
 
 249 
 264 
 
 291 
 
 ■::a 
 ■: ] 
 
 276 
 247 
 
 245 
 
 275 
 
 CO 
 261 
 
 2 , 
 255 
 239 
 
 255 
 375 
 
 286 
 2fi 1 
 222 
 
 I 
 
 rob 
 
 220 
 
 406 
 
 326 
 
 406 
 
INDEX. 
 
 45-1 
 
 Page. 
 
 Solution 116 
 
 Spirits of turpentine 39 1 
 
 Soaps 390 
 
 Sodium 233 
 
 Soda 234 
 
 Solder 282 
 
 Specific gravity " 129 
 
 of essential and other oils 427 
 
 Spongy platinum 291 
 
 Spermaceti oil 389 
 
 Starch 342 
 
 Steam 56 
 
 artillery 59 
 
 engine 58 
 
 generator. •. 58 
 
 Stearine 388 
 
 Steel 255 
 
 Stream tin 259 
 
 Strontia 239 
 
 Strontium 239 
 
 Strychnia 386 
 
 Sugar 346 
 
 of grapes 347 
 
 of lead 358 
 
 S ubphosphuret of cobalt 263 
 
 nickel.... : 264 
 
 Subsesquiphosphuret of cop- 
 per 280 
 
 Sublimation 198 
 
 Suet 390* 
 
 Sulphur 198 
 
 flowers of 198 
 
 rool-brimstone 198 
 
 Sulphates 302 
 
 Sulphate of ammonia 303 
 
 alumina 303 
 
 baryta". 304 
 
 lime 304 
 
 lithia 303 
 
 magnesia 305 
 
 methyle . . .' 363 
 
 potassa 302 
 
 soda 303 
 
 strontia 304 
 
 potassa and alumina 308 
 
 potassa and magnesia 308 j 
 
 protoxide of copper 307 
 
 cobalt 306 
 
 iron 305 
 
 copper 307 
 
 manganese 305 
 
 mercury 307 
 
 nickel 306 
 
 silver 307 
 
 Page. 
 
 Sulphate of zinc 306 
 
 Sulphamylic acid 366 
 
 Sulphocyanide of potassium. . 375 
 
 Sulphureted springs 417 
 
 Sulphuret of barium 238 
 
 boron 217 
 
 bismuth 277 
 
 cadmium 258 
 
 cobalt 263 
 
 copper 280 
 
 cyanogen 210 
 
 ethyle 
 
 kakodyle 361 
 
 lead 282 
 
 methyle 363 
 
 potassium 232 
 
 silicon 221 
 
 sodium 235 
 
 silver 287 
 
 uranium 276 
 
 zinc 257 
 
 Sulphur-salts 330 
 
 Sulphuric ether 352 
 
 Sweat 404 
 
 Synaptose 369 
 
 Sympathetic ink 262 
 
 T 
 
 Table of discovery of metals . . 227 
 
 Tannin 381 
 
 Tapioca 343 
 
 Tar 392 
 
 Tartar emetic 381 
 
 Tartrate of antimony 381 
 
 potassa 381 
 
 soda 381 
 
 Taurin fJh. 403 
 
 Tears 404 
 
 Teeth 405 
 
 Tellurium 278 
 
 Tendons 406 
 
 Terchloride of boron 217 
 
 molybdenum 272 
 
 gold 290 
 
 chromium 270 
 
 Terfluoride of chromium 270 
 
 Teroxide of potassium 231 
 
 Teriodide of nitrogen .^ 177 
 
 Terphosphuret of tin 261 
 
 Tersulphate of alumina 301 
 
 sesquioxide of chromium. 306 
 
 Tests of metallic ores 415 
 
 Teroxide of gold , 289 
 
 potassium 231 
 
452 
 
 INDEX. 
 
 Page. 
 
 Tersulphuret of tin 261 
 
 Tertrasulphuret of iron 254 
 
 Theory of animal heat 
 
 constitution of salts 299 
 
 compound radicals 346 
 
 fermentation 351 
 
 substitutions 341 
 
 Thermo-electricity 108 
 
 Thermometers 42 
 
 air 42 
 
 differential 43 
 
 mercurial 44 
 
 graduating of 44 
 
 register 45 
 
 Thorina 247 
 
 Thorium 247 
 
 Tin 249 
 
 Tin foil 259 
 
 Tincal 322 
 
 Titanium 277 
 
 Torpedoes 287 
 
 Train oil.. 389 
 
 Triacic acid 
 
 Triphosphate of potassa 316 
 
 soda 317 
 
 soda and basic water .... 317 
 
 acid triphosphate 317 
 
 lime 318 
 
 magnesia 3l8 4 
 
 ox. silver 3" "' 
 
 Triphosphuret of copper 28D« 
 
 Trisilicates *V3^ 
 
 Trona ^823 
 
 Tungsten r Cj . 272 
 
 Tungstosulphurets '^t> • • 333 
 
 Turkey red . > ^^^^^ . . 397 
 
 Turpentine it> 392 
 
 Turpeth mineral ... .7 307 
 
 U 
 
 Universal cement 426 
 
 Uranium 275 
 
 Urine 404 
 
 Urea 373 
 
 Urinary calculi 405 
 
 Vanadium 270 
 
 18^-W. 
 18 W< 
 3<VW 
 
 Page. 
 
 Vaporization 52 
 
 Variegated copper pyrites 254 
 
 Varvicite 250 
 
 Vegetable alkalies 384 
 
 Verdigris 359 
 
 Verditer 325 
 
 Vermilion 285 
 
 Vinegar, distilled 358 
 
 Vinous fermentation 349 
 
 Viscous fermentation 350 
 
 Voltaic electricity 79 
 
 circles 79 
 
 pile 79 
 
 Volta-electric induction 101 
 
 Volatile , 52 
 
 oils 391 
 
 W 
 
 Water...".. 158 
 
 of crystallization 297 
 
 of nitre 167 
 
 Water gilding 290 
 
 Wax 391, 393 
 
 White oxide of arsenic 
 
 White vitriol 306 
 
 r&ad 
 
 Wollaston's scale of chemical 
 
 * equivalents 420 
 
 Weod spirit 362 
 
 ""ool. . 406 
 
 oulfe's apparatus loo 
 
 Xanthic oxide 405 
 
 Xyloridine 345 
 
 Yellow dyes 397 
 
 Yttria 246. 
 
 Yttrium , 246 
 
 Zaffre 262 
 
 Zinc 256 
 
 Zinc blende 257 
 
 Zinetum 256 
 
 Zirconia 247 
 
 Zirconium 247 
 
 F£B 281950 
 
INDEX OF FIGURES. 
 
 Fig. Page. 
 
 1. Conductometer 27 
 
 2. Apparatus for heating liquids. . . 28 
 
 3. 4. " for conduc'n of liquids 29 
 5. " for radiation of cal . • 30 
 6 " for reflection of caloric 31 
 
 7. Concave mirrors 31 
 
 8. Pyrometers 37 
 
 9. 10. App. for expansion of liquids 38 
 
 11. App. for expansion of air 38 
 
 12. Air thermometer 42 
 
 13. Differential thermometer 43 
 
 14. Common and laboratory do 44 
 
 15. Blowpipes 44 
 
 16. Different scales of thermometers 45 
 
 17. Register thermometer 45 
 
 18. Metallic thermometer 46 
 
 19. Influence of pressure on the boil- 
 
 ing point 53 
 
 20. Pulse glass 53 
 
 21. App. culinary paradox 54 
 
 22. Marcet's digester 55 
 
 23. Spirit lamp 55 
 
 24. Steam engine illustrated 58 
 
 25. 26. Distillation. Cryophorus 59, 60 
 
 27. Hydrometer 62 
 
 28. App. for refraction of light 68 
 
 29. Prism 68 
 
 30. Gold leaf electrometer 75 
 
 31. Electrical machine. 76 
 
 32. Apparatus for induction 77 
 
 33. Electrophorus 78 
 
 34. Balance electrometer 78 
 
 35. Simple voltaic circles 80 
 
 36. Caliromotor 81 
 
 37. Voltaic pile 8> 
 
 38. Deflagrator 82 
 
 39. Grove's battery 83 
 
 40. Smee's battery 85 
 
 41. App. for decomposition of water 89 
 
 42. Transfer of chemical substances 90 
 
 43. App. for change of colors 90 
 
 44. Galvanometer 95 
 
 45. Revolving rectangle 96 
 
 46. Helix and stand 98 
 
 47. Magnet with three poles 98 
 
 48. Electro-magnet 98 
 
 49. Magic circle 99 
 
 50. Vibrating magic circle 99 
 
 51. Page's revolving magnet 100 
 
 52. 53. Separable helices 102, 103 
 
 54. Secondary currents 103 
 
 55. Magneto-electric machine 105 
 
 56. Theory of electro-magnetism.. . 107 
 
 57. Electro-magnetic telegraph 109 
 
 58. Electrotype 112 
 
 59. Dropping tube 120 
 
 60. App. for change of form 121 
 
 61. Ills, of atomic theory 126 
 
 Fig. Pags. 
 
 62. Specific gravity 129 
 
 63. Aerometer 136 
 
 64. Pneumatic cistern 137 
 
 65. Retorts 138 
 
 66. Lead tubes for connection 139 
 
 67—69. App. for oxygen 140 
 
 70. App. for collection of gases 
 
 heavier than the air 147 
 
 71. App. decomposition of water .. 154 
 
 72. Gas bag and bubble pipe 156 
 
 73. Method of filling gas bags 156 
 
 74. 75. Balloon. App. musical 
 
 sounds 157 
 
 76 Hydrogen pistol 157 
 
 77. Eudiometer 160 
 
 78. Compound blowpipe 161 
 
 79. Woulfe's apparatus 163 
 
 80. App. for nitrogen 167 
 
 81. " analysis of the air 170 
 
 82. " for nitric acid 171 
 
 83. " for showing properties of 
 
 nitric acid 175 
 
 84. " for gases lighter than air. . 178 
 
 85. " carbonic acid 186 
 
 86. Gauze wire for flame 195 
 
 87. Safety lamp 195 
 
 88. Platinum wire for wicks 195 
 
 89. Crystallization of sulphur 199 
 
 90. Crucibles 200 
 
 91. Sulphur in volcanoes 207 
 
 92. Phosphorus in oxygen gas 207 
 
 93. Phosphuret of hydrogen 214 
 
 94. Evaporating dishes .* 216 
 
 95. Hexahedron 294 
 
 96. Right square prism 294 
 
 97. '' rectangular prism 294 
 
 98. " rhombic prism 294 
 
 99. Hexagonal prism 295 
 
 100. -Rhombohedron 295 
 
 101. Oblique rhombic prism 295 
 
 102. " .rectangular prism 295 
 
 " rhomboidal prism 295 
 
 103. Regular octohedron 295 
 
 104. Square " 295 
 
 105. Rectangular " 296 
 
 106. Rhombic " 296 
 
 107. " dodecahedron 296 
 
 108. Combustion tube 337 
 
 109. Organic analysis 338 
 
 110. Analysis of liquids 339 
 
 111. " gases 412 
 
 112. " minerals 414 
 
 113. " mineral waters 417 
 
 114. Test tubes 417 
 
 115. 116. Making filters 418 
 
 117. Filtration 419 
 
 118. Supports 419 
 
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