OTHER WORKS OF THIS SERIES OF TECHNOLOGICAL HANDBOOKS. BREWING, DISTILLING, AND WINE MANUFACTURE. 6s. 6 d. BLEACHING, DYEING, AND CALICO PRINTING. 5s. SOAPS AND CANDLES. 7s. OILS AND VARNISHES EDITED BY JAMES CAMERON, F.I.C. ANALYST IN THE LABORATORY, SOMERSET HOUSE. THIRD EDITION LONDON J. & A. CHURCHILL, 7 GREAT MARLBOROUGH STREET. 1896 c 0! S S TP (d1 0 c IS THE GETTY CENTER LIBRARY PREFACE. In the preparation of this volume, the information in Cooley’s “ Cycloptedia ” has been supplemented from the latest publications, with the object of producing a handbook useful to all interested in Oils and Varnishes, and especially to analysts, pharmacists, manufacturers, and technological students. The Editor desires to express his indebtedness to Mr. W, H. Bailey, of Salford, for his revision of the section dealing with the lubricating qualities of oils. London, April 1886. J. c. CONTENTS. CHAP. PAGES I. Chemistry of Oils.—Animal and Vegetable Fixed Oils. — Glycerin. — Obganic Acids. — Glycer¬ ides.—Vegetable and Mineral Volatile Oils. —Sources.—Classification .... i— 15 II. Animal Oils.—Fish Oils.—Insect Oils . . 16— 33 III. Vegetable Oils—Fixed.34— 62 IV. Vegetable Oils—Volatile or Essential . . 63—119 V. Empyreumatic, Medicated, Mixed, and Perfumery Oils.120—141 VI. Waxes—Animal, Vegetable, Artificial.—Testing 142—152 VII. Mineral Oils—Crude Oils obtained by Distilla¬ tion—Crude Oils occurring ready formed.— Ozokerit.—Vaseline.—Storage of Petroleum. —Construction and Management of Petroleum Lamps.153—191 VIII. Purification, Bleaching, and Refining of Oils . 192 — 205 IX. Testing Oils.— I. Purity :—Fixed Oils : Physical and Chemical Tests—Essential Oils—Mineral Oils.— II. Lubricating Qualities.— III. Illu¬ minating Efficiency—Standards of Light . 206 — 315 X. Resins and Varnishes.—Rosin Oil.—Formulae . 316 — 349 XI. Testing Resins.350—356 Appendix.357—365 Index.. . 367—376 BIBLIOGRAPHY, {English .) Muspratt’s “ Chemistry applied to the Arts and Manufactures.” Spon’s “Encyclopaedia of the Industrial Arts.” Ure’s “Dictionary of the Arts and Manufactures.” Watts’ “ Dictionary of Chemistry.” Allen’s “ Commercial Organic Analysis.” Bailey on “ Apparatus for testing the Value of Lubricants.” Bell’s “ Analysis and Adulteration of Foods.” Dragendorff’s “ Plant Analysis” (Translation by Greenish). Fluckiger and Hanbury’s “ Pharmacographia.” Gmelin’s “ Chemistry.” Veitch Wilson on “ Lubrication.” “ Analyst.” “ Chemical News.” “ Chemist and Druggist.” “ Journal of the Chemical Society.” “ Journal of the Society of Arts.” “Journal of the Society of Chemical Industry.” “ Oil Trade Review.” Pharmaceutical Journal.” “ Year Book of Pharmacy.” OILS AND VARNISHES. CHAPTER I. CHEMISTRY OF OILS. Oils are a numerous class of bodies widely distributed in each of the three kingdoms of Nature. Under the term “oil" we include not only certain well-known liquid and solid compounds occurring in, or derived from, animals and plants, but also the rock oils or petroleums, peat oils, shale oils, and coal-tar oils. Oils from animal and vegetable sources have been known and used extensively from the earliest times, and springs of mineral oils have been known in several localities from time immemorial, but it is only recently that the last have acquired great general importance. When any oily body is dropped or spread upon paper, it produces a greasy stain. On warming, in the case of some oils, this stain entirely disappears, while in other cases, after the application of heat, the stain still remains. The former distil without decomposition ; the latter do not. By this difference of behaviour all oils may be divided into two classes, volatile and fixed. The animal and vegetable king¬ doms each afford examples of both fixed and volatile oils, but mineral oils are all volatile. B 2 OILS AND VARNISHES. Nearly all the fixed oils, when exposed to the air, absorb oxygen rapidly, and either gradually harden or become nauseous and rancid. From the former are selected the “drying” oils used by painters, and the latter are used as food, in cookery, and for machinery, lamps, &c. Some of the fixed oils, especially linseed, rape, and olive oils, when absorbed by porous substances and thus freely exposed to the atmosphere, unite with oxygen so rapidly as to generate a considerable degree of heat. Hence paper, tow, cotton-waste, wool, shoddy, hemp, straw, shavings, &c., if slightly soaked with such oils and left in a heap, often spontaneously inflame. The specific gravity of oils fluctuates a little on either side that of water—fixed animal and vegetable oils in this respect varying from o'86o to o'gjo at 6o e Fahr. (i5’5° Cent.), volatile animal and vegetable oils from o - 847 to i’096, and mineral oils from o’8oo to, i’ioo— water being i # ooo. I. Chemistry of the Fixed Oils ( Animal and Vegetable). Animal and vegetable oils and fats are salts of glycerin with organic acids, or, more accurately, are “ mixtures of ethereal salts formed from glycerin and acids of the acetic and oleic series ” (Armstrong). By “ ethereal salt ” we understand a compound derived from the union of an organic base with either a mineral oxy- acid, or an organic acid. Thus common alcohol, an organic base, and acetic acid, an organic acid, produce an “ ethereal salt ” called acetic ether ( ethylic acetate) thus :— CH 3 CO.OH + C 2 IT..OH = CH 8 CO(OC 2 H 5 ) + OH, Acetic acid + Alcohol = Acetic ether + Water It will help to make the chemical constitution of these CHEMISTRY OF OILS. 3 oils clear if we consider (i°) glycerin itself, the organic base, then (2 0 ) the organic acids, and lastly (3 0 ) glance at the manner in which we find them naturally united together in the oils. (i°) Glycerin. —C 8 H 6 (OH) 3 .—Pure glycerin is a colour¬ less, viscid liquid of specific gravity 1-27 or r28. Its taste is intensely sweet, and it is miscible in all proportions with water. It is unfermentable, and has no action on vegetable colours. In presence of aqueous vapour, under pressure in air, and in vacuo, it can be distilled, but it decomposes when heated in air at the ordinary pressure, with production of acrolein, which has a well-known peculiarly penetrating odour. It boils in vacuo at 179*5° (C.). It is represented OH by the formula given above, or thus : < OH ; and is OH classed as a tri-hydric, tri-atomic, or tri-valent alcohol According to Werner,* commercial glycerin may be made to crystallize by passing a few bubbles of chlorine into it. When acted on slowly by dilute nitric acid, it is converted into glyceric or glycerinic acid, thus :— Glycerin + Oxygen = Glyceric acid + Water H 3 being exchanged for 0 . Glyceric acid thus stands in the same relation to glycerin that acetic acid does to ordinary ethyl alcohol. If the nitric acid emjfioyed be concentrated, instead of dilute, another compound called glyceric trinitrate (tri- nitrin, trinitroglycerin, or nitroglycerin) is formed. This consists of glycerin with 3 atoms of H replaced by N 0 o , thus:— * “Zeitschr. f. Cliem.” [2] iv. 413. 4 OILS AND VARNISHES. C„II (OH l OH (oh Glycerin ( 0 (N 0 ,) o,hJo(no;) t 0 (N 0 3 ) ^ v --- * Nitroglycerin Nitroglycerin is thus an ethereal salt formed by union of glycerin with a mineral oxyacid. It explodes violently on percussion, hut it may be rendered non-explosive by mixture, or dilution, with ordinary wood spirit, and when required for use may afterwards be recovered by adding water to the mixture, whereby the nitroglycerin is pre¬ cipitated. When mixed in the proportion of 75 parts to 25 parts of an infusorial earth known as “ Kieselghur,” it forms Nobel’s dynamite. (2 0 ) The following are the most important organic acids met with in oils and fats, and belong either (a) to the acetic or fatty series of the general formula C n H 2n + 1 .CO(OH), or (0) to the acrylic or oleic series having the general formula C n H 2n _ j.CO(OH). (a) Acetic or C n H 2n + 1 .CO(OH) Series. Name. Formula. Fusing point (Cent.). Boiling point (Cent.). Butyric acid. C,H, . CO(OH) Below — 20 0 163° Valeric „ . C 4 H 9 . CO(OH) » °° i 84 ‘ 5 ° Caproic ,, . C 5 11 ,, . CO(OH) - 2° 205° (Enanthylic „ . C 6 H 14 .CO(OH) - IO ’ 5 ° 223-5° Caprylic „ . C 7 H,.C 0 (OH) 236° Pelargonic „ . C a H„ . CO(OH) 12° 253 - 5 0 Capri c „ .. C s H„ . CO(OH) 3 °° Cocinic ,, . C 1& H 21 . CO(OH) 35 ° Laurie „ . C u H m .CO(OH) 40-5° Myristic „ . C, s H 27 . CO(OH) 53 Palmitic ,, .. C,AV ■ CO(OH) 62° Margaric „ . c 16 h, 3 . CO(OH) 59 ' 9 ° Stearic „ . C 17 1 I 35 . CO(OH) 69'2° Arachidic „ . C w H m . CO(OH) 75 ° Behenic „ . C 21 H 43 .CO(OH) 76° Cerotic „ C ?c H 53 . CO(OH) 78 ° Melissic „ . C m H m . CO(OH) 88° CHEMISTRY OF OILS. 5 ( 0 ) Acrylic or C 11 H 2n _ 1 .CO(OH) Series. Name. Formula. Name. Formula. Oleic acid Elaidic ,, Linnleic „ Ricinoleic „ C 17 H 3 3. 00 ( 0 H) C 17 H S3 . CO(OH) s O a C 1 S H 3!°3 Doeglic acid Brassic or Erucic „ c, 2 h Glycerin. Butyric acid ) When ordinary animal fat is melted and mixed with butyrin or tributyrate of glycerin, (C 4 H f 0 3 )C 3 H 5 0 3 , the latter com¬ pound is entirely removed by treatment with warm alcohol, and the animal fat is recovered in practically the same con¬ dition as before the admixture. When, however, butter-fat is treated with hot alcohol, from 2 to 3 per cent, only of its weight is dissolved. This does not consist, as might be sup¬ posed, of compounds of glycerin with butyric and caproic acids, but of a fat which is liquid at 6o° F. (15-5° C.), and yields on saponification from 13 to 14 per cent, of soluble fatty acids and from 79 to 80 per cent, of insoluble fatty acids. The low melting point of the extracted fat does not arise from an increased proportion of oleic acid, as the in- CHEMISTR V OF OILS. 13 soluble acids obtained after saponification have a higher melting point than the mixed insoluble acids obtained from the butter-fat. These results closely agree with a com¬ pound of the following composition :— C 18 K 33 0 ) c 16 h;;o >c 3 h 6 o 3 , c 4 h 7 o ) that is, oleo-palmito-butyrate of glycerin.” II. Chemistry of the Volatile Oils (Vegetable and Mineral). None of these oils can be termed “ fats.” Their chemical composition is quite different from that of the “ fixed ” oils or fats. (i°) Vegetable Oils.—The volatile oils obtained from plants are variously designated as essential oils, essences, ethereal oils, distilled oils. They chiefly consist of carbon and hydrogen, and are chemically classed as hydrocarbons of the C n H 2n-4 series, or terrenes, n atoms of carbon being associated with 2 n _ 4 atoms of hydrogen. The oils of this class best known have all the composition of common oil of turpentine, or C l0 H 16 . Besides carbon and hydrogen, how¬ ever, there are present in these substances varying, but smaller, proportions of oxygen, nitrogen, and sulphur. Many of the compounds containing oxygen are solids dis¬ solved in the oil, and often separating therefrom in a crystalline form. Such solid portions are often called stearoptenes, and are represented by such formulae as C 10 H 14 O, C 10 H 16 O, C 10 H js O. The fluid portion of an oil yielding a stearoptene is called elceoptene. ' These oils thus are, chemically, divisible into three classes, containing (a) Carbon and hydrogen onlyj M OILS AND VARNISHES. (/3) Carbon and hydrogen + oxygen ; (•y) Carbon and hydrogen + sulphur or nitrogen. (e°) Mineral Oils.—Like the vegetable volatile oils, these are composed of carbon and hydrogen. Chemically they are classed as hydrocarbons of the C n H 2n+s or marsh-gas series, and, from a well-known and important member of the series, are also generically known as paraffins , a term which was proposed for these bodies by Mr. Watts to indicate the chemical indifference which characterizes the entire group.* They are fully saturated compounds, and hence have no tendency to enter into combination with any other sub¬ stances. At ordinary temperatures they are scarcely affected by strong acids, such as fuming nitric or concentrated sul¬ phuric acids. Shale oils contain also hydrocarbons of the ethylene series, having the general formula C n H 2u . Sources. —In plants, oily substances are met with chiefly in the seed, more rarely in the bark, root, or other parts. It is only in the olive that oil is found in the fleshy integu¬ ment of the fruit. In seeds it does not occur in the plumule or radicle, but only in that part from which the cotyledons arise. The seeds of plants belonging to the natural order CrucifercB are the richest of all in oil, and next in oil-pro¬ ducing value are plants belonging to the natural orders Drupacece, Amentacece, and Solaneue. In animals, oil or fat occurs in the cellular tissue between the skin and flesh, among the fibres of muscle, in the mem¬ brane covering the intestines, and in the region of the kidneys. Butter-fat occurs naturally as an oil in the milk of the mammalia. In the whale the fat known as sperma¬ ceti is found in a bony cavity in the head. The mineral oils, petroleums, rock oils, or naphthas are met with ready formed in certain geological strata in many * Paraffin —parum, little, and ajjinis, related to. CHEMISTRY OF OILS. 15 parts of the world, while peat oils, shale oils, and coal-tar oils are obtained artificially by the distillation of peat, bituminous shales, and coal-tar respectively. In considering these various substances it will be con¬ venient to arrange them in three classes, according to their origin :—I. Animal oils; II. Vegetable oils ; III. Mineral oils. CHAPTER IT. ANIMAL OILS. (a) fixed ; ( 5 ) volatile. Under this head we have three natural divisions accord¬ ing to the origin of the oil:— A. Animal oils (proper). B. Fish oils. C. Insect oils. A. Animal Oils. The most important, or interesting, fixed and volatile animal oils are the following :— (a) Fixed Animal Oils. Butter-fat.—This is the oily portion of the milk of mammals, but the name butter is generally restricted to that obtained from the milk of the cow. The method of extracting butter from the liquid in which it naturally occurs varies in different countries, but the object is always to cause the coalescence of the fat globules, and this is effected by the simple operation of churning. The chief objects to be attended to in this operation are the maintenance of a proper temperature—about 6o° F. (15-5° C.) in summer and 65° F. (i8‘3° C.) in winter—and a certain degree of exposure to the air. Extreme cleanliness ANIMAL OILS. 17 must also be observed, the churn and other vessels employed being well scalded with hot water. AVdien the butter is “ come,” it should be put into a fresh-scalded pan, or tub, which has been standing in cold water, cold water poured on it, and, after it has acquired some hardness, it should be well beaten with a flat board, until not the least taste of the butter-milk remains, and the water, which must be often changed, becomes quite colourless and tasteless. It may then be flavoured with a little salt. It must be remembered that butter is not pure butter-fat, but consists of a mixture of water, curd, and salt, with from 78 to 90 per cent, of butter-fat. The water, curd, and salt may be separated by heating; the melted butter-fat soon rises, and may be removed from the underlying strata of curd and water. AVIien so freed from impurities, butter-fat may be kept good for a considerable time, if air be excluded. It does not fall within the scope of this volume to treat fully of the analysis and adulteration of butter, occupying as this article does so important a place among foods. In several recent works on Food, Ambergris Grain musk Oil of cloves . 6 oz. • 3 dr. „ i dr. Oil of rhodium . Liquor ammonite . i fl. oz. Beat to a smooth hard mass with mucilage, and make into lamps whilst soft. This fraud is easily detected. C. Insect Oils. Ant Grease is obtained by boiling white ants in water, and skimming off the fat as it rises. It is used as food. Cochineal Fat, from the well-known cochineal insect (Coccus cacti). Niin Oil.—This interesting oil is very fully described in Spon’s “ Encyclopaedia ” : “ It is extracted from the insects, a species of Coccus, by broiling or boiling them, and amounts to 26—28 per cent, of their weight. It is bright yellow to yellowish-brown in colour, and possesses a peculiar odour. Melts at 120 0 F. (49 0 C.). At ordinary temperatures it is thick and pasty, like lard, and its specific gravity is about 0*920. It is a thorough drying oil, though its absorption of oxygen is slow, and this is not hastened by oxide of lea.d. The present native uses of this remarkable oil, which has yet to find its way into general commerce, are almost con¬ fined to admixture with pigments employed by the Indians in Yucatan and in the vicinity of Yera Cruz for adorning small household articles. In the industrial arts its drying solution in turpentine will make it valuable to artists ; it remarkably brightens colours prepared with it. The turpentine solution of niin oil renders even the most porous filter-paper absolutely impervious to water. Articles to be waterproofed with it might be saturated in the solution and then heated in an oven till the grease volatilizes. The coating then defies most solvents of oils.” D CHAPTER III. VEGETABLE OILS. (a) fixed; ( b) volatile. (a) Fixed Vegetable Oils. The fixed oils, except where otherwise directed, are obtained from the bruised or ground fruit or seed, by means of power¬ ful pressure, in screw or hydraulic presses, and are then either allowed to clarify themselves by subsidence or are filtered. Both methods are frequently applied to the same oil. In some cases the impurities are removed by ebullition with water, and subsequent separation of the pure oil. Heat is frequently employed to increase the liquidity of the oil, and thus lessen the difficulty of its expulsion from the mass. With this object the bruised mass, placed in bags, is commonly exposed to the heat of steam, and then pressed between heated plates of metal. This is always necessary with the u butyraceous oils.” Another method is by boiling the bruised seed in water, and skimming off the oil as it rises to the surface. This is the plan adopted for castor oil in the West Indies. In a few cases, for medicinal purposes, the bruised mass is mixed with half its weight, or an equal weight, of alcohol or ether, and after twenty-four hours’ digestion the whole is submitted to pressure, and the alcohol or ether removed by distillation at a gentle heat. The first menstruum is com- VEGETABLE OILS. 35 monly employed for croton oil on the Continent; the second, for that of ergot of rye. It has been already stated (p. io) that certain oils treated with nitrous acid afford a solid substance called elaidin, and that certain other oils are unaffected when so treated. The former are called “ non-drying oils,” the latter “drying oils.” The fixed vegetable oils may be con¬ veniently studied under these two heads. The following list, taken from Watts’ “ Dictionary of Chemistry,” includes the more important of these oils Drying Oils. Name. Plant from which derived SpeciSc Gravity. Solidifying Point (Cent.). I. Castor. Ricinus communis 0-963 -18 0 2. Cress-seed ... Lepidium sativum Gossypium barbadense 0-924 -i 5 ° 3. Cotton-seed... 0-9306 4. Deadly night- shade . Atropa belladonna 0-925 -27-5° 5. (fold ot plea- sure. Camelina sativa 0-9307 -19° 6. Gourd-seed ... Cucurbita pepo 0-9231 - 15 ° 7. Grape-seed ... Vitis vinifera 0-9202 - ii° 8. Hemp-seed ... Cannabis sativa 0-9307 -27-5° 9. Honesty . Hesperis matronalis 09232 Below - 15 0 10. Linseed . Linum usitatissimum 0-9351 ,, - 20° 11. Madi . Madia sativa 0-9286 „ - IO° 12. Loppy . Papaver somniferum 0-9270 - 18° 13. Sunflower ... Heiianthus annuus 0-9250 - 16 3 14. Scotch-fir seed Pinus sylvestris 0-9312 - 30° 15. Silver-fircones Abies picea 0-926 16. Spruce fir ... Abies excels a 0-9283 Below — 15 0 17. Tobacco-seed Nicotiana tabacum 0-9232 - 1 5 ° 18. Walnut, or nut Juglans regia 0-9287 - 18° 19. Weld-seed ... Reseda luteola 0-9358 Below — 15 0 Note.— The principal vegetable drying oils are linseed, poppy-seed, grape-seed, and nut oils. Castor and cotton-seed oils seem to be inter¬ mediate between drying and non-drying oils, and are sometimes classed among the latter. 36 OILS AND VARNISHES. Non-drying Oils. Name. Plant from which derived. Specific Gravity, j Solidifying Point (Cent.). I. Almond. Amygdalus communis 0-9184 - 21° 2. Beech-nut. Fagus sylvatica 0-923 - 1 7 * 5 ° 3. Colza. Brassica campestris 0-9136 - 6 4. Croton . oleifera Croton tiglium 0-94263 t;. Cyperus-grass. Cyperus esculentus 0-918 6. Daphne. (root) Daphne mezereum 0-914-0-921 7. Earth-nut. Arachis hypogcea 0-918 8. Ergot. Secale cornutum 0-922 - 37 ° 9. Hazel nut. Corylus avellana 0-91987 -19° 10. Henbane-seed Hyoscyamus niger 0-913 11. Horse-chestnut (Esculus hippocasta- 0-915 + 8° 12. Black mustard 7 TTC 777 Sinapis nigra O-92102 Below 0° 13. White „ „ alba 0-93383 Does not 14. Olive. Olea europcea 0-916 solidify 15. Palm. Elceis guineensis 0-968 16. Palm-nut . 17. Parsley. Petroselinum sativum I -078 at I2°C. Turbid at 12° but does not 18. Plum-kernel ... Prunus domestica 0-9127 solidify - 87° 19. Rape-seed (summer)... Brassica prcecox 0 - 9 I 555 20. Rape-seed (winter) ... ,, napus Sesamum orientate 0-91648 Below 0” 21. Sesame . 0-92415 - 5 ° 22. Spindle-tree ... Euonymus europceus 0-95717 - 12° to -15° 23. Spurge . Euphorbia lathyris 0-92613 . . - ni° Note.—T he most important non-drying oils are almond, colza, rape- seod, olive, and palm oils. Drying Oils. Belladonna Oil. — Syn. Oleum belladonna seminum, O. b. bacca, L. —From the seeds or berries of Atropa bella¬ donna, or deadly nightshade. It is of a yellow colour and insipid taste. It is used for lamps in Swabia and Wurtem- VEGETABLE OILS. 37 berg, and as an application for bruises. The marc is poisonous. Freezes at 34 0 F. Specific gravity, o - g25o. Castor Oil.— Syn. Ricini oleum (B. P.), Oleum castorei, O. ricini (Ph. L., E., and D.).—“The oil prepared by heat or by pressure, from the seed of Iiicinus communis , Linn.” (Ph. L,), the Palma christi, or Mexican oil-bush. Cold-drawn castor oil (Oleum ricini sine igne) is the best quality, and the only one fit for medicinal use, except in veterinary practice. It is prepared by pressing the shelled and crushed fruit, or seed, in hempen bags in hydraulic presses. The oil, as it escapes, is received into well-tinned vessels, in which it is afterwards mixed with water and heated till the water boils, and the albumen and gum separate as a scum. This is carefully removed, and the oil, as soon as it has become cold, is filtered through Canton flannel and put into canisters. It is termed “ cold drawn,” and is of a light straw colour. Commoner kinds of oil are prepared by gently heating the crushed seeds, and pressing them while hot. Another method sometimes adopted is to put the crushed seed into loose bags, to boil these in water, and to skim off the float¬ ing oil. The oils prepared by combined roasting and boil¬ ing are darker in colour than when “cold drawn; ” they are also more viscid, and soon become rancid. They are used for lamps in Indian bazaars. In the United States a somewhat different method of extraction is adopted. The cleansed seeds are heated in an iron tank, with care to avoid scorching. Pressure is then applied, and “ 1st quality” oil is drawn off. The pressed residue is again heated and squeezed, the product being “2nd quality” oil. A “3rd quality” oil is obtained after a repetition of the heating and pressure. Each of these three products has to be further purified by heating with water, as described above under “cold-drawn” oil. 33 OILS AND VARNISHES. It is the most viscid of all the fixed oils. When pure, it mixes in all proportions with alcohol and ether, and also dis¬ solves, to a certain extent, in rectified spirit, hut a portion of the oil separates on standing. Camphor and benzoic acid increase its solubility in spirit. By long exposure to the air it becomes rancid and thick, and is ultimately trans¬ formed into a transparent, yellow mass; light hastens these changes. Exposed to cold, a solid, white, crystalline fat separates from the liquid portion, and when cooled to o° F. ( _ 18° C.) it congeals to a yellow, transparent mass, like varnish, which does not again liquefy until the temperature rises to about i8° F. Sp. gr. 0-9611 to 0-9612 at 6o° F., 0-9690 at 55 0 F. (Saussure), 0-9575 at 77 0 F. (Saussure). Produce, 38 to 40 per cent. Castor oil is sometimes adulterated with rape oil or lard oil, a fraud which may be detected by its diminished density, and, when the added oil exceeds 33 per cent., by its insolu¬ bility in its own weight of alcohol of 0-820. In some cases, it is said, croton oil is added to increase the purgative quality of the mixture. A compound of this kind has been vended in gelatine capsules under the name of “ concentrated castor oil,” the use of which is fraught with danger. Pereira says, “ I have heard of several cases in which very violent and dangerous effects were produced by these capsules.” The best castor oil is imported from the East Indies in tin canisters. The oil obtained from the seeds of Ricinus viridis (Willd.), or lamp-oil seeds, is often mixed with, or sold for, castor oil. In medicine, castor oil is exceedingly useful as a mild purgative, particularly when abdominal irritation should be avoided, as in inflammation of the stomach and bowels, pregnancy, surgical operations, &c. Dose, 2 fi. dr. to 1 fl. oz. Italian castor oil is said to have a less nauseous taste than VEGETABLE OILS. 39 the Indian or American oils, and this has been ascribed * to the fact that it is prepared from fresh seeds, well decorti¬ cated, and often not bruised, and to its extraction without heat. Castor oil rotates a ray of polarized light, io per cent, solu¬ tions of pure Italian and Ostend castor oil in absolute alcohol gave, as a mean result, a direct deviation of io°tothe right, which gives as the specific rotatory power of castor oil (a) = + 12 • 15 0 . This behaviour may be used as a test of its purity, although the rotation is too small to allow a slight adultera¬ tion to be detected. Castor oil also contains a small quantity of nitrogen, which may be due to the presence of an alkaloid. It is possible, indeed, that not only the purgative properties, but also the circular polarization, are due, not to the oil itself, but to the presence of this alkaloid, f Cotton-seed Oil.— Syn. Oleum gossypii seminum.— Prepared from the seeds separated from the “lint” or “ wool ” of Gossypium barhaclense. The cleaned and decor¬ ticated seeds are pressed into cakes, which are subjected to heat and again pressed so as to liberate the oil. The yield is from 12 to 20 per cent. The specific gravity of the crude oil, according to W. Gilmour, varies from 0-928 to 0-930, and of the refined oil from 0-920 to 0-923, and the congealing point from 45 0 F. to 32° F. The refined oil has a yellowish-brown colour and a somewhat pleasant flavour. It possesses slight drying properties, but is sometimes classed among non-drying oils. It is used for paints, lamps, and in soap-making. It has also a limited use for lubricating purposes. It is largely used as an adulterant of other oils, especially of olive, linseed, sperm, and lard oils. Cotton-seed oil treated with oil of vitriol gives a violet colour, increased by stirring. With caustic alkalies (sp. gr. * “Pharm. Jour.” [2] vi. 230. t Porr. “Arch. Pharm.” [2] cxlv. 233; Watts’ “ Dictionary of Chemistry,” 2nd Suppt. 270. 4o OILS AND VARNISHES. 1-24) the oil thickens, becomes straw-coloured, while the alkaline solution separates and takes a deeper colour. If the mixture is stirred with a glass rod, the upper layers become bluish-coloured and gradually violet. Cress-seed Oil. —Obtained from the seeds of Lepidium sativum. It has a brownish-yellow colour, and a specific gravity of about 0-924. On cooling to 21 0 F. (— 6° C.) it becomes thick, and solidifies at 5 0 F. (—15° C.). It dries slowly. Dilo Oil. — Syn. Tamanu oil. —Procured from the seeds of Calophyllum inophyllum, a large tree growing in India, Ceylon, and other tropical countries. The seeds, after exposure for some w T eeks to the heat of the sun, are sepa¬ rated from the shells, crushed or ground, and pressed. The yield varies in different localities, through differences of treatment, from 30 to 80 per cent. Colour greenish; specific gravity about 0-940. It is suitable for soap-making, and for paints. It dries rapidly. Gold of Pleasure Oil. —Extracted from the seeds of Camelina saliva by pressure. It has a specific gravity of 0-925. It is of a clear golden colour, and mild taste. It solidifies about — 2 0 F. (18-9° C.). It dries rapidly. Its chief uses are for lamps, dressing woollen goods, and in paints. Grape-seed Oil.— Syn. Wine-seed oil, Grape-stone oil, Oleum vitis vinifer.® lapidum. —The seeds are separated from the marc, cleaned, dried, and finely ground. Subsequently both cold and hot pressure are employed, and a yield of from 14 to 18 per cent, obtained. The fresh oil is of a pale-yellow colour, but darkens with age. Its sp. gr. is from 0-918 to 0-920. It has a low congealing point— about 5 0 F. ( — 15 0 C.)—and hence has been sometimes used for lubricating, but it is mostly employed for salads and lamps. VEGETABLE OILS. 4i Hemp-seed Oil. — Syn. Hemp oil, Oleum cannabis._ Obtained from the seeds of Cannabis sativa, or common hemp. It has a mild odour, mawkish, unpleasant taste, and a greenish yellow colour, turning brown with age. In sp. gr. it varies from 0-925 to 0-931. It does not thicken till cooled to 5 0 F. ( - 15 0 C.). It is freely soluble in boiling alcohol. It is sometimes used for frying, but chiefly for paints and soft-soaps. The seeds yield from 18 to 30 per cent, of oil. Linseed Oil. — Syn. Oleum lini.— Commercially, this oil is obtained from the seeds of Linum usitatissimum as imported from Russia and India, which contain varying j proportions of different cruciferous weed-seeds. The oil has : usually, therefore, an acrid taste, derived from the presence of these impurities. There are three kin ds of the oil, according to the method of preparation :— (i°) Cold drawn—Syn. Oleum lini sine igne.— 1 The seeds are bruised or crushed, ground, and expressed without heat. This is considered the best oil. It is pale, tasteless if pure, viscous, but does not keep so well as the next. By this process the seeds yield only from 17 to 22 per cent, of oil. ( 2 0 ) Ordinary linseed oil. —Prepared as the last, but with a steam heat of about 200° F. It is amber-coloured or dark yellow, and is less viscous than the last. It solidifies about 2°-4° F. (—18-9° to — 20 0 C.). It is soluble in 5 parts of boiling and 40 parts of cold alcohol. Produce, 22 to 28 per cent. Both these are drying and cathartic, and are extensively used in paints, printing inks, varnishes, &c. In sp. gr. they vary from 0-930 to 0-935. Linseed oil is also largely used in the manufacture of floorcloths, “ Baltic ” being the most suitable for this purpose. The best way to test the oils before use is the 42 OILS AND VARNISHES. following* :—Boil about 2 gallons in an iron pot with the addition of \ per cent, of ground litharge and \ per cent, of red lead. The temperature should not rise above 260° 0 . (500° F.). In order to accelerate the process of oxidation, air is blown into the hot oil by means of a pair of ordinary bellows. Samples are taken from time to time and cooled upon an iron plate. As soon as it appears stringy when cool, the pot is removed from the fire, and its contents are stirred till cold. If it is then solid, it is suitable : bad oil remains sticky and semi-liquid. The time occupied by the above test is from two to four hours. Frothing over the edge of the pot may be prevented by continually raising some of the oil in a ladle and letting it fall back again into the pot. (3 0 ) Boiled linseed oil .—The resinifying or drying pro¬ perty of oils is greatly increased by boiling them, either alone or along with some litharge, sugar of lead,f or white vitriol, when the product forms the “boiled oil” or “drying oil” (Oleum desiccativum) of commerce. The efficacy of the process, according to Liebig, depends on the elimination of substances which impede the oxidation of the oil. The following form ulie are adopted for this purpose :— (1) Linseed oil, 1 gall.; powdered litharge, | lb.; simmer, * Spon’s “Encyclopaedia,’’ iii. 1002. ”f Driers. —Driers are substances employed to facilitate the drying of paints. The driers most commonly employed are sugar of lead, litharge, and white copperas. Either of these when well ground, and mixed in small proportion with paints, very materially hastens their drying. Indeed, some colours will not dry without them. Eed lead is also well adapted for a drying agent, and, in cases where its colour does not preclude it, is much used. The best drier is sugar of lead. Its cost, however, is somewhat higher than that of the other driers. It is im¬ portant to bear in mind that in the finishing coats of delicate colours driers are not generally had recourse to, as they have a slight tendency to injure the colour. VEGETABLE OILS. 43 with frequent stirring, until a pellicle begins to form; re¬ move the scum, and, when it has become cold and has settled, decant the clear portion. Dark coloured; used by house- painters. (2) Linseed oil and water, of each 1 quart; white vitriol, in powder, 2 oz.; boil to dryness. Paler than the last. (3) Pale linseed or nut oil, 1 pint; litharge or dry sul¬ phate of lead, in fine powder, 2 oz.; mix, agitate frequently for ten days, then set the bottle in the sun or a warm place to settle, and decant the clear portion. Very pale. (4) Linseed oil, 100 galls.; calcined white vitriol (“ sul¬ phate of zinc”), in fine powder, 7 lb. : mix in a clean copper boiler, heat the whole to 285° F., and keep it at that temperature, with constant stirring, for at least one hour; then allow it to cool, in twenty-four hours decant the clear portion, and, in three or four weeks more, rack it for use. Used for varnishes. (5) (Liebig.) Sugar of lead, 1 lb., is dissolved in rain water, \ gall.; litharge, in fine powder, 1 lb., is then added, and the mixture is gently simmered until only a whitish sediment remains ; levigated litharge, 1 lb., is next diffused through linseed oil, 2\ galls., and the mixture is gradually added to the lead solution, previously diluted with an equal bulk of water; the whole is now stirred together for some hours, with heat, and is, lastly, left to clear itself by ex¬ posure in a warm place. The lead solution which subsides from the oil may be used again for the same purpose by dissolving in it another lb. of litharge, as before. (6) (Wilks.) Into linseed oil, 236 galls., pour oil of vitriol, 6 or 7 lb., and stir the two together for three hours; then add a mixture of fuller’s earth, 6 lb., and hot lime, 14 lb., and again stir for three hours; next put the whole into a copper, with an equal quantity of water, and boil for about 44 GILS AND VARNISHES. three hours; lastly, withdraw the fire, and when the whole is cold, draw off the water, run the oil into any suitable vessel, and let it stand for a few weeks before using it. {Patent.') (7) (“ Allg. Polytech. Zeitung.”) Binoxide of manganese (in coarse powder, but not dusty), 1 part; nut or linseed oil, 10 parts; mix, and keep the whole gently heated and frequently stirred for twenty-four to thirty-six hours, or until the oil begins to turn reddish. Becommended for zinc paint, but is equally adapted for other purposes for which boiled oil is employed. There is often a difficulty in obtaining the oils “ bright ” after boiling or heating them with the lead solutions; the best way, on the small scale, is either to filter them through coarse woollen filtering paper, or to expose the bottle for some time to the sun or in a warm place. On the large scale, the finer oils of this kind are often filtered through Canton-flannel bags. The litharge and sulphate of lead used in the above processes may be again rendered available for the same purpose by washing them in hot water, to remove adhering mucilage. The specific gravity of boiled linseed of good quality varies from 0-940 to o'95o, and on ignition it leaves a mineral residue of from o - 2 to 0-4 per cent. Poppy-seed Oil.— Syn. Oleum papaveris. —Obtained from the seeds of Papaver somniferum, the opium poppy, Glaucium luteum, the yellow-horn poppy, and Argemone mexicana , the spiny poppy, by pressure. It is of a pale colour, and slightly sweet taste. It dries and keeps well, and has a specific gravity of 0-913-0-924. It is used for salads, paints, and soaps, and also extensively to adulterate almond oil. It does not freeze till cooled to 0° F. The yield of the seeds is from 32 to 48 per cent. Sunflower Oil.— Syn. Oleum helianthi.— Prepared from seeds of Ilelianthus annuus and Ilelianthus perennis. It is VEGETABLE OILS. 45 clear, tasteless, and of a pale yellow colour. It dries slowly, thickens and becomes tux-bid at 60° F. (i5'5° C.), and solidifies at 4 0 F. (— 16 0 C.). Its specific gravity is 0-926. Messrs. Mills and Muter found its bromine absorption 51-45. It is used for salads and for lamps, and also for adultera¬ ting olive oil. The seeds yield from 15 to 28 per cent, of oil. Tobacco-seed Oil. — Syn. Oleum tabaci expressum.— From the seeds of Nicotiana tabacum and other species of Nicotiana. The seeds are ground to a powder, made into a paste with water, and pressed hot. The oil is of a pale- yellow colour, and dries well, being considered by some equal in this respect to nut oil. Its production has recently been carried on with success in Kussia. Its specific gravity is 0-923. Walnut Oil. — Syn. Oleum juglandis, Oleum nucis, Nut oil. —The kernels of the nuts of Juglans regia, or common walnut tree, ai-e separated from the shells and skins, crushed, and pressed. After the “ cold-drawn ” or “ virgin” oil has been obtained, the residue is pressed, with the aid of heat, and a further quantity of oil, called “ fine¬ drawn,” is procured. The former, when well washed, is of a pale colour and has a slight smell. It is sometimes used as a salad oil. Its specific gravity is about 0-926 at common temperatux-es, and it solidifies at about — i7|° F. ( — 27^° C.). The latter di-ies well, but soon gets rancid. As a drying oil, many prefer it to linseed. The kernels yield from 48 to 52 per cent, of oil. Non-drying Oils. Almond Oil.— Syn. Oleum amygdalae, Ol. amygdalarum, O. amygdali com. —There is both a fixed and a volatile oil obtained from almonds. The latter will be found described on p. 80. The following remarks apply only to the fixed oil. The medicinal (B. P.) oil, and also that of commerce, 46 OILS AND VARNISHES. are obtained by pressure both from sweet and bitter almonds, but mostly from the latter, because it is cheaper, and because of the value of the residual cake, which is available for the preparation of the essential oil. It is odourless, and has a yellow colour. It is to the palate one of the most agreeable of the fixed oils. Its specific gravity varies from C915 to o’920 at 60° F. (15-5° C.). It chiefly consists of olein (tri¬ olein) and hence requires great cold to solidify it ( — 25 0 C.), being less affected by cold than olive oil. It is soluble in 25 parts of cold and 6 of boiling alcohol, and mixes in all proportions with ether. It is used as a medicine, and is bland, demulcent, and emollient. It is considered nutritious, though difficult of digestion. The following are the alleged adulterants of this oil:—lard oil, nut oil, olive, teel (sesame or gingelly oil), poppy, rape or colza, and castor oils. Also mustard and peach-kernel oils (Spon). Produce obtainable from sweet almonds, 46 per cent.; from bitter almonds, 41 per cent. The presence of teel oil, when it amounts to about 1 o per cent., may be detected in almond oil by the following test: * “ The oil shaken with a mixture of equal weights of sul¬ phuric and nitric acids previously cooled takes a fine green hue, as shown in 1852 by Behrens, who at the same time pointed out that no other oil exhibits this reaction.” Maben in 1883 pointed out that this green quickly changes to brown. Castor oil j - may be detected by shaking with ammonia. Pure almond oil gives a perfect emulsion, whereas, in the presence of 5 per cent, of castor oil, drops of oil separate at the bottom, the quantity increasing with the percentage of the adulterant. Allen has suggested J that the presence of mustard oil * “ Pharmacographia.” + “Chemist and Druggist,” May 1SS3. J “Commercial Organic Analysis,” ii. 1S2. VEGETABLE OILS. 47 might be detected by boiling the sample with an equal measure of a io per cent, solution of catistic soda, filtering through a wet filter, and testing the filtrate with lead acetate, when a dark coloration would indicate the probable presence of mustard, oil, as the oils from cruciferous seeds contain traces of sulphur compounds. The presence or absence of these and the other adulter¬ ants mentioned may also be indicated in the course of the examination laid down in Chateau’s tables (see Chap. IX.). Bay Oil.— Syn. Laurel oil.— 1° (Expressed oil of bay, Oleum lauri, 0 . laurinum, L.).—By expression from either fresh or dried bay-berries. It is limpid and insipid. 2° By decoction (Butter of bay, Oleum lauri nobilis, 0 . laurinum verum, L.)—From the berries by boiling them in water and skimming off the oil. It is of a greenish colour, and buttery consistence. It is chiefly imported from Italy, and is a popular remedy for bruises, sprains, rheum¬ atism and deafness. It is also used by veterinary surgeons. A volatile bay or laurel oil is also known (see p. 84). Beech Oil.— Syn. Oleum fagi. —Extracted by cold or hot expression of the decorticated nuts of the beech tree (Fagus sylvatica). It is a clear oil, of a yellow colour, and, when fresh, has a slightly acrid taste, which, however, diminishes by keeping, or by ebullition with water. It keeps well, and, after washing with hot water, is used for salads in France, for burning in lamps, and for making soap. Its specific gravity is 0-9225 at 6o° F. (i5'5° C.). The nuts yield, on an average, 16 per cent, of oil. Ben Oil.— Syn. Beiien oil, Oleum balatinum. —Ob¬ tained by simple expression from the seeds of various species of Moving a, trees resembling willows, indigenous to Arabia and Syria, but grown also in the West Indies. The oil is coloui-less and odourless, and possesses an agreeable flavour. By cooling, the more solid portions separate and the parts 43 OILS AND VARNISHES. remaining fluid, which are not apt to turn rancid, are much used for lubricating clocks and watches. Owing to the power of the oil for retaining odours, it is highly valued by perfumers, and is used in the preparation of macassar oil. It is also used in medicine, and sometimes as a salad oil. Its specific gravity varies from o'g 12 to o’915 at 6o° F. (i5 , 5°C.). It is said to be occasionally adulterated with olive oil. Benne-seed Oil. — See Gingelly Oil. Brazil-nut Oil.-— Syn. Oleum Bertholletle.— From the kernels of the fruit of Bertholletia excelsa , or Brazil nuts. It is of a bright amber colour, congealing at 24 0 F. Specific gravity, o - gi7. It has been used as a substitute for olive oil in plasters and ointments. Cacao Oil or Butter. — Syn. Butter of cacao, Oleum CACAO CONCRETUM, BUTYRUM CACAO, OLEUM THEOBROMATIS. —From the seeds or nibs of Theobroma cacao, or chocolate nuts, gently heated over a fire, then decorticated, and pressed between hot iron plates. The nibs are capable of yielding about 50 per cent, of fat. When pure, it is white, and has a pleasant odour and taste. It does not readily become rancid. It is soluble in boiling alcohol, from which it crystallizes on cooling. It fuses at about 86° F. (30° C.). Its specific gravity varies from 0^945 to CC952. It is used in pharmacy as a basis for suppositories and pessaries. Cocoa-nut Oil. — Syn. Cocoa-nut butter, Oleum cocois nucifeRjE, L.—A species of vegetable butter obtained from the common cocoa-nut ( Cocos nucifera) or cocoa palm. It is separated from the dried kernels by hydraulic pressure. It contains olein and a solid fat often used as a candle material. Large plantations of the cocoa palm connected with Price’s Candle Company exist in Ceylon. Cocoa-nut oil is frequently confounded with cocoa or cacao-butter, which is the produce of a very different plant, the Tlieobroma cacao. The dried VEGETABLE OILS. 49 pulp of the cocoa-nut is called “copra” or “ copper ah,’’ and hence the oil is sometimes called copra oil. As imported, the oil is of the consistence of butter, but has a lower melt¬ ing point, fusing at about 73° to 8o° F. (227° to 26 6° 0 .). When fresh, it has the sweet taste and agreeable odour of the cocoa-nut, but has a great tendency to become rancid. Its specific gravity closely approximates to that of pure butter- fat, and if its flavour could be masked so as to admit of its use for adulterating butter, the specific-gravity test would not indicate the sophistication. The adulteration, however, would be detected, according to Dr. J. Bell,* by the abnor¬ mally low melting point, and the diminished percentage of soluble fatty acids, when calculated as butyric acid. It is largely employed in the manufacture of candles and soap. Croton Oil.— Syn. Crotonis oleum (B. P.), Oleum cro- tonis (Ph. E.), Oleum tiglii (Ph. L.).— This valuable oil is procured from the shelled seeds of Croton tiglium, or Molucca grains. It is imported chiefly from the East Indies. The oil is extracted from the ground seeds by pressure in bags between iron plates. It is allowed to stand for some days before being filtered. In France the marc is after¬ wards extracted with alcohol, and the oil thus obtained is added to the quantity previously expressed from the same seeds. The East Indian oil (Oleum crotonis exoticum) is usually of a pale colour; that pressed in England ( 0 . crotonis anglicanum) is much darker. It has an acrid flavour, and slight odour. In specific gravity it varies from about o'942 to o - 953. AVarington j- states that fresh croton oil, or oil expressed from fresh seeds, does not dissolve in alcohol of sp. gr. 0794-0796 to a greater extent than 20 per cent, at a temperature of 50° F., but if the oil be old or * “ Analysis and Adulteration of Foods,” Pt. II. 72. f “Pharrn. Journ.” [2], vi. 384, 385. E 5 o OILS AND VARNISHES. resinous, it is freely soluble. Hence this is not reliable as a test for purity. It is one of the most powerful cathartics known, and acts either when swallowed or merely placed in the mouth. Externally it is a rubefacient and counter-irritant, often, like tartar emetic, causing a crop of painful pustules. Dose, i to 2 drops, on sugar; in apoplexy, &c. The unshelled seeds yield 22 to 25 per cent, of oil; the shelled seeds from 32 to 35 per cent. Senier has shown* that the part of croton oil soluble in alcohol (sp. gr. 0*794—0*800) contains the vesicating prin¬ ciple, while the insoluble portion is entirely non-vesicant, but contains the purgative constituents. He attributes the purgative properties to the combined non-volatile fatty acids, and chiefly to those which have the lowest melting points, and which are also the least saponifiable. Colza and Rape Oils are practically identical. They are extracted from the seeds of Brassica campestris, var. Oleifera, or Colza de printemps, a variety of Brassica campestris (Linn.). The seeds are called cole-seed or rape-seed. Colza may be regarded as a superior sort of rape oil, the term “ colza oil being commonly applied to ordinary refined rape oil. Its specific gravity varies somewhat—from 0*912 to 0*920 but a fair density is 0*9136 at 6o° F. It congeals at 21 F. ( - 6° C.). Its colour is yellowish, or brownish yellow. It is sparingly soluble in cold, but readily soluble in hot, alcohol. It is largely used for burning in lamps, for lubricating pur¬ poses, and also in the manufacture of india-rubber. G-ingelly Oil.— Syn. Teel or Til, Benn^j oil, or Sesame oil.— The plant which yields this oil is called Sesamum orientate (or indicum), and is much cultivated in India. The seeds yield about 45 per cent, of oil. Its specific gravity * “Pharm. Jonm.” [3] xiv. 416, 447. VEGETABLE OILS. 5i is 0-923. Its presence, to the extent of not less than 10 per cent., may be recognized when mixed with other oils by the test given under the head of Almond oil. It may be used instead of olive oil, and, according to Pereira, for almond oil. Ground-nut Oil. — Syn. Arachis oil. —Obtained from the seeds of Arachis hypogcea (ground nut, earth nut, or pea nut) by cold or hot pressure. The cold-drawn oil is nearly colourless, and resembles olive oil in flavour. Its specific gravity is about 0-916 at the usual temperature. It is used in making soap, as a lubricant, as a substitute for olive oil in many cases, and as an ingredient in artificial butter. Horse-chestnut Oil. —From the fruit of AEsculus hip- pocastanum. It has a brownish-green colour, and keeps well. On the Continent it is used medicinally. Mustard Oil.— Syn. Oleum sinapis. —Three species of mustard are grown for the preparation of mustard, and each of these is capable of furnishing an oil by expression of the seeds :— i°. White mustard oil. —From Sinapis alba, or white mustard, but chiefly from Sinapis arvensis, S. chinensis, S. dichotoma, S. glauca, S. ramosa, and S. tori. The yield is about 22 per cent, of the seed. Its specific gravity is 0-9142. 2 0 . Black mustard oil. — Oleum sinapis nigri. — The seeds yield about 23 to 30 per cent, of oil by expression. It is viscid, and has stimulant properties, which make it useful as an application in rheumatism. Specific gravity, 0-921. 3 0 . Wild mustard oil. — Syn. Oleum raphani. —Obtained from seeds of Raphanus raphanistrum. From these seeds about 30 per cent, of oil is expressed. From black mustard seed a volatile oil can be produced (see under Volatile Oils). 52 OILS AND VARNISHES. Mustard oils (fixed) vary in specific gravity from about 0-921 to 0-9142. They chiefly consist of glycerides of stearic, oleic, and brassic or erucic acids. Nutmeg Oil (Expressed).— Syn. Expressed oil of mace, Butter of nutmeg or mace, Oleum myristicas (concretum) (Ph. L.), Myristicas adeps (Ph. E.), M. BUTY- RUM, Oleum myristicas expressum (B. P.).— The concrete oil expressed from the seed of Myristica officinalis, or com¬ mon nutmeg. The nutmegs are beaten to a paste, enclosed m a bag, exposed to the vapour of hot water, and then pressed between heated iron plates. The product is orange coloured, fragrant, and spicy, and of a butyraceous or solid consistence. It is a mixture of the fixed with about 6 per cent, of the volatile oil of nutmeg. When discoloured and hardened by ace it is called “Banda soap” (Ol. macis in massis). When pure, it is soluble in 4 parts of hot alcohol and in 2 parts of warm ether. Among other glycerides, it contains a large proportion of myristin. It has been used in rheumatism and palsy, but is now chiefly employed for its odour and aromatic qualities. It is chiefly imported from Singapore. Nutmegs yield from about 17 to 28 per cent, of this fat. Olive Oil. — Syn. Salad oil, Sweet oil, Olivas oleum (B. P.), Oleum olivarum, Oleum oliv;e (Ph. L., E., & D.), J _rphe “oil expressed from the fruit” of Olea europaia, Linn. (Ph. L.), or common olive. Five different methods are employed to obtain the oil from the fruit. 1 (Virgin oil, 0 . o. virgineum, L., Huile vierge, Er.) From olives, carefully garbled, either spontaneously or only by slight pressure, in the cold. That yielded by the pericarp of the fruit is the finest. 2. (Ordinary “fine oil.”) This is obtained by either pressing the olives, previously crushed and mixed with boiling water, or by pressing, at a gentle heat, the olives from which the virgin oil has been obtained. The a :>o\ e VEGETABLE OILS. 53 processes furnish the finer salad oils of commerce. The cake which is left is called “ grignon.” 3. (Second quality.) By allowing the bruised fruit to ferment before pressing it. Yellow ; darker than the pre¬ ceding ; but mild and sweet tasted. Much used for the table. 4. (“ Gorgon.”) By fermenting and boiling the pressed cake or marc in water, and skimming off the oil. Inferior. 5. (Oil of the infernal regions, Oleum omphacinum.) Is a very inferior quality of oil, which is skimmed off the surface of the water in the reservoirs into which the waste water which has been used in the above operations is received, and allowed to settle. The last two are chiefly used for lamps, and in soap-making, &c. Of the principal varieties of olive oil known in commerce, and distinguished by the place of their production, “Provence oil” is the most esteemed; “Florence oil” and “Lucca oil” are also of very fine quality; “ Genoa oil” comes next, and then “ Gallipoli oil,” which forms the mass of what is used in England; “Sicily oil,” which has a slightly resinous flavour, is very inferior; and “ Spanish oil ” is the worst imported. Olive oil is a nearly inodorous, pale greenish-yellow, unc¬ tuous fluid, with a purely oleaginous taste, peculiarly grate¬ ful to the palate of those who relish oil. It does not suffer active decomposition at a heat not exceeding 6oo° F.; and when cooled to 32 0 F. it congeals into a granular solid mass. It is very slightly soluble in alcohol, but its solubility is increased by admixture with castor oil. It is soluble in ij part of ether. When pure, it has little tendency to become rancid. Sp. gr. varies from about *914 to o 'g 18 at 60° F. (15-5° C.). Prod. 32 per cent., of which 21 percent, is furnished by the pericarp, and the remainder, which is inferior, by the seed and woody matter of the fruit. Olive oil being, with the exception of almond oil, the 54 OILS AND VARNISHES. most costly of the fixed oils of commerce, is consequently very subject to adulteration. Nut, poppy, rape, lard, and cotton-seed oils are very common adulterants. Refined tallow olein, including that obtained from the knackers’ yards of Paris, is said to have been used in the same way. lhe addition of any other oil to olive oil renders it far less agreeable to the palate, and, by increasing its tendency to rancidity, makes it more likely to offend and derange the stomachs of those who consume it. When pure and fresh, olive oil is most wholesome as an article of food, or as a condiment. In addition to the specific gravity of a sample, the follow¬ ing tests will aid n forming an opinion as to purity:— i . Olive oil loses its transparency and begins to solidify /:t 32—50 F. (o°-io° C.) and is completely solidified when a small vessel containing it is surrounded by ice or a freezing mixture; but when mixed with poppy oil, it remains partly liquid even when the latter forms only one- fourth of the mass; if more than one-third of poppy oil is present, it does not solidify at all, unless cooled much below 32 0 F. (o' C.). 2 0 . The elaidin test, described in Chapter IX., is a very useful one in the examination of olive oil. If pure, it becomes, in three or four hours after the application of the test, like a firm fat, without any separation of liquid oil, and, after twenty-four hours, the mass will be found so hard that some 1 ittle force must be employed to push a glass rod into it. The other edible oils do not behave in this way. The solidity of the mass is inversely proportionate to the quantity of foreign oil present. When the sophistication is equal to one-eighth of the whole a distinct liquid layer separates; when the sample contains half its volume of an inferior oil, one-half only of tiae mixture becomes solid, and the other half continues liquid. When the adulterant is an animal oil, the mixture solidifies in about five hours, but in this case the coagulum contains the animal oil, whilst the olive oil floats on the VEGETABLE OILS. 55 surface, and may be decanted for further examination. The coagulum in this case, when heated, exhales the odour of rancid fat or melted tallow. 3°. Dr. Ramon Cordina Langlies recommends the follow¬ ing test for the examination of olive oil:— Mix 3 gms. of the oil to be tested with i gm. of nitric acid (3 of nitric acid to 1 of water) in a test tube, or small stoppered flask, and heat in a water-bath. If the oil is pure, the mixture becomes clearer, and takes a yellow colour, like purified oil; if it is adulterated with seed oil, it acquires the same transparency as the pure oil, but becomes red. With 5 per cent, of seed oil, the reddish colour is perceptible; with 10 per cent., it is decided. This reaction does not require more than from fifteen to twenty minutes for its development. The colouring lasts for three days. 4 0 . Bach’s method of testing olive oil.* a. Nitric-acid test .— 5 c.c. of the sample are shaken in a convenient tube with 5 c.c. of nitric acid of sp. gr. i’3o for one minute, and the resulting colour observed, (a) after one minute, and (6) after standing five minutes in boiling water, and (c) the consistence noted after standing for twelve to eighteen hours at about 6o° F. (15‘ 5 ° 0 .). Colour. Consistence. One minute. Five minutes. Pure olive oil Cottou-seed „ Sesame „ Sunflower „ Ground-nut „ Rape-seed „ Rioinus „ Pale green Yellowish brown White _ Dirty white Pale rose >> Orange yellow Reddish brown Brownish yellow Reddish yellow Brownish yellow Orange yellow Golden yellow Quite solid Salve-like or smeary Perfectly liquid Quite solid Quite solid Salve-like or smeary * “ Amer. Journ. Pluirrn.” 1883, 354. OILS AND VARNISHES. 56 Mixtures of olive oil with small amounts of cotton-seed and sesame oils are distinguished by the entire mass, though at first more darkly coloured and solidifying like pure olive oil, yielding, after from twenty-four to thirty-six hours, a brown oil upon the surface of the firmly solidified mass, whilst the lower layer shows the yellow colour of the pure olive oil. Oils which have been treated with alkalies show the same reactions as the pure oils. b. Melting point of the fatty acids .—This may be obtained by the process described in a subsequent chapter. As, however, the melting point of fats and fatty acids is apt to vary according to the method employed, to obtain figures comparable with those of Bach it will be advisable to follow the details recommended by him. His process is as follows:—A small test tube containing the fatty mass is placed in a beaker filled with water, and heated by a small flame. A thermometer is dipped into the fatty acids, gently stirred about during the observation, and the temperature noted when the entire mass becomes perfectly clear. This is the melting point. The flame is removed, and, when clouds begin to form about the bulb of the thermometer, the temperature is again observed. This is the solidifying point. The following are the results obtained by Bach in this way:— The Patty Acids of Melt at (Cent.) Solidify at (Cent.) Pure olive oil. Cotton-seed „ _ Sesame „ . Ground-nut „ . Sunflower ,, . Rape-seed „ . Ricinus „ . 26-5-28'5° 3 §'o° 35 -0° 33 o° 23-0° 20 7 0 13 o° Not lower than 22° 35 '°° 32 - 5 ° 31-0° 170° 150° 20° The melting and solidifying points of olive oil deviate so VEGETABLE OILS. 57 far from those of the other oils that adulteration with them, to the extent usually occurring in commerce, is said to be thus readily detected. The following cases of adulteration are given :— Tatty Acids from Mixture of Melt at (Cent.) Solidify at (Cent.) Gallipoli olive oil + 20 per cent. Sunflower oil Nizza „ ,,+20 „ Cotton-seed,, Gallipoli „ „ +334 „ Rape-seed „ » i» » + 5 ° » >> » 24° 3 r 5 ° 2 3 ' 5 ° 20° 1 8° 28° i 6 ’ 5 ° I 3 ‘ 5 ° 5°. Beciii’s method of detecting cotton-seed oil in olive oil.* Bechi finds the following method to give good results : — 5 c.c. of the sample are mixed with 25 c.c. alcohol of 98 per cent., and 5 c.c. of a silver-nitrate solution (1 gm. of the nitrate in 100 c.c. of 98 per cent, alcohol). The mixture is heated to 84° C. If cotton-seed oil be present, even in very small quantity only, the mixture will become coloured, and take a tint more or less deep according to the amount of cotton-seed oil present. This method depends on the property possessed by cotton-seed oil of reducing silver nitrate. It is necessary to avoid heating by a direct fame, or other oils which may be present, such as linseed oil, colza, &c., will give colorations. 6°. Benard’s method of detecting earth-nut oil in olive oil. f The oil is saponified, and the resulting soap decomposed by hydrochloric acid. The fatty acids which separate are then converted into lead salts, and the oleate of lead removed by ether. The remaining lead salts are then de- * “ Journ. Pbarm.” [5] ix. 35-36. f “ Compt. Rend.” Ixxiii. 1330. 58 OILS AND VARNISHES. composed by hydrochloric acid, and the fatty acids obtained are dissolved in alcohol of 90 per cent., and the solution is left to cool. If earth-nut oil is present, abundant crystals of arachidic acid will soon be seen to form. The crystals are washed in alcohol of 70 per cent., in which they are perfectly insoluble, dissolved in boiling absolute alcohol, and the solution is evaporated to dryness and weighed. In reckoning the amount of arachidic acid obtained, allowance must be made for the quantity dissolved by the alcohol. 100 parts of 90 per cent, alcohol dissolve C25 of arachidic acid. The process does not succeed with a mixture containing less than 4 per cent, of earth-nut oil, but M. Renard states that with a 10 percent, mixture the proportion of the adulterant may be ascertained within 1 per cent, of the truth. 7°. The following tests for the detection of the presence of linseed, sesame, and colza oils in olive oil have also been proposed: *— Linseed .—2 c.c. nitric acid are mixed with 5 c.c. of the sample, and a piece of bright copper wire is introduced into the mixture. If after half an hour the wire has acquired a rose colour, the olive contained linseed oil. Sesame .—An equal quantity of hydrochloric acid (23 0 B.) is added, and a fragment of cane sugar dissolved in the mixture. If, after shaking and standing, a red colour is developed, sesame oil is indicated. Colza. —iogms. of the sample are saponified with alcoholic potash (free from sulphur). If there is a darkening in colour, it shows the probable presence of colza oil. The dietetical uses of olive oil are well known. In Spain and Italy it is commonly employed as a substitute for butter. It is highly nutritious, but is digested with difficulty by some * “Aieh. Pliarm.” iii. 23, 280; “Journ. Soc. Chem. Ind.” 1885, 601. VEGETABLE OILS. 55 persons, and hence should he avoided by the dyspeptic. Like almond oil, it is occasionally employed as a laxative and vermifuge, and is, perhaps, one of the mildest known. In pharmacy it is extensively employed in the preparation of cerates, liniments, ointments, and plasters. Dose, for an adult, | to i wineglassful as a mild aperient; for an infant, 2 to i teaspoonful mixed up with an equal quantity of honey, syrup of roses, or syrup of violets. The white fibrous sedi¬ ment which forms in the recently expressed oil is the Amurca of Pliny, and was formerly highly esteemed in medicine. The commoner kinds of the oil are used for lubricating, illuminating, dressing of wool, and for soap-making. As a lubricant and illuminant, its value is liable to serious depre¬ ciation, according to Mr. L. Archbutt, F.C.S., from excessive quantities of free oleic acid. In 89 samples Mr. Archbutt found the proportion of acidity (expressed as oleic acid) to vary on the average from 5-3 to i2'2 per cent., and when the amount exceeded about 3 to 5 per cent., the oil was found, when burnt in lamps, to have a great charring action on the wicks.* Olive Oil Droppings. — Syn. Sweet oil droppings.— The “ foots,” or “ droppings ” and “ drippings ” of the casks, cisterns, and utensils used in the storage of olive oil. It is used for machinery, making soap, &c. Palm Oil. — Syn. Palm butter, Oleum palm^e. —This oil is obtained from the fruit of several species of palm, chiefly of Elceis guineensis. The nuts or fruit, after sepa¬ ration from the spadices containing them, are allowed to decompose to a certain extent in the open air. By pounding with wooden pestles, the pulp is then detached from the hard nuts, mixed with a little water, and heated. * “Analyst,” Sept. 18S4. 6o OILS AND VARNISHES. The oil is then forced out by pressure. This process does not free the oil from all fragments of pulp, and hence it has a great tendency to become rancid and acid. Fresh palm oil has an orange-yellow tint, a sweetish taste, and an odour somewhat resembling that of violets or orris root. It is of the consistence of butter or lard. Its melting point varies greatly—from 76° to 95 0 F. It is bleached by ex¬ posure to sunlight, chlorine, chromic acid, and sulphuric acid. Specific gravity, about o - 968. It is soluble in ether and in alcohol of specific gravity o - 848. Mr. Archbutt found a very large proportion of free fatty acid in several samples examined by him, varying from i2‘o to 79^0 per cent, calculated as palmitic acid. It is used in candle and soap making, and also to colour and scent ointments, pomades, soap powders, &c. “Lagos” oil generally is most neutral, and “ Brass ” oil hardest of the several kinds im¬ ported. Palm-nut, or Palm-nut Kernel, oil is extracted from the nuts or kernels of the fruit. It has a primrose-yellow colour, and an odour like that of cocoa-nut oil. It is often used instead of the latter in soap-making, and contains, like it, both fixed and volatile acids. Piney Oil. — Syn. Piney tallow, P. dammar, P. resin.— To prepare this oil, the seeds of Vateria indica, or Piney tree, are roasted, then ground, and boiled with water. The oil is skimmed off. When cold, it is a solid fat, which melts at about 95° to 97°F. (35 0 —36° C.) Its specific gravity is about o'g26. Its colour is white, and it has a somewhat fragrant odour. It is made into candles. Rape-seed Oil.— Syn. Colza oil, Brown oil, Oleum raPjE.—T his is identical with colza oil (see above). Refined or pale rape oil is prepared from the crude oil by agitating it with 2 per cent, of oil of vitriol previously diluted with about twice its weight of water, and after ten or twelve days’ VEGETABLE OILS. 61 repose, decanting the clear oil, and filtering it through Can¬ ton flannel or felt. The quality is improved by washing it with water or steaming it before filtration. It is used for lamps, blacking, and machinery; and also for adulterating both almond and olive oils. It is the common “ sweet oil ’ of the oilmen and druggists. Usual specific gravity, about °' 9 I 3 — ‘ 9 I S- Sesame Oil. — See Gingelly Oil. Teel or Til Oil. — See Gingelly Oil. Turkey-red Oil.—This oil is the soluble product obtained by the action of sulphuric acid on different oils. It may be prepared by mixing castor oil with sulphuric acid diluted with one-third of its bulk of water, and leaving the mixture over night. It is then washed, to remove the acid, with water containing common salt, and the fatty acids are saponified with ammonia, either alone or with potash or soda. Fremy long ago investigated the action of sulphuric acid on olive oil; and the use of sulpholeic acid for preparing cotton tissues was first proposed by Runge in his book on the chemistry of colours, published in 1834. In 1876 the sulpholeic acid from castor oil was introduced with marked advantage. According to Miller-Jacobs, Turkey-red oil is a mixed solution of sulpholeic acid, 0 l8 H 33 (SO a II)O J (soluble in water), hydroxyoleic acid (C 18 H 34 0 ,),and hydroxy- stearic acid (C 18 H 36 0 3 ) (soluble in alcohol), and unaltered oil, or triglyceride (soluble in ether). When sulpholeic acid is boiled with water, the following decomposition, according to H. Schmid,* takes place :— 2 C 18 H 34 S 0 5 + 2 OH 2 = S 0 4 H 2 + S 0 2 + + C i 8 H 3 6 °s Sulpholeic Water Sulphuric Sulphurous Hydroxyoleic Hydroxy- acid acid anhydride acid stearic acid Muller-Jacobs considers that the action of Turkey-red * “Dingl. Polyt. J.” 254, 346-350; “ J. Soc. Chem. Ind.” 1883. 62 OILS AND VARNISHES. oil as a mordant is due to its yielding oil to the fibre in a finely divided form, and, in the best processes, the remain¬ ing sulpholeates are said to be removed by washing. Liechti and Suida, however, state that many more experi¬ ments require to be made before the chemical changes which take place in this process are completely understood. Muller-Jacobs says that the strongly diluted solution of Turkey-red oil treated with aqueous ammonia until it has an alkaline reaction should remain clear, and show no turbidity after the lapse of some hours. The turbidity would be caused by the presence of more or less considerable quantities of solid fats, or their glycerine ethers (palmitin and stearin), and proves that either very impure castor oil, or generally other crude oils, such as rape-seed oil, sesame oil, blubber oil, cotton-seed oil, olive oil, were employed for the preparation of the red oil in question. Formerly the oil used in Turkey-red dyeing was Galli¬ poli oil (Huile tournante), but this has now to a great extent been superseded by the preparations above noticed. ■Watchmaker’s Oil. —Prepared by placing a clean strip or coil of lead in a small white-glass bottle filled with pure almond or olive oil, and exposing it to the sun’s rays for some time till curdy matter ceases to deposit and the oil has become quite limpid and colourless. It does not become thick by age, and hence is suitable for fine work. Specific gravity, 0-916-0-917. Chaulmoogra Oil. — Syn. Lukrabo oil. —From Gyno- cardia odorata, a native of India. It contains palmitic and gynocardic. acids, and, according to Messrs. Naylor and Mass, cocinic acid. Solid at 6o° F. Melts about io8° F. Specific gravity 0-930. Both the oil and gynocardic acid have been used with success in skin diseases. In eczema, Dr. W. Cottle has found an ointment made of gynocardic acid 15 to 25 grains, vaseline 1 oz., almost a specific. CHAPTER IV. VEGETABLE OILS. ( b ) Volatile. Syn. Olea destillata, Olea distillata, Olea essen- tialia, Olea yolatilia, L , Huiles volatiles, Fr.—The volatile oils derived from the vegetable kingdom are an extensive and important class of bodies, found in almost every part of the majority of the plants which produce them, except the cotyledons of the seeds, in which, in general, the fixed oils are exclusively stored up. Their presence confers upon flowers, leaves, fruit, seeds, roots, bark, and woods their peculiar and characteristic odours ; but among these they are not equally distributed in the same individual, and are often altogether absent from some of them. To them we are indebted for our most delightful perfumes and our choicest spices and aromatics. Some of them are found to possess valuable medicinal properties, and others are in¬ vested with the highest possible interest on account of their peculiar chemical constitution, and the reactions which occur when they are brought into contact with other bodies. The volatile oils are often called “ essences,” and the same term is also commonly applied to their alcoholic solutions. Although essential oils are volatile, volatile oils are not always essential ones as the term is understood. For instance, the petroleum and paraffin oils obtained by the 6 4 OILS AND VARNISHES. distillation of native petroleum and bituminous bodies, though not essential, are volatile oils. To describe the two as synonymous is therefore incorrect. Preparation .—The volatile vegetable oils are procured in several ways:—(i°) By distillation; (2 0 ) By absorption or “enfleurage;” (3°) By means of solvents; (4 0 ) By ex¬ pression ; (5°) By maceration. (i°) Distillation.— According to the common method of proceeding, substances which part freely with their oil are put into the still along with about an equal weight of water, and are at once admitted to distillation. Those sub¬ stances which give out their oil with difficulty are first soaked for twenty-four hours, or longer, in about twice their weight of water, to each gallon of which 1 lb. of common salt has been added, in order to raise its boiling point. The distillation is conducted as quickly as possible, and when one-half the water has come over, it is returned into the still, and this cohobation is repeated, when necessary, until the distilled water ceases to be mixed with oil. The heat of steam, or a salt-water bath, should be preferably employed. When a naked fire is used, the still should be deep and narrow, by which means the bottom will be better protected by the gradually decreasing quantity of water towards the end of the process, and empyreuma prevented. When the distilled water is to be repeatedly cohobated on the in¬ gredients, a convenient and economical plan is to so arrange the apparatus that, after the water has separated from the oil in the receiver, it shall flow back again into the still. An ordinary worm-tub, or other like condensing apparatus, may be employed; but, in the case of those oils which readily solidify, the temperature of the water in the condenser must not fall below about 5 5 0 F. The mixed vapours which pass over condense and fall as a milky-looking liquid into the receiver. This separates VEGETABLE OILS. 65 after a time into two portions, one of which is a solution of a part of the newly eliminated oil in water, and the other is the oil itself. The latter either occupies the upper or the lower portion of the receiver, according as its specific gravity is less or greater than that of distilled water, The separation of the oil and water is effected by allowing the mixed liquids to drop into a “ Florentine receiver’’ (Fig, 1), when the oil is the lighter of the two, by which means the latter accumulates at a, and the water flows over by the spout b. The same receiver may be em¬ ployed for oils heavier than water, by reversing the arrangement; but a glass “separator” (Fig. 2) is, in general, found more conve¬ nient. In this case the oil accumu¬ lates at the bottom of the vessel, and may be drawn off by the stop¬ cock provided for the purpose, In 1836, the I^ondon College gave the following directions for the preparation of the essential oils: “ The fruit of anise, caraway, and juniper, the flowers of chamomile, lavender, and elder, the berries of allspice, the tops of rosemary, and the entire recent plants of the other herbs ax'G to be employed.” “ Put any one of these into an alembic, then pour in as much water as will cover it, and distil the oil into a large vessel kept cool.” (Ph. L. 1836.) But these were excluded from the Phar¬ macopoeia of 1851, on the ground that these substances are seldom prepared by the druggist or apothecary. Fig. 2. Fig. 1. 66 OILS and varnishes. The Edinburgh College directs—“ As much water only is to be .employed as will prevent empyreuma during the distillation. The distillation may be immediately com¬ menced after a proper maceration, and the oil afterwards separated from the water,’’ in the manner already noticed. “ It is also necessary to observe, in preparing these oils, as well as the distilled waters, that the quality of the sub¬ stances, their texture, the season of the year, and similar circumstances must occasion so many differences that it is scarcely possible to give any certain and general rules which shall strictly apply to every example. Many things, there¬ fore, must be regulated by the judgment of the operator. The Dublin College directs the vegetable substances to be macerated in the still with about 5 times their weight of water, for twenty-four hours, when one-half of the water is to be drawn over. The oil having been separated from this in the usual manner, it is to be returned to the still, and the same quantity drawn over as before, from which the oil must again be separated. Chevallier gives the following rules for the distillation of essential oils :— 1. Operate upon as large quantities as possible, in order to obtain a greater product, and one of finer quality. 2. Conduct the distillation rapidly. 3. Divide the substances minutely, in order to facilitate the extrication of the oil. 4. Employ only sufficient water to prevent the matter operated on from burning, and the product from being con¬ taminated with empyreuma. 5. For substances whose oil is heavier than water, satu¬ rate, or nearly saturate, the water in the still with common salt, to raise the boiling point, and thus to enable the vapour to carry over more oil. 6. Employ, when possible, water which has been already VEGETABLE OILS. 67 distilled from off the same substances, and has thus become saturated with oil. 7. For oils naturally fluid, keep the water in the re¬ frigerator cool; but for those oils which easily become solid, preserve it at 8o° to 90° F. To the above may be added— 8 . Collect the oil as soon as possible after it separates from the water with which it passes over, and in its subse¬ quent treatment keep it as much as possible from free contact with the air. Dr. Ure remarks : “ The narrower and taller the alembic is, within certain limits, the greater will be the proportion of oil, relative to that of the aromatic water, from like pro¬ portions of aqueous and vegetable matter employed.” “ Some place the plants in baskets, and suspend these im¬ mediately over the bottom of the still, under the water, or above its surface in the steam; but the best mode, in my opinion, is to stuff an upright cylinder full of the plants and drive down through them steam of any desired force, its tension and its temperature being further regulated by the size of the outlet orifice leading to the condenser. The cylinder should be made of strong copper, tinned inside, and encased in the worst conducting species of wood, such as soft deal or sycamore.” The newly distilled oils may be separated from adhering water, which frequently renders them partially opaque or “cloudy,” by repose at a temperature between 6o° and 70° F., and subsequent decantation; but to render them quite dry (anhydrous), it is necessary to let them stand over some fragments of fused chloride of calcium. This is not, however, required with the commercial oils. ( 2 °) Absorption or “ enjleurage .”—The odours of some flowers, such as jessamine and mignonette, are too delicate to bear heat, and for these the process of absorption is 68 OILS AND VARNISHES. employed. Sheets of glass in wooden frames, called chassis, are coated on their upper and lower surfaces with grease about a tenth of an inch in thickness. The flowers are spread upon this grease, and a number of frames are super¬ imposed on each other. After a day or two the flowers are carefully removed, and replaced by fresh ones, and this is continued for two or three months till the fat is impregnated with the odours. It is then removed, and extracted with alcohol. Recently the grease has been replaced in some cases by paraffin, glycerine, or vaseline. (3°) Solvents .—For this process various solvents are used, such as alcohol, ether, chloroform, petroleum, bisulphide of carbon, &c., and the oil is extracted by these in a percolator. (4 0 ) Expression .—The essential oils of lemons and oranges of commerce, and of some other fruits, are chiefly obtained by submitting the yellow rind to powerful pressure; but in this way they are not so white, nor do they keep so well, as when distilled, although in the case of the fruits referred to the oils are more fragrant than when prepared by any other method. This process is only adapted for substances which are very rich in essential oil. (5 0 ) Maceration .—Flowers with very delicate perfume, such as those of the bitter orange, violets, &c., which would be spoilt by distillation, are treated by this method. The medium used for infusion is clarified beef or mutton suet, or lard. The fat is melted, the flowers immersed, and the mixture stirred occasionally for a day or so. The exhausted flowers are removed and fresh ones introduced, and such renewals are continued till it is judged that the fat is sufficiently charged with the oil. Rectification .—This is commonly performed without water, by the careful application of a heat just sufficient to make VEGETABLE OILS. 69 the oils flow over pretty rapidly, so that they may be kept heated for as short a time as possible. One-half, or at most two-thirds only, is drawn off, that left in the retort being usually mixed with raw oil intended to be sold in that state. This method often leads to much loss and disappointment, and more than one rather dangerous explosion has been known to result from its use. A better plan is to rectify the oil from strong brine, and then to separate any adhering water, either by repose or chloride of calcium. "Volatile oils should be preserved in well-closed and nearly full bottles, in the shade, and should be opened as seldom as possible. By age they darken, lose much of their odour, increase in density, and become thick and clammy. It is then necessary to distil them, by which the undecomposed portion is separated from the resin. Agitation along with animal charcoal will restore their clearness and original colour, but nothing more. Prop. The volatile or essential oils are usually more limpid and less unctuous than the fixed oils, but some of them are butyraceous or crystalline. Nearly all of them consist of two or more oils, differing in their sp. gr. and boiling points, one of which is generally liquid, the other, in some cases, crystalline. All of them, when perfectly pure, are colourless, though before rectification nearly the whole of them have a pale yellow tint, and some of them are brown, blue, or green. Their odour is that of the plants which yield them, and is usually powerful; their taste is pungent and burning. They mix in all proportions with the fixed oils, dissolve freely in both alcohol and ether, and are sparingly soluble in water, forming “perfumed” or “medicated waters.” Their boiling point usually ranges between 310° and 325 0 F., and is always considerably higher than that of water. They resist saponification, and 70 OILS AND VARNISHES. (excepting oil of cloves) do not combine with the salifiable bases. Their density fluctuates a little on either side of water. The lightest oil is that of citrons (sp. gr. '847), and the heaviest that of winter green (sp. gr. ri73). When cooled sufficiently, they all solidify. The common temperature of the atmosphere is sufficient for this with some of them, as the oils of roses and aniseed; whilst others require to be cooled below the freezing point of water before they assume the solid form. In this state they appear to consist of a crystalline or semi-crystalline substance (stearoptene, stear- essence), and a fluid portion (elseoptene, olei-essence). The two may be separated by pressing the concrete oil between the folds of bibulous paper, in the cold. By exposure to the air, the volatile oils rapidly absorb oxygen, and become partially converted into resin. This is the cause of the deposit that usually forms in them (especially in the expressed oil of orange) when kept in an ill-corked vessel. The solid crystalline matter which separates from them when kept in closed vessels is stearoptene. Chemically considered, the essential oils may be divided into three classes :— 1. Oils composed of carbon and hydrogen only (binary volatile oils, hydrocarbons, terebenes, camplienes), of which oil of turpentine may be regarded as the type. These are characterized by being, as a class, less soluble in rectified spirit and in water than the other essential oils. The oils of bergamot, capivi, cubebs, elemi, hops, juniper, lemons, orange peel, pepper, the grass oil of India, the laurel oil of Guiana, and some others belong to this class. 2. Oils containing carbon, hydrogen, and oxygen (oxygeii- ated oils), including most of those used in medicine and perfumery. These, as a class, are more soluble in rectified spivit and in water than those containing carbon and hydrogen only. To this class belong the oils of almonds, VEGETABLE OILS. 7 i aniseed, cassia, cedar-wood, cinnamon, cumin, jasmin, lavender, meadowsweet ( Spircea ulmarici ), orange flowers, pennyroyal, peppermint, spearmint, rosemary, rose-petals, valerian, winter green ( Gaultheria procmnbens), and others too numerous to mention. A few of these oxygenated oils contain nitrogen. 3. Oils containing sulphur (sulphuretted oils). These are characterized by their extreme pungency, suffocating odour, vesicating power, property of blackening silver, and being decomposed by contact with most other metallic bodies. The oils of assafoetida, black mustard seed, garlic, horseradish, and onions are of this kind. Some sulphuretted oils contain nitrogen. Uses, cfrc.—The volatile oils are chiefly used by perfumers and rectifiers, and in medicine. Some of the cheaper kinds are largely employed as vehicles for colours, and in the manufacture of varnishes. The dose of the aromatic and carminative oils is from 1 to 10 drops, on sugar, or dis¬ solved in a little weak spirit. This does not apply to oil of bitter almonds, the dose of which is | to ^ a drop. *** The following list includes short notices of nearly all the volatile oils which have been examined, as well as of some other substances of a similar character which commonly pass under the name. These will be most conveniently studied if classed accord¬ ing to the natural orders of the plants from which they are derived Class, Thalamiflor^e. Natural Order, Anonacece. Ilang-Ilang Oil.— Syn. Cananga oil, Oleum anon^e, Oleum unon^e. —The flowers of Cananga oclorata —the Uva- ria oclorata of Roxburgh and the earlier Indian botanists— 72 OILS AND VARNISHES. yield this oil. It is interesting as contain’ng benzoic ether. Fluckiger has shown that it also contains a phenol-like body, and an aldehyde or ketone-. ^Natural Order, Aurantiacece. Bergamot* Oil of. — Syn. Essence of bergamot. Oleum Bergamii, 0 . bergamot.*.— Prepared by expression, or ex¬ pression and scarification, from the rind of the Citrus bergamia , or bergamot orange. It is of a pale-greenish colour, and highly fragrant. It is obtained purer by distil¬ lation, but its perfume is then less delicate. Its specific gravity varies from o’86 to o - 885. The rind bf xoo bergamot oranges will yield nearly 3 oz. of oil (M. Raybaud). It is very frequently adulterated—with rectified spirit, or with oil of lemons, orange, or turpentine. The presence of these substances will be found to be indicated by the methods given finder Testing of Oils. It may be herb mentioned that pure bergamot oil is much more soluble in rectified spirit than either of the adulterants specified, and it dissolves completely in solution of potash. Its chief use is in perfumery, but it has been recently recommended * as a reliable and quick acting remedy for scabies-. Cedrat Oil.— Syn. Essence of cedra, Oleum cedri-, O. citri finuM} L.—- From the exterior yellow rind of thh fruit of Citrus medica, or citrons-, either by expression or distillation, as oil of bergamot. The first portion of oil that comes over is colourless; the latter portion greenish. Yery fragrant. Specific gravity^ '847. Prod. 100 citrons yield nearly 1 fl. oz. of pale and \ fl. oz-. of green oil. Citron Oil. — Syn. Essence of citron, Oleum citri.— Obtained from the lees of citron juice, < >r from the peel of citrons. The latter generally goes by the name of oil of cedrat-. Both are fragrant. * ‘‘Pharmaceut. Zeitung,” 7 081, 306. I EG ETABLE OILS. 73 Lemons, Oil of.— Syn. Essence of l., Oleum limonis (B. P.), Oleum limonis, O. limonum (Ph. L., E., & D.).— From the yellow portibh of the rind, grated, placed in hair hags, and exposed to powerful pressure ; also by distillation, but the product is then less agreeably fragrant and sweet, though it ke'eps better. Nearly colourless; odour that of the fruit. Specific gravity, '’8752 to *8785. Expressed oil, *8517, distilled oil, "845, at 72°E. (Ure). Prod. 100 lemons yield, by expression, if to £ oz. (nearly); by distillation, 1^ to ij. It is commonly adulterated with oil of turpentine, and occasionally with nut or poppy oil. When pure, it is soluble in all proportions in absolute alcohol, but rectified spirit only dissolves 16 per 'cent, of it. It also boils at 148° F., whereas oil of turpentine boils at 312 0 , and mixtures of the two at intermediate temperatures, depending on the pro¬ portions. Gf. Heppe * tests for turpentine as follows :— A portion of the oil is gradually heated on a sand-bath in A perfectly dry test tube; with a small quantity of cupric butyrate (size of pin’s head) to about 172 0 C. If the oil of lemons is pure, the copper salt dissolves and colours the oil green. If oil of turpentine be present, the oil becomes turbid, turns yellow, and deposits reddish-yellow cuprous 'oxide. Too much 'of the reagent must not be used ; other¬ wise the oil will be green after cooling, even if oil of turpentine be absent. Limes, Oil of.— Syn. Oleum limetile, L.—From the rind of the fruit of Citrus limetta, or lime, as oil of lemons, which it somewhat resembles. Prod. 100 limes yield 2\ to 2J oz. of oil. Neroli Oil. — Syn. Oil of orange flowers, Essence of neroli, Oleum napiue, O. aurantii florum, Aurantii oleum (Ph. E. & D.).—Prepared from the flowers of either * “Clicni. Teel). Centr. Anz.” iii. 371. 74 OILS AND VARNISHES. the bitter (Seville) or sweet orange (Citrus vulgaris or C. aurantium ) by distillation with water. That from the fruit is said to be preferred, but there does not appear to be any actual difference between the two. It is very fluid, and lighter than water, in which it is slightly soluble. It is delightfully aromatic and fragrant, but the odour differs slightly from that of the flowers, ioo lb. of flowers gathered in May or December yield 3 to 6 oz. of oil; 6 cwt. of the fresh flowers yield 1 lb. of oil. Neroli is commonly adulterated with alcohol or essence de petit grain, and often with both. The presence of the first is easily determined; that of the second can only be discovered by comparing the odour evolved during the evaporation of a drop of the suspected oil, placed on a piece of white paper with a like drop of pure neroli similarly treated. Orange Oil. — Syn. Essence of orange, Oleum aurantii O. aurantiorum, 0 . aurantiorum corticis.— Prepared from the yellow portion of the rind of either the Seville or sweet orange, preferably of the latter, in the same way as oil of bergamot, or of lemons. It closely resembles oil of lemons, but is more agreeably fragrant. The expressed oil is very apt to become opaque, and deposit a stearoptene, especially in cold weather, unless well kept from the air. Specific gravity, about 0-875. 100 fruits yield 4 to 5 oz. Orange Berries, Oil of. — Syn. Oleum aurantii bacca3. —Prom the small unripe fruit of the orange tree. It does not keep well. Orange Leaf Oil. — Syn. Essence de petit grain, Oleum aurantii folii. —From the leaves of either the bitter or sweet orange—that from the first being preferred. It is delightfully fragrant. Extensively used to adulterate od of neroli, and is itself commonly sophisticated with both alcohol and oil of orange berries. VEGETABLE OILS. 75 Natural Order, CaryoiAyllacece. Cajeput Oil.— Syn. Cajeputi oil, Kyapootie oil, Cajeputi oleum (B. P.), Oleum cajaputi (Ph. L., E., & D.), L.—From the dried leaves of the Melaleuca cajeputi (Melaleuca minor , B. P.). Colourless* when pure (that of commerce is usually green); odorous; aromatic; taste, hot and penetrating. Its odour has been compared to a mixture of those of camphor and cardamoms. It boils at 343 0 F. Sp. gr. -920 to -927. When rectified, about three-fourths of the quantity passes over colourless, and has the density •897 ; the remaining portion is green, and has the density •920 to ‘925. Its green colour is derived from a salt of copper, the presence of which may be recognized by the red precipi¬ tate occasioned by agitating the oil with a solution of ferro- cyanide of potassium (Guibourt). From the East Indies. Pure oil of cajeput is slightly soluble in water; entirely and freely soluble in alcohol; dissolves iodine ; and when dropped on water, rapidly diffuses itself over the surface, and soon completely evaporates. A spurious kind (Factitious oil of cajeput), made of oil of rosemary, flavoured with camphor and the oils of peppermint and cardamoms, and coloured with verdigris, is occasionally met with in the shops. Oil of cajeput is a powerful antispasmodic and diffusible stimulant. Dose, 3 to 6 drops, on sugar; in cholera, colic, epilepsy, hysteria, rheumatism, spasms, toothache, &c. Cloves, Oil of.— Syn. Essence of cloves, Oleum caryopiiyllorum, Oleum caryophylli (B. P., Ph. L., E., & D.), Oleum Eugenle caryophylli (Ph. D. 1826), L.—. Obtained from the Caryophyllus aroviaticus, or Molucca clove tree, cultivated in Penang, Bencoolen, and Amboyna. The unexpanded flowers (cloves) and flower-stalks are soaked for some time in salt and water, and then submitted to distillation, the distilled water* after having deposited its oil, 76 OILS AND VARNISHES. being returned three or four times into the still, and again “ worked off ” from the same materials. Nearly colourless, when recent, gradually becoming pale yellow, and ultimately light brown, by age; highly aromatic, with the characteristic odour and flavour of cloves. It is the least volatile of all the essential oils. Soluble in alcohol, ether and strong acetic acid. Specific gravity, 1*055 to 1*061 (1*034 to 1*061, B. P.). Prod. 16 to 22 per cent. As a medicine it is stimulant and carminative. It is used as an adjunct to purgatives and as an application to carious teeth. Oil of cloves is frequently adulterated with inferior essential oils, especially with those of pimento, pinks, and clove-gillyflowers, and, occasionally, with castor oil. The following methods have been recommended for testing its purity.—1. Pure oil of cloves forms a butyraceous coagulum when shaken with pure liquor of ammonia, which crystallizes after fusion by a gentle heat.—2. Treated with an alcoholic solution of potash, it entirely congeals into a crystalline mass, with total loss of its characteristic odour.—3. Shaken with an equal volume of strong caustic soda lye, it forms, on repose, a mass of delicate lamellar crystals.—4. Solution of chromate of potash converts it into brown flakes, whilst the salt loses its yellow colour.-—5. Chlorine turns it first green, and then brown and resinous.—6. Nitric acid turns it red, and a reddish-brown solid mass is formed; with heat, it converts it into oxalic acid.—7. It dissolves freely in sulphuric acid, yielding a transparent, deep reddish-brown solution, without any visible decomposition.—8. Mixed, gradually, with about one-third of its weight of sulphuric acid, an acid liquor is formed, together with a resin of a rich purple colour, which, after being washed, is hard and brittle, and forms a red tincture with rectified spirit, which is pre¬ cipitated of a blood-red colour by water.—9. It dissolves VEGETABLE OILS. 77 iodine freely, without any marked reaction.—10. It dissolves santaline freely. ix. M. Jacquemin recommends the following as a very delicate test for the presence of carbolic acid when used as an adulterant for oil of cloves:—One drop of the suspected oil is mixed with a very small quantity of solution of aniline by means of a glass rod, and then shaken with 5 or 6 c.c. of distilled water. By the addition of a few drops of sodium hypochlorite to the mixture the characteristic blue colora¬ tion due to carbolic acid will be developed in a few minutes if the adulterant is present, whereas, with the pure oil, nothing but the purplish-violet colour of aniline will be perceived. Stirring or shaking must be avoided after the addition of the hypochlorite. The presence of 1 per cent, of phenol can thus be demonstrated in j drop of the oil. By distilling commercial oil of cloves from solution of potash, Ettling obtained two volatile oils—a light oil, sp. gr. 0-918, isomeric with oil of turpentine (C 10 H 16 ), and a heavy oil (caryophyllic or eugenic acid, C 10 H 12 O 2 ). The latter remained in the retort, combined with the alkali, while the light oil passed over. On addition of phosphoric or sulphuric acid to the residue the heavier oil was liberated and also distilled off. Its sp. gr. was 1-079. Artificial vanillin may be prepared from oil of cloves* in the following manner : —1 °. The oil is diluted with three times its volume of ether, and agitated with a very dilute aqueous solution of potash. z . The resulting alkaline solution of eugenol is separated, the alkali neutralized by acid, and the eugenol dissolved in sufficient ether. 3 0 . The ether is distilled off, and the eugenol treated with anhydrous acetic acid. 4 0 . The aceto-eugenol thus formed is oxidized by a weak and warm solution of potassic permanganate, and * “ Chemist and Druggist,” 1881,442. 78 OILS AND VARNISHES. the product filtered, rendered slightly alkaline, and concen¬ trated. 5 0 . It is, lastly, acidulated, and agitated with ether to remove the vanillin. Natural Order, Dipterocarpaccw. Camphor Oil.— Syn. Liquid camphor, Oleum cam¬ phors, Oleum camphors volatile, L.— Obtained from incisions in the wood of the camphor tree of Borneo and Sumatra ( Dryabalanops ciromatica), in which it exists in cavities in the trunk; also by distillation from the branches of the Camphora officinarum, or laurel camphor tree (natural order, Lauraceal). Colourless when rectified. Prod. 60 lb. of the crude brown oil yield 40 lb. of pure white oil and 20 lb. of camphor. It rapidly oxidizes in the air. Used to scent soap, The specific gravity of camphor oil varies somewhat. Mr. Peter MacEwan* finds that of Bornean camphor oil, 0-900 ; Johore oil, 0-882 ; Formosa oil, 0-943 ; Japanese oil, 0-951. According to IT. Oism,t the specific gravity of crude Japanese oil is 0-959, and after purification and separation of camphor, 0-895. The camphor-tree oil is used in Japan as an illuminant, and also for the preparation of carbon for Chinese ink. YoshidaJ separated a camphor oil five years old into 65 fractions, and these finally into 5 portions, as follows :— (i°) Boiling below 145° C. • . 0-2 (2 0 ) A hydrocarbon, B.P. 156° c. # . 7-0 ( 3 °) „ 99 °co M Q l M c. . 20’0 (4°) Camphor 99 205° c. • . 22-8 (5°) An oxygenated oil 99 2I2°— 213° 0. . 50-0 100-0 * “Pkarm. Journ.” 1S85, 1045. f “Chem. News/' Dec. 12, 1884. I “ J. Chem. Soc.” 1S85, 779. VEGETABLE OILS. 79 Of these portions (i°) was too small for examination; (2 0 ) was found to be a terebenthene, C l0 H 16 , identical chemically with, but differing physically from, that yielded by turpentine. Specific gravity at 15 0 C., 0-8641; and rotatory power, [a], = — 76-1°. (3°) Probably citrene, having a pleasant lemon odour. Rotatory power, [a]j = — 68-3°. (5 0 ) The author concludes that the formation of camphor by the ageing of the oil, or by boiling, is due to the presence of this oil, and he names it, provisionally, camphorogenol, or camphor hydrate (C 10 H 16 O.OH 2 ). It is a colourless, heavy oil; specific gravity, 0-9794 at 2o°C.; camphoraceous odour, milder than that of camphor. Soluble in alcohol, ether, and bisulphide of carbon, but insoluble in water. Warmed with dilute nitric acid (1—20) it yields a large quantity of camphor and yellow oil, from which more camphor may be obtained by freezing. Natural Order, Geraniacece. Geranium Oil. — Syn. Oil of Ginger-grass, Oil of spikenard. —The oil of commerce which passes under this name, and which was formerly imported from the East Indies, was not obtained from any species of Geranium or Pelargonium , but probably from a species of Andropogon. Properly, however, the term geranium oil is only applicable to that obtained from some species of Pelargonium. The genuine oil from the rose geranium ( Pelargonium roseum) is prepared in large quantities at La Trappe de Staonelli, not far from the Pay of Sidi Ferruch, in Algiers, where about 40 acres of the plant are in cultivation. “ Three harvests are gathered every year, and each yields from 170 to 200 kilograms of oil, or equal to 500 to 600 kilo¬ grams per annum. The value of this product never falls below 40 francs the kilogram, the average value being, therefore, from 20,000 to 25,000 francs, or at least £20 So OILS AND VARNISHES. per acre.” * A finer oil is yielded by the rose geranium grown in France, but it is much dearer, The geranium oils aro much used in perfumery and to adulterate otto of roses. The precious oil called spikenard (Oleum nardi) is sup¬ posed by some to have been derived from a species of Andropogon, but, commercially, geranium oil is also called by this name. Balfour, however, states that spikenard was supplied by NardostachysJatamansi(N&t. Ord. Valerianacece ), Natural Order, Magnoliacece. Star-anise Oil. — Syn. Badian oil, Oleum badiani, Oleum anisi stellati, —From the capsules of Illicium anisatum , or star-anise. It continues liquid at 35‘5° F. It is used for the same purposes as aniseed oil, and is often mixed with it, or substituted for it. Produce, 2 to 4 per cent, Natural Order, Resedacece. Mignonette Oil. —A thick yellowish-coloured oil, ex¬ tracted by ether, or “ enfleurage,” from the flowers of Reseda, odorata , or mignonette. Class, Calyciflorje. Natural Order, Amygdalacece. Almond Oil (Bitter). — Syn. Essence of b. a., Oleum amygdala AMAR/E, 0 . A. essentiale, L.—From the ground cake of bitter almonds from which the fixed oil has been expressed, The common plan is to soak the cake (crumbled to fragments) for about twenty-four hours in twice its weight of water, to which one-third or one-fourth of its weight of common salt has been added, and then to submit the whole to distillation, allowing the first half of the water that passes over to deposit its oil, and to run back again into the still. Pale golden yellow; colourless when rectified ; tastes * “Pliarm. Journ.” [3] No. 433. VEGETABLE OILS. and smells strongly nutty, like peach-kernels. It consists of 85 to 90 per cent, of hydride of benzoyl, with a vari¬ able quantity of benzoic acid and benzoin, and 8 to 12 per cent, of hydrocyanic acid (4*15 to 6-38 per cent., Braith- waite*). M. Fileti is of opinion that the great difficulty of separating the whole of the hydrogen cyanide, in this oil and in the oil of cherry-laurel, renders it probable that it is present in some form of combination with the benzaldehyde, such as C 6 H 5 .CH(OH).CN. The density varies a little with the age of the oil, and the tem¬ perature and rapidity with which it has been distilled. Sp.gr. (recent) 1*0525; (trade crude oil) 1*079 (Gr. Wippel); (old) 1*081 (1*0836, Pereira). 1*0524 to 1*0822 (Bed- wood). “ Essential oil of almonds, free from adulteration, should have a specific gravity at most of 1*052 ” (Ure). The light oil contains the most hydride of benzoyl, and the heavy oil the most benzoin. Prod. From less than *2 to *5 per cent. This oil is generally adulterated with cheaper oils, and in nearly every case with alcohol. When it is pure— 1. Mixed with sulphuric acid, it strikes a clear crimson-red colour, without visible decomposition.—2. Mixed with an alcoholic solution of potash, crystals are eliminated.— 3. Iodine dissolves only partially and slowly in it, without further visible results.—4. Chromate of potash does not affect it.—5. Nitric acid (specific gravity, 1*42) causes no immediate reaction, and in the course of three or four days crystals of benzoic acid begin to appear; but if only 8 or 10 per cent, of alcohol or rectified spirit is present, a violent effervescence speedily commences, and nitrous fumes are evolved. By using nitric acid (sp. gr. 1*5), the smallest quantity of alcohol may be detected. —6. M. Ferrand states that the presence of nitrobenzol in essence of bitter almonds may be detected * “Pharm. Journ.” 1886, 659. G 82 OILS AND VARNISHES. as follows:—Heat to ebullition, in a test tube, 3 or 4 c.c. of a 20 per cent, alcoholic solution of potash, together with 10 drops of the suspected essence. If nitrobenzol be present, the mixture takes a red colour ; if the essence of bitter almonds be pure, it becomes a pale straw colour.— 7. Hager * has proposed a solution of mercuric nitrate (10 per cent.) as a test of the purity of bitter-almond oil. Four drops of the essential oil are dissolved in 2 c.c. alcohol, and 2 or 3 drops of the nitrate solution added. Pure bitter- almond oil gives no reduction. The greater number of essential oils, however, reduce the nitrate, and their presence in the above is indicated by the formation of a grey pre¬ cipitate of metallic mercury. This oil does not pre-exist in the almond, but is formed by the action of water on a peculiar crystallizable substance, called amygdalin. It is essentially the hydride of benzoyl, but it always contains a portion of hydrocyanic or prussic acid, to which it owes its very poisonous properties. It is occasionally employed as a substitute for hydrocyanic acid in medicine; but its principal consumption is as a flavouring ingredient and a perfume by cooks, confectioners, liqueurists, and perfumers. For this purpose it is dissolved in rectified spirits. Dose, | to 1 drop. An oil closely resembling that from bitter almonds is obtained by distillation from the leaves of the peach and cherry-laurel, the bark of the plum-tree, the bruised kernels of cherries, plums, and peaches, the pips of apples, and from several other vegetable substances that possess a nutty odour and flavour. A non-poisonous oil of almonds has been introduced. This is simply the ordinary oil of commerce freed from hydrocyanic acid, and is intended to be substituted for the * “ J. Soc. Chenj. Ind.” 1885, 611. VEGETABLE OILS. 83 crude, poisonous oil for domestic purposes. Unfortunately, the purified essence does not keep well, and is often con¬ verted after a few months into little else than a solution of benzoic acid, almost devoid of the usual odour and flavour of the bitter almond. “Uo wonder, then, under such circumstances, that the public preferred the preparations they had been accustomed to, which were not so liable to change” (Redwood). The following methods have been adopted for this purpose :— 1. (Liebig.) Agitate the crude distilled oil with red oxide of mercury, in slight excess, and, after a few days' contact, lectify the oil from a little fresh oxide of mercury. The product is quite pure, when the process is properly managed. The cyanide of mercury thus formed may be either employed as such, or reconverted into mercury and hydrocyanic acid. 2. (Mackay.) Commercial oil of almonds, 1 lb.; fresh- slaked lime, q. s. to form a milk-like liquid: afterwards add, of solution of potash, i| lb.; water, 3 pints; agitate occasionally for forty-eight hours, then distil over the oil, and rectify it from a fresh mixture of lime and potash. 3. (Redwood.) The oil is mixed with an equal quantity of water, and the mixture is digested in a water-bath with red oxide of mercury, and small quantities of fresh-slaked lime and protochloride of iron, with as little access of air as possible ; as soon as decomposition of the acid has taken place, the whole is introduced into a copper retort, and sub¬ mitted to distillation. The product is perfectly free from hydrocyanic acid. The first process is, however, the simplest, cheapest, and best. The specific gravity of this non-poisonous oil is 1*051 (G. Whippell). That of pure colourless hydride of benzoyl is 1-043 J ^ boils at 356° F., is soluble in 35 parts of water, and in all proportions in alcohol and ether. Exposed to the air, it greedily absorbs oxygen, and becomes converted into 84 OILS AND VARNISHES. a mass of crystallized benzoic acid. The purified oil of almonds does the same, only less rapidly. Almond Oil (Factitious).—^. Essence of mirbane, Uitrobenzol. —It is now extensively prepared as a sub¬ stitute for the oil of almonds obtained by distillation. The following is Mansfield’s process :—The apparatus consists of a large glass worm, the upper end of which is divided into two branches, gradually dilating so as to form two funnel-shaped tubes. Into one of these, concentrated nitric acid is poured, and into the other benzol, which need not, for this purpose, be chemically pure. These bodies meet at the point of junction of the two tubes, and the rate of their flow is regulated by any appropriate means. Chemical reaction instantly takes place, and the new compound is cooled by its passage through the worm, which is refrigerated for the purpose. It has then only to be washed with water or a very weak solution of carbonate of soda for the pro¬ cess to be complete. The product has specific gravity 1-209, boils at 415 0 F., has an intensely sweet taste, and an odour closely resembling, but not actually identical with, that of oil of bitter almonds. Unlike genuine oil of almonds or hydride of benzoyl, it is insoluble in water, and does not distil without suffering partial decomposition. It is chiefly used to scent soaps, and to adulterate the genuine oil. The benzol for this purpose is obtained from coal-tar. Laurel Oil. — Syn. Oil of sweet bay, Oleum lauri volatile, 0 . l. essentiale, L.—From the berries or leaves of Laurus nobilis (Linn.) (Is at. Ord. Lauracece), or sweet bay-tree. Pale-yellow, clear, aromatic, stimulant, and narcotic. It is a solvent for india-rubber. Specific gravity, •864 to -871. Produce, from the leaves, f to 1 per cent. Cherry-laurel Oil. — Syn. Oleum laurocerasi, L.— From the leaves of Cerasus laurocerasus, or common laurel. Closely resembles oil of almonds, but is said to be weaker. VEGETABLE OILS. 85 It behaves like bitter-almond oil when treated with a 10 per cent, solution of mercuric nitrate (Hager). Like that sub¬ stance, it is powerfully poisonous. Prod. 100 lb. fresh leaves (undeveloped, June), 10U3 oz. j do. (half-grown, June), 7*2 oz.; do. (full-grown, eight weeks on tree, July), 4-96 oz.; do. (do., three months on tree, Sept.), 7-04 oz.; do. (fifteen months on tree), 2^24 oz. (Christison). Natural Order, Posacece. Rose Oil.— Syn. Oleum rosas, Attar or Otto of roses. _(!°) From the petals of Rosa sempervirens, or musk-rose, as oil of cloves, observing to keep the water in the worm tub at 85° F., and afterwards subjecting the water in the receiver to refrigeration. Produce, 0^05 to o'io per cent. (2 0 ) From the petals of Rosa centifolia or sempervirens (damask and musk rose), principally the first, by saturating the water by returning it repeatedly on fresh flowers, and then exposing it to a low temperature. In the East Indies it is obtained by stratifying gingelly seeds in alternate layers with rose petals, for some days, and repeating the arrange¬ ment with fresh roses till the seeds are saturated, when the oil is expressed and distilled along with water. In the neighbourhood of Mecca the rose leaves (petals) are macerated in salt and water for two or three days and then distilled, the water being received in separate vessels at different parts of the process. The water is afterwards ex¬ posed in earthenware vessels, tied over with linen or muslin, in trenches dug in the earth, and over which moistened straw is thrown, when, in a short time, the otto separates and floats on the surface. In Bulgaria (Spon) the flowers are not salted, nor sub¬ jected to any treatment, before they are introduced into the stills. The stills are made of tinned copper, and are heated by a wood fire. Each charge consists of from 25 to 5° lh. 86 OILS AND VARNISHES. of roses, not previously deprived of their calyces, with double the volume of spring water. The distillation is carried on for about an hour and a half, and the distillate is a very oily rose-water. The first distillates from each apparatus are mixed and re-distilled by themselves, one-sixth being drawn off: the residue replaces spring water for subsequent operations. The receivers are long-necked bottles, of about 1 i gallon capacity. Kept for a day or two at a temperature not lower than 6o° F. (15-5° C.), most of the oil reaches the surface, and, when skimmed off, is ready for sale. It is stated that 3200 kilo, of roses give 1 kilo, of oil. The pure oil is colourless, or nearly so, but soon acquires a yellowish colour. Its odour is intense, penetrating, and diffusive, and, in a concentrated state, by no means pleasant, but, when dilute, very agreeable. Its taste is bland and sweetish. When pure, it congeals at 8o° F., and does not re-melt until heated to fully 85° F. 1000 parts of alcohol of 0-806 dissolve only 7 parts of otto at 57 0 F., and only 33 parts at 72 0 F. Sp. gr., 0-832 at go° F. Prod. 100 lb. of roses yield 2 to 3 dr. oil. Otto of roses is frequently adulterated with the oils of rhodium, sandal-wood, and geranium, and with camphor; and occasionally also with spermaceti to give the spurious compound the usual crystalline appearance. The following tests are considered reliable :—(T) Odour and taste. The purity of the odour can be determined only after consider¬ able experience. The taste of the pipe otto is bland and sweet. If it is bitter., it contains probably either oil of rhodium or of sandal-wood ; if it is pungent, or “ bites ” the palate, it contains either oil of geranium, or camphor, or both ; if it imparts an unctuous sensation, the presence of spermaceti is indicated. (2 0 ) Its congealing point.* A good * G. W. Lock, “Journ. Soc. Arts,” Feb. 11, 1881. VEGETABLE OILS. oil should congeal well in five minutes at 54'5° F. (i2’5 C.) —-fraudulent additions lower the congealing point. The crystals of rose-stearoptene are light, feathery, shining plates, filling the whole liquid. Almost the only material used for artificially heightening the apparent proportion of stearoptene is said to be spermaceti, which is apt to settle down in a solid cake, and melts at 122 0 F. (50° C.), whereas stearoptene fuses at 91’4° F. (33° C.). Possibly paraffin wax would more easily escape detection. (3 0 ) Exposed for some hours to the fumes of a small quantity of iodine under a bell-glass in the cold, pure otto remains white, and continues so when exposed to the air; an adulterated sample, on the contrary, becomes yellow, or brown, and afterwards, on ex¬ posure to the air, continues to darken in colour, until it becomes of a deep brown, or even perfectly black, according to the quantity of foreign oil present. A single drop may be thus tested. (4°) (Guibourt.) One or two drops of the suspected oil are put into a watch-glass; the same number of drops of concentrated sulphuric acid are added, and the two fluids are mixed with a glass rod. All the oils are rendered more or less brown by this proceeding; but otto of roses retains the purity of its odour; oil of geranium acquires a strong and disagreeable smell, which is perfectly charac¬ teristic ; the odour of oil of rhodium is increased and becomes somewhat unctuous, and, in general, acquires an odour dis¬ tinctly like that of cubebs. (5 0 )* Put into a small test tube 1 drop of the otto, and add 4 drops of concentrated sul¬ phuric acid. When the mixture has cooled, add 2 gms. of absolute alcohol and shake well. If the oil is pure, the mixture is slightly opalescent, and, on heating, becomes a yellowish brown, which remains after cooling. But if geranium, pelargonium, or palma rose oil has been mixed Repartono di Chimica et Farmacia.” 88 OILS AND VARNISHES. with it, the solution becomes cloudy, and, after a little time, an insoluble precipitate separates. Fatty oils, such as almond or sesame oil, which are sometimes employed to dilute otto, are recognized by leaving a greasy stain on paper after warming. Fluckiger* states that Turkish oil of roses is in¬ variably adulterated, and may contain no stearoptene. In a sample made in the laboratory from roses grown in neigh¬ bourhood of Leipzig he found 28’8 per cent, of stearoptene. Natural Order, Leguminosce. Copaiba Oil.— Syn. Oil of capivi, Oleum copaiba (F. P., Ph. L. & E.), L.—Yielded by various species of Copaifera. —1. (Ph. E.) Balsam of capivi, 1 oz.; water, 1^ pint; distil, returning the water into the still, until oil ceases to pass over.—2. (Wholesale.) From the crude oil which separates during the manufacture of “ specific solution of copaiba ” and “ soluble capivi,” by distillation along with a little salt and water. Colourless when pure; that of commerce has frequently a greenish tinge, derived from the copper utensils; odour, not disagreeable when recent. Sp. gr. -876 to -878. Prod. 50 to 55 per cent. When adulterated with oil of turpentine, its solubility in rectified spirit is greatly diminished, and the solution is turbid. Pose, 10 to 15 drops, on sugar; in the usual cases in which copaiba is ordered, 20 to 60 minims, three times a day (B. P.). Natural Order, Amyridacece. Olibanum Oil.—The resin obtained from Boswellia floribunda and Boswellia thurifera (serrata) contains 4 or 5 per cent, of a volatile oil, which may be separated by distil¬ lation with water. It has a yellowish colour, and pleasant, terebinthine odour. Specific gravity, about o - 866. * “Arch. Pbarm.” [3] 23, 185-188. VEGETABLE OILS. 89 Myrrh Oil.— Syn. Oleum myrrile, Oleum myrrh.e essentiale, L.—Colourless; thin ; heavier than water ; stimulant; smells strongly of the drug. 100 lb. of myrrh, obtained from Balsamodendron Myrrha, or an allied species, yield about 8 oz. of the oil. Natural Order, Myrtacece. Pimento Oil.— Syn. Oil of allspice, Oleum piment/e (B. P., Ph. L., E., and D.)—Prom the bruised fruit of Eugenia pimenta , allspice, or Jamaica pepper. It is of a pale-yellow colour, growing reddish-brown by age ; odour, a combination of cloves and cassia; taste, pungent. Its specific gravity is variously stated as I’ozi—U037, and the produce from 3 to nearly 6 per cent. Nitric acid turns the pure oil red, with active effervesence, and the assumption of a rusty-Drown colour. It combines with the salifiable bases in a nearly similar manner to oil of cloves. It is much used in perfumery, especially in hair cosmetics. Eucalyptus Oil. —The Eucalypti, of which there are many species furnishing this oil, are natives of Australia, where they are known as “ gum-trees,” or “ stringy-bark ” trees. The most interesting and important characteristic of these plants is the power which they undoubtedly possess of correcting, if not of removing, the pestilential exhalations which are regarded as the origin of the fevers that occur in marshy localities. This discovery is due to M. Hamel, and was made by him in 1856. The leaves contain the essential oil, and from them it may be obtained by aqueous distilla¬ tion. Cloez found the oil chiefly to consist of a substance allied to camphor, which he termed eucalyptol. A. Faust and J. Homeyer * consider this eucalyptol to be a mixture of a terpene and cymol with two other substances, boiling at * “ Per. deutsch. Chem. Ges.” 1874. 90 OILS AND VARNISHES. about 156° C. and 200° C. respectively. Kingzett, whc has recently given great attention to the eucalypti, considers the oil * to be practically identical in composition with the oil of turpentine derived from pine trees, and with most of the so-called essential oils or perfumes. He is of opinion that all these oils, when subjected to the action of atmo¬ spheric oxygen and moisture, produce peroxide of hydrogen and a number of camphoraceous substances having marked antiseptic properties. Any therapeutic power possessed by the tree is to be referred mainly, if not entirely, to the oil. The oil varies in colour, according to the species of the plant from which it is obtained, from light yellow to light blue. It is largely employed as a diluent for the more delicate oils used in perfumery. As an antiseptic dressing for wounds it is claimed t for the oil that it possesses not only the advantage over carbolic acid of being non-poisonous, but also of preventing the development of bacteria when it is present in the proportion of 1 in 666 of the dressing, whilst carbolic acid does not do so until the amount reaches 1 in 200. Eucalyptus oil is soluble in oil and pure paraffin, as well as in alcohol. Eor spray and irrigation, Professor Schulz recommends a mixture of the alcoholic solution with water. Dr. SiegekJ states that a 5 per cent, solution may be employed without drawback. Eor gauze bandages, he dissolves 3 parts of the oil in 15 of alcohol, and dilutes with 150 parts of water. The following list includes the chief varieties of eucalyp¬ tus oil : §-- * “Chem. News,*’ xl. 183. *f “Pharrn. Journ.” [3] xi. 250. X “Lancet/ September 1880, p. 387. § “ Zeitschrift d. Oester. Apotli. Ver.” Nos. 24-26. VEGETABLE OILS. 9i Species. Colour and Odour. Taste. Sp. gr. at I 5° C. Boiling- point (C.). Eucalyptus : amygdalina. Pale yellow; odour, like oil of lemon. Mild, afterwards bitter. o'88i 165 0 —188 0 oleosa. Pale yellow; odour, mint-like. Camphor-like. 0*911 i6i u - 177“ sideroxylon. Very pale yellow; odour, mint-like. ” 0*922 I5S°-W8° gonioealyx. Pale yellow; odour, disagreeable. Very disagree¬ able. C918 152 0 -175 0 globulus. Very pale yellow ; odour, like oil of cajuput. Cooling, mint¬ like. 0917 149°-177° corymbosa. Colourless; odour, faintly lemon and rose-like. Feebly bitter, slightly cam- phoraceous. o’88i obliqua. Yellowish - red ; odour, mild. Bitter. 0^899 I7 l °- l 95° fissilis. Pale yellowish red; odour, mild. 0*903 I77 0 — 196° odorata. Pale yellowish green ; odour, aromatic. 0899 — 0*922 i 57°-i99° longifolia. Thicker than pre¬ ceding oils; odour, strongly camphor- aceous. Cooling and aro¬ matic. 0*940 194°-215 0 rostrata. Pale yellow to am¬ ber; odouraslast. ” 0-918 131 0 —181 0 viminalis. Pale greenish yel¬ low ; odour un¬ pleasant. 0*921 159°-182° Eucalyptus oil has been placed in the new Pharmacopoeia (1885), where it is thus described :—“The oil distilled from the fresh leaves of Eucalyptus globulus, Labill. ; Bentley and Trim. Med. PI. vol. ii. pi. 109; Eucalyptus amygclalina, Labill.; and probably other species of eucalyptus. Charac¬ ters and tests .—Colourless or pale straw coloured, becom¬ ing darker and thicker by exposure. It has an aromatic odour, and a spicy and pungent flavour, leaving a sensation of coldness in the mouth. It is neutral to test-paper. Spe¬ cific gravity, about 0-900; soluble in about an equal weight of alcohol.” With regard to tests, Mr. P. Mac Ewan * says that, as regards acidity, it develops with age, and at the Pharmaceutical Conference, 1885. 92 OILS AND VARNISHES. same time the oil improves in the ordinary sense of the term. The alcohol used as a test of solubility therein should be rectified spirit, not absolute alcohol; oils above specific gravity o - 88o should be soluble in their own volume, and those of less specific gravity should require not more than six volumes. Presence of turpentine reduces the solubility. Mr. MacEwan considers that the best test for the detection of turpentine is Langbeck’s salicylic acid test.* An oil above o‘88o should dissolve not less than a tenth of its weight of salicylic acid, and lighter oils not less than a sixteenth. Natural Order, Umbelliferce. Angelica Oil.—The root of Angelica archangelica ( An¬ gelica officinalis), dried, and submitted to aqueous distilla¬ tion, yields about i per cent, of oil. This oil, and also that from the seeds, have recently been studied by L. NAUDiN,t who finds the sp. gr. of the former to be 0^875 at o° C. and that of the fruit to be o'S'] 2. Aniseed Oil. — Syn. Oleum anisi (Ph. L., E., & D.), O. essentials anisi, L.— From the fruit (seeds) of Pimpinella anisum, or anise. Nearly colourless. It is very frequently adulterated with one or other of the cheaper oils, in which case spermaceti or camphor is added to it to make it “ candy.” When pure, it congeals into a solid crystalline mass on being cooled to 50° F., and does not melt again until heated to about 63°. Treated with iodine, it quickly congeals into a solid hard mass, with a perceptible increase of tempera¬ ture, and the development of orange-coloured and grey fumes. Sulphuric acid, with heat, turns it of a rich purple- * “Pharm. Joum.” [3] xv. 309. f “Comptes Rendus,” xciii. 1146, anti “ Bull, de la Soc. Chirn.” xxxix. 406-409. VEGETABLE OILS. 93 red colour, and the compound soon afterwards becomes in¬ spissated and hard (resinified). In alcohol of -8o6 it is soluble in all proportions, but rectified spirit (‘838) dissolves only 42 per cent, of this oil. Sp. gr. (recent) -9768; (one year old) -9853 to -9855 ; (old) -9856 to -9900. The foreign oil is generally the heaviest. Oil of aniseed is carminative and pectoral; and both itself and preparations have long been in favour with the masses in coughs, colds, &c. In preparing it, care must be taken that the temperature of the water in the receiver and refri- gerator does not fall lower than about 68° F. Prod, (from the dried fruit of commerce) 2 per cent, (nearly). Caraway Oil.— Syn. Oleum carui (B. P., Ph. L., E., and is said to have been a very clever imitation externally of the genuine substance, which it closely resembled in appearance, colour, fracture, bitterness, pliability, and odour. Upon analysis, it was found to be composed of 60 parts of paraffin and 40 parts of yellow resin, covered with a thin coating of pure bees’-wax. The specific gravity of the counterfeit article was identical with that of many samples of true bees’-wax. Saline matter may be detected by the loss of weight when a weighed quantity of the wax is boiled with water. Heavy substances, as chalk, plaster of Paris, white lead, oxide of zinc, &c., may also be thus separated, since they subside, owing to their superior gravity, to the bottom of the vessel. The rough mealy fracture of pure wax is rendered finer grained, smoother, and duller by the addition of lard or spermaceti, and becomes sparkling and more granular by the addition of resin (Proctor). White Wax.— Syn. Bleached wax, Cera alba (B. P., 144 OILS AND VARNISHES. Ph. L., E., & D.), L.—Prepared by exposing pure bees’-wax in thin flakes to the action of the sun, wind, and rain, fre¬ quently changing the surface thus exposed, by remelting it, and reducing it again to thin flakes. It is used in making candles, and in white ointments, pomades, &c., for the sake of its colour. Block white wax (Cera alba in massis) is the above when cast into blocks; the best foreign white wax is always in this form. Virgin wax (cake white wax, Cera alba in offis) should be the last made into round flat cakes; but this is seldom the case, the mixture sold under the name generally containing from one-third to one-half its weight of spermaceti. The “ white wax ” supplied by certain wholesale druggists to their customers is alleged to be often totally unfit for the purposes to which it is applied. Mr. B. S. Proctor* states that wholesale houses of the highest reputation supply as white cake wax an article which is in many cases half spermaceti. Spermaceti. — Syn. Cetaceuji (B. P., Ph.'L., E., & D.).— This is the solid fat which is dissolved in sperm oil in the head cavity of the sperm whale yPhyseter macrocephalus), and which, after death, separates as a solid. The oil is filtered from the solid fat, the latter is heated with potash solution, and afterwards melted. Thus purified, it is white, scaly, brittle; specific gravity, 0-943 at 15° C.; melting point, 38°-47° C.; neutral, inodorous, and nearly tasteless. Chemically, spermaceti is chiefly cetylic palmitate, C 16 H 31 0 2 (C 1g H 33 ). It is demulcent and emollient, and chiefly used in oint¬ ments and cerates. * “ Chemist and Druggist,” iv. 1863. WAXES. 145 2'. Vegetable Waxes. Carnauba Wax.— This is obtained from the leaves of the carnauba palm, Copernicia cerifera, a native of Brazil. The leaves are collected and dried, and the wax, which can then be peeled off, is melted in earthen pots, from which, when cold, it is turned out. It is brittle, and of a yellowish colour. It melts at about 83°-84° C., and its sp. gr. is about o‘gg. It is extensively used in the manufacture of candles. Mr. Consul Morgan, in a paper laid before Parliament in 1876 on the trade and commerce of Brazil, states that the exportation of this wax is calculated at 871,400 kilos., exceeding in value ^162,500. Japan Wax.*— There are three principal sources of this fat or tallow in Japan, Rhus succedanea, L., Rhus vernicifera , D.C., and Rhus sylvestris. The first two, according to Prof. J. Bien. of Marburg, are not natives of Japan, but were probably introduced from the Loochoo Islands. R. sylvestris , however, is a true native of Japan, but is only cultivated for domestic use, the commercial products being furnished by R. succedanea and vernicifera . The usual method of obtaining the wax is the following : —The fruits are previously well dried, and then ground by means of mill-stones, or in mortars with wooden pestles, or by bamboo flails. They are then freed, by sifting and winnowing, from shells and epidermis ; sometimes, however, these latter are not separated’. The mass is then heated over boiling water in order to melt the fat in the cells, which is then expressed by means of different presses. Curing the second pressing, a little fatty oil is occasionally added to the mass in order to retard the congelation of the * A. Meyek, “Year Book of Pharmacy,” 1S80, 218. L 146 OILS AND VARNISHES. fat. The crude tallow thus obtained is now boiled with dilute lye, whereby it becomes granular and more susceptible to the bleaching process, then exposed to the sun, and several times melted with water. The bleaching and melt¬ ing are repeated until the product is pure and white. Formerly, the wax was only imported in round cakes of about 4§ inches in diameter and 1 to i T 3 g inch in thickness; but at present it occurs also in square cakes, or blocks, the latter of about 143 lb. each. When freshly broken, the fractured surface is almost white, or, sometimes, slightly yellowish-green and the odour is tallow-like and disagreeable. Its sp. gr. is about 0-916. It melts at 52°-53° C. when old, and at 42 0 0 . when recently solidified. At 30° C. it is soluble in about 700 parts of 97 per cent, alcohol. Warm ether dissolves it readily, but deposits it in flakes or granular masses on cooling. Japan wax is chiefly used in Europe and in the United States for mixing with bees’-wax in the manufacture of candles, as it facilitates the removal of the latter from the moulds ; it is also used in the manufacture of wax matches. Shoe and furniture makers likewise use it in considerable quantity as an ingredient in polishing materials. For pharmaceutical purposes, such as ointments, it is not well adapted, since it is, like bleached bees’-wax, already a rancid substance, and promotes the rapid deterioration of fats mixed with it. Perfumers make use of it for preparing a castor-oil pomade, a mixture of castor oil and Japan wax having the property of becoming entirely transparent by repeated melting. The following are some other vegetable waxes of minor importance :— Chinese Wax. — Syn. Pelawax. —Produced by an insect (Ooccus pe-la) upon young branches of Fraxinus chinensis. Melts at about 82°-83° C. WAXES. 147 Chinese Vegetable Tallow. — Syn. Stillingia tallow. Obtained from kernels of Stillingia sebifera. Melts at about 40° C. Used in China for making candles. Myriea Wax. — Syn. Myrtle tallow. —This is a solid fat obtained by pressure from the berries of Myriea cerifera. Sp. gr. 1 -005 (Moore). Melts at 47°~49° C. (Moore). Palm Wax. Obtained from trunk of Ceroxylon andicola. The crude wax does not melt below the temperature of boiling water. Sugar-cane Wax. — Syn. Cerosin. —Obtained by rasp¬ ing the bark of the cane, and purifying by recrystallization from boiling alcohol. Its composition is said to be C 48 H 0 . Melts at about 82° C. Fossil Wax. — See Ozokerit. Mineral Wax. — See Paraffin. 3*. Artificial Waxes. Factitious Wax. — Syn. Cera flava factitia, L._ A spurious compound sold by farriers’ druggists for veteri¬ nary purposes. Prep. i°. From yellow resin, 16 lb.; hard mutton suet, or stearin, 8 lb. ■ palm oil, 2^ lb. • melted together. 2 . As last, but substituting turmeric, 1 lb., for the palm oil. 3 . Best annotta, 6 oz., or q. s.; water, 1 gallon ; boil; add of hard mutton suet or stearin, 35 lb. j yellow resin, 7 ° lb .; again boil, with constant agitation, until perfectly mixed and of a proper colour, and, as soon as it begins to thicken, pour out into basins to cool. When cold, rub each cake over with a little potato starch. Modelling Wax.— Prep. Take of bees’-wax, lead plaster, olive oil, and yellow resin, equal parts; whiting, q. s. to form a paste j mix well, and roll into sticks. Colours may be added at will. 14 ? OILS AND VARNISHES. Sealing Wax.— 1. Red.—(a) Take of shellac (very pale), 4 oz.; cautiously melt it in a bright coppei pan over a clear charcoal fire, and, when fused, add of Venice turpentine, il oz.; mix, and further add of vermilion, 3 oz. ; remove the pan from the fire, cool a little, weigh it into pieces, and roll them into circular sticks on a warm marble slab by means of a polished wooden block; or it may be poured into moulds whilst in a state of fusion. Or the sticks, when cold, may be polished with a rag. \'b) Shellac, 3 lb.; Venice turpentine, lb. ; finest cinnabar, 2 lb.; mix as before. Both the above are “ fine.” (c) As 1 (a), but using half less vermilion. Inferior. (d) Resin, 4 lb.; shellac, 2 lb.; Venice turpentine and red lead, of each i| lb.; as before. Common. 2. Black.—(a) Shellac, 60 parts; finest ivory black, reduced to an impalpable powder, 30 parts; Venice turpen¬ tine, 20 parts. Fine. (, b) Resin, 6 lb.; shellac and Venice turpentine, of each 2 lb.; lampblack, q. s. Inferior. 3. Gold-coloured .—By stirring gold-coloured mica spangles, or talc, or Aurum musivum into the melted resins just before they begin to cool. Fine. 4. Marbled .—By mixing two or three different coloured kinds just as they begin to cool. 5. Soft. —(a) Red. Bees’-wax, 8 parts; olive oil, 5 parts; melt, and add of Venice turpentine, 15 parts; red lead, to colour. (, b) Green. As the last, but substituting powdered verdi¬ gris for red lead. Both are used for sealing official documents kept in tin boxes; also as cements. 6. Bottle-wax.—{a) Black. Black resin, 6| lb.; bees’- wax, \ lb.; finely powdered ivory black, 1^ lb.; melted together. WAXES. 149 (b) Red. As the last, but substitute Venetian red, or red lead, for ivory black. All the above formulas for “ fine ” wax produce “ super¬ fine ” by employing the best qualities of ingredients, and “ extra superfine,” or “ scented,” by adding 1 per cent, of balsam of Peru, or liquid storax, to the ingredients when considerably cooled. The “ variegated ” or “ fancy ” coloured kinds are commonly scented with a little essence of musk or ambergris, or any of the more fragrant essential oils. The addition of a little camphor, or spirit of wine, makes sealing wax burn easier. Sealing wax containing resin, or too much turpentine, runs into thin drops at the flame of a candle. Testing Bees’-wax. —If the specific gravity is higher than 0*964, it indicates the presence of stearin, resin, or Japan wax; and if lower than 0*956, paraffin, ozokerit, or tallow may be suspected. Chloroform, or fatty oils, form a clear solution with dry, and a slightly turbid solution with moist, wax. By treating pure bees’-wax with a saturated solution of borax at 8o° C., the aqueous solution is rendered turbid. When Japan wax, or stearin, is present, a milky solution is obtained, remaining opaque after cooling. By boiling wax with a solution of soda (1 : 6), pure wax gives a translucent solution—if milky, stearin may be present; if pasty or stiff, Japan wax may have been added. When the specific gravity is less than 0*956, and the wax behaves with borax and soda like pure wax, paraffin or ozokerit is indicated. Heiiner’s method of analysis of bees’-wax (yellow).—The following particulars are extracted from Otto Hehner’s elaborate paper on the analysis of bees’-wax: f— Hager, “Dingl. Polyt. J.” 238, 356; “J. Chem. Soc." xl. 316. t “Analyst,” 1883, 16. OILS AND VARNISHES. 150 Process .—Alcoholic potash solution is made from pure potash, and from spirit which has been distilled from caustic alkali. Each c.c. should correspond to from 0*3 to 0-4 c.c. of normal acid. Two or three standardizing experiments must he made, and the average taken. From 3 to 5 gms. of the wax are weighed on a watch-glass, transferred to a flask holding about 400 c.c. and heated with about 50 c.c. of methylated spirit distilled from alkali. When the wax is perfectly liquefied, alcoholic phenol-phthale'in solution is added in not too small amount. The phenol-phtlialein must not be acid, as it generally is, but must be rendered pink by a few drops of alkali. The alcoholic potash solution is then added drop by drop from a burette, the mixture being kept well agitated, until the pink colour is permanent. The number of c.c.’s added is then read off, and an excess of the alcoholic potash solution is run into the flask, 50 c.c. being the quantity which Mr. Hehner generally uses. The whole is then briskly boiled, under a reflux condenser, for one hour. If any particle of wax hang above the level of the fluid on the sides of the flask, shake well from time to time. After one hour the solution should be clear, or nearly so. The excess of potash is then titrated back with standard sulphuric acid, the fluid being kept boiling. From the data thus obtained, the free acid (calculated as cerotic acid, C 26 H 53 .CO.OH) and the saponifiable substance (calculated as myricine, C 16 H 31 (C 30 H 6l )O,) are obtained. An actual ex¬ periment will render the above details clearer :— Wax used, 37417 gms. KHO (10 c.c. of which = 4-64 c.c. normal sulphuric acid) required to neutralize free acid, 2 '82 c.c. Total KHO added, 49-96 c.c. Titrated back with 16*97 c.c. normal acid. Hence cerotic acid = 07371 gm. or 14-35 P er cent., and myricine = 3-3124 gms. or 88-55 per cent. Total, 102-90. As the result of the analysis of eighteen English and seventeen foreign samples, Hehner WAXES. 151 finds, as regards the English, that the free acid (calculated as cerotic) varies from 13 to 16 per cent., the average being 14-40 per cent., and the saponifiable matter (calculated as myridne) from about 86 to 89*6 per cent., the average being 8 8’09 per cent. In all cases the sum of the cerotic acid plus myricineis somewhat higher than 100, the average amount being 102-49. The tendency of these figures is to show that English bees’-wax consists almost completely of cerotic acid and myricine, but that it also contains a small quantity of a substance of lower molecular weight, probably Lewy’s ceroleine. The fluctuations in the case of the foreign samples was found to be much more considerable than in the above, and point to a greater degree of sophistication. Hehner classifies the actual and possible adulterants of wax thus :— i°. Acid substances, embracing the solid fatty acids, mainly palmitic and stearic, and the acids of resin, particularly sylvic acid. 2°. Neutral , but saponifiable compounds, such as stearin and palmitin, Japanese wax, spermaceti, and carnauba wax. 3 0 . Non-saponifiable bodies .—The only representative of this class, for practical purposes, is paraffin. The presence of an adulterant belonging to class i° would be indicated by increase in the acidity, calculated as cerotic acid, and decrease in the saponifiable matter, calculated as myricine. An adulterant of class 2° would, on the other hand, decrease the calculated proportion of cerotic acid and increase that of the myricine. As to class 3 0 , the addition of paraffin would lower both the amounts of cerotic acid and of myricine. The specific gravity of the sample would also be lowered. Distinction of Waxes.* —Heat the sample with 10 * Hirscholm, “Pharm. J.” [3] x. 749; “Year Book of Pharmacy, 1880, 143. 152 OILS AND VARNISHES. times as much chloroform to boiling, and, when completely dissolved, cool in cold water. I. The chloroform solution remains clear. A. Ether dissolves completely—Myrica wax. B. Ether dissolves incompletely. A portion is boiled with ten times the quantity of alcoholic potash solution till saponified, and the soap heated with ioo volumes of water. (a) Soap completely soluble—Japanese wax. ( b) Soap partially soluble. — Bees-wax. £ 1 . The chloroform solution becomes cloudy. Carnauba wax. CHAPTER V 1 T. MINERAL OILS. Syn. Hydrocarbon Oils. —The principal kinds of mineral oils met with in commerce are Boghead or Bathgate naphtha, coal naphtha, shale naphtha, naphtha from caoutchouc, native naphtha or petroleum, and their derivatives. As in the case of the animal and vegetable oils, we may arrange the mineral oils according to their origin i°. Crude oils obtained by distillation of bituminous shales, cannel coal, coal-tar, lignite, or 'peat. 2°. Crude oils occurring ready-formed in various parts of the world. i°. Crude oils obtained by distillation of bituminous shales or schists, cannel, Boghead, or Bathgate coal. For many years the manufacture of burning oils by the distillation of bituminous schists has been extensively carried out on the Continent, but the discovery which formed the foundation of the modern manufacture was made nearly thirty years ago by our countryman, Mr. James Young. This gentleman took the lease of a spring of petro¬ leum at Alfreton, in Derbyshire, in 1847, and, after numerous experiments, succeeded in obtaining two useful oils from the crude liquid; the one being adapted for lubricating machinery, and the other for burning in lamps. The almost total cessation of the flow of petroleum terminated the business after two years’ working, and led Young to institute a series of experiments to try if petroleum could OILS AND VARNISHES. iS 4 be produced artificially by the destructive distillation of coal. These experiments resulted in the discovery of an oil which he named “ paraffin oil,” as it had many of the chemical properties of the solid paraffin discovered twenty years before by Reichenbach in beech-wood tar. Young’s patent (dated October 7, 1850) involved the slower distilla¬ tion of coals, at a lower temperature than had hitherto been employed for the purpose, and this change in practice was followed by the novel result of a copious production of liquid hydrocarbons. The gas or cannel coals were found to yield the liquids in largest quantities, that variety known as Boghead coal, or Torbane Hill mineral, being specially adapted for the patented process. The following is a brief outline of Young’s process:— Boghead coal,* broken into small fragments, is introduced into perpendicular tubes or retorts, about 11 feet in height, by conical hoppers at their upper extremities. Four of these tubes constitute a set, being built into one furnace, and charged by a single workman. They pass completely through the furnace, and are closed below by dipping into shallow pools of water, while the openings into the hoppers above may be shut by valves. The coal in each tube is gradually heated as it descends to that part which passes through the furnace, and when it reaches the bottom of the tube it has parted with its volatile constituents, and is raked away as refuse, the coal from above descending as it is removed. Thus the action of these perpendicular retorts is continuous, and the distillation goes on uninterruptedly both day and night. The vapours produced are conducted by iron tubes to the main condensers, which consist of a series of syphon pipes * When the supply of Boghead coal became exhausted, recourse was had to the bituminous schists or shales of the lower carboniferous for¬ mation which abound in West- and Mid-Lothian. MINERAL OILS. 155 freely exposed to the air. The quantity of incondensable gas formed is inconsiderable; and it is this result, so different from that obtained in the ordinary gasworks, that marks the great value of Young’s process. The crude oil, a dark- coloured, thick liquid, is then distilled to dryness in large iron cylindrical stills, and is thus freed from the excess of carbon, which is left behind as coke. The oil, after distilla¬ tion, is further purified by being acted upon by strong sul¬ phuric acid, which chars the principal impurities, and causes them to subside in the form of a dense black, heavy acid tar. To separate the remaining impurities and that portion of the sulphuric acid which remains in the oil, it is next subjected to the action of caustic soda. Thus purified, the paraffin oil contains four distinct commercial products. To effect their separation, the process of fractional distilla¬ tion is employed. 1 . The first elevation of temperature drives over the lighter and more volatile portions, which, when purified by a subsequent distillation, yield the fluid known as 11 paraffin naphtha,” “ petroleum spirit,” “ benzoline.” This product is used as a substitute for “ turps,” as a solvent for india- rubber, for cleaning gloves, and for burning in those naphtha lamps so much employed by costermongers, and workmen in railway tunnels and similar situations. On the perfect separation of this naphtha the safety of the burning oil depends.—2 0 . This burning oil, the “ paraffin oil ” of com¬ merce, comes over at a much higher temperature than the naphtha. It is a perfectly safe lamp oil, and has a greater illuminating value than any other oil in the market. Its properties are noticed below.—3 0 . The tliivcl product in point of volatility, is a comparatively heavy liquid (machinery oil), largely used for lubricating purposes.—4 0 . From this oil, and others which come over at a very high temperature, th e fourth commercial product is separated by the action of 156 OILS AND VARNISHES. artificial cold. This last product is the beautiful translucent solid paraffin, now much used as a candle material. In many parts of Germany the extraction of the crude oil or tar from bituminous substances is effected in ovens. In these ovens the bituminous body is thrown upon a layer of burning fuel which covers the bottom of the oven, the result being that the bituminous matter is resolved into gaseous bodies which are lost, and tar which flows down¬ wards toward the burning fuel, which, being covered with a layer of clay, is prevented from entering into violent com¬ bustion. This method, however, is only had recourse to on a small scale, since it is found that in most cases the tar obtained by means of it is not of a kind suited for yielding paraffin and paraffin oils. The preparation of the tar or crude oil from fossil fuel, of the character already specified, constitutes one of the most delicate and difficult branches in the manufacture of paraffin oils, and paraffin, &c. The chief sources of failure to be avoided are the overheating of the oil vapour, and consequent decomposition (varying in amount) into useless gaseous products, and its inefficient condensation. It has been shown by Vohl that, even when the con¬ struction of the retorts is not of the best, an average yield of tar may be obtained by the proper condensation of the vapours. “ The complete condensation of the vapours of the tar is one of the most difficult problems the mineral oil and paraffin manufacturer has to deal with, while the means usually adopted for condensation, such as large con¬ densing surfaces, injection of cold water, and the like, have proved ineffectual. It has often been attempted to con¬ dense the vapours of tar in the same manner as those of alcohol, but there exist essential differences between the distillation of fluids and dry distillation. In the former case the vapours soon expel all the air completely from the MINERAL OILS. 157 still and from the condenser, and provided, therefore, that, in reference to the size of the still and bulk of the boiling liquid, the latter be large and cool enough, every part of the vapour must come into contact with the condensing surfaces. In the process of dry distillation, however, the case is entirely different, because with the vapours, say of tar, permanent gases are always generated. On coming into contact Avith the condensing surfaces, a portion of the vapours is liquefied, leaving a layer of gas as a coating, so to speak, on the con¬ densing surface. The gas, being a bad conductor of heat, prevents to such an extent the further action of the con¬ densing apparatus that a large proportion of the vapours is carried on, and may be altogether lost. A sufficient condensation of the vapours of tar can be obtained only by bringing all the particles of matter which are carried off from the retorts into contact with the condensing surface, which need neither be very large nor exceedingly cold, because the latent heat of the vapours of tar is small, and consequently a moderately low temperature will be sufficient to condense those vapours to the liquid state. The mixture of gases and vapours may be compared to an emulsion such as milk, and as the particles of butter may be separated from milk by churning, so the separation of the vapours of tar from the gases can be greatly assisted by the use of exhausters acting in the manner of blowing fans. It is of the utmost importance in condensing the vapours of tar that the molecules of the vapours be kept in continuous motion, and thus made to touch the sides of the condenser. The condenser should not be constructed so that the vapours and gases can flow uninterruptedly in one and the same direction.” An important condition for the safe and quiet distillation of the tar, or crude oil, when obtained is that it should be free from water. Unless the removal of the water is 153 OILS AND VARNISHES. •effectually accomplished, the tar may boil over during its distillation, and, coming into contact with the fire under the still, may give rise to an alarming conflagration. The dehydration of the tar is effected in an apparatus constructed for the purpose, consisting of an iron tank placed within a larger tank, a space of about two inches intervening between the two tanks is filled with water, which is heated to, and kept at a temperature of between 6o° and 8o° C., for ten hours, by the end of which time the ammoniacal water, having separated from the lighter tar, is drawn off by a stop-cock placed at the bottom of the tank, whilst the tar is decanted through a valve at the top. An improvement in the distillation process has been patented by Mr. Norman Henderson, of the Broxbourn Oil Company. The purified once-run oil is fractionated continuously in a connected series of three cylindrical stills. Each still is fitted with inlet and outlet pipes, the mouths of which, opening upwards, are placed at opposite extremities of the still. The outlet pipe of No. i passes as inlet into No. 2, and similarly the outlet of No. 2 is connected as inlet with No. 3, while the outlet of No. 3 passes into one or more common residue stills. The inlet, or feed pipe, of No. 1 traverses the long horizontal condensing pipes of the whole three, and thus the once-run oil, while absorbing heat before entering No. 1 still, also aids the condensation of the va¬ pours ; or,alternatively, it coils through No. 2, taking up heat there. In working, there is a constant feeding of heated once-run oil into No. 1 still, a like steady flow from No. 1 to No. 2, from No. 2 to No. 3, and from No. 3 to a residue still. The oil, of course, increases in density as it passes on¬ wards; but the specific gravity in each still is practically constant, and, as the heat applied is in proportion to the gravity, the oil vaporized in each still is of uniform quality and specific gravity. In No. 3 still, where, in consequence MINERAL OILS. 159 of the high gravity and temperature, there is a tendency to deposit carbonaceous matter, circulating plates or dishes hinged to each side of the still, and concentric with the bottom shell, are placed. The circulation of the oil from the bottom up the sides in the space between the shell and the circulating plates is directed and assisted by jets of steam from a pipe laid along the bottom of the still. In this way the oil is kept in steady circulation up the sides and down the centre, and any deposit of coke which may take place forms on the inner side of the circulating plates, from which there is provision for its easy removal when required. The advantages claimed for this system are—(i°) The stills may be worked continuously for weeks, or months, without stopping. (2 0 ) Impurities and heavy oil never accumulate in any still, but pass on till they reach the final residue or coking still. (3 0 ) The quality of the products is much im¬ proved. The oils possess more equal gravity and constant boiling point, and the paraffin scale is of better colour, crisper, and more easily pressed than with the ordinary method. (4 0 ) A saving of 50 per cent, in plant, because, with continuous working and steadily maintained tempera¬ ture, a set of three stills in twelve days will pass through 285,000 gallons of oil, while the same stills in the same period under the old system can work off not more than 126,000 gallons. (5 0 ) A saving of about 60 percent, in the labour of working the still. (6°) The quantity of fuel used is only about one-half of that required by the old method.* The manufacture of oils and paraffin from cannel coal is thus conveniently summarized by Dr. Frank land :— i°. The coal is distilled in such a way as to get the maximum amount of paraffin, and much depends on the manner in which the distillation is performed. A high * “Oil Trade Eeview,” Oct. 4, 1884. i6o OILS AND VARNISHES. temperature gives a large quantity of gas, but comparatively little paraffin; a low temperature much paraffin, and but little gas. Besides paraffin, several analogous bodies are produced—marsh gas itself, hydrides of ethyl and propyl probably, also hydrides of butyl, amyl, and others. The crude oil which first comes over is of a dark-brown colour, and contains from i to about 5 per cent, of paraffin. 2. The crude product is then exposed to a current of steam in a close vessel, till all the volatile products are taken away; e.g. —coal-naphtha, containing benzol, and the lower hydrides belonging to this series, as hydride of amyl. The residue contains the higher members of the marsh-gas family up to paraffin, which is probably not a single substance, but a mixture of several solids belonging to this family, as its melting point varies in different samples. 3. After the treatment by steam, the oily and non¬ volatile residue is treated with concentrated sulphuric acid to remove the diatomic radicals, homologous with ethylene, which it contains. These are readily absorbed by the acid. 4. The oil is then removed from the acid, which has become jet-black, and agitated with strong caustic soda to remove a product of the action of the acid on the oil which remains dissolved. After agitation, this forms a layer be¬ tween the oil at the top and the soda at the bottom, and the oil can easily be run off from the two lower strata. 5. The separated oil is then rectified, and three products are obtained. No. 1 is sold as illuminating oil— kerosene. No. 2 is sold as paraffin oil for lubricating purposes. It is mixed with Gallipoli oil to give it consistence. No. 3 is crude paraffin, which solidifies on cooling. The waste carbolate of soda resulting from the treatment of the oil with the caustic alkali is decomposed by sulphuric acid, and the liberated carbolic acid is utilized either as a MINERAL OILS. i6r disinfectant, or for saturating railway sleepers; and some¬ times as a source of certain tar colours; or it may be used in the manufacture of gas, the soda which remains in the coke being extracted by lixiviation. The waste sulphuric acid combined with the ammoniacal liquors that always ac¬ company the first stages of the distillation of the tar is made into sulphate of ammonia. Purification of the, Crude Paraffin.— i. The crude solid is placed in a centrifugal machine, by which paraffin oil is expelled from its pores. 2. The residual mass is cast into cakes, placed in layers on cocoa-nut matting on hollow iron plates containing water to regulate temperature, and submitted to hydraulic pres¬ sure. As much as possible is squeezed out in the cold, and then the temperature is gradually raised to from 35 0 to 40° C., by which means the paraffins of lower melting points are squeezed out, the object being to produce a paraffin with a high melting point, so as to make it like wax or sperma¬ ceti. The remaining cakes are of a dark-brown colour. 3. To further purify these cakes, they are melted, heated to 155 0 C., and 2 per cent, of sulphuric acid added to remove any of the C n H an bodies still present. 4. The cakes are again melted with soda, cooled, and again submitted to pressure, well washed with hot water, cooled, mixed with cold, colourless naphtha to assist filtra¬ tion, and then filtered through animal charcoal to remove colouring matters. 5. It is next placed in steam-jacketed wrought-iron cylinders, and superheated steam passed through to remove naphtha. The residue is then pressed, and cast into cakes. Pure paraffin thus obtained is a colourless, inodorous, tasteless, translucent solid. Sp. gr. 0-870. Melts at 45 0 to 65° C. Boils at 370° C. Insoluble in water, and only slightly so in alcohol. Sulphuric and nitric acids and H i 62 OILS AND VARNISHES. chlorine are without action upon it in the cold. Chlorine passed through melted paraffin slowly attacks it with evolu¬ tion of hydrogen alone. This last reaction establishes its position among members of the marsh-gas family. Paraffin is now largely used for making candles, for which purpose it is specially adapted, being a most elegant sub¬ stance, and surpassing all other candle materials, even spermaceti, in illuminating power. Its property of not being acted upon by acids or alkalies renders it suitable for stoppers for vessels bolding chemical liquids, for electrotype moulds, and for coating the inside of casks. It is not acted upon by ozone, so that it has been employed with advantage in experiments on this body for rendering air-tight joints formed by the union of glass tubes. As it contains no oxygen, it might be used to protect oxidizable metals like sodium and potassium from contact with the air. One use of paraffin candle-ends may be referred to—a small piece added to starch will be found to give a gloss and brilliancy of surface to starched linen that can be obtained by no other addition. A patent has been taken out* to prevent caoutchouc materials from hardening and cracking, by steeping them in a bath of melted paraffin for a few seconds or several minutes, according to their size, and then drying in a room heated to about 100° C.t The members lower than solid paraffin in the marsh-gas series are also valuable as illuminants, and are sold under the name of paraffin oil. The production of this oil, as described above, and of a similar material from petroleum, or rock oil, has almost again revolutionized our artificial lighting. Lignite, or brown coal , is extensively used on the Continent * No. 18740, Aug. 1881. + “J. Soc. Cliem. Ind.” 1882, 415. MINERAL OILS. 163 for preparing paraffin and paraffin oil.* The following are the final products of the distillation:— («) Volatile oils, called photogen, and solar oils, for illumi¬ nating. Of these there are three qualities : i°. Photogen S.G-. 0785 2°. Photogen „ 0-805 3° Solar oil\ „ 0-835 Rather yellow. Yellow. (b) Paraffin. ( c ) Volatile spirit, called benzol. (d) Phenol, or carbolic acid. Bituminous deposits in the Camamu basin, Brazil, have been recently visited and examined by Mr. J. Macdonald Cameron, M.P., who considers that they may in the future afford an important supply of oil. The material, locally known as “ turfa,” is called brazilite, and appears to be a kind of brown coal, or lignite. The deposits are said to exist over an area of at least 300 square miles, but the outcrop is not continuous. According to the analysis of Mr. W. Wallace, of Glasgow, the yield of crude oil per ton of “turfa” is 68 gallons of specific gravity o‘888, and the ultimate products of refining are :— Per 100 galls, crude oil. • 367 Burning, or light oil S.G. 0-812 . Intermediate oil „ 0-884 • Heavy, or lubricating oil „ 0-955 • Paraffin scale, or crude paraffin . 0-884 • • 3i'i °'955 • • 97 Loss in refining IOO'OO * Hofmann’s Report on Chemical Products and Processes in Inter¬ national Exhibition of 1862. f The name solar oil is applied also to the heavier portions of shale and petroleum oils. 164 OILS AND VARNISHES. Solid paraffin per ton of “turfa,” 3I lb. Sulphate of ammonia „ „ „ It will be seen from the above figures that the yield of solid paraffin is small. The light or burning oil is nearly colourless and of fine quality, resembling petroleum rather than paraffin oil. The intermediate oil is suitable for light¬ houses and railway carriages. Peat Oil.—In 1849 it was attempted to obtain paraffin and paraffin oil from peat in Ireland, but the quantity procured in this way—only 2 gallons per ton of peat—was found to be too small to be remunerative. It is interesting to note that the first paraffin candle was made by Messrs. J. C. & J. Field, in 1852, from a sample of paraffin prepared by the Irish Peat Co. under Bees Peace’s patent. Paraffin is prepared from wood-tar in the following manner:—Distil beech-tar to dryness, rectify the oily portion of the product, which is heavier than water, until a thick matter begins to rise; then change the receiver, and moderately urge the heat as long as anything passes over; next digest the product in the second receiver in an equal measure of alcohol of 0-833, gradually add 6 or 7 parts more alcohol, and expose the whole to a low temperature; crystals of paraffin will gradually fall down, which, after being washed in cold alcohol, must be dissolved in boiling alcohol, when crystals of pure paraffin will be deposited as the solution cools. The solid paraffin obtained from cannel coals, brown coal, or lignite, and shales does not exist ready formed therein, but is the product of destructive distillation. American petroleum, or “ rock oil,” however, contains it ready formed to the extent of about 2| per cent., and Burmese petroleum yields from 5 to 10 per cent. Solid deposits of paraffin are also met with in the neighbourhood of the Caspian Sea. (See Ozokerit, p. 185.) MINERAL OILS. 165 Goal In aphtha. —One of the products of the distillation of coal-tar. The light oil, after separation from the heavier “ creasote oil,” or “ dead oil,” is rectified, whereby a further portion of heavy oil is separated and crude coal oil is obtained. This is agitated with sulphuric acid to free it from organic bases, and the supernatant liquid, after further rectification, yields the “ highly rectified naphtha,” or “ benzole ” of commerce, which is chiefly a mixture of five oily hydrocarbons of the benzene series—viz.: £>enzene . Toluene , Xylene , Cumene , Cymene , • C«H e . c 7 h 8 . c 8 h 10 . c 9 h 12 Boiling point So - 4° C. „ „ 114° C. „ ,, 126 C. „ ., 144 0 C. rc „ I77'5° G - The basic constituents of crude coal naphtha, which are removed by agitation with sulphuric acid, may be obtained in the free state by distilling the acid liquid with excess of alkali, and separated from one another, partly by fractional distillation, and partly by fractional crystallization of their platinum salts. These bases belong to two series, one represented by the general formula C n H 2 —viz.: Pyridine . Picoline and its isomerp . CdLN Aniline . . ) ' ' . C 6 H 7 N Lutidine ...... . C.H,N Collidine. . C s HjjN The other series C n H 2n _ ir N, isomeric CH 7 N; and its homologues—viz.: with chinoline, Leucoline . . C 9 H.N Iridoline ...... . C ] 0 H,N Cryptidine. . C n H n N “ Dead oil,” the less volatile portion of coal-tar, contains a considerable quantity of carbolic acid or coal-tar creasote, with other bodies more imperfectly examined. OILS AND VARNISHES. 166 Coal naphtha has a more disagreeable odour than native naphtha, and is denser, its sp. gr. ranging from 0 860 to o‘9oo. A glance at the tabular statement on p. 167, prepared by Mr. S. B. Boulton, will help to make plain the position of the naphthas among the numerous other products of the distillation of coal. Caoutchouc Oil.— Syn. Caoutchoucin. — This is an extremely light fluid obtained by distilling india-rubber. Barnard’s patent process is as follows:—India-rubber or caoutchouc, as imported, cut into small lumps, of about 2 cubic inches each, is thrown into a cast-iron still, connected with a well-cooled worm tub (any flat vessel with a large evaporating surface will do, the entire top of which can be removed for the purpose of cleaning it out); and heat is applied in the usual way, until the thermometer ranges to about 6oo° F., when nothing is left in the still but dirt ana charcoal. The dark-colourecl fetid oil which has distilled over is next rectified along with one-third of its weight of water, once or oftener; and at each rectification it becomes brighter and paler, until at about sp. gr. o-68o it is colourless, and slightly volatile. The product is then shaken up with nitro-hydrochloric acid, or chlorine, in the proportion of | pint of acid to 1 gallon of the liquid. To enable the dirt to be the more easily removed from the bottom of the still, common solder, to the depth of about \ an inch, is thrown on. Prod. 80 per cent. Mixed with alcohol, caoutchoucin dissolves gums and resins, especially copal and india-rubber, at the common temperature of the atmosphere, and it speedily evaporates, leaving them again in the solid state. It mixes with the oils in all proportions. It has been used in the manufacture of varnishes, and for liquefying oil paints, instead of turpen¬ tine. It is very volatile, and requires to be kept in close MINERAL OILS . 167 Table showing most important products derived from New¬ castle coal, when carbonized by the usucd method for the manufacture of gas (S. B. Boulton). h ci The substances which can be separated as they come over from the still, by filtra¬ tion or other simple process, are in ordinary type. Those prepared by further chemi¬ cal treatme&t are in italics. The direct products of the dead oils are arranged as nearly as possible according to their respective volatilities, and to the order in which they come over from the still. ■ For the manufacture of pure carbolic, cresylic, and other tar acids, further and elaborate treatment is required. Those marked with an asterisk are “ green ” oils distilling from 550° to 750° F. OILS AND VARNISHES. 168 vessels. According to the researches of Himly, Gregory, and Bouchardat, the caoutchoucin of Barnard consists of several liquids, some of which have the composition of olefiant gas, and others that of oil of turpentine. Caoutchouc oil is a great preventive of rust, and has been adopted for this purpose in the German army.* It is applied by means of a piece of flannel over the metallic surface, and allowed to dry. To remove it, the article is treated with caoutchouc oil again, and washed after twelve to twenty-four hours. The Mineral Oil Trade of Scotland has grown to great importance since the date of Young’s patent in 1850. The capital invested amountsto about ^2,000,000. Difficulty has, however, been experienced in maintaining a footing against the American natural supply, and the Scottish industry could hardly have continued to exist, under such circumstances, unless there had been great skill in utilizing waste products. The original horizontal retorts have been completely super¬ seded by the “ vertical,” and various improvements on the vertical, such as Henderson’s and Young and Beilby’s retorts are now in use, though apparently not with uniform success. For instance, the directors of the Midlothian Oil Co. have recently advised a discontinuance of the “ Henderson ” and also of the “Young and Beilby ” process, and a return to the vertical retort, in order to effect a saving. On the other hand, at the Oakbank Oil Co.’s works, retorts known as the Beilby pattern of the “Youngand Beilby” patent have given satisfaction under the supervision of the inventor, and at the Burntisland Oil Works the “ Henderson ” retorts are used with complete satisfaction. At the works of the Clippen Oil Co. the “ Henderson ” retorts have been replaced by the “ Pentland,” an adaptation, or alteration, by Mr. * “Chem. Zeitung,” vi. 477. MINERAL OILS. 169 Young of the “ Young and Beilby.” It may be termed a duplicate or composite retort, the top portion consisting of iron, into which the shale is first placed, and where it is distilled at the lowest heat adapted for the production of scale, after which the coke or residue is dropped into a bottom chamber, constructed of fire-brick, where high temperatures are employed, and a large yield of ammonia successfully liberated. The advantages claimed for it are (i°) that it secures the maximum yield from shale of its two most valuable products, scale and ammonia, as by other processes any increase of one was only obtained by the diminution of the other; (2 0 ) the partial purification of the oil under the most favourable conditions before it leaves the retort, thus effecting a considerable saving. Refrigerating processes are more important and more used than formerly. Much solid paraffin used to be allowed to go away in solution in the oils. At one time the prices of the solid and liquid were much nearer to each other, so tnat it was not of so much consequence, whereas now the relative prices of the liquid and solid are as 6 d. to 2 s. 6 d The following figures, representing the annual production at Young’s Paraffin Light and Mineral Oil Co.’s works, will give an idea of the relative proportions of commercial products obtainable from shale :— Shale distilled . Crude oil distilled and refined . Burning oil ... Naphtha . . . „ # Heavy lubricating oil „ Solid paraffin . . „ , Sulphate of ammonia , . 500,000 tons 16,000,000 galls. 6,500,000 „ 900,000 „ 9,000 tons 6,000 „ 4,000 „ * “ Oil Trade Review,” 1885. !70 OILS AND VARNISHES. Definite Character of Destructive Distillation.— Prof. Mills, F.RS., in an interesting paper,* considers that the results of all kinds of destructive distillation are of a definite nature, and that they cannot be susceptible of indefinite variation, because the law of multiple proportions must apply, without exception, to every one of them, though it has been hitherto customary to regard them as if of indefinite character, and open to a vast variety of modification at the hands of the chemical inventor. In his work on Destructive Distillation,t Prof. Mills has shown that the organic matter in a good average Scotch shale has almost exactly the composition C 6 H 10 O. The changes which this undergoes at a low temperature may be represented by the equation 7 C 6 H l0 O = 1 80 + C 24 H 62 0 3 + 4 H 2 0 . Fixed Carbon. Gas and Oil. (Calculated) 100 . 3 i ‘5 . . 5 8 '° • • IO ‘5 (Found) . . • 3 r2 • • 5 8 '3 • • IO '5 At a high temperature we have 7 C 6 H 10 O = 6C + C 36 H 62 0 3 -t- 4 H 2 0 . Fixed Carbon. Gas and Tar. (Calculated) ioo . 10-5 . . 79 ‘° • • IO '5 (Found) . . . 12-8 . . 7 6-o . . ira The Heywood cannel gas coal, which represents an average Scotch cannel, gives the following reactions : - At a low temperature, 4 c 9 h 12 o = 2 7 c + c 9 h 46 o 3 + h 2 o. Fixed Carbon. Gas and Tar. (Calculated) 100 . 59'6 . . 37-1 . • 3'3 (Found). . • 5 8 ' 1 • • 3 8 '3 • • 3 ’6 At a high temperature, 4 C 9 H 12 0 = 2 4 C + c 12 h 4G o 3 + h 2 o. * “J. Soe. Chem. Ind.” 1885, 325. F Second Edition, p. 28. MINERAL OILS. 171 Fixed Carbon. Gas and Tar. (Calculated) 100 . 52-9 . . 43'8 . » 3'3 (Found). . . 52-5 . . 43-9 . . 3-6 The results for Boghead coal are as follow :•— At a low temperature, 3 C i ^, 0 -i 5 C + C„H„ 0 , + H, 0 . Fixed Carbon. Gas and Oil. (Calculated) 100 . 33-3 . . 63-3 . . 3*3 (Found). . . 33'3 . . 6 a'i . . 2*6 At a high temperature, 3 C i2 H i0 O = 6C + C 10 H 51 O, + H 2 0 . Fixed Carbon. Gas and Tar. (Calculated) 100 . 13-3 . . 83-3 . . 3*3 (Found). . . I2’8 . . 84'6 . . 2'6 Thus considerable evidence is obtained in favour of the definite character of the destructive distillation of coal and shale. It is probable that the organic matter in these minerals can be always represented with an nC s formula, and that a very simple relation exists between the C of the fixed carbon on the one hand and the C of the gas and tar (or oil) on the other. It is clear also that C 3 is the funda¬ mental unit, or stable condition, in these effects, and that not less than this unit must be removed from, or left in, the “ fixed carbon ” during destructive distillation. Hence it is hopeless to expect that, for instance, more than fractional variations in the yield of oil from a shale can be effected in modern retorting. 2 0 . Crude oils existing ready-formed.—T he various names, naphtha, mineral naphtha, mineral tar, petroleum, rock oil, liquid bitumen, Erdol, Steinol, are applied somewhat loosely to certain inflammable liquids occurring naturally in various localities. The term “ naphtha ” (Gr. vdcjjdn = rock oil) is traced to a Persian word Nafata, meaning to exude, and was originally applied to an inflammable liquid which exudes from the soil in various parts of Persia. The word 172 OILS AND VARNISHES. was extended to the similar fluids so exuding in different parts of the world, and more recently has been applied to many of the inflammable liquids, produced by the dry distillation of organic substances, resembling true naphtha chiefly in inflammability and volatility—e.g., products of the distillation of wood and coal are respectively called wood naphtha and coal naphtha. Generally, it may be mentioned that the thinner and least coloured mineral oils, or the more volatile portions of the native oils, are called naphthas, while the darker and more viscid kinds are called mineral tar, and the intermediate varieties are called petroleum [petri-oleum = rock oil). Native Naphtha, or Petroleum, is found in Japan, Burmah, shores of the Caspian Sea, Siberia, Italy, Spain, France, Germany, Galicia, Moldavia, Roumania, Great Britain, United States, Canada, &c., and quite recently it has been found at Sibi, in Southern Afghanistan. It occurs, as stated by Prof. Dewar,* in lines intimately connected, for the most part, with the principal mountain chains of the world. For instance, “ on the American continent it is met with along a line extending from Point Gaspe, in Canada, to Nashville, Tennessee ; and in Europe and Asia along a line extending from Hanover, on the North Sea, through Galicia, the Caucasus, and the Punjaub. These are the principal lines. In America it also occurs on the Pacific coast from the Bay of San Francisco to San Diego; again, from Northern Nebraska to the mouth of the Sabine river, on the Gulf of Mexico ; again, from Havana, near the west¬ ern end of Cuba, through San Domingo and the Leeward and Windward Islands to Trinidad, thence westward on the mainland to the Magdalena river, and southward from that point to Cape Blanco, in Peru.” * Lecture on “ American Oil and Gas Fields,” Society of Arts, May 20, 1885. MINERAL OILS. 173 “ In Europe and Asia bituminous deposits also occur on the lower Rhine and in the valley of the Rhone; from Northern Italy, following the Apennines to Southern Sicily ; along the eastern shores of the Adriatic, through Albania into Epirus; along the depression in which lie the Jordan and the Dead Sea; along the mountains bordering the valley of the Tigris on the east; from Western China, through Burmah, Pegu, Assam, Sumatra, Java, and Japan.” Petroleum varies greatly in character, in density, in boil¬ ing point, in colour, &c., from the thin, light, colourless fluid of Persia, with sp. gr. about 0750, to a substance as thick as butter and about as heavy as water. The products of shallow wells in America are, generally speaking, darker than those of deep wells. Various suggestions have been made to account for the occurrence of native naphthas. It is most generally believed that the chief cause is the decomposition, at great depths beneath the earth’s surface, of vegetable and animal re¬ mains, but it is by no means known with any certainty how this decomposition has been brought about, whether it is still going on, or whether the process has long ceased to be in active operation. Mendelejeff * supposes that, as a consequence of the condensation of the earth’s substance from vapours, the interior must consist of metals, chiefly iron, in combination with carbon, and that water, acting on these carbides at high temperatures and pressures, produced metallic oxides and hydrocarbons, which latter, rising in a state of vapour, became condensed in the superincumbent strata, especially in porous sandstones. Most probably, however, more than one cause has been at work, and pos¬ sibly the American deposits occurring in Palaeozoic strata may be due to causes differing from those which have originated the Russian petroleum occurring in Tertiary formations. * “ Eevue Scientifique,’’ Nov. 1877. 174 OILS AND VARNISHES. Petroleum can rarely be procured without boring wells, from which it is obtained by pumping, or, in some cases, by means of buckets and windlass. In America the boring is very rapidly accomplished. Prof. Dewar states that wells of 1500 to 2000 feet in depth are pierced in from about one to two months.* The oil is largely conveyed from the neighbourhood of the wells by pipes, and these pipe-lines have, since 1865, become a great feature of the American oil industry. The oil from many thousand wells is passed through these pipes, the aggregate length being several thousand miles, worked by various companies. American Petroleum consists chiefly of paraffins of the 0 n H 2n + 2 series, from C 4 H 10 to C 15 H 32 . By fractional distillation, sometimes with aid of steam, ordinary or superheated, and purification of the distillate by potash, a number of commercial products are obtained. The lighter oils are useful as solvents for resins, &c., and the heavier for burning in lamps and as fuel for steam- boilers. Of these the following may be noticed :— i°. Rliigolene .—Boiling point, 30° C. Employed as an anaesthetic. 2 0 . Petroleum Ether (I.).— Syn. Rliigolene, Sherwood oil. —This distils over at 45 0 to 6o° C. Boiling point, 50° to 6o° C. Sp. gr. about o'S 6 $. Absorbs oxygen from the air, and becomes heavier (sp. gr. then o'G’jo to C675). It is extremely inflammable. Used as a remedy for rheumatic pains and as a local anaesthetic. 3 0 . Petroleum Ether (II.). — Syn. Gasoline, Canadol.— Distils at between 6o° and 70° C. Sp. gr. o'665. 4 0 . Petroleum Benzine .—Distils at between 70° and 120 0 C. Sp. gr. o’68o to 0700. Dissolves in alcohol and ether. Boils at 6o° to S'o° 0 . Absorbs oxygen and increases in * For a very full account of the apparatus used at the wells, see Spon’s 5 55 . Hard paraffin . 38 ° 43 ° 43 ° 46° 47 ° 51 ° 56 ° 0'872 0-883 0-889 0-887 0-900 0-908 0-912 0-779 0-788 0785 0781 0775 0775 0-777 * Albrecht, “ Dingl. Polyt. J.” ccxviii. 2S0. MINERAL OILS. 185 Albrecht also observed that solutions of paraffin in mineral oils have lower specific gravities than either the oils or the paraffins separately, so that, in selecting for technical purposes lubricating oils of as great a density as possible, it is best to take oils from which the greater portion of the solid paraffin has crystallized out. Ozokerit.— Syn. Fossil wax, Mineral wax. —This sub¬ stance, which has recently been utilized as a source of paraffin and the mineral hydrocarbon oils, is found in various localities in the Tertiary strata, mostly occurring in, or in close proximity to, the coal measures. But, although exten¬ sive deposits of it are to be met with in Galicia, on the slopes of the Carpathian Mountains, and in the island of Tcheleken in the Caspian Sea, it is by no means an abundant body. In the Austrian empire there are many large manu¬ factories for its conversion into paraffin and the mineral oils. In our country there is, we believe, only one—that of Messrs. Field. Ozokerit is usually met with as a compact brown substance, occasionally yellow, sometimes black. It melts at a temperature varying from 6o° to 8o° C. Neft-gil is the name of a substance very similar to ozo¬ kerit, and is found on the island of Swatoi-Ostrow in the Caspian Sea. According to Bossmassler, neft-gil is treated in the following manner:—i5-cwt. of the crude material is put into iron stills provided with a leaden worm, and sub¬ mitted to fractional distillation. It yields 68 per cent, of distillate, consisting of 8 per cent, of oil and 60 per cent, of crude paraffin. The oil obtained is yellow, opalescent, and possesses an ethereal odour, and a sp. gr. of 0*75 to o’Si. Each distillation yields a quantity of a light oil, boiling be¬ low ioo° C., which is used for the purpose of purifying the paraffin. The crude paraffin obtained by the first distil¬ lation is tolerably pure, has a yellow colour, and can at once be treated by the hydraulic press and centrifugal machine. OILS AND VARNISHES. 186 The oil expressed in these operations is again submitted to fractional distillation in order to obtain more paraffin. The pressed paraffin is melted and treated at 170° to i8o°0. with sulphuric acid, which is next neutralized by means of lime, and the paraffin again rapidly distilled, then again submitted to strong pressure, and the material obtained treated with 25 per cent, of the light oil; then again melted, again pressed, and finally treated with steam for the purpose of eliminating the last trace of oil. The substance obtained by this treatment is a perfectly pure, colourless material, free from smell, transparent, and so hard as to afford in large blocks almost a metallic sound when struck. Its fusing point is about 63" C. Vaseline.— Syn. Saxoleum purificatum, Petroleum jelly.— The residual matters after the distillation of petro¬ leum, purified by charcoal, have been introduced into com¬ merce under the name of “ vaseline ” by the Chesebrough Manufacturing Co. According to Moss, its composition is— Hydrocarbons (paraffin V) „ * .97-54 Moisture . 0 , . . .0-50 Ash „ » « „ » 0-05 98-09 It melts at 37 0 0 ., and at 55 0 0 . has a sp. gr. of 0-840. It is of a pale-yellow colour, translucent, slightly fluorescent, semi-solid, insoluble in water, slightly soluble in alcohol, freely soluble in ether, and unaffected by hydrochloric acid and solution of potash. The process of manufacture is as follows:—The crude oil is highly concentrated, the lighter hydrocarbons being driven off by simple heat, without dis¬ tillation ; the product is then carefully and repeatedly fil¬ tered through bone-black or animal charcoal, just as syrup is filtered in sugar refining, and the result is either pale MINERAL OILS. 187 yellow or pure white, according to the length of the treat¬ ment. It is extensively used instead of lard in the prepara¬ tion of ointments, a purpose for which its freedom from smell, its negative properties, and its unalterable qualities when exposed to the air, render it very suitable. It has also been successfully used for lubricating surgical instru¬ ments and as a basis for pomades. In Germany the following methods of production are in use: *—A. i°. The material, either crude ozokerit or petroleum residue, is heated by steam to about 30° C. (86° F.), mixed at this temperature with 10 per cent, of its weight of sulphuric acid of 60° B., stirred for half an hour, and then allowed to stand at rest so that the carbonized portions may settle. 2°. When clear, the oil is washed with an aqueous solution of potassium bichromate, whereby any remaining excess of sulphuric acid is at the same time removed. 3 0 . The residue from the acid treatment is mixed with lime, neutralized, and disposed of to manure factories. 4 0 . The clear oil from the second step of the process, after being washed, is heated by steam to 8o° C. (176° F.), mixed with 10 per cent, of its weight of granular spodium, f and then allowed to rest to permit the spodium to settle. 5 0 . After the latter is separated, the liquid portion is fil¬ tered through filters heated by steam. 6°. The residuary magma of spodium is subjected to hydraulic pressure, the ex¬ pressed oil filtered, and the solid residue again used in the next operation, a sufficient quantity of fresh spodium being added to make up for any loss or waste. B. i°. The petroleum residue, or the natural ozokerit containing vaseline, is rendered fluid, and the liquid, after the separation of all extraneous matters, is passed through a series of charcoal filters, such as are used in sugar * “J. Soc. Chem. Ind.” 1882,97. + Metallic soot from furnaces. OILS AND VARNISHES. j 88 refineries. After the liquid has passed twelve or fifteen of these cylindrical filters, its original brownish-black colour has become yellowish. To render it colourless and limpid as water, double the number of filters are required. The specific gravity diminishes as the colour is removed, but, when it has become colourless, the specific gravity remains stationary, no matter how long the filtration may be continued. 2°. After it has been thus freed from all bituminous matters, it is transferred to the “ duplicator,” where it is brought into direct contact with superheated steam, and the temperature is allowed to rise to 250° C. (482° F.). Samples which are taken from the boiler from time to time show that no further alterations can be observed in the product after it has been at this temperature for a few hours. 3 0 . The finished vaseline, amounting to 25 or 30 per cent, of the raw material, is finally filtered and filled into cans for ship¬ ping. A great drawback in this method is the rapid exhaustion of the animal charcoal, which can decolorize only a small percentage of its own weight of crude vaseline. It is therefore necessary to have extensive facilities for extracting the portion retained by the charcoal, and to regenerate the latter, which may be done by superheated steam at a temperature of 400° to 500° C. (752 0 to 932 0 F.). It is for this reason that most factories use sulphuric acid for purifying, by means of which the material may be brought to the colour of beer, so that only one-third as much charcoal is required for final decolorization as in the other process. It is, however, almost impossible to get rid of the last traces of the chemicals employed.* Russian vaseline differs from the European article in its consistency, and in this respect closely resembles the Ameri¬ can product. It resembles the latter also in its softness and * “Pharm. Central.” 1881, 42. MINERAL OILS. 189 tenacity, whether it has been previously melted and cooled without stirring or not. American vaseline dissolves to a clear solution on warming in ether and petroleum benzine, and remains so after cooling, or is at most slightly turbid. European sorts, however, form a thick solution with the above solvent, and deposit a considerable amount of sedi¬ ment on cooling. The Russian vaseline occupies in this respect an intermediate position. It dissolves completely and gives a clear solution, but becomes turbid on cooling. On account of its comparative cheapness, Russian vaseline appears to offer considerable advantages over other kinds. * Storage of Petroleum. —The following are the best means of securing the safe storage of petroleum :— 1°. The barrels or cases to be kept in warehouses of one storey only, built of incombustible materials. 2°. The oil to be kept in metallic tanks. 3 0 . A large storage tank made of masonry, filled with water, in which can be placed, mouth downwards, a vessel like a gas-holder, containing the petroleum, which is to float on water within the inverted vessel. 4 0 . Attaching weights to the ordinary barrels and sinking them in water. M. Pelzer points out that if a ship laden with petroleum takes fire in a crowded port it is worse than useless to scuttle her, because the water rushing in displaces the oil, and thus causes it to float on the surface of the water, instead of being confined to the burning ship. Hotes on the Construction of Petroleum Lamps.— The Metropolitan Board of Works have recently issued the following instructions as to the construction and management of ordinary mineral-oil lamps :— * “Biel. Pharm. Ztschr. Kussl.” 21, 41; “ J. Soc. Chem. Ind.’’ 1882, 98. OILS AND VARNISHES. 150 A. Lamps. 1. That portion of the wick which is in the oil reservoir should be enclosed in a tube of thin sheet-metal, open at the bottom, or in a cylinder of fine wire gauze, such as is used in miners’ safety-lamps (28 meshes to the inch). 2. The oil reservoir should be of metal, rather than of china or glass. 3. The oil reservoir should have no feeding-place or open¬ ing other than the opening into which the upper part of the lamp is screwed. 4. Every lamp should have a proper extinguishing apparatus. 5. Every lamp should have a broad and heavy base. B. Wicks. 1. Should be soft, and not tightly plaited. 2. Should be dried at the fire before being put into lamps. 3. Should be only just long enough to reach the bottom of the oil reservoir. 4. Should be so wide that they quite fill the wick-holder without having to be squeezed into it. 5. Should be soaked with oil before being lit. C. Management. 1. The reservoir should be quite filled with oil every time before using the lamp. 2. The lamp should be kept thoroughly clean. All oil should be carefully wiped off, and all charred wick and dirt be removed, before lighting. 3. When the lamp is lit, the wick should be first turned down and then slowly raised. 4. Lamps which have no extinguishing apparatus should MINERAL OILS. 191 be put out as follows :—The wick should be turned down until there is only a small flickering flame, and a sharp puff of breath should then be sent across the top of the chimney, but not down it. 5. Cans or bottles used for oil should be free from water and dirt, and should be kept thoroughly closed. CHAPTER Till. PURIFICATION, BLEACHING, AND REFINING OF OILS, &c. Several methods are adopted for refining or purifying the fi xed oils, among which are the following :— 1. The oil is violently agitated along with i| to 2 per cent, of concentrated sulphuric acid, when it assumes a greenish colour, and, after about a fortnight’s repose, deposits much colouring matter, becomes paler, and burns with greater brilliancy, particularly if well washed with steam or hot water, and clarified by subsequent repose or by filtration. This answers well for most of the recently expressed vegetable oils. It also greatly improves most of the fish oils. 2. A modification of the above method is to well mix the acid with the oil, then to blow steam through the mixture for some time, and afterwards to proceed as described. 3. Pish Oil (Whale, Seal, &c.) is purified by— a. Violently agitating it with boiling water or steam, by placing it in a deep vessel with perforated bottom, through which high-pressure steam is forced for some time; it is afterwards clarified by repose, and filtered through coarse charcoal. b. The oil is violently agitated with a boiling-hot and strong solution of oak bark, to remove albumen and gelatin, REFINING OF OILS. 193 and next with high-pressure steam and hot water ; it is, lastly, dried and filtered. c. The oil, gently heated, is stirred for some time with about x per cent, of good chloride of lime, previously made into a milk by trituration with water ; about 1J per cent, of oil of vitriol, diluted with 20 times its weight of water, is then added, and the agitation renewed and maintained for at least two hours; it is, lastly, well washed with steam or hot water. d. Mr. Davidson treats the oil first with a strong solution of tan, next with water and chloride of lime, then with dilute sulphuric acid, and, lastly, with hot water. e. Mr. Dunn’s method, which is very effective, and admir¬ able on account of its simplicity, is to heat the oil by steam to from 180 0 to 200 3 E., and then to force a current of air of corresponding temperature through it, under a flue or chimney, until it is sufficiently bleached and deodorized ; it is, lastly, either at once filtered or is previously washed with steam or hot water. f. Another method, formerly very generally adopted and still in use, is to violently agitate the oil for some time with very strong brine, or with a mixed solution of blue vitriol and common salt, and then either to allow it to clarify by repose or to filter it through freshly burnt charcoal. 4. Almond, Castor, Linseed, Nut, Olive, Rape, and some other vegetable oils are readily bleached by either of the following processes :—• a. Exposure in glass bottles to the sun’s rays, on the leads or roofs of houses, or in any other suitable position, open to the south-east and south. This is the method employed by druggists and oilmen to whiten their castor and linseed oils. Fourteen to twenty-one days’ exposure to the sun in clear weather during summer is usually sufficient for castor oil when contained in 2- to 4-quart pale-green glass bottles o 194 OILS AND VARNISHES. (preferably the former), and covered with white gallipots inverted over them. The oil is filtered before exposing it to the light, as, if only in a slight degree opaque, it does not bleach well. Almond and olive oil are, when thus treated, apt to acquire a slight sulphurous smell; but this may be removed by filtration through a little animal charcoal, or, still better, by washing the oil with hot water. b. Another method employed to decolour these oils is to heat them in a wooden, tinned, or well-glazed earthen vessel along with some dry “ filtering powder” (i to 2 lb. per gall.), with agitation for some time, and, lastly, to filter them in the usual manner through an oil-bag. In this way the West-end perfumers prepare their “ white almond oil ” (Oleum amygdalae album) and their (C white olive oil” (Oleum oliwe album). Formerly, freshly burnt animal charcoal was used for this purpose, and is still so employed by some houses. 5. Mr. Bancroft refines Oils for Machinery and Lu¬ bricating Purposes generally, by agitating them with a lye of caustic soda of the sp. gr. 1-2. A sufficient quantity is known to have been added when, after repose, a portion begins to settle down clear at the bottom. About 4 to 8 per cent, is commonly required for lard oil and olive oil. After twenty-four hours’ repose, the clear supernatant oil is decanted from the soapy sediment, and filtered. 6. Not only the oils above referred to, but all other oils and fats, may be rendered perfectly colourless by the use of a little chromic acid; or by a mixture of a solution of bichromate of potassa and sufficient sulphuric, hydrochloric, or nitric acid to seize on all the alkali, and thus liberate the chromic acid. 7. Palm Oil and Cocoa-nut Oil are generally refined and bleached by either chromic acid, or chlorine, or by heat:— REFINING OF OILS. 195 a. The “butyraceous oil” is liquefied by beat in a wooden vessel, and 7 to 9 per cent, of good chloride of lime, pre¬ viously made into a smooth cream with water, is added, and the whole assiduously stirred until the ingredients appear united ; the mixture is then allowed to cool, and is next cut up into small lumps, which are exposed to a free current of air for two, three, or even four weeks; these are melted in a wooden vessel heated by high-pressure steam circulating through leaden pipes, or in a cast-iron boiler lined with lead, and an equal weight of oil of vitriol (diluted with about 20 times its weight of water) is poured in, and the whole gently boiled until the oil is decoloured and runs clear; the fire is then moderated, and the whole allowed to settle ; lastly, the fire is removed, and the oil is left to cool very slowly. b. The process with chromic acid has been already noticed (No. 6, p. 194), but is more fully explained below ( b , p. 196). c. The oil, heated to the temperature of about 250° F., is exposed to the action of high-pressure steam, which is con¬ tinuously “ blown ” through it for ten or twelve hours, or even longer. The process is greatly facilitated by the in¬ troduction of some chromic acid. 8. Mr. Watts’ methods of purifying fats and oils are very effective, more especially for those intended for illumination. They are as follow :— a. For Fish Oils. —Each ton is boiled for half an hour with caustic soda, J lb., previously made into a weak lye with water; or steam is blown through the mixture for a like period; oil of vitriol, ^ Ik., diluted with 6 times its weight of water, is next added, the whole again boiled for fifteen minutes, and allowed to settle for an hour or longer, when the clear oil is run off' from the water and sedi¬ ment into the bleaching tubs; here solution of bichro¬ mate of potash, 4 lb., in oil of vitriol, 2 lb., previously 196 OILS AND VARNISHES. diluted with water, q. s., together with a little nitric acid and some oxalic acid, are added, and after thorough admix¬ ture of the whole, by blowing steam through it, strong nitric acid, 1 lb., diluted with water, 1 quart, is poured in, and the boiling continued for half an hour longer; a small quantity of naphtha or rectified spirit of turpentine is then mixed in, and the oil is, finally, well washed with hot water, and left to settle. b. For Palm Oil.—The oil is melted by the heat of steam, and, after it has settled and cooled down to about 130° F., is carefully decanted from the water and sediment into the steaming-tubs ; here a mixture of a saturated solu¬ tion of bichromate of potash, 25 lb., and oil of vitriol, 8 or 9 lb. is added, and, after thorough admixture, hydrochloric acid, 50 lb., is poured in; the whole is then constantly stirred until it acquires a uniform greenish colour, or is sufficiently decoloured, a little more of the bleaching mate¬ rials being added if the latter is not the case, after which it is allowed to repose for half an hour to settle; it is next run into a wooden vat, where it is washed, &c., as before. c. For Vegetable Oils. —These are treated with a solu¬ tion of chromic acid, or with a solution of bichromate of potash, and a mineral acid, as noticed under No. 6, p. 194. For colza, linseed, mustard, nut, and rape oils, a little hydrochloric acid is added; but for almond, castor, olive and poppy oils, no such addition (at least in excess) is re¬ quired. 9. Rancid Oils and Pats are recovered by boiling them for about fifteen minutes with a little water and calcined magnesia; or by filtering them through freshly burnt charcoal. In reference to the above processes, it may be useful to remark that chlorine, the common bleacher and deodorizer of other substances, cannot be well employed directly in the REFINING OF OILS. 197 purification of oils, as certain chemical reactions occur when these substances are brought together, which increase the colour instead of removing it, and are often otherwise injurious. The same remarks apply to the use of the “chlorides,” which frequently fails in unskilful hands, and is, indeed, of questionable utility, except, perhaps, in the case of palm oil. Even charcoal exerts little of its usual energy on the oils, and, whilst it removes or lessens their offensive odour, sometimes increases their colour. The addition of 1 or 2 per cent, of very pure and recently recti¬ fied naphtha or oil of turpentine (camphine) to lamp oil is a real improvement, since it increases its combustibility and its illuminative power. Oils for Medical Purposes, as castor oil, cod-liver oil, &c., must not be subjected to any process beyond mere clarification by subsidence, filtration through Canton flannel or porous paper, or, at the utmost, washing with warm water, as otherwise their active and valuable properties, if not wholly removed, will be considerably lessened. Rancid Castor Oil.*— Heat 100 lb. to 8o° E. in a boiler. Then a mixture of J lb. of alcohol (96 per cent.) and lb. sulphuric acid is added and crutched in. The mixture is allowed to settle, and the oil is drawn off from the impurities which have settled at the bottom. The oil is again washed by boiling it uninterruptedly with water for half an hour. After resting, the oil is again drawn off. Eancid oil treated in this way is fit for use in the manufacture of transparent soap. Purifying Fatty Oils.— Oils which hold in solution fatty acids or other substances may be easily purified by the process of Viallis Freres, by filtering through saw¬ dust impregnated j with a solution of soda. Barrels sawn * “ American Druggist.” + Corps Gras Industriels. ig8 OILS AND VARNISHES. in two can be used, the bottoms of which are pierced with holes. In the bottom is placed a layer of flannel, on which the sawdust is placed to the depth of 6 or 8 inches. If a colourless oil is desired, a thin layer of animal black is placed upon the sawdust. By placing two or three of these vats above each other, a perfectly pure oil is obtained. Tallow. —The following is recommended as a good process for bleaching tallow * :—About 50 lb. of caustic soda lye are placed in a clean boiler and the steam turned on. Salt is then added to the lye until it shows 25 0 to 28° B. The fat—300 lb.—is now placed in the boiler and heated to boiling. It is allowed to boil up x to 2 inches at most, and then left for three to five hours to clarify. At the end of this time the upper saponified layer is ladled off; the purer tallow is removed and passed through a hair sieve into a clean vessel until the lower saponified layer is reached. The residue in the boiler, consisting of saponified fat and lye, together with the upper layer, may be used in the preparation of curd soap. The boiler having been thoroughly cleansed, about 30 lb. to 35 lb. of water, with | lb. to 1 lb. of alum, are placed therein and heated to boiling. To this solution the fat is added, and the whole is boiled for about fifteen minutes, till the filth has disappeared from the fat. Trans¬ ferred after this to another vessel, it is left to itself for three to five hours. The pure fat obtained from this is again placed in the boiler and heated to the temperature of 170° to 200° C. In this last operation the fat becomes snow- white and fit for use. The steam must be turned off as soon as the slightest trace of vapour of disagreeable odour is thrown off', whether the temperature be 150° or 170° C., otherwise the fat will again turn dark. Freshly rendered, sweet fat is most readily bleached, and may be heated quite * “Oil Trade Review,” Oct. 1884. REFINING OF OILS. 199 high. Still the fat used should not be too fresh, or there will be risk of saponifying the whole of the 300 lb. without leaving any to bleach. Tallow which has been tieated in this way, when used in toilet soaps, gives them a white colour and agreeable odour. It is also well adapted for candle-making, as it becomes exceedingly hard. Refining Wax.—Crude wax, especially that imported, is generally loaded with dirt, bees, and other foreign matter. It is freed from these by the operation of refining. This is done by melting the wax along with about 4 or 5 P er cent, of water in a bright copper or stoneware boiler, preferably heated by steam, and, after the whole is perfectly liquid and has boiled for some minutes, the heat is withdrawn, and a little oil of vitriol is dropped over its surface in the propor¬ tion of 5 or 6 fi. oz. to every hundredweight of wax. This operation should be performed carefully, otherwise the melted wax froths up and boils over the sides of the pan. The melted wax is next covered over, and left for some hours to settle, or until it becomes sufficiently cool to be drawn oft for “ moulding.” It is then very gently skimmed with a hot ladle, baled or decanted into hot tin “ jacks,” and by means of these poured into basins, where it is left to cool. Great care must be taken not to disturb the sediment. When no more clear wax can be drawn off, the remainder in the melting-pan is allowed to cool, and the cake, or “ foot as it is called, is taken out, and the impurities, mostly bees, scraped from its under surface. The scraped cake is usually reserved for a second operation; but, if required, it may be at once re-melted and strained through canvas into a mould. Much of the foreign wax has a pale, dirty colour, which renders it, no matter how pure, objectionable to the retail purchaser. Such wax undergoes the process of “ colouring ” as well as “ refining.” A small quantity of the best rol 200 OILS AND VARNISHES. annotta, cut into slices (|- lb., more or less, to each hundred¬ weight of wax, depending on the degree of paleness of the latter), is put into a clean boiler with about a gallon of water, and boiled for some time, or until it is perfectly dissolved, when a few ladlefuls of the melted wax are added, and the boiling continued until the wax has taken up all the colour, or until the water is mostly evaporated. The portion of wax thus treated has now a deep-orange colour, and is added in quantity as required to the remainder of the melted wax in the larger boiler until the proper shade of colour is produced when cold, the whole being well mixed, and a sample of it cooled now and then to ascertain when enough has been added. The copper is next brought to a boil, and treated with oil of vitriol, etc., as before. Some persons add palm oil (bright) to the wax until it gets sufficient colour, but this plan is objectionable from the quantity required for the purpose being often so large as to injure the quality of the product, besides which the colour produced is inferior and less transparent and permanent than that given by annotta. Another method of refining crude wax, producing a very bright article, is to melt it in a large earthen or stoneware vessel heated by steam, or a salt-water bath, then to cau¬ tiously add to it about i per cent, of concentrated nitric acid, and to continue the boiling until nitrous fumes cease to be evolved, after which the whole is allowed to settle and is treated as before. The great art in the above process is to produce a wax whicn shall at once be “ bright,” or semi-translucent in thin pieces, and good-coloured. The former is best ensured by allowing the melted mass to settle well, and by carefully skimming and decanting the clear portion without disturb¬ ing the sediment. It should not be poured into the mould too warm, as, in that case, it is apt to “ separate,” and the REFINING OF OILS. 201 resulting cakes become “ streaky,” or of different shades of colour. Again, it should be allowed to cool very slowly. When cooled rapidly, especially if a current of air fall upon its surface, it is apt to crack, and to form cakes full of fissures. Sometimes the cakes are polished with a stiff brush when quite cold and hard. It is absolutely necessary that the “ jacks ” or cans, ladles, and skimmers used in the above process be kept pretty hot, as, without this precaution, the wax cools and accumulates upon them in such quantity as to render them inconvenient, and often useless, without being constantly scraped out. Refining Petroleum. —The following method is one of those practised in Canada :— The charge, taken from the under-ground store tanks, is introduced into wrought-iron stills, of about 1600 gallons content. These stills are flat-bottomed and are provided with man-holes, through which the black pitchy residue is removed. The distillation is effected by a fire placed underneath. The charge takes a week to work off; the distillate being collected in large wooden tubs, a small quantity of a thick greenish substance which separates is returned to the stills. The pitch-like residue is used for fuel for the next operation. The liquid collected is mixed with 5 to 10 per cent, of sulphuric acid, and agitated by rotatory paddles at a steam heat for the purpose of bleaching it. After this is done, the bleached oil is washed with water, the last traces of acid are neutralized with potash, and it is finally deodorized with ammonia. The loss in distillation is about 30 per cent. The refined oil is packed in 40-gallon barrels made of oak, lined, to prevent leakage, with an elastic cement, resembling vulcanized india-rubber, the principal ingredients of which are glue and white lead. 202 OILS AND VARNISHES. According to H. Vohl,* petroleum may be purified from sulphur by treatment with acids and alkalis. The impurity is most easily detected by heating the petroleum with metallic sodium. If sulphur is present, the bright metal soon becomes covered with a yellow crust of sodium sul¬ phide, which may be dissolved off by water, and tested. The quantity of sulphur may be estimated by distilling the petroleum over red-hot lime, and subsequently weighing the sulphur, as barium sulphate. In this way "Voul found different kinds of petroleum to yield from 0*300 to 3*114 per cent, of sulphuric acid. The following process for refining petroleum has been patented by J. C. Mewburn :—The crude oil is first divided into two portions, possessing distinct characteristics, called “ primary oil ” and “ secondary oil.” The average yield of the primary oil is about 35 per cent. The division is effected by mixing any quantity of the crude oil with commercial benzene, previously obtained from petroleum by distillation, using enough benzene to effect a complete separation. The mixture is placed in an open vessel, and the latter placed in a larger vessel. The benzene volatilizes and leaves the mixture, carrying with it the “primary oil,” which drops into the larger outer vessel, the benzene itself passing off as vapour. After the benzene has all evaporated, it will be found that the crude petroleum has been divided, the inner vessel containing the “ secondary oil ” and the outer the “ primary.” • If the latter is to be employed as an illuminant, no further treatment is necessary, but if it is to be used as a lubricant it is mixed with about 1 per cent, of amyl alcohol, and the mixture treated with ordinary (ethylic) alcohol, until it becomes milky or opal- * “ Dinpl. Polyt. J.” ccxvi. 47 ; Watts’ “ Diet, of Cliem.” suppt. iii. pt. ii. p. 1511. t Tat. 12498, 18S4. REFINING OF OILS. 203 escent. The supernatant oil is drawn off, and the purified “ primary oil ” removed. The oil thus treated has a density of about 28° B. Only about 1 per cent, of each alcohol is usually needed to effect the removal of the small proportion of light hydrocarbons contained in the “ primary oil.” This treatment imparts to the oil greater wearing qualities as a lubricant. The “ secondary oil ” has a density of about 36 ° B. It is subjected to fractional distillation as follows :—The first distillate is naphtha, which is allowed to run until the temperature rises to about 120° E. The receiver is then changed, and the distillation continued until the temperature reaches 288° E. This second distillate is kerosene, or burn¬ ing oil. The receiver is changed again, and the temperature raised to about 326° E. This third distillate is a heavy burning oil, which the author of the process calls “ petro- sperrn oil.” The residuum in the still is a heavy oil, which makes a good lubricant. 100 parts of crude petroleum yield when thus treated :— “ Primary oil ” . (31 0 B.) Naphtha . . (65° B.) Kerosene . . (50° B.) “Petro-sperm” . (36° B.) Residuum . . (27° B.) 35 P arts 3 ” 40 „ No tar or waste products are obtained by this process. The purification of the kerosene is effected by adding to 95 parts 5 parts of sulphuric acid. The resulting “ sludge ” is allowed to subside; the oil is then drawn off and agitated with a small quantity of alcohol, which mixes or combines with the small portion of acid remaining in the oil, and carries it to the bottom. The kerosene will now be clear, limpid, entirely free from fluorescence, and neutral to test. The “ petro-sperm ” may be puirfied in the same manner as 204 OILS AND VARNISHES. the kerosene, and will stand a fire-test of 149 0 F. It con¬ tains no paraffin, and does not form a crust on the wick when burned. Like the kerosene, it is almost odourless. By first separating from the crude petroleum the “ primary oil,” the inventor claims the removal of the principal diffi¬ culties incident to petroleum distillation by former methods, making this portion a valuable illuminant and lubricant. The “ secondary oil,” on the other hand, becomes nearly as valuable as the entire quantity of crude petroleum, from which it is obtained, would ordinarily be, owing to the im¬ provements in the products obtained therefrom, their quantity, the ease with which it can be fractionally dis¬ tilled, and the absence of waste products.* Crude Paraffin.—FoRDREDf purifies crude paraffin by melting, leaving mechanical impurities to settle down, then transferring to smaller vessels to cool. The cakes are next warmed till they become kneadable, and are then w r ashed with a solution of 10 parts of soft soap in 90 parts of water, and heated to about 38° C. Colouring matters and any oils that may be present are transferred by this treatment to the soap water, and the solid paraffin comes out purified and bleached. Recovery of Paraffin or Stearin from Petroleum or other Oil.J—Instead of separating the solid constituents of oils from the liquid ones by filtration or hydraulic pres¬ sure, the patentee proposes to effect the same object by spraying the oil upon a travelling blanket, which afterwards passes between pressing rollers; the oil is squeezed out, and the solid matters which are left on the blanket are removed from it by a scraper, and carried away by a travelling belt. The process is said to be rapid and continuous, but requires * “ J. Soc. Chem. Ind.” 1885, 49. + “Monit. Scien.” [3] iii. 826. t Eng. Pat. 13579, Dec. 15, 1884 ; “J. Soc. Chem. Ind.” 1885, 2S8. REFINING OF OILS. 205 close attention to the temperature of the room and of the oil. Crude Resin Oil.* —The decolorization is effected by heating in an iron boiler over a clear fire until it has be¬ come quite fluid. It is then drawn off into a wooden vat, frequently stirred, and 10 lb. of concentrated sulphuric acid is added for every 100 lb. of oil. After being allowed to rest twelve to eighteen hours, the oil is drawn off and washed several times with hot water. When it is completely freed from acid, it is dark-yellow, and almost inodorous. In order to obtain a bright-yellow product, the oil is now mixed with 50 per cent, of water, 10 per cent, of soda ash, and 10 per cent, of slaked lime, and finally submitted to distil¬ lation. * G. Schwarz, “ Seifen Sieilzeit.” 23, 271 j “ J. Cliem. lad.” 1883, 481. CHAPTER IX. TESTING OILS. I. PURITY. (i) Fixed or Fatty Oils. Oils vary greatly in value, and hence there exists a con¬ stant inducement to adulterate the more expensive ones •with those of a similar character but of an inferior kind. Many methods have been proposed for detecting these frauds, the chief of which we now proceed to notice. At the outset, it must be borne in mind that genuine oils, like other natural productions, are subject to considerable varia¬ tions, according to the time of year when obtained, the country in which produced, age, &c., and that no sharp line of demarcation exists between them such as we are familiar with in inorganic analyses. It is also desirable to remember that it is not always safe to take the recorded results of one operator for comparison with those obtained by another, so much depending, in these cases, on individual methods of manipulation and individual accuracy of observation. It should be an axiom never to decide upon a “ rough ” exami¬ nation, but each test should always be employed in precisely the same manner, with careful attention to exact quantities of the reagents and definite quantities of the samples under examination. It has also been often pointed out, and cannot, indeed, be too strongly insisted on, that a given sample should not be pronounced adulterated without com- TESTING OILS. 207 parison, side by side, with a sample of known purity, unless the amount or kind of adulteration is more than ordinarily gross. The tests capable of general application may be classified as follows :— I. Physical Tests. —1°. Odour; 2° Specific gravity; 3° Melting and solidifying points; 4 0 . Drying properties; 5 0 . Viscosity; 6°. Spectroscopic examination; 7 0 . Cohesion figures. II. Chemical Tests. —A. Qualitative. —1°. Colour tests ; 2 0 . Rise of temperature with sulphuric acid; 3 0 . Elaidin test; 4 0 . Spontaneous combustion; 5 0 . Solubility in acetic acid. B. Quantitative. —1°. Amount of free acidity, and action on copper; 2°. Saponification; 3°. Determination of oleic, stearic, and palmitic acids; 4°. Koettstorfer’s saponification equivalents ; 5 0 . ITubl’s iodine process; 6°. Mills’ bromine absorption process; 7 0 . Reichert’s process. Of the physical tests, the most useful are the specific gravity and the melting points of the solid fats and of the fixed fatty acids. Of the qualitative chemical tests, the colour tests, the temperature reaction with sulphuric acid, and the elaidin test often give useful indications. Of the quantitative tests, the processes of saponification, determina¬ tion of the free acidity, and the iodine or bromine methods, especially the latter, are generally valuable. I. Physical Tests. 1°. Odour.—The method of applying this test is to heat a few drops of the oil under examination in a small porcelain basin, platinum capsule, silver spoon, or watch- glass. When sufficiently cool, rub some on the palm of the hand, and again smell. Carefully compare the odour evolved with that arising from a known pure sample of the same 208 OILS AND VARNISHES. kind and quantity of the oil similarly treated. The odour of the two, when each is pure, is alike, and, after some ex¬ perience, suggests the plant, fish, or animal from which the oil has been obtained. The presence of linseed, nut, rape, seal, train, or whale oil is thus readily detected, and the imperfections of the sample, even if pure, may become per¬ ceptible. 2°. Specific Gravity.—The first to apply this test appears to have been M. Penot, who was of opinion that oils from the same plant, or animal, never deviated from one specific gravity by more than a few thousandths. Yarious plans have been employed for ascertaining this by the specific gravity bottle, and several forms of oleometer.* M. Lauret has observed that the variations of the density of an oil from adulteration are rendered much more apparent when it is examined in a heated state. To render this dis¬ covery practically available, he plunges an “ elaiometer,” graduated for the given temperature, into a small tin cylin¬ der nearly filled with the oil, and then places this in a vessel containing boiling water; as soon as the whole has acquired * Oleometer. — Syn. Elaiometer, Elaeometer, Oil-balance.— A delicate areometer or hydrometer, so weighted and graduated as to adaDt itself to the densities of the leading fixed oils. As the differences of the specific gravities of these substances are inconsiderable, to render it more susceptible the bulb of the instrument is proportionately large, and the tube or stem very narrow. The scale of the oleometer in general use (Gobby’s) is divided into 50°, and it floats at o° or zero in pure poppy oil, at 38° or 38'5° in pure almond oil, and at 50° in pure olive oil. The stan¬ dard temperature of the instruments made in this country is now 6o° F. ; those made on the Continent, 54-5° F. The oil must therefore be brought to this normal temperature, before testing it, by plunging the glass cylinder containing it into either hot or cold water, as the case may be ; or a correction of the observed density must be made. The last is done by deducting two from the indication of the instrument for each degree of the thermometer above the normal temperature of the instru¬ ment, and adding two for every degree below it. Thus: suppose the TESTING OILS. 209 a uniform temperature, he observes the point on the scale of the instrument at which it floats. This point is for— Colza oil . . o c Fish oil . • Poppy oil . . . 124 Hemp-seed oil • • I 3 6 Linseed oil . . . 210 The specific gravity of an oil, or of a melted fat, is ascer¬ tained with great ease and accuracy by the specific-gravity bottle. To the student the following hints as to the mani¬ pulation of the melted fat of butter, extracted from “ The Analysis and Adulteration of Foods,” by Dr. J. Bell, part ii. p. 55, will prove useful:—“ The fat is first separated from the water, curd, and salt by heating the butter in a glass beaker on a water-bath at about 150° F. (65*5° C.), and filtering to remove any particles of curd or salt it may con- temperature of the oil at the time of the experiment is 6o° F., and the oleometer indicates 61°; then— 60’0° Actual temperature 54*5 Normal temperature 5'5 Difference Indication of the oleometer . . . . 6ro° The difference 5‘5X2= . . . . . n o Real density ..... 50^0 * Mr. Estcourt 1 obtains very satisfactory results at high temperatures by using a hydrostatic balance, made by Gf. Westphal, of Celle, Hanover. The bulb, or plummet, suspended from the balance, is immersed in the test-tube (ij inch by 5) containing the melted fat, or oil. The desired temperature is obtained by placing the test-tube in a paraffin-bath. The latter is heated by an outer water-bath, and, when it arrives at a constant temperature (2o6°-2o8° F.), the weights on the arm of the balance are exactly adjusted, and the specific gravity of the oil under examination may be read off. A sketch of this apparatus, by Mr. J. Carter Bell, appears in the “ Chemical News,” 1878, 267. 1 “ Chemical News,” 1876, 255. P 210 OILS AND VARNISHES. tain. The separation should be conducted as quickly and at as low a temperature as possible. The specific gravity of the perfectly clear and dry fat is then taken at the temperature of ioo° F. (377 0 C.). For this purpose an ordinary specific- gravity bottle ” (of which, of course, the accuracy has been tested by the analyst himself) “ of a pear shape is used, into which a sensitive thermometer can be inserted, the bulb of which extends nearly the whole depth of the bottle. The fat is introduced at about 115 0 F., and gradually brought down to ioo° F., when the bottle should be quickly filled from the residue of the fat, also cooled to ioo° F. ( 377 ° C.), care being taken to push the glass stopper home, otherwise an excessive gravity will be obtained. It has been recom¬ mended to adjust the temperature of the fat in the bottle by placing it in water kept at ioo° F. ; but we have found this an unnecessary precaution, as, where the requisite care is taken, the first mode gives perfectly reliable results.” If a bottle adjusted to contain 1000 grs. of water at 6o° F. (i5'5° C.) is employed, to obtain the true specific gravity of the fat, the weight obtained must be divided by the weight of water which the bottle will contain at ioo° F., and the result multiplied by 1000. If a bottle were used which contains 50 gms. of distilled water at 100° F., and the weight of the fat at the same temperature was found to be 45'58 gins., then the specific gravity of the fat would be x 1000 = 91 r6, water being 1000. When the density of the given sample has been taken, and the name of the oil used to adulterate it is known, the quantity of the latter present may be approximately deter¬ mined from the specific gravities by the common method of alligation. Mr. L. Archbutt adopts the following plan for taking the density of oils and fatty acids at a steam heat:—He takes a small Sprengel tube, which is hung by the horizontal capil- TESTING OILS. 211 lary portions in the neck of a 20-oz. flask containing water in a state of rapid ebullition. A watch-glass or porcelain crucible cover is placed over the neck of the flask so as to prevent cooling. The open mouths of the Sprengel tube project on opposite sides of the neck of the flask, while the mouth of the flask is sufficiently closed by the watch- glass or porcelain cover. When it is observed that the expansion of the oil has ceased, the mouths of the tube are touched with a piece of filter-paper to remove adhering oil, and the tube may then be taken out, wiped, cooled, and weighed. Fig. 3 will make the arrangement clear. The following are some of the densities of fatty acids obtained by Abchbutt in this way : *— Source of fatty acids. Pure olive oil 55 55 Earth-nut oil Pure rape oil. Colza oil Cotton-seed oil Niger-seed oil Linseed oil . Train oil Palm oil Density at ioo° C. • '8444 . 8429 • '8475 • -8439 . '8464 • 8494 . '8562 • -8599 • 8597 • ’8389 3 0 . Melting Point. —Various methods have been sug¬ gested for determining the melting points of solid fats and fatty acids. a. Dr. Bell’s method.—The melted fat is suddenly * “ J. Soc. Chem. Ind.” ii. 55. 212 OILS AND VARNISHES. cooled by floating the platinum capsule containing it in ice water. A small portion of the fat, which has a somewhat vitreous appearance, is then taken up on the loop of a pla¬ tinum wire, and introduced, close to the bulb of a thermo¬ meter, into a beaker of water at 6o° F. set in a porcelain dish also containing water. The heat of the water is then slowly raised, and the temperature read off immediately the fat assumes the liquid condition. b. Dr. Redwood’s method.— A 20-oz. flask from which the neck has been removed is filled with water, and a small beaker is fitted into the mouth. The beaker is then half filled with clean mer¬ cury, and a small fragment of the solid fat or fatty acid is placed on the surface of the metal. The thermometer bulb must be wholly immersed in the mercury. The melting point is readily observed, and several samples may be tested simultaneously. Fig. 4 is an illustration of this arrange- Fig. 4. ment. c. Capillary tube method.—The apparatus employed is that last described with the addition of a capillary tube in close proximity to the bulb of the thermometer. The small beaker is in this case filled with water instead of mercury. Mr. Allen says very good results are obtainable by this method, provided the following points are rigidly attended to :— (1) To allow the melted fat to solidify slowly, avoiding all artificial means of cooling. (2) To allow at least an hour to elapse after solidification before taking the fusing point. TESTING OILS. 213 (3) To heat the water very slowly. It may be useful here to note the following melting points of fatty acids obtained by this method by Mr. Archbutt :*— Melting Point. Source of fatty acid. Fahr. Cent. Olive oil . • 75 to 76 ° 23-8 to 24 - 4° Earth-nut oil . 82-3 27-9 Rape oil . • 65 i8-3 Colza oil • • 65 i8'3 Cotton-seed oil . • 955 35'2 Niger-seed oil . 76'5 to 80 247 to 26*6 Linseed oil • 52-5 IO'2 Train oil . • • 87 3°'5 cl. An apparatus for the determination of melting points, by 0 . F. Cross and E. J. Sevan, was described in a paper read before the Chemical Society, January 19, i882.t It consists of a small platform of thin ferrotype iron, or silver, having an opening for the reception of a thermometer bulb, and a small indentation or depression about i‘5 mm. deep and 2 mm. in diameter. A very small quantity of the substance is melted in the little depression, and, while still liquid, a thin platinum wire, bent like aq, L and fused at its upper extremity into a little glass float, is immersed in the liquid and held there till the substance solidifies; a thermometer is then inserted into the opening, and the whole apparatus plunged under mercury ; the mercury is gently heated, and the thermo¬ meter carefully watched. (Water might be used instead of mercury.) As soon as the substance melts, the float rises, and the temperature is noted. Stirring is unnecessary; the whole of the substance is surrounded by mercury, and the attention can be concentrated on the thermometer. * “ Journ. Soc. Chem. Ind.” ii. 55. t “ Year Book of Pharmacy,” 1882, 102. 214 OILS AND VARNISHES. e. Bensemann’s method.*—A drop of the previously fused fat or mixture of dried fatty acids is placed in the wide portion of a drawn-out tube, as shown at a in Fig. 5, and is then allowed to completely solidify. The tube is placed perpendicularly, or nearly * so, in a beaker of cold water containing a thermometer, and heated as gradually as possible over a very small flame until some of the fat begins to flow down the side of the tube. The temperature observed at this mo¬ ment is called by the author the “ initial point of fusion.” The application of heat is con- b tinued until the fat drop has taken the ap¬ pearance and position shown at b; and when the last trace of turbidity has disappeared, the temperature is again read off. This is the “concluding point of fusion.” The author finds that this method gives very satisfactory and concordant results; the two points are very closely marked, and are about 3°-4° C. from one another. With pure fats the con¬ cluding point is less clearly marked than with fatty acids ; in the examination of the former, therefore, the initial point only need be noticed. The table on p. 215 contains some of the results obtained. 4 0 . Drying Properties of Oils. — The drying quality of oils may he ascertained by placing a drop or two in a flat porcelain capsule, or spreading a drop or two upon a piece of glass, and setting aside overnight at common temperature, or, more quickly, at a gentle heat (about ioo° F.). Or one of the methods given on pp. 292 and 302 may be adopted. * “ Rep. Anal. Cliem.” n, 165 ; “ J. Soc. Cliem. Ind.” 1885, 535. TESTING OILS. 215 A similar quantity of a standard sample should be treated in the same way for comparison. Table of Melting Points (Bensemann). Initial Point of Fusion of the Fat. Percentage of Insoluble Fatty Acids Initial Point of Fusion of Insoluble Fatty Acids. Concluding Point of Fusion of In¬ soluble Fatty Acids. Genuine butter-fat... 34 - 35 ° 0 , 8777 42-43° C. 45-46° C. Sesame oil . Fluid 9586 25-26 29-30 Cotton-seed oil . 95 75 39-40 42-43 Olive oil . )J 95-43 23-24 26-27 Refined rape oil H 9514 18-19 21-22 Earth-nut oil . J1 95-86 3 I- 3 2 34-35 Cacao fat from— 48-49 Maracaibo beans ... 25-26° 94’59 51-52 Caraccas ,, ... 27-28 95 31 48-49 51-52 Trinidad „ 26-27 95-65 49-50 51-52 Porto Plata ,, ... Machala Guayaquil 28-29 95 46 49-50 52-53 beans . 28-29 95-24 49 - 5 ° 52-53 5 0 . Viscosity. —For the method of ascertaining the quality of an oil in this respect, see pp. 292 and 302. 6°. Spectroscopic Examination. —The fatty oils may be, according to Doumer, divided into four classes with reference to their spectroscopic behaviour :— 1. Oils which show the absorption spectrum of chlorophyll, such as olive, hemp, and nut oils. 2. Oils which show no absorption spectrum (■ i.e ., which allow all the rays to pass unabsorbed), such as castor oil and oil of sweet and bitter almonds. 3. Oils which absorb all chemical rays of the spectrum. To this class belong rape, linseed, mustard, and other oils. Their spectrum is very characteristic: it only shows the warmer portion of the spectrum—red, orange, yellow, and one-half of the green. The balance of the spectrum is absorbed. 4. Oils whose absorption spectrum only comprises bands 216 OILS AND VARNISHES. of the chemical portion of the spectrum, instead of being complete—such as sesame, poppy-seed, cotton-seed, and pea¬ nut oils.* 7°. Cohesion Figures. —Miss Kate Crake f states that the cohesion figures of oils may be usefully employed as tests of the identity and purity of the oils. She says “ a number of experiments on this subject have led her to the conclusion that a little patient practice will teach the eye of the observer in a short time to detect the charac¬ teristic differences of the figures. To make these perfect, it is necessary to observe the time in forming, for at different periods some varieties form figures very like ; but with this precaution each is entirely characteristic. “ It is essential that the dish used, &c., be perfectly clean, so that when filled with water no dust or lint floats upon the surface, as this materially interferes with the perfect formation of the figure. — 2 8’07 Tallow 40 — Butter. 48-52.) Cocoa-nut 8-9 6'8 Olive oil. 68-24 ) Coeoa-butter 34'4 Cotton - seed > — 88-54 Muskat-butter . — 3i'6 oil. 3i'76) _ Butter. 47-88 > Lard. _ 55 '° Oleomargarin 33'2 q ( . r Beef-suet. — 3 S ‘4 Cotton - seed 1 Oleic acid. — 86-2 oil. 18-82.) * The “ butters ” marked (a), (b), and (c) contained 90 to 91 percent, insoluble and 4'2 to 4'6 per cent, soluble fatty acids. “ Olive oil ” (b), though sold for genuine oil, was apparently (by this test) mostly cotton¬ seed oil. (Note.—Iodine absorptions x ’63 = bromine absorptions.) 250 OILS AND VARNISHES. Some of HtiBL’s conclusions from his experiments * are t he following:— 1. Linseed oil is distinguished by its high iodine degree, and any addition of a foreign oil must reduce that degree. (It will be seen from the table, however, that Moller found • a higher figure for shark-liver oil than he did for linseed oil.) By boiling linseed oil, its iodine degree is lowered, but the fusing point of its fatty acids is increased. (Com¬ pare its behaviour with bromine, p. 253.) 2. An addition of 5 to 10 per cent, of cotton-seed or rape-seed would be readily detected in nut or poppy oil, but not much less than 20 per cent, of linseed. 3. Rape-seed oil, as regards the iodine absorption, is affected by the method of extraction and refining. The refined oil usually has an iodine degree 2 or 3 degrees below that of the raw product. A falsification with 15 per cent, of linseed oil would be detected with certainty. 4. Castor oil possesses a very constant iodine degree—■ from 84^0 to 847, and is distinguished from all other oils and fats by this figure, by the points of fusion and solidi¬ fication of its fatty acids (13 0 and 3 0 C. respectively), by the saponification test, and by its ready solubility in alcohol and acetic acid. 5. In twenty samples of olive oil, collected from various sources, the absorption of iodine varied only within 3 degrees. (It is important to notice that the degree for olive oil is con¬ firmed by Moller.) The addition of about 5 per cent, of a drying oil, or 15 per cent, of cotton-seed, sesame, arachis, or rape-seed, may be established with certainty. 6. Animal fats, as is well known, are liable to alteration in respect of their consistency and proportion of oleic acid owing to variety, age, and food of the animal whence * “J. Soc. Chem. Ind.” 1884, 642. TESTING OILS. 251 derived. In the case of butter-fat the absorption of iodine varies between the limits of 26 and 35. 7. When the nature of two fats in a mixture is known, their proportion may be determined approximately by the formula 100 ( 7 — n) X ~ m — n where x = the percentage of one fat y = „ „ the other 7 = iodine degree of the mixture m — „ „ „ fat x n — >5 ss j? » y 8. The age of a fat, so long as great alterations have not taken place, does not affect its iodine absorption. If, however, an oil has become rancid, and contains free acid, the iodine degree suffers considerable depression. 6*. Mills’ Bromine Absorption Process.— This is de¬ scribed by Messrs. Mills and Snodgrass in “ Journ. Soc. Ckern. Ind.” Nov. 5, 1883, and is an improvement on that first suggested by Cailletet in 1S57. The details are as follow:— 1. The substance is dried by heat, or by filtration through dry paper scrap (which is usually quite sufficient). 2. It is then dissolved in carbon disulphide, so as to make a solution of 10 per cent., or less strength. 3. A definite volume of this solution is then placed in a narrow-mouthed, stoppered bottle of 100 c.c. capacity, and diluted with more disulphide to about 50 c.c. 4. A deci-normal solution of bromine in carbon disulphide is then run in gradually, in successive portions, with agita¬ tion, until the colour of the free, bromine remains permanent for fifteen minutes. During this operation, direct sunlight must be carefully avoided. 5. At the end of the fifteen minutes, to 50 c.c. of disul- 252 OILS AND VARNISHES. phide, in another exactly similar bottle, standard bromine is added until the tint in both bottles is the same. The number of cubic centimetres used in this blank experiment is then deducted from the number used in the absorption experi¬ ment, and the remainder gives the requisite datum for calcu¬ lating the percentage of bromine added. Tabular Statement of Absorptions obtained by above Process* Substance. Absorption per cent. Eemarks. Illuminating mineral oil (A) ... 27-57 S.G. ‘8069 „ „ (B) ... 30 - 3 I ,, '8045 Lubricating shale oil . 22-24 „ 860 5 5 >5 . 20-59 » '870 55 5 ) . 12-59 » S90 5 5 5 5 . 11-72 „ -900 Vaseline . 555 American Paraffin . 0-52 Pale yell. M.P. 51-7° Cocoa-nut oil .. 5-70 Palm oil . 34'79 Acid to litmus Cotton-seed oil . 49'97 Olive oil . 54'0 Castor oil... 5 S -34 Absorption rapid Rape oil . 69-43 Old sample Linseed oil . 76-09 „ (boiled). 102-36 Made from above Stearic acid . O'O Butter (from fresh cream) . 27 93 Made in laboratory ,, (commercial) . 24-49 Butterine (Scotch ?) . 36-32 ,, (French). 39 - 7 I Marseilles Beef fat. 35 01 Lard Winter speri Cod-liver oil Skate oil .... Aniline. Purified resin oil Turpentine . (Russian) 37^9 156-0 81-91 WS 109-2 1698 40-69 255-0 236-0 2207 Absorption slow ( Henry’s unrefined (_ Very slow absorption Refined by filtration Pine oil Moist Dry Moist * “Jour. Client. Ind.” Nov. 29, 1883. TESTING OILS. 253 The authors prefer this colorimetric comparison at the end to titration for the sake of expedition. If, however, the operator should prefer the more exact method, he must trans¬ fer the carbon disulphide to a flask containing excess of aqueous potassic iodide, add a little starch solution, and de¬ colorize with standard thiosulphate. In considering the above results, the authors call attention to the following points :— 1 . The absorption by paraffin oils increases as the sp. gr. diminishes. 2. Pure solid paraffin— i.e., free from liquid oils—should exhibit no absorption ; hence the absorption is a useful measure of its more or less imperfect purification. 3. As regards cotton-seed and olive oils, the distinction is not so great as by MaumenAs test. 4. Fish oils will all, probably, resemble cod oil by absorb¬ ing much bromine. 5. The fact that boiled linseed absorbs so much more bromine than the unboiled shows that the process of boiling implies de-hydrogenation. 6. In the case of cocoa-nut and palm oils, cod and skate oils, this method shows a striking difference. 7. There is a well-marked distinction between butter and its imitations or its allied fats (beef and lard). As the method is more readily applied than that of saponifica¬ tion, it may prove useful to public analysts, as well as to butterine manufacturers.* * During the discussion of this process, Mr. Allen stated he preferred ■what he called the “ moist ” bromine process to that of Messrs. Mills and Snodgrass. He takes a known quantity of the oil to he tested, and adds a known measure of a standard solution of sodium hypobromite and excess of dilute hydrochloric acid (for details, see p. 289). The decomposition of the hypobromite and consequent liberation of bromine occur in the aqueous layer, and hence the oil is not subjected to treatment with nascent bromine 254 OILS AND VARNISHES. Messrs. Mills and Akitt* describe an improvement of this process, which consists in substituting carbon tetra¬ chloride for the bisulphide. The method is as follows 1. About o'i gm. of the oil is dissolved in 50 c.c. of the tetrachloride. 2. Standard bromine solution is added till at the end of fifteen minutes a permanent coloration remains. 3. This is compared with a coloration similarly produced in a blank experiment, and thus a measure of the bromine absorption is obtained, or it may be titrated in the ordinary manner by adding the solution of the brominated substance to potassic iodide with starch and sodic thiosulphate to this, or the converse. Or the excess of bromine may be titrated back in the same solvent by using / 3 -naphthol as indicator. In presence of carbon tetrachloride / 3 -naphthol forms a mono-bromo-derivative, and the indicator is made to corre¬ spond to the bromine solution in the ratio Br, : C lo H s O. The table on p. 255 exhibits some of the results obtained. at all, unless the momentary action at the point of contact of the two strata be so considered. The essential difference between Allen’s method and the one above described is that the latter is performed in the absence of water. The following figures were obtained by the moist bromine process Petroleum spirit.io'o i Shale naphtha ..... 94-9 Howard’s American turpentine oil . 192-0 - A. H. Allen English resin spirit .... 252-0 j Prussian resin spirit .... 246-0 / Genuine turpentine oil . . . 223-0 and 224-0^ Commercial 2330 2 33 '° 1920 L. Archbutt. * “Journ. Soc. Chem. Ind.” June 29, 1SS4. TESTING OILS. 255 The average probable error of a single result is 0*62 ; where ^-naphthol was used as an accessory this was reduced to 0-46. Mean strength of the standard bromine, '00644 gm. per c.c. Substance. Absorp¬ tion per cent. Sp. gr. at I I°-I 2 °. Melt¬ ing Point. Remarks. Almond oil. 26'27 ■9168 Expressed from bitter almonds ” . 53"74 '9154 „ „ sweet „ Yellower Bees’-wax . °'S 4 63'9 English 1883. Very yellow }J . 0*00 63*2 Scotch 1876. Pale „ . 0*00 ... 62-9 ,, 1882. Yellow ff . o'oo 63-3 ,, 1883. Much solid fat Ben oil. 52-95 •9198 Carnauba wax . 50-89 ■91OI No solid fat 33 ' 5 ° S 4 "i Cod oil. 83-12 ■9269 1877. Scotch, rancid with age. One hour’s absorption 84-03 •9292 1882. Norwegian refined 82-94 -9257 1882. Japanese 8i'6i •9277 1882. Scotch 86-69 •9281 1883. Crude, from liver refuse 83 'OX • 93 IS 1883. Norwegian 82-07 •9278 1883. Scotch Croton oil . 46-66 -9441 Twenty hours’ absorption Eucalyptus oil . 94-09 "8691 Fifteen minutes’ absorption Horse fat. 3 S '67 Pasty, well mixed Japan wax (I.) . 2’33 5 o ‘5 „ (II.) . i '53 5 o'S Java-nut oil . 3024 Ling-liver oil. 82-44 '9295 1882. One hour’s absorption Maize-germ oil . 74 42 •9262 1880. Mustard-seed oil . 46-iS "9152 East Indian Myrtle wax. 6-34 44'3 Neat’s-foot oil . 38-33 " 9 r 47 Thick Niger-seed oil . 35 * 1 1 -9244 Olive oil. 59'34 •926b Thick, brown, “best sulphocar- bon ” Thinner, greener, “low quality sulphoearbon ’’ J) . 6o'6t •9382 Palm oil . 35-44 Crude old Calabar Peach-kernel oil . 34'96 „ Lagos 2 5*40 * 9 r 75 Poppy oil. 56-54 '9244 Turbid, filtered Resin (common) . 112*70 Light colour Seal oil. 57*34 •9241 Pale. One hour’s absorption „ . . 59 ' 9 2 ■9216 Dark Sesame oil . 47 *35 -9250 Shark-liver oil . 84-36 '9293 Dec. 1883. One hour’s absorption Sunflower oil . 54'32 '9391 Colourless. About 1868 Whale oil. 3092 •9190 Norwegian white whale. Very thick ” . 48-69 •8780 “ Bottle-nose whale ” Note. —Bromine absorptions x 1'5875 =iodine absorptions. 256 OILS AND VARNISHES. 7°. Reichert’s Process for Butters.*— The fat is dried and filtered through cotton-wool, 2*5 gms. are weighed in a liquid state into a flask of 150 c.c. capacity, and 1 gm. of solid potassium hydrate and 20 c.c. of 80 per cent, alcohol are added. The whole is heated on a water-bath, with constant shaking, until the soap is no longer a frothing, slimy mass ; 50 c.c. of water are then added, and, as soon as the soap is dissolved, 20 c.c. of dilute sulphuric acid (1—xo) are poured into the mixture and distilled, a slow stream of air being constantly passed to avoid bumping. A conical tube should be connected with the flask so as to prevent any sulphuric acid spirting over. If necessary, the distillate is filtered into a 50 c.c. flask through a wet filter-paper to separate solid fats. After about 15 c.c. have passed over, the distillate is poured back into the distillation flask, and the distillation is continued until exactly 50 c.c. are obtained. This distillate, which will be quite clear if the process has been slowly conducted, is mixed with 4 drops of litmus solution, and titrated with deci-normal soda solution. The process, according to the author, yields very constant results when repeated on different portions of the same sample. Any butter requiring less than 127 c.c. for this titration is considered adulterated. Cocoa-nut oil, lard, suet, and other adulterants of butter yielded distillates requiring from 37 to o'25 c.c. only of soda solution. Prof. Cornwall has compared the methods of Hehner, Koettstorfer, Hubl, and Reichert, and considers that, of these, the last is the most reliable process for butters.f (2) Essential Oils.- The essential or volatile oils of commerce are very frequently adulterated with the fatty oils, resins, spermaceti, or alcohol, or with other essential oils of a cheaper kind or lower grade. * “Zeitschr. Anal. Chem.” 1879, 68-73; “I- Chem. Soc.” 1879, 407 + Beport to the New Jersey State Board of Health for 1884. TESTING OILS. 257 Detection of Fatty Oils, Resins, or Spermaceti.— Place a drop of the suspected oil on a piece of white paper, and expose it for a short time to heat. If the oil is pure, it will entirely evaporate ; but, if one of these adulterants is present, a greasy or translucent stain will be left on the paper. These substances also remain undissolved when the oil is agitated with thrice its volume of rectified spirit. Detection of Alcohol. —1. Agitate the oil with a few small pieces of dried chloride of calcium. These remain unaltered in a pure essential oil, but dissolve in one con¬ taining alcohol, and the resulting solution separates, forming a distinct stratum at the bottom of the vessel. When only a very little alcohol is present, the pieces merely change their form, and exhibit the action of the solvent on their angles or edges, which become more or less obtuse or rounded. 2. Another test for alcohol in the essential oils is the milkiness occasioned by agitating them with a little water, as well as the loss of volume of the oil when it separates after repose for a short time. 3. M. Beral considers the following a more delicate test for alcohol than either of the preceding:— 12 drops of the oil are placed on a perfectly dry watch-glass, and a piece of potassium, about the size of an ordinary pin’s head, set in the middle of it. If the small fragment of metal retains its integrity for twelve or fifteen minutes, no alcohol is present; but if it disappears after the lapse of five minutes, the oil contains at least 4 per cent, of alcohol; and if it disappears in less than one minute, it contains not less than 25 per cent, of alcohol. 4. Boettger states that anhydrous glycerine possesses the property of dissolving in alcohol, without mixing with the volatile oils. The mode of applying the glycerine is as follows :—The oil to be examined is well shaken, in a gra- s OILS AND VARNISHES. 258 duatecl tube, with its own volume of glycerine (sp.gr. i’2 5). Upon being allowed to settle, the mixture separates into two layers. The denser glycerine separates rapidly, and if the essence has been mixed with alcohol this is dissolved in the glycerine, the augmentation in the volume of glycerine showing the proportion of alcohol. 5. If alcohol is present, a colorization is obtained when a few drops of the essential oil are poured on a granule or two of fuchsine or rosaniline. No change of colour is produced by pure oils. This species of adulteration is very common, as it is a general practice of the druggists to add a little of the strongest rectified spirit to their oils to render them trans¬ parent, especially in cold weather. Oil of cassia is nearly always treated in this way. Detection of Inferior Essential Oils. —1. The admix¬ ture of an inferior oil with one more costly may be detected by pouring a drop or two on a piece of porous paper or cloth, and shaking it in the air, when, if occasionally smelled, the difference of the odour at the beginning and the end of the evaporation will show the adulteration, especially if the added substance is turpentine. 2. Another method for the detection of turpentine, is based upon its power of dissolving fats:—Take about 50 grs. of oil of poppy in a graduated glass tube, and add an equal quantity of the sample of essential oil. Shake the mixture up thoroughly, and then allow it to stand. If the essential oil be pure, the mixture becomes milky, and does not clear until after several days have passed, whereas it will remain transparent if even so little as 5 per cent, of essence of turpentine be present. 3. Zeller proposed alcohol as a means of detecting admixture with oil of turpentine. Dragendorff applies this test in the following way:—The alcohol is first diluted TESTING OILS. 259 till 2-4 volumes of it are required to dissolve 1 volume of the oil. It will then he found that the presence of a small quantity of turpentine is indicated by the decreased solubility of the adulterated oil in the alcohol. 2 c.c. of the sample are placed in a stoppered bottle, and the diluted alcohol is then added from a burette, shaking after each addition. It will be found that a larger proportion of alcohol will be required to produce a clear liquid in the bottle in a sample containing turpentine than in a pure oil. 4. Many of the more expensive oils are adulterated with sassafras oil, the presence of which, according to Hager, may be easily detected by mixing the sample with sulphuric acid and diluting the mixture with alcohol, when a cherry- red colour is produced if sassafras oil has been added. 5. The adulteration of a heavy oil with a light one, or the reverse, may be detected by agitating the suspected oil with water, when in many cases the two will separate and form distinct strata. The purity of essential oils may likewise, in many cases, be determined by taking their sp. gr.; or, with still greater accuracy and convenience, by measuring their index of refraction, as suggested by Dr. Wollaston. A single drop of oil is sufficient for the application of the last method. (For Table of Refractive Indices, see p. 271.) Cohesion Figures.—Miss Crane believes that the cohesion figures afforded by the volatile oils, like those of the fixed ones, will be found useful indications of their purity. The application of her method is precisely similar to that followed in her examination of the fixed oils as already described (see p. 216). She finds that— Oil of Turpentine by itself spreads instantly to the whole size of the plate (a common soup-plate), and almost imme¬ diately the edge begins to break into irregular shapes, when a rapid motion takes place over the surface of the film, and 260 OILS AND VARNISHES. there seems to be a contest between the cohesion of the oil particles and the adhesion between them and the water. The oil makes repeated efforts to gather itself closer together, when the water instantly reacts, giving a wavy appearance to the whole figure. The play of colours at this point is beautiful, and serves to bring out the lines more perfectly. In a few seconds innumerable little holes appear over the surface, which soon are separated only by threaded lines, and the figure is like the most exquisitely fine lace. Oil of Cinnamon forms a figure not more than half the size of the last-named. In a few seconds small portions are detached, and shortly separate into distinct drops, four or five larger and a number of smaller ones scattered about. With mixtures in different proportions of oil of turpentine the figures formed differently, taking more of the character¬ istics of the adulterant as it predominated. Oil of Nutmeg forms a large figure instantly, the edge showing a beaded line. It gathers itself together and spreads again, very like oil of turpentine, but the surface presents more the appearance of watered silk. Within sixty seconds some holes appear, and in eighty more the surface is covered with them. These scarcely spread to more than a sixteenth of an inch in diameter, but from the first each is bordered with a dotted edge. The figure lasts some time without changing materially, except that the openings lengthen out into an oblong shape, remaining entirely distinct. The play of colours is very fine. With the addition of one-third of the oil of turpentine , the first spreading is little different, but openings appear in half the time, and the dotted border does not come as soon; in about four minutes the figure is most characteristically marked, and soon breaks up entirely, this being the distinctive difference between the pure oil and the mixture. TESTING OILS. 261 Oil of Peppermint spreads instantly to a large figure, and in ten or fifteen seconds openings appear, which increase rapidly in size. At first they look somewhat like the last- named, but are not nearly so numerous, and the border soon is more like tiny drops. In one and a half or two minutes they begin to run together, and the figure breaks up. With the addition of turpentine oil the figure forms more slowly, and the breaking up is less rapid, but in five minutes the outlines only remain. Oil of Bergamot spreads instantly. In thirty seconds tiny openings appear, not very abundant, and increase in size slowly. In five minutes they are not larger than oil of nut¬ meg at one and a half minute. At first they have a dotted border, but as they increase in size this changes to a scalloped film, which spreads until, in eight or ten minutes, they are joined together over the whole surface. This, witl 1 the turpentine oil, gives a watered surface in spreading, much more marked, and with a fine play of colours. Forney’s Iodine Pentabromide Test.— Forney* states that he applied this test by placing 5 or 6 drops of the volatile oil on a watch-glass and adding 1 drop of the pentabromide. This reagent, IBr., was prepared by dis¬ solving 127 grs. of iodine in 400 grs. of bromine. All the oils used were of best quality, and pure. Corresponding experiments were performed also with the same oils pre¬ viously mixed with 25 per cent, of oil of turpentine and the same proportion of 95 per cent, alcohol. The following table (pp. 262, 263) shows the results, and, it will be observed, exhibits an increased reaction with oil of turpen¬ tine and a less intense one with alcohol. * “Amer. Journ. Pharm.” 1882, 546; “Year-Book of Pharmacy,” 1883, 154. Action of Iodine Pentabromide on Volatile Oils. 262 OILS AND VARNISHES. Oils + 25 per cent. Alcohol. Colour. Orange red Cloudy olive ; black precipitate Brown red Olive green Brownish Brown red Cloudy, brown¬ ish yellow Yellowish to greenish brown Brown red Cloudy yellow Green Cloudy, yellow Dark to light green Bed brown Reaction. None Slight effer¬ vescence [Brisk; slight elf. and sputtering Ditto Ditto Brisk eff. Slight eff. Ditto Ditto Brisk; slight eff. Slight green vapours None Like pure oil Slight eff. Oils + 25 per cent. Oil of Turpentine. Colour. Brownish yellow Biown red Yellowish brown Colourless, or yellowish Brownish, then greenish yellow Brownish red Reddish brown Cloudy; blackish brown Olive green, then greenish black Dark brown Brownish, then olive green ; black precipitate Brown red Cloudy, inky, then clear olive green Dark brown Reaction. Slight reaction and sputtering Brisk eff. ; slight sputtering Very violent Ditto Ditto Ditto Ditto Brisk efferves¬ cence Very violent Ditto Brisk efferves¬ cence ; green vapours Brisk eff. Very violent Ditto Pure Oils. Colour. Orange red Cloudy green dark precipitate Brown red Brownish green Olive green Brownish red Greenish yellow Greenish brown Cloudy, black¬ ish brown Brown sediment Green Greenish yellow Greenish yellow; dark green on stirring Brown red Reaction. None Slight Violent; sput¬ tering Violent; brisk effervescence ; sputtering Ditto Ditto Ditto Slow ; slight effervescence Violent; brisk eff.; sputtering Ditto Slight gentle effervescence ; green vapours None Violent; brisk eff.; sputtering Ditto O Almond,bitter Amber, recti¬ fied Anise . Bay. Bergamot ... Camphor. Caraway. Cassia. Cinnamon (Ceylon) Cloves. Copaiba . Croton. Cubebs . Fennel . TESTING OILS. ;63 T3 ,2 S £ " ^ rfi P~> g “ r ^ ^ r- ^ -O 5 ? u>^ s 2-n O p t-S- 2 M "§ S ^ F 3 CD r-< . - O G CD P Cij^r o G K~> H O ^ rH O^ — Jx ^ ■p M ? >» tojj -^> ° !£p s pq'* 3 bOoJ I- _ t- _ -3 >p>-s ^ i'j o s o^; fco G sri G b.0 ^ to !* G to’ to : G bp .2'to' r~£n P CL, ®T3: P i £t5 G w & 03 PQ P -r g>«w • 8-5 _2 fcD O ° P 3 ^ g t^Ts'C G r- TH O PH £ G co p 9 , M ’cq o pq P rPPP pq * to 2 •| c ® S3 * o ca o ^ to £ rt c 3 § 0^2 o o ^ c— ° o 2, - 1 ' J2 Ir* Tl! Mill p * JTJA &>'3 c -g g as ■'-' 7; cd ° _EH g o ° Q o ^ " _o « •>a ^ 6 ■^3 -3 o o ci >* ^ 3 -S "5 •£ •-.2 H ’3 ^ § S & ' PQ J 3 ~ r= & ; pq C5 £ I OcS 23 ft o o is 2 . & £■5 £>£ ^ 3 - 5 b^ JZ* 03 »--« .2 ’> 2 -3 S S.tog *3 ■—■ •'-. )r. ®"3 £3 pq >q o a> CD ?h >- 3 -. O ^ O rS . «2 u M o t> Co > rj o P p J P P ^ P PP PP P P P PP P PPP 3 CD K S o ‘3 (bloom¬ less) S' 1 IO’O 17-2 21'6 (valvoline) 3r8 (oleo- nap'ntha) 19-7 41*6 48-7 27-9 36-0 3V2 (bloom¬ less) 4-8 8’8 *4'7 17-7 • (valvoline) 241 (oleo- naphtha) i&'S From these results it will he seen that there is in each case a striking difference between the proportion of bromine assimilated by any of the shale products and the quantity which combines with the parallel product from petroleum. Thus, while the shale naphtha took up nearly its own weight of bromine, the petroleum product combined with only 10 per cent., and the gasolenes, burning oils, and lubricating oils exhibit similar but less striking differences. Testing Ozokerit. — Dr. B. Lach* determines the value of ozokerit in the following manner:—roo gms. of the wax are treated at i7o°-i8o° C. with 20 gms. fuming sulphuric acid in a weighed dish, the mixture being con¬ stantly stirred until sulphurous acid ceases to be given off. The difference in weight gives the loss due to volatilization (petroleum and water). The residue is mixed with 10 per * “ Chem. Zeit.” 51, 905; “Analyst,” 1885, 153. 2 9 2 OILS AND VARNISHES. cent, of a decolorizing powder (tlie residues of blood-lye salt) previously dried at 140° C., and allowed to cool. One-tenth part of the mixture is then weighed out and extracted with benzol. The residue is dried at about 180 0 G.; the difference in weight gives the amount of wax. The operation takes about four hours, but does not require much attention. II. LUBRICATING- QUALITIES. Lubricating Values of Oils.—The following charac¬ teristics of an efficient lubricator are given in Spon’s “ En¬ cyclopaedia ” :— (1) Sufficient “ body ” to keep the surfaces, between which it is inter¬ posed, from coming into contact. (2) The greatest fluidity consistent with (1). (3) A minimum co-efficient of friction. (4) A maximum capacity for receiving and distributing heat. (5) Freedom from tendency to “ gum,” or oxidize. (6) Absence of acid and other properties injurious to the materials in contact with it. (7) High vaporization and decomposition temperature, and low solithfa- cation temperature. (8) Special adaptation to the conditions of use. (9) Freedom from all foreign matters. In testing an oil to ascertain how far it meets the above requirements, the following points should be investigated . 1 . Identification and purity 1 p>y general methods. 2 0 . Specific gravity J 3 0 . Viscosity; 4 0 . Gumming. — These can be both ascer¬ tained at once by noticing the time required by a drop to traverse a known distance. Or, a piece of blotting- paper dipped in the oil is held up to drain—symmetrical drops indicate good fluidity; a spreading tendency, viscosity. Retention of the oil on the paper for some hours at 93J 0 0 . TESTING OILS. 293 (200° F.), or for some clays at ordinary temperatures, will show rate of gumming. (See also p. 303.) 5 0 . Testing as to decomposition, vaporization, and ignition temperature. Animal and vegetable oils do not vaporize, but decompose at high temperatures. 6°. Acidity. (See p. 236.) 7 0 . Co-efficient of friction (i.e., the proportion which re¬ sistance to sliding bears to the force which presses the sur¬ faces together). (See p. 300.) The suitability of a lubricant depends on the work to be done, and is not constant. In order to procure the nearest possible approach to what is required for special purposes, compounds are used which are mainly mixtures of mineral and animal or vegetable oils in proportions calculated to give the particular properties required. The general experience gained tends to the following results : *— i°. A mineral oil flashing below 300° F. (149° C.) is un¬ safe, on account of causing fire. 2 0 . A mineral oil evaporating more than 5 per cent, in ten hours at 140° F. (6o° C.) is inadmissible, as a viscous residue is apt to be left, or the bearings are left dry. 3 0 . The most fluid oil that will remain in its place, ful¬ filling other conditions, is the best for light bearings at high speeds. 4 0 . The best oil is that which has greatest adhesion to metallic surfaces, and the least cohesion in its own particles. In this respect we have— 1. Fine mineral oils. 3. Neat’s-foot. 2. Sperm. 4. Lard oil. * Spok’s “ Encyclopaedia.’ 294 OILS AND VARNISHES. 5°. Consequently, finest mineral oils are best for light bearings and high velocities. 6°. The best animal oil to give body to fine mineral oil is sperm. 7°. Lard and neat’s-foot oil may replace sperm when great tenacity is required. 8°. Mineral oils alone are unsuitable for the heaviest machinery, on account of their want of body, and their high degree of inflammability. 9°. Well-purified animal oils are suitable for very heavy machinery. io°. Olive oil is the best of the vegetable oils, as it can be purified without the use of mineral acids. n°. The other vegetable oils, admissible but far inferior, stated in order are:— 1. Gingelly. I 3. Colza. 2. Ground-nut. | 4. Cotton-seed. 12 0 . No oil is admissible which has been purified by mineral acids. I 3°- The Best Mineral Oil for H as a sp. gr. at 6 o°F. (iS'S°C.) Evaporating .Point. Flashing Point. Cylinders. 0-893 Fahr. 5 5o° ■ Cent. . 288° Fahr. 680° . Cent. • 3 6o ° Heavy machinery o-88o 443 • . 229 578 • . 269 Light bearings & high velocities 0-871 424 ... 218 5°5 • . 262 For practically testing the lubricating values of oils, one of the following machines (Figs. 7, 9, 10, 11) made by Messrs. W. H. Bailey &, Co., of Salford, may be employed:— TESTING OILS. 29s i. Stapfer’s Apparatus.—In this machine, designed by H. Stapfer, the frictional surface steps (A A) are subjected to great pressure by the weights (B B) sliding on levers (C C), and capable of being fixed at any desired distance from the drum. A small quantity of the oil (about 2 drops) Fig. 7. is placed on the drum, or roller, and the machine is driven at 2000 revolutions per minute. That oil which permits the greatest number of revolutions to be made before the thermometer registers 200° F. is considered the best oil. The following table may serve as a guide to those using this tester:— 296 OILS AND VARNISHES. Name of Oil. (5 No. of Revolu¬ tions. Degree of Tempera¬ ture. No. of Detrees raised. No. of revolu¬ tions to 1 degree. Remarks. From To 1st (lay No. 1 ox $/6 i 3 .°°S 80 200 120 108^ 1st trial new oil and day Do. S/6 11,787 78 200 122 9 KL No fresh oil was added for the second trial 1st day Sperm oil 9 /- 16,944 6S 200 13s 1st trial new oil 2nd day Do. 9/ 13,104 62 200 138 94 x 11 No fresh oil was added for the second trial 1st day Minrl. oil 3/6 11,831 6S 200 135 87tsV 1st trial 2nd day Do. O O O O O 2nd trial, after standing 24 hours, the saddles were found to be so glued to the drum that the machine could not be started, though the belts were tightened, showing that the oil was of so gummy a nature as to he useless after once using. The results obtained may be recorded as in the following diagram, showing the revolutions required to produce fric¬ tional heat:— Fig. 8. WEcaco »iHl Hours and minutes may be observed instead of the exact TESTING OILS. 297 number of revolutions, as it really amounts to the same thing if the speed is anything like equal. Fig. 8 shows a simple design for diagram of comparative results attainable. The two lines illustrate the behaviour of two different samples of oil under test. The bottom line shows a splendid quality of prepared and purified sperm that, starting at a temperature of 67° F., has with 70,000 revolutions only attained 176°; while the other, an indifferent mixed oil, attains 200° with only 19,000 revolutions. By means of a diagram like this a permanent record of all tests can be kept for future guidance. If the diagram is made large enough, it may be used for a dozen different tests. A good way is to use a different coloured ink for each distinct oil. The following results were obtained by Mr. J. Yeitcii Wilson, of Manchester, by the Stapfer apparatus, but operating in a different manner from that recommended above. Wishing to ascertain the effect of different oils, as nearly as possible, under conditions of actual working, Mr. Wilson used 10 or 12 drops of oil, and ran the machine for one hour and a half, noting the time taken to get up full speed, the temperature attained and maintained during each experiment, and, in the case of some oils, the point at which they began to smoke and the condition of the brasses after each trial. Each oil w T as tested three times—once in the morning, once in the forenoon, and once in the afternoon, and the instrument was thoroughly cleaned between each test. The figures in last column, headed “ Heat,” represent the average maximum temperature maintained during three tests of an hour and a half each, of each oil examined, save in the case of the mineral oils, the trials of which had to be stopped in from thirty to sixty minutes, as the oil became 298 OILS AND VARNISHES. by that time exhausted, and there was danger of spoiling the tester. Name of Material. Sp. gr. at 6o°F. 1. Rody, in Seconds, at Heat Developed. S- 6o° F. 2. 120° F. 3 - 180 0 F. 4 - Wafer. IOOO Fahr. Castor oil. 960 — 132 41 15S 0 Resin oil ...... 990 — — 155 Engine tallow . Solid 41 26 '1'allow or animal oil — M3 37 25 141 Neat’s-foot oil . — 112 40 29 Rape oil. 916 108 41 3° 148 Lard oil. 916 96 38 28 146 Olive oil. 915 92 37 28 143 Sperm oil .. 880 47 30 25 133 Mineral oil. 905 45 121 )) . 875 30 — — 117 The figures in the second, third, and fourth columns indicate in seconds the relative “body” of each oil at 6o°, X2o°, and 180° F., obtained by noting the time taken by a given quantity of oil in flowing through the orifice of Townson & Mercer’s viscosity apparatus (see Fig. 13, p. 306). Mr. Wilson points out that there is a uniform coincidence between the body or thickness of the oil, as shown in columns 2, 3, and 4, and the temperature developed by each, as shown in the last column. The only apparent discrepancy occurs in the case of tallow oil, which, although much thicker than rape, lard, or olive oil, at 6o° F. develops a lower temperature than these; but if attention be directed to the respective bodies of these oils at 120° F., and more particularly at 180° F., it will be found that the anomaly disappears, and the irregularity may be explained by the fact that, as tallow oil frequently contains a good deal of TESTING OILS. 299 * Directions for using Thurston’s Friction Apparatus—Test the lubricant at the pressure under which it is proposed that the journal on which it is to he used shall run. The machine is fitted for a wide range of pressures, as is seen on the index-plate M FT, on the pendulum H H (Fig. 9), where the large figures represent the total pressures on the journal, and those opposite, the cor¬ responding pressures per square inch. Ihe speed of the machine, when the belt is upon the largest pulley of the cone C, should he that which will give the least speed of rubbing at the surface of the testing journal, which is to be usually adopted. Co-efficient of Friction .—'Ihe figures on the arc P P, traversed by the pointer 0, attached to the pendulum, are such that the quotient of the stearine, a higher temperature may be required to thoroughly liquefy it than is required by the other oils. Fm. 10. 2. Thurston’s Apparatus.— This is the invention of Prof. E. H. Thurston, of Hoboken, Hew Jersey.*' Figs. 9 300 OILS AND VARNISHES. and io are illustrations of the machine—differing slightly in form, but identical in principle. In each there is a journal carrying a small shaft in two bearings. The journal is grasped by brass steps which are in connection with a pendulous weight and are forced against the journal by means of a screw which com¬ presses a coil spring. The amount of this pressure is indicated on a scale like that of a spring balance. A “ bob ” at the end of the pendulous arm gives the weight necessary to resist deflection. The angle of deflection is measured on reading on the arc P P, by the total pressure read from the front of the pendulum at M N, gives the “ co-efficient of friction ”— i.e., the propor¬ tion of that pressure which measures the resistance due to friction. A printed table is furnished with each machine, giving these co-effi¬ cients for a wide range of pressures and arc-readings. To determine the Lubricating Quality .—Remove the pendulum H H from the testing journal G G, adjust the machine to run at the desired pressure by turning the screw-head K projecting from the lower end of the pendulum, until the index M above shows the right pressure ; adjust it to run at the required speed by placing the belt on the right pulley C. Throw out the bearings by means of two little cams on the head of the pendulum H in the small machine, or by setting down the brass nut immediately under the head in the large machine. Carefully slide the pendulum upon the testing-journal G G, and see that no scratching of journal or brasses takes place. Oil the journal through the oil-cups or the oil-holes ; set the machine in motion, running it a moment until the oil is well distributed over the journal. Next stop the machine ; loosen the nut or the cams which confine the spring, and, when it is fairly in contact and bearing on the lower brass with full pressure, turn the brass nut or the cams fairly out of contact, so that the spring may not be jammed by their shaking back while working. Now, start the machine again and run until the behaviour of the oil is determined, keeping up a free feed throughout the experiment. At intervals of one or more minutes, as may prove most satisfactory, observe and record the temperature given by the thermometer Q Q, and the reading indicated on the arc P of the machine, by the pointer 0. When both readings have ceased to vary, the experiment may be terminated. Remove the pendulum, first relieving the pressure of the spring, and TESTING OILS. 301 an arc or quadrant in such, units that the division of the figures may be read off’, and give, not only the angle of deflection, hut also the co-efficient of friction. A thermo¬ meter on the top brass gives the temperature in a manner similar to that of the Stapfer tester. The machine is used much in the same way as that previously described. It is employed in the engineering department of the United States Navy and by various Railway Companies. The following table gives the results of experiments conducted under the personal direction of Prof. Thurston, the rubbing surfaces being driven at the rate of 750 feet per minute:— Co-efficients of Friction and Endurance of Lubricants. Name of Oil. Pressure. Endurance. Rise of Temperature. | Co-efficient. Name of Oil. | Pressure. | Endurance. Rise of 1 Temperature. Co-effieient. lb. Min F. lb. Min F. f S III 230 C13 f 8 107 185 o'i6 Sperm—winter l6 29 225 O'lO Cotton-seed. l6 45 275 0*12 (. 48 9 195 o'o8 c 48 12 310 o'o7 c 8 I^O 0-13 r 8 49 i 95 o’i7 ,, summer.... s l6 33 21S 0*11 Palm.-< l6 15 335 o'i3 (. 48 7 265 0*10 (. 48 9 295 o'o7 r 8 77 i 75 o‘i6 c 8 45 160 0*19 Lard.j l6 27 250 O'12 Castor.-j l6 35 180 0*11 l 48 I I 2bO o’o7 V 48 II 375 0*07 ( 8 106 2°$ °'I 3 ( 8 40 200 °'i 5 Neat’s-foot .•{ l6 31 273 o‘io Cod .4 l6 14 175 O* I 2 t 48 6 190 0*10 (. 48 9 220 0*07 f 8 83 I^O 0T3 ( 8 129 i °5 O'lO Olive. < l6 4 i 243 0*10 Crude Mineral l6 97 285 o’10 l 48 14 240 o'o6 48 5 270 O’lO clean the journal and brasses with exceedingly great care from every sign of grease; and he especially careful not to leave a particle of lint on either surface, or any grease in the oil-cup or oil-passages. A comparison of the results thus obtained with several oils will show their relative values as reducers of friction. In each case, record in tables like the blanks sent with the machine:— 302 OILS AND VARNISHES. This high speed was purposely chosen, otherwise the trials under moderate pressure might occupy many days. It will he observed that, in addition to giving the time of endurance in minutes, the pressure per square inch on the journal has been noted, as well as the rise of temperature and the co-efficient of friction. It will also be seen that the various lubricants were tested with 8 lb., with 16 lb., and with 48 lb. pressure per square inch, so that the behaviour of each oil under heavy and light pressure could be criticized. 3. Pendulum Test.—Mr. Bailey has designed a pendu¬ lum test which may be found useful in testing oils which will not be subjected to heavy pressures, such as those for clocks and watches, and light spindles. It consists of a pendulum (Fig. 11) to which is attached a link, which imparts a reciprocating motion to a small piece of brass. By simply placing one drop of oil on the surface of the brass and noticing how many times different oils will permit the pendulum to vibrate without stopping, useful information may be obtained about the value of a lubricant when not sub¬ jected to heavy wear and tear. The behaviour of an oil may 1. The pressure and speed of rubbing at each trial. 2. The observed temperature. 3. The readings on the arc of the machine. 4. The calculated co-efficients of friction. Enter at the end of the trial the average and the minimum co¬ efficients, and the total distance rubbed over by the bearing surfaces. An Approximate Value, by which to compare the oils, can be calcu¬ lated, based on the assumption that they will have a money-value proportionate to their durability and to the inverse ratio of the value of the co-efficient of friction. Thus: suppose two oils to run, the one ten minutes and the other five, under a pressure of 100 lb. per square inch, and both at the same speed, and suppose them to give on test for friction the co-efficients o - io and o - o6 respectively. Their relative values might be taken at ££ = 1, and £- = C833. If the first is worth say 100 pence, the second should be worth 83^ pence. TESTING OILS. 303 Fig. 11. be also noticed when subject to atmospheric influences by taking note of the different vibra¬ tions, with one, two, or more days of an interval ; it may thus indicate any process of deterioration and any incapacity to resist oxidation and tendency to become varnish. This mode of testing may be valu¬ able to those who have not steam power to drive the Thurston or Stapfer testers, and, the inventor claims, it will give, in a very definite manner, the test for oxidation after exposure, quicker, probably, than those instruments. Viscosity.—The determination of the viscosity of oils is of great importance in forming a judgment as to their relative value for lubri¬ cating purposes. Lamansky * uses the apparatus represented in Fig. 12. The arrangement consists of two concentric cylindrical vessels of sheet brass. The inner one serves for the reception of the oil, and is provided with a metal tube having a bore 1 mm. wide. The latter can oe closed by means of a sliding, shutter at the bottom of the out.^12 !% 1111. , , i n side vessel. The oil to be tested Pe , ldulu fTw “ n Te»t. having been introduced into the * “ Dingl. Pol. Journ.” 248, 29; “J. Soc. Chem. Ind.” ii. 417. 3°+ OILS AND VARNISHES. Fig. 12 . inner vessel, the outer one is filled with water, which, by means of a steam pipe, can he heated to the desired tem¬ perature. As soon as the oil is of the required temperature the slide is drawn, and i oo c.c. of the oil are allowed to run out through the narrow tube, the time occupied being noted. Taking the time occupied in running out ioo c.c. of water from the same appara¬ tus as unity, the viscosity of the oils can be expressed by the ratio existing between this time and that required by oil at the same tempera¬ ture. This ratio Lamansky calls “ specific viscosity.” It is desirable that the viscosity should be determined at, at least, three different temper¬ atures—say io°, 30°, and 50° C.—as the viscosity of oils exhibits great differences at various temperatures. The following are the spe¬ cific viscosities of various oils obtained by this method:— TESTING OILS, 305 Name of Oil. Sp. gr. at 15 0 C. Spec, viscosity at 19 0 C. Cylinder oil, G. •917 191 Machine oil, I a, G. •914 102 Wagon oil, G. •914 80 >> It. •911 70 Naphtha residues, N. •910 55 Oleo-naphtha, 0 , ft... •910 121 Wagon oil, 0 , G. •907 60 Machine oil, x b, G. •907 59 Oleo-naphtha, 1, R.. •904 66 Machine oil, 2, G. •898 20 Oleo-naphtha, 2, R. Oleonide, 16, R. •894 20 •884 28 1, 12, R. •881 24 „ best quality, R. •881 26 Olive Oils. Huile vierge . •916 23 01. prov. opt. rect. I. •916 22 „ II. •916 22 Sperm Oils, Winter oil . •879 9 Summer oil . •875 8 In practice it will be found desirable for each operator to determine his own rates for the oils he examines, as the results by different apparatus are not strictly com¬ parable. Coleman found the following figures:— Oils Examined. Equal Measures required the following Number of Seconds to run out at Jo 0 C. Olive . 495 Colza (French refined). 660 Earth-nut . 480 Sperm. 300 Seal . 390 Whale . 460 Neat’s-foot. 510 Lard . 420 Tallow . 45 ° x OILS AND VARNISHES. 306 Another convenient viscometer is one manufactured by Messrs. Townson & Mercer, and represented in Fig. 13. Fluidity of Oils.—It is often advantageous to compare the thinness or fluidity of oils at increased temperatures. The following arrangement, shown in Fig. 14, designed by Mr.W. H. Bailey, affords a ready method for testing oils in this way:— It consists of a tin box in which is fixed at an angle a piece of plate-glass 12 inches in length. A thermometer can be seen through it. A graduated scale at the side of the box enables the track of the oil to be measured. The box has a door at the back through which a coppervessel full of boiling water can be introduced. The box is lined with felt to prevent rapid radiation, and, when the door is closed, several experiments may be conducted before the apparatus becomes too cool for use. At the commencement the thermometer should indicate 200° F., and a drop of the oil being then placed upon the upper end of the glass will flow down a few inches, and thus the varying fluidity of oils subjected to increase of temperature may be compared. There are many oils, otherwise good lubricants, which become too thin when exposed to slight heat. Watchmakers’ oil should be tested both by heat and cold. If, after exposure to the temperature of 200° F. as above, the oil dries to a var¬ nish in two or three days after the test, it is considered unfit TESTING OILS. 307 for use. The “ cold ” test is applied thus:—15 parts of Glauber s salt are put into a small glass vessel, and a small bottle of the sample is immersed in this. A mixture of 5 parts of hydrochloric acid and 5 parts of cold water is Fig. 14. then added. The temperature is ascertained by a ther¬ mometer, and the behaviour of the oil noted. Instead of the freezing mixture mentioned, pounded ice, or a mixture of ice and common salt, may be employed. The following tests for the purity of mineral lubricating oils have been proposed by P. Falke :*■— i°. Colour .—The oil must be perfectly clear, and as light as possible. It should not be turbid, which may be caused by the presence of water or other substances. If the tur¬ bidity is due to water, the sample froths on heating, whereas turbidity caused by solid matters, such as paraffin, dis¬ appears on warming and reappears on cooling. * “Chem. Zeit.” 9, 906; “ J. Soc. Chem. Ind.’’ 1885. 3°8 OILS AND VARNISHES. 2°. Smell .—This should be as little as possible, and should not increase on warming. 3°. Behaviour with Water .— If 3 parts of oil be shaken with 1 part of water in a test-tube, warmed, and allowed to stand in a water-bath for some time, no emulsion must appear between the water and the oil, but the latter should stand clear above the water, which should be only faintly opalescent, and perfectly neutral. 4 0 . Behaviour with Caustic Soda .—The oil should not be attacked by a caustic lye of 1*40 sp. gr., either in the cold or on warming. Saponification indicates either animal or vegetable fat. 5 0 . Behaviour with Sulphuric Acid .—On mixing with sul¬ phuric acid of sp. gr. r6o, it must not be coloured brown, but yellow at the most; otherwise, resins have not been care¬ fully removed. 6°. Behaviour with Nitric Acid .—On mixing with nitric acid of sp. gr. 1*45, a rise of temperature takes place, but this should not exceed a certain limit. 7 0 . Behaviour on Exposure to Air and Heat .—Spread in a thin layer and exposed to the air for some time, its con¬ sistency must not change, and it should not become acid on being heated continuously above 150° C. Heated in open vessels, it should not give off combustible vapours, except at a high temperature, which is usually specified in contracts. Its flashing point should be ascertained by Abel’s appa¬ ratus. 8°. Behaviour at a Low Temperature .—It should bear a low temperature without losing its lubricating power, and it should not become solid even with very great cold, but should rather assume the appearance of an ointment. g°. Consistency .—This determination is most important. The velocity of efflux of pure rape-seed oil is taken as a standard and that of the mineral oil compared with it. TESTING OILS. 309 100 c.c. of the sample are allowed to flow out of a burette with tap, and the time noted. Or, one of the several viscometers is used. io°. Specific Gravity .—Oils suitable for various machinery range in sp. gr. from ©‘875 to 0^950, but only a small latitude ('003 at most) is allowable in contracts. Comparison of Russian and American Lubricating Oils.* Russian. American. Refined Rape Oil (for com¬ pari¬ son). Viscosity. Sp. gr. '913 Sp. gr. ' 9°7 Sp. gr. •898 Sp. gr. •914 Sp. gr. ' 9°7 Sp. gr. •891 At 70° F. 1400 649 i 73 231 171 81 331 At i2o u F. 166 i 35 56 66 58 40 112 Loss in viscosity per cent. 88 79 67 71 66 S° 6S Russian lubricating oil, besides being, as a rule, prac¬ tically free from solid hydrocarbons, and therefore bearing exposure to very low temperatures without becoming solidified and clogging the bearings of machinery, has a remarkably high viscosity, in relation to its specific gravity. Notwithstanding its high viscosity Russian oil rapidly loses “ body ” upon being raised in temperature, and a reference to the viscosity figures for temperatures of 70° and 120° F. in the above table will show that this is the case, the loss of viscosity between the two temperatures being, in the case of the sample having a sp. gr. of ’907, 79 per cent., against 66 per cent, in the case of an American sample of the same sp. gr. Where, however, it is desirable to employ an oil of high viscosity at comparatively low temperatures, as in the lubrication of slow-running heavy machinery, the Russian product is superior to the American. Moreover, it may bo * Boverton Kedwood, “ J. Soc. Chem. Ind.” 1885, 77. 3io OILS AND VARNISHES. urged that it is because of its high viscosity that the Russian oil is so much affected by rise of temperature, for it will be noted that in the case of the American oils, as well as in that of the Russian oils, the percentage of loss increases with the viscosity, the oils of greatest body being most affected. III. ILLUMINATING EFFICIENCY. In deciding upon the relative illuminating efficiency of oils it is first necessary to determine whether or not the sample is a pure specimen. For certain uses, it is also desirable to determine the behaviour of the oil when submitted to low temperatures, and to ascertain its solidify¬ ing point. It should then be tested side by side with a standard sample, as to the duration of the combustion of equal weights of the two oils, the lamps and wicks, of course, being of similar construction and dimensions, and all the other conditions of the experiment being also exactly parallel. Some form of the Argand lamp is the most suitable for this purpose. The wick must be trimmed and slightly charred before the commencement of the operation, the lamps and contents weighed, the lamps lighted and placed in position. The duration of the test depends upon the purpose for which the light is required, and may extend from six to sixteen hours. During the combustion, photo¬ metric observations may be taken at intervals. There are various photometers for measuring the illumi¬ nating intensity (e.g., Bougner’s, Rumford’s, Wheatstone’s, Ritchie’s, Bunsen’s, and others), but the limits of this volume do not permit a detailed description of each. The fundamental principle on which all depend is the law that the amount of light which falls on any given surface placed oppo¬ site to the light is inversely as the square of the distance of TESTING OILS. 3ii the surface from the light. The standard of comparison, and, at present, the only legal standard in England, is a sperm candle, of six to the pound, which burns ordinarily at the rate of 120 grs. per hour. This amount of light is the “ unit ” of illumination. Owing to fluctuations, however, in the rate of burning, no reliable determinations can be made without weighing the candies before and after each experi¬ ment. Instead of using candles themselves as a standard, the Keate’s Moderator lamp,* burning sperm oil, may be used. This is suspended at the end of the photometer bar by means of a collar with lateral steel plates which rest on the knife-edges of the forked extremity of the balance. It is provided with a Methven screen, having a slit of such a size as to allow a portion of the whole light of the lamp equal to that of 2 candles to pass through it. When the wick is turned up so as to give a flame of 2 inches in height, the lamp burns at the rate of 925 grs. of sperm per hour. Or, the gas Referees’ burner, consuming 5 cubic feet of gas per hour, provided with the Methven slit, allowing a light equal to that of 2 candles to pass through, may be em¬ ployed, and, when gas is available, this is the most con¬ venient method, as it does away with the necessity, so far as the standard is concerned, of weighing. Rumford’s photometer consists of a screen of white paper, before which is placed, on a table in a dark chamber, a black cylindrical rod. In operating, the two lights to be compared are so placed that two shadows are thrown upon the screen side by side, with an interval between them about equal in breadth to either shadow. The weaker light is then brought nearer to the screen till the intensity of each shadow is equal. The respective distances of the lights from the screen are next measured, or read off from * Made by Messrs. Sugg & Co., Westminster. 312 OILS AND VARNISHES. fixed scales, on the table. The illuminating powers will be in direct ratio of the squares of the distances. Thus, suppose the standard candle or lamp to be 2 feet from the screen, and the light under examination at the distance of 8 feet from the same, then = 6 T 4 = 16 ; i.e., the light afforded by the sample is equal in intensity to that afforded by 16 candles. If 2 candles have been used, or a lamp having the light equal to 2 candles, the result must be doubled. Sir William Thompson says the “shadow” method of Rumford will give, with care, results within 2 or 3 per cent, of accuracy. Bunsen’s photometer, or some modification of it (Letheby’s or Evans’) is the one generally employed in this country for testing illuminants. In it there is a sheet of thin paper, with a circle, or preferably a star, in the centre, rendered translucent by being impregnated with a mixture of benzol and spermaceti. The light to be tested is placed on one side the disc, and the standard light on the other side. The first is generally kept stationary, while the latter can be moved towards or from the disc till both sides are equally illuminated. A graduated scale then shows at a glance the number of standard candles to which the light is equal, or the distances may be measured and the calculation made as already described. When the lamps are finally weighed, an examination is made as to the degree of charring which the wicks have sustained. An average is struck of the photometric obser¬ vations taken during the testing of the duration of combus¬ tion. Those oils are to be preferred which, cceteris paribus , show the least falling off in light intensity towards the end of the trial. The following calculation has to be made when the stan¬ dard candles used do not burn at the normal rate of 120 grs. per hour. Suppose, for example, in burning ten minutes TESTING OILS. 313 the candle has lost 21 grs. instead of the normal 20 grs., and that the average light during the ten minutes, read off from the scale or calculated, is 6 candles. Then, as 20 : 21 :: 6 : 6-3 standard candles burning at the normal rate. The value of an oil expressed in terms of the “ unit ” of illumination may be found as follows:—Suppose that in burning for one hour an oil lost in weight 54 grs., and gave during that time a light equal to a sperm candle burning at the rate of 120 grs. per hour, then 120 x 70,000 (grs. in gallon)* 54 x 7,000 (grs. in lb.) = 22 2 i.e., 1 gallon of the oil is equal to 22'2 lb. standard candles. The following table by Dr. Frankland shows the illumi¬ nating equivalents of different light-givers :— Paraffin oil . . Quantities producing an Equal Amount of Light. ° 0 .1 gallon Rock oil . 1-25 „ Paraffin candles . . 18-6 lb. Sperm ,, . 22 '9 „ Wax „ » • • 26-4 „ Stearin „ . • • • 27-6 „ Composite ,, . . . 29 "f ,, Tallow ,, 36-0 „ Cost of Light equal to 20 standard sperm candles burn- ing for ten hours at the rate of 120 grs. per hour (Frank land) : — s. d. 8 . d. Wax . . . 7 Benzene „ 0 ( 0 4 Sperm , « . 6 8 Coal gas . 0 a 0 4] Tallow . „ 2 8 Cannel gas . .03 Sperm oil . 1 10 Petroleum or Rock oil 0 3 Cost of Petroleum as an Illuminant. —Experiments * If the sp. gr. of the oil were (say) C870, then the gallon would weigh 70,000 x "87 = 60,900 grs., instead of as above. OILS AND VARNISHES ,. 314 have been made by Messrs. B. and T. H. Redwood* as to the comparative cost of a given amount of light from petroleum oil, colza oil, and coal gas. The following table shows the mean results for the amount of light which would be ob¬ tained by burning a standard sperm candle for 1000 hours: Cost of 1000 “ Candle-hours.” From Petroleum Oil. From Colza Oil. From Coal Gas. Price per gallon. Price per gallon. Price per 1000 cubic ft. d. 9 s. d. I 0 s. d. 1 3 s. d. i 6 8 . d. 3 0 8 . d. 3 6 8 . d. 4 0 s. d. 3 0 s. d. 3 6 8. d. A 0 d. 74 d. 9| d. Hi s. d. 1 3 8. d. 2 4 s, d. 2 8 8. d. 3 0£ 8. d. 1 3 s. d. 1 0 ^ 8. d. 1 8 These numbers show that, taking petroleum oil at is. per gallon, and colza oil at 3s. 6 d. per gallon, the cost of a given amount of light is more than three times greater for the latter than for the former ; and that, taking petroleum at is. per gallon, and coal gas at 3s. 6d. per 1000 cubic feet, a given amount of light from the former costs only about half what it does when obtained from the latter, while there is the additional advantage that properly purified petroleum oil in burning does not produce sulphur-compounds. 1" The “ Carcel,” a mechanical lamp invented in 1800, by Carcel, of Paris, is the legal standard in France. The oil is forced into the wick at the foot of the reservoir by means of a pump moved by clockwork. It requires winding up * “ Chemist and Druggist,” Dec. 15, 1879. f The Trinity House Committee have recently reported on the rela¬ tive cost and efficiency of electricity, gas, and oil as illuminants, and conclude that, “ for all practical purposes, gas and oil are equal,” and that, “ for the ordinary necessities of lighthouse illumination, mineral oil is the most suitable and economical illuminant.”—“Nature, 1886, 273. TESTING OILS. 3 T 5 once in twelve or fifteen hours, and in burning seven or eight hours the action is said to be sufficiently uniform to maintain a light of equal intensity for that time. It should burn at the rate of 42 gms. (or 648’14 grs.) of colza oil per hour, and, under these circumstances, the French authori¬ ties claim that the light is equal to that of ten English sperm candles, but, according to the experiments of Mr. Dibdin, the average light so obtained is only equal to 9^5 average sperm candles. Formerly, Kumford’s shadow test was used with this lamp, but this has now been superseded by the Bunsen disc.* * Standards of Light.—The Committee appointed to examine the standards of white light report that the present standard candle, owing to the fact that the spermaceti is not a definite chemical substance, and that the constitution of the wick is not sufficiently well defined, is not, in any sense of the word, a standard; that the French “ Carcel” is also liable to variations ; and that the difficulty of applying the molten platinum standard, proposed by Violle, is so great as to render its general adoption almost impossible. The majority of the Committee feel satisfied that, for all present commercial requirements, the Pentane (C 5 Hj„) standard of Mr. Vernon Harcourt —since it has no wick, and consumes a material of definite chemical composition—when properly defined, is an accurate and convenient standard, and gives more cor¬ rectly than the so-called standard candle an illumination equal to that which was legally intended. They, however, consider that further in¬ vestigation is necessary before any standard can be recommended for tmiversal adoption.—“Nature,” 1886, 236. CHAPTER X. RESINS AND VARNISHES. A varnish — Syn. Vernis (Fr.), Firniss (Ger.)—is any liquid matter which; when applied to the surface of a solid body, becomes dry and forms a hard, glossy coating, imper¬ vious to air and moisture. Varnishes generally consist of some resinous substance dissolved in a volatile liquid, which on evaporation leaves the resin in the form of a film. They are commonly divided into two classes—(a) oil varnishes, (b) spirit varnishes —according to the substance employed as the vehicle or solvent. For oil varnishes the solvents are fixed or volatile oils, or mixtures of them. The fixed oil used is generally pale linseed, but poppy and nut oils are also employed. The volatile oil is generally oil of turpentine, which should be pure and colourless. Turpentine varnishes dry more readily than fixed oil varnishes, are of a lighter colour, more flexible, and cheaper. They are, however, more liable to crack, and are less durable. The drying of spirit varnishes is due to the evaporation of the spirit, but the drying of oil varnishes is due to oxidation. For spirit varnishes the solvents are spirits of wine, of not less strength than 67 o.p. (sp. gr. ’8156), and naphtha or methylated spirits for the cheaper kinds. A little cam¬ phor is sometimes dissolved in the alcohol to increase the solvent power. Spirit varnishes are the most rapid in dry- RESINS. 3*7 ing, but are still more apt to crack and peel off than turpentine varnishes. The principal substances which are dissolved in the above menstrua are the following :— For body and lustre. Amber Anime Copal Elemi Lac Mastic 2*. For odour. Benzoin 3 o For tinctorial effect. Annotta Gamboge Saffron Socotrine aloes Turmeric Dragon’s blood 4 0 . For black colour and body. Asplialtum 5°. For toughness and elasticity. Caoutchouc Sandarac Bed sandal wood Cochineal Indigo Resins, which are so largely used in the preparation of varnishes, are compounds of vegetable origin, exuding spon¬ taneously from plants, or from incisions in the trunk or branches, and hardening on exposure to the air. From observations on the resinification of essential oils, Dragen- dorfp * expresses himself in favour of the theory that all resins are formed by the oxidation of hydrocarbons. Resins containing gum or mucilage are called gum resins; those containing volatile oils are called balsams. The resins cannot be very accurately defined, but in a general way they may be described as substances which are solid at ordinary temperatures, more or less transparent, * “ Archiv der Pharm.” [3] xv. 50. OILS AND VARNISHES. 3i8 inflammable, readily fusible, do not volatilize unchanged, become negatively electrified by rubbing; are insoluble in water, but soluble in alcohol; mostly inodorous, and readily incorporated with fatty bodies by fusion. Their specific gravity varies from 0-9 to 1*2. The following is a brief description of the resins and other substances chiefly used in varnish-making:— Amber.— Syn. Electron, Gr.; Electrum succinum (Ph. D.), L.; Ambre, Succin, Fr.; Bernstein, Ger.; Lynx- stone, Lapis lyncis. —A well-known, yellowish, semi¬ transparent, fossil resin, of which trinkets and the mouth¬ pieces of pipes are commonly made. It is found in detached pieces on the sea-coast, and is dug up in diluvial soils. The amber of commerce comes chiefly from the southern coasts of the Baltic, where it is cast ashore between Konigsberg and Memel, and from Germany, Poland, Sicily, and Maryland (U.S.), where it is dug out of beds or mines. It has also been found on the shores of Nor¬ folk, and small pieces are occasionally dug up in the gravel pits around London. It is probably an antediluvian resin, and when found on the coast is supposed to have been separated, by the action of the sea, from neighbouring beds of lignite. Much diversity of opinion formerly prevailed amongst naturalists and chemists as to the origin of amber, but its vegetable origin is now generally admitted. According to Sir David Brewster,* its optical properties are those of an indurated vegetable juice. Insects and vegetable fragments are frequently found imbedded in it, and this in a manner which could only have occurred when the resin was a viscid fluid. Microscopical researches have led to the conclusion that it is the production of some species of pine, closely allied to Pinus balsamea. f * “Edin. Phil. Joum.” ii. t “Entom. Transac.” i. and'ii. RESIJVS. 319 Prop. Hard ; brittle; tasteless; glossy; generally trans¬ lucent, but sometimes opaque, and occasionally, though rarely, transparent; colour generally yellow or orange, but sometimes yellowish-white; becomes negatively electric by friction; smells agreeably when rubbed or heated ; fracture conchoidal and vitreous or resinous; soluble in alkalies and, without decomposition, in oil of vitriol, which then becomes purple; insoluble in the essential or fixed oils without long digestion and heat • soluble in chloroform ; melt's at about 55 o°F.; burns with a yellow flame, emitting at the same a peculiar fragrant odour, and leaving a light and shiny coal. By dry distillation it yields inflammable gases, a small quantity of water, a little acetic acid, a volatile oil (oil of amber, Oleum succini), at first pale, afterwards brown, thick, and empyreumatic and succinic acid (Acidum suc- cinicum) with 12 to 13 per cent, of residual charcoal. Sp. gr. ro65 to i'09, but usually about 1*07 (1-074 to 1-094, Hager). It cannot be fused without undergoing more or less chemical change. Amber may be known from mellite and copal, both of which are occasionally substituted for it, by the following characteristics:—1. Mellite is infusible by heat, and burns white. 2. A piece of copal, heated on the point of a knife, catches fire, and runs into drops, which flatten as they fall. 3. Amber burns with spitting and frothing, and when its liquefied particles drop they rebound from the plane on which they fall (M. Hauy). 4. Neither mellite nor copal yields succinic acid by distillation, nor the agreeable odour of amber when burnt; nor do they become so readily elec¬ tric by friction. 5. The “ bromine absorption ” of amber is much lower than that of copal. The chief use of amber is to be made into the mouth¬ pieces for pipes, beads for necklaces, and other ornaments and trinkets. It also forms the basis of several varnishes. 320 OILS AND VARNISHES. In medicine, it was formerly given in chronic coughs, hysteria, &c. ^ The finer sorts of amber fetch very high prices. A piece i lb. in weight is said to be worth from to ;£i5» 5000 dollars are said to have been offered, some years since, in Prussia, for a piece weighing 13 lb. It is more valued in the East than in England, chiefly, perhaps, on account of the Turks and other Orientals believing it to be incapable of transmitting infection. In the royal cabinet, Berlin, there is a piece weighing 18 lb., supposed to be the largest ever found. The coarser kinds alone are employed in medicine, varnishes, &c. Amber may be coloured by heating in linseed oil to about 150° or 200 0 C. Dragon’s-blood, alizarin, purpurin, and indigo will all dissolve in this oil, and are not decomposed at the temperatures mentioned. Fuchsine, aniline violet, methyl green, and alkali blue will not dissolve in linseed oil. The oil and colouring matter are mixed in weighed quantities, the amber hung in the mixture, and the whole heated to ic)0 0 -2oo 0 , kept at that temperature for a few minutes, and then allowed to cool slowly to the temperature of the air. By varying the amounts of colour used, different tints are produced; e.g., indigo gives a lighter or darker green, dark blue, or black, according to the quantity used. To obtain pure colours, the bath should be changed from time to time, except for black, when it is not so necessary.* Natural amber is adulterated to a large extent with colophony,t and insects, moss, &c., such as occur in genuine amber, are introduced into the substitute in order to heighten the deception. The artificial product is, however, * Hanausek, “ Chemisches Centralblatt,” 15, 461 > " J* Soc. Chem. Ind.” 1884, 491. t “ Chem. Zeitung,” 56, 1035 ; “ Oil and Paint Rev.” 1, 6 ; “ J. Soc. Chem. Ind.” 1882, 459. RES/NS. 32 r easily known by the fact that it melts at a much lower tem¬ perature than true amber. Pieces also of genuine amber, after softening the edges with caustic potash solution, can be joined together very easily, while fragments of the fictitious article,, similarly treated, will only re-unite with great difliculty. Anime.— Syn. Gum-amim*, A. resin, Amaifi (Fr.), Anime- Harz, Kourbarill-Harz (Ger.), Courbaril jutaiba (Nat.). —A pale, brownish-yellow, transparent, brittle resin, which exudes from the Hymencea courbaril (Linn.), or locust-tree, the H. martiana, and other species of Ilymcncea growing in tropical America. It contains about o - 2 per cent, of volatile oil, which gives it an agreeable odour; melts without decomposition; is (nearly) insoluble in alcohol and in caoutchoucine, but forms a gelatinous mass in a mixture of the two (Ure). It burns readily, emitting a very fragrant smell. Sp. gr. 1*054 to 1-057. It is used as a fumigation in spasmodic asthma; in solu¬ tion, as an embrocation; and in powder, as a substitute for gum guaiacum. In this country, however, its chief use is in varnishes. Benzoin.— Syn. Gum benzoin, Benjamin, Gum benjamin, Benzoinum (Lat.), Benjoin (Fr.), Benzol (Ger.).—The bal¬ samic resin exuded from incisions made in the stem of the Sty rax benzoin, a native of Sumatra, Java, Borneo, Laos, and Siam. Odour, agreeable, somewhat like that of vanilla, but more balsamic , fracture, conchoidal; appearance, greasy ; sp. gr. 1-063 to 1'092. According to Hager, the sp. gr. of Siam benzoin is 1-235; Penang benzoin, 1-145 to 1-155; and of Borneo benzoin, from 1-165 to 1-170. It fuses at a gentle heat, and exhales white fumes, which, on condensation, are found to be benzoic acid contaminated with a little volatile oil. Alcohol dissolves the larger portion of it, ether much less, and the volatile and fixed oils only a little. It contains Y 322 OILS AND VARNISHES. from 9 to 18 or 20 per cent, of benzoic acid, according to quality. It burns with an agreeable odour. The resin and its alcoholic solution strike a bright-red colour with oil of vitriol, and a green colour with perchloride of iron. It is chiefly employed in perfumery, and as an ingredient in incense, fumigating pastilles, &c .; also in court-plaster, in certain cosmetics, and to scent the varnish used for snuff¬ boxes, walking-sticks, &c. Colophony. — Syn. Rosin.— This is the residue remaining in the retort after the distillation of common turpentine. When it retains some water, it is known as white and yellow resin, and is in this state translucent. When deprived of water by fusion, it is called brown or black resin, colophony, rosin, or fiddler’s rosin. Rosin is a brittle, tasteless, and almost inodorous substance, of a smooth shining fracture. Sp. gr. about ro8o. Hager finds the sp. gr. of pine resin 1-083-1 ‘084, and of very dark colophony i’ioo. It softens at 160° F. Fuses at 275 -P* Resin, or Rosin, Oil .—This is a product of the dry distillation of resin. The apparatus for its production con¬ sists of an iron pot, a head-piece, a condensing arrangement and a receiver. In distilling the resin, a bright oil first comes over with water. As soon as a cessation in the flow of the distillate occurs, the receiver is changed, and the heat is further raised, when a red-coloured and heavy rosin oil comes over. The black residue remaining in the pot is used as pitch. The light oil, called “ pinoline,” is rectified, and the acetic acid water, which passed over with it, is saturated with calcium hydrate, filtered, and evaporated to dryness, and the calcium acetate obtained is employed in the manufacture of acetic acid. The rosin oil, obtained after the light oil has passed over, has a dark violet-blue colour, and is called i( blue rosin oil.” The red oil is boiled for a day with water, EES/NS. 323 the evaporated water being returned to the vessel; next day the water is drawn off, and the remaining rosin oil is saponi¬ fied with caustic soda lye of 36° Baume, and the resulting solid mass is distilled so long as oil passes over. The product obtained is “rectified rosin oil,” which is allowed to stand in iron vessels protected by a thin layer of gypsum, whereby, after a few weeks, a perfectly clear oil is obtained free from water. The oil of first quality is procured by a repetition of the foregoing process upon the once rectified oil. The residues of both operations are melted up with the pitch.* Rosin oil is employed in the manufacture of axle grease, the oil being previously converted into a soap by heating with slaked lime. Rosin oil gives a characteristic violet colour with anhydrous stannic chloride. If it is mixed with fatty oils, Mr. A. H. Allen has pointed out that the test may still be successfully applied by distilling the mixture and applying the test to the first fractions which pass over. Nitric acid is also said to be a good test for rosin oil when mixed with fat oils, as the colour thereby developed is much greater than in pure oils. Sometimes it may be detected by the smell. The presence of 10 percent, of rosin oil in non-drying oils delays their solidification with the elaidin test. For methods of detecting its admixture with mineral oils, see p. 281. Copal.— Syn. Gum copal. —This resin exudes spon¬ taneously from various trees belonging to the genera HymencBa, Guibourtia , and Trachylobium. The varieties commonly met with in commerce are East Indian copal, or anime (produce of Hymencea courbaril), and West Indian copal, obtained from numerous species. * “Dingl. Poly tech. Journ.” ccvi. 246; “ Jour. Chem. Soc.” New Series, vol. xi. 304. 324 OILS AND VARNISHES. When of good quality, it is too hard to be scratched by the nail, has a conchoidal fracture, and a specific gravity ranging from 1*059 to ro8o. Unlike others, the copal resins are soluble with difficulty in alcohol and essential oils, and this property, combined with their extreme hardness, renders them very valuable for making varnishes. Dammar.— Syn. Gum dammar, Dammara, Dammar- Puti (i.e., Cat’s-eye resin, on account of its lustre).—This is obtained from the Pinus dammara, or Dammara alba, a coniferous tree, indigenous in the East Indies and the Moluccas, and also from the Dammara australis, which grows in New Zealand. The product of the former is known as East Indian dannnar, and the latter as Australian dam¬ mar. The East Indian dammar is that ordinarily met with in commerce. As it exudes from the tree, it occurs in somewhat trans¬ parent lumps, varying in size from that of a pea to that of a hen’s egg. Sp.gr. 1*04 to 1*09; odour, resinous; frac¬ ture, conchoidal; ash, about o*2 per cent. The resin is separable into— i°. a-resin, or hydrated dammarylic acid: about one- third of the whole, soluble in weak alcohol; 2 0 . /3-resin, or anhydrous dammarylic acid : soluble, after removal of a-resin, in absolute alcohol; 3 0 . Dammaryl, extracted by ether from the residue after separation of T and 2 0 . Elemi.— Syn. Gum elemi. —“ A terebinthinate concre¬ tion from an uncertain plant ” (Ph. L.). Mexican elemi is known to be the produce of a species of the genus Ela- phrium. Manilla elemi is probably the product of Canarium commune. The elemi of commerce is of a pale-yellow colour, brittle superficially, but soft and tough within. It has a warm bitter taste and a fragrant aromatic smell, resembling fennel EES/NS. 325 and juniper. It is only partially transparent even in thin plates, is very fusible, and has density a little greater than that of water. It contains about 12^ per cent, of volatile oil (oil of elemi). It is used to give toughness to lacquers and varnishes. It is often adulterated, or a factitious pre¬ paration is sold for the genuine gum. The fraud may be detected by exposing the suspected article to beat, along with a little water, when the factitious fragrance of the spurious article evaporates, and the coarse terebinthinate smell of the resin used becomes readily distinguishable. Lac.— Syn. Lacca, L.—This resin, combined with much colouring matter, is produced by the puncture of the female of a small insect called the Coccus lacca, or ficus, upon the young branches of several tropical trees, especially Ficus indica , Ficus religiosa, and Croton lacciferum. The crude exudation constitutes the stick-lac of commerce. Sliell-lac or shellac is prepared by spreading the resin into thin plates after being melted and strained. Seed-lac is the residue obtained after dissolving out most of the colouring matter contained in the resin. Shellac is the kind most commonly employed. The palest is the best, and is known as “ orange-lac.” The darker varieties—“liver-coloured,” “ruby,” “garnet,” &c.—respec¬ tively diminish in value in proportion to the depth of their colour. Lac was formerly much used in medicine; its action, if any, is probably that of a very mild diuretic. It is now chiefly used in dentifrices, varnishes, lacquers, and sealing-wax. Lae, Bleached. — Syn. White lac, Lacca alba.— Prepared by dissolving lac in a boiling lye of pearl-ash or caustic potash, filtering, and passing chlorine through the solution until all the lac is precipitated. This is then col¬ lected, well-washed, and pulled in hot water, and, finally, twisted into sticks and thrown into cold water to harden. 3-6 OILS AND VARNISHES. It is used to make pale varnishes and the more delicately coloured sealing-wax. Specific gravities (Hager)— light shellac, 1-113-1-114; dark, 1-23; bleached, 0-965-0-968. Mastic. — Syn. Mastich, Gum mastic, Mastiche, L.— The “ resin flowing from the incised bark of Pistacia lentiscus, var. Ghia ” (Ph. L.). It occurs in pale-yellowish, transparent, rounded tears, which soften between the teeth when chewed, and giving out a bitter, aromatic taste. Sp. gr. 1-07 (1-056 to 1-060, ITager). It is soluble both in rectified spirit and oil of turpentine. Sandarach.— Syn. Sandrac. —A resin obtained from Thuja articulata and Juniperus communis (in warm climates). It is slightly fragrant, and freely soluble in rectified spirit. Its specific gravity is from 1-05 to 1-09 (Hager’s deter¬ minations are from 1-038 to 1-044). It is used as incense, pounce, in varnishes, &c. Annotta. — Syn. Anotto, Annatto, Annatta, Arnatto, Arnotto; Orleana, Terra orleana; Roncol, Rocon, Roncon (Fr.); Orleans (Ger.).— A colouring matter forming the outer pellicle of the seeds of theBixa orettana (Linn.),an exogenous evergreen tree, common in Cayenne and some other parts of tropical America, and extensively cultivated in the East and West Indies. It is usually obtained by macerating the crushed seeds, or seed-pods, in water for several weeks, ultimately allowing the pulp to subside, which is then boiled in coppers to a stiff paste, and dried in the shade. Some¬ times a little oil is added in making it up into cakes or lumps. Good annotta is of a brilliant red colour, brighter in the middle than on the outside, soft and smooth to the touch; has a characteristic, but not a putrid, smell. It is scarcely soluble in water: freely soluble in alcohol, ether, oils, and fats, to each of which it imparts a beautiful orange colour, and in alkaline solutions, which darken it. Strong sulphuric acid turns it blue. RES/NS. 327 Annotta is very frequently adulterated. The adulterants which have been used are meal, flour, or farina, chalk, gypsum, pearl-ash; oil, or soap, to give it an unctuous character; turmeric, Venetian red, red ochre, orange chrome, and red lead, to give it colour; common salt and sulphate of copper, to prevent decomposition. Sometimes a little carbonate of ammonia is added to improve the colour. When pure, it contains about 28 per cent, of resinous colouring matter and 20 per cent, of colouring extractive matter (Dr. John), and should leave only a small quantity of insoluble residuum after digestion in alcohol, while the ash resulting from its incineration should not exceed 1*5 to 2 per cent. The quantity, colour, &c., of the ash will give a clue to the inorganic adulterants, if any are present, which may then be followed up by a chemical ex¬ amination. A correct determination of ash and resin is all that is required to definitely pronounce upon the purity or impurity of a sample. The following is an analysis by Mr. A. W. Blyth of a fair commercial sample. The sample was in the form of a paste ; colour, deep red; odour, peculiar but not disagreeable. Water ..... # e . 24-2 Resinous colouring matter 8 . 28-8 Ash . . . * . 223 Starch and extractive matter * * • 243 100-o The following is Blyth’s analysis of an adulterated specimen. The sample was in a hard cake of a brown colour, with the maker’s name stamped upon it, and marked “patent;” texture, hard and leathery; odour, disagreeable. Water . . . . . . , 13-4 Resin . . . . . . . x 1 ‘o Ash, consisting of iron, chalk, salt, alumina, silica . 483 Extractive matter . . . . . .273 IOO'O 328 OILS AND VARNISHES. Thus in the one the resin was 28 per cent, and the ash 2 2 per cent. ; in the other the resin was only 11 per cent, and the ash 48 per cent. It is used to colour varnishes and lacquers. Dragon’s-blood.— Syn. Sanguis draconis, L.—A rich red-coloured resin, obtained from various species of the genus Calamus. Its colour, in the lump, is a dark brownish- red ; in powder, bright red. It is friable, breaks with a shining fracture, and has a sp. gr. not higher than i‘ig 6 or 1 ■ 1 97 * When pure, it readily dissolves in alcohol, ether, and oils, yielding rich red, transparent solutions. Adul¬ terated and factitious dragon’s-blood is only partly soluble in the above menstrua, and lacks the rich colour of the genuine article. It is chiefly used to tinge varnishes and lacquers. Gamboge.— Syn. Camboge, Cambogia (L.), Gambogia (L.), Gomme-gutte. —“A gum-resin obtained from Garcinia morella ” (B.P.). Also from Stalagmites cambogioides, a tree belonging to N. 0 . Guttiferce , and growing in the peninsula of Cambogia, in Siam. The juice, which is of a yellow colour, is obtained from the bruised leaves and branches, and, having been received into cocoa-nut shells or earthen vessels, it is allowed to thicken and is afterwards made into rolls ; this is “ pipe-gamboge ” of Siam. A portion is also formed into cakes. Cake-gamboge is a manufactured article, not entirely natural. The pieces of gamboge are of a yellowish colour externally, and are covered with a yellow powder. Fracture, vitreous or conchoidal, with brown or saffron-yellow colour. At common temperatures, odourless, or nearly so ; on heating, gives out a peculiar odour. It is a drastic purgative. Gamboge dissolves in alcohol, in resins, and in ammonia. EE SINS. 329 Analyses of Gamboge (Christison). Siam Ceylon Gamboge. Pipe-gamboge. Cake-gamboge. Resin . Gum . Amylaceous matter... VVcodv fibre Moisture . 74 '' 2 21 - 8 4-8 71-6 24-0 4*8 64 '3 20-7 6-2 4'4 4 *o 65-0 19-7 S*o 6 - 2 4-6 68-8 20-7 6-8 4-6 75 *5 18-5 o-6 4-8 ioo - 8 100-4 99 '6 100-5 100-9 99'3 The resin is easily dissolved out by ether. It has an acid character, decomposing alkaline carbonates at a boiling heat, and forming salts with the alkalies of a red colour. Saffron.—A yellow substance, consisting of the dried stigmas, with part of the styles, of the saffron crocus ( Crocus sativas), a plant indigenous to Greece and Asia Minor, and cultivated in Austria, Prance, and Spain. The length of the stigmas is from 1 to i| inch; they are narrow and roundish where attached to the style, but spreading and club-shaped near the extremity, which is truncated. They have an orange or brownish-red colour, yellow in the narrower part; a strongly aromatic, almost intoxicating, odour; an aromatic, bitter taste; and impart a strong yellow colour to the saliva, to water, alcohol, and oils. Strong sul¬ phuric acid colours them first indigo-blue, then red, and finally brown. It is often adulterated with other substances of similar colour, such as the florets of the safflower or the marigold, but these are easily detected on close examination by their different shape, &c. Turmeric.— Syn. Curcuma, PvAdix curcuma, Terra merita. —The root of Amoinum curcuma, cultivated in India 33° OILS AND VARNISHES. and Java. According to Pelletier and Vogel, it contains a strong-smelling volatile oil, gum, a yellow colouring matter (Curcumin), a brown colouring matter, starch, cellu¬ lose, and a small quantity of calcium chloride. It is used for colouring varnishes. Asphaltum. — Syn. Asphalt, Compact bitumen, Mine¬ ral pitch, Jew’s pitch, Fossil bitumen, Bitumen fossile, Bitumen judaicum, Bitumen solidum, Bitumen vitreum ; Mumia, Mumia mineralis, L.; Asphalte bitume massif, Bitume solide, Poix juive (Fr.); Asphalt, Erdpech, Judenpech (Ger.).—It is a black, hard, brittle, and glossy variety of bitumen, found on the shores of the Dead Sea, on and near the shores of the Great Pitch Lake of Trinidad, and as a mineral product in various other parts of the world. Melts without decomposition, and, when pure, burns without residue. It is distinguished from other varieties of bitumen by its more difficult fusibility, and by its fracture being clean, conchoidal, and vitreous. Distilled by itself, it yields about 36 per cent, of a peculiar bituminous oil (crude petrolene), together with combustible gases, ammonia, and water. Average sp. gr. from i‘ to i'68. By friction it yields negative electricity. It is soluble in oil of turpentine, benzol, mineral and coal-tar naphtha, fixed oils, and solutions of the caustic alkalies, by the aid of heat. The finer varieties are chiefly used as a “ glazing colour ” by artists, and in the manufacture of black varnishes and japans. The Egyptians used it in embalming under the name of mumia, and the Babylonian builders are said to have employed it as a cement, in lieu of mortar. A factitious asphalt is made from the “ bottoms ” of Barbadoes tar, and other bitumens, by heating them until quite hard; and sometimes a little Scio turpentine, balsam of copaiba, or even common resin is added. Colour, hard¬ ness, &c., inferior to native asphalt. VARNISHES. 33i D. Claye* recommends the following method for testing the purity of asphaltum :—The mass is dissolved in carbon bisulphide, filtered, evaporated to dryness, and heated until it can be ground to powder in a mortar. o - i gm. of the substance thus obtained is treated with 5 c.c. of fuming sulphuric acid for twenty-four hours. It is then mixed with 10 c.c. of water, with continuous stirring. Pure asphalt may be recognized by the light-yellow solution that is obtained, while, when pitch, coal-tar, &c., are present, the solution is of a dark-brown or blackish colour. Preparation of Varnishes.—To ensure the excellence of oil varnishes, one of the most important points is the use of good drying oil. Linseed oil for this purpose should be very pale, perfectly limpid or transparent, scarcely odorous, and mellow and sweet to the taste. 100 galls, of such an oil are put into an iron or copper boiler capable of holding fully 150 galls., gradually heated to a gentle simmer, and kept near that point for about two hours, to expel moisture ; the scum is then carefully removed, and 14 lb. of finely pulverized scale litharge, 12 lb. of red lead, and 8 lb. of powdered umber (all carefully dried and free from moisture) are gradually sprinkled in; the whole is then kept well stirred, to prevent the driers sinking to the bottom, and the boiling is continued at a gentle heat for about three hours longer; the fire is next withdrawn, and, after thirty to forty hours’ repose, the scum is carefully removed, and the clear supernatant oil decanted from the “ bottoms.” The product forms the best boiled or drying oil of the varnish- maker. Another method is to heat a hogshead of the oil gradually for two hours, then to gently simmer it for about three hours longer, and, after removing the scum, to add, gradually, 1 lb. of the best calcined magnesia, observing to * “ J. Soc. Chem. Ind.” 1882, 203. 333 OILS AND VARNISHES. miy it up well with the oil, and afterwards to continue the boiling pretty briskly for at least an hour, with constant agitation. The fire is then allowed to die away, and, after twenty-four hours, the oil is decanted as before. Ti e product is called “ clarified oil,” and requires to be used with driers. It should be allowed to lie in the cistern for two or three months to clarify. In the preparation of oil varnishes, the gum is melted as rapidly as possible, without discolouring or burning it ; and, when completely fused, the oil, also heated to nearly the boil¬ ing point, is poured in, after which the mixture is boiled until it appears perfectly homogeneous and clear, like oil, when the heat is raised, the driers (if any are to he used) gradually and cautiously sprinkled in, and the boiling continued, with constant stirring, for three or four hours, or until a little, when cooled on a palette-knife, feels strong and stringy between the fingers. The mixture is next allowed to cool considerably, but, while still quite fluid, the turpentine, previously made moderately hot, is cautiously added, and the whole thoroughly incorporated. The varnish is then run through a filter or sieve into stone jars, cans, or other vessels, and set aside to clarify itself by subsidence. When no driers are used, the mixture of oil and gum is boiled until it runs perfectly clear, when it is removed from the fire, and, after it has cooled a little, the turpentine is added as before. It is generally conceived that the more perfectly the gum is fused, or run, as it is called, the larger and stronger will be the product; and the longer the boiling of the “ gum ’ and oil is continued, within moderation, the freer the resulting varnish will work and cover. An excess of heat renders the varnish stringy, and injures its flowing qualities. Tor pale varnishes, as little heat as possible should be employed throughout the whole process. Good body var- VARNISHES. 333 rushes should contain ij lb.; carriage, wainscot, and mahogany varnish, fully i lb.; and gold size and black japan, fully i*r lb. of gum per gall., besides the asphaltum in the latter. Spirit varnishes should contain about 2\ lb. of gum per gall. The use of too much driers is found to injure the brilliancy and transparency of the varnish. Copperas does not combine with varnish, but only hardens it; sugar of lead, however, dissolves in it to a greater or less extent. Boiling oil of turpentine combines very readily with melted copal, and it is an improvement on the common process, to use it either before or in conjunction with the oil, in the preparation of copal varnish that it is desired should be very white. Gums of difficult solubility are rendered more soluble by being exposed, in the state of powder, for some time to the air. Varnishes, like wines, improve by age; and should always be kept as long as possible before use. From the inflammable nature of the materials of which varnishes are composed, their manufacture should be only carried on in some detached building of little value, and built of uninflammable materials. When a pot of varnish, gum, or turpentine catches fire, it is most readily ex¬ tinguished by closely covering it with a piece of stout woollen carpeting, which should be always kept at hand, ready for the purpose. In the preparation of spirit varnishes care should be taken to prevent the evaporation of the alcohol as much as possible, and also to preserve the portion that evaporates. On the large scale, a common still may be advantageously employed; the head being furnished with a stuffing-box, to permit of the passage of a vertical rod, connected with a stirrer at one end and a working handle at the other. The gum and spirit being introduced, the head of the still closely fitted on and luted, and the connection made with a 334 OILS AND VARNISHES. proper refrigerator, heat (preferably that of steam or a water-bath) should be applied, and the spirit brought to a gentle boil, after which it should be partially withdrawn, and agitation continued until the gum is dissolved. The spirit which has distilled over should be then added to the varnish, and after thorough admixture the whole should be run off, as rapidly as possible, through a silk-gauze sieve, into stone jars, which should be immediately corked down, and set aside to clarify. On the small scale, spirit varnishes are best made by maceration in closed bottles or tin cans, either in the cold or by the heat of a water-bath. In order to prevent the agglutination of the resin, it is often advan¬ tageously mixed with clean siliceous sand or pounded glass, by which the surface is much increased, and the solvent power of the menstruum greatly promoted. A writer in the u Chemical Review”* points out that the chief properties to be sought in a varnish are (a) good work¬ ing, (b) hard drying and free rubbing, and (c) non-liability to crack, but that these qualities are so closely connected with one another that a superior excellence in one respect is only obtained at the expense of a corresponding deteriora¬ tion in another, and that, consequently, it is impossible to make a varnish which shall excel in every respect. Application of Varnishes.—To give the highest degree of lustre to varnish after it is laid on, as well as to remove the marks of the brush, it is necessary to polish. This is performed by first rubbing it with very finely powdered pumice-stone and water, and afterwards with an oiled rag and tripoli, until the required polish is produced. The sur face is last of all cleaned with soft linen cloths, cleared of all greasiness with powdered starch, and then rubbed bright with the palm of the hand. * May 1882 ; “ J. Soc. Chem. Ind.” 1882, 181. VARNISHES. 335 In applying a varnish, care must be taken that the surface is free from grease or smoke, as, unless this is the case, the best oil or turpentine varnish in the world will not dry and harden. Old articles are usually washed with soap and water by painters before being varnished, to prevent any failure of the kind alluded to. Japanning is the art of covering paper, wood, or metal with a coating of hard, brilliant, and durable varnish. The varnishes or lacquers employed for this purpose in Japan, China, and the Indian Archipelago are resinous juices derived from various trees belonging to the natural order Anacardiacece, especially Stagmaria vernicijlua, Holigarna longifolia , Semicarpus anarcardium, and species of Rhus (sumach). For use, they are purified by defecation and straining, and are afterwards mixed with a little oil and colouring matter, as required. In this country varnishes of amber, asphaltum, or copal, or mixtures of them, pass under the name of “ japan,” or “ japan varnish.” In the process of japanning, the surface is coloured or painted with devices, &c., as desired; next covered with a highly transparent varnish (amber or copal), then dried at a high temperature (135 0 to 165° F.), and lastly, polished. Wood and paper are first sized, polished, and then varnished. For plain surface, asphaltum varnish or japan is used. Formulae :—Amber Varnish.— Prep. 1. Take of amber (clear and pale), 6 lb.; fuse it, add of hot clarified linseed oil, 2 galls .; boil until it “ strings well,” then let it cool a little, and add of oil of turpentine, 4 galls, or q. s. Nearly as pale as copal varnish ; it soon becomes very hard, and is the most durable of the oil varnishes; but it requires some time before it is fit for polishing, unless the articles are “ stoved.” When required to dry and harden quicker, dry¬ ing oil may be substituted for the linseed oil, or “ driers” may be added during the boiling. 336 OILS AND VARNISHES. 2. Amber, 4 oz.; pale boiled oil, 1 quart; proceed as last. Very hard. 3. Pale transparent amber, 5 oz.; clarified linseed oil or pale boiled oil, and oil of turpentine, of each 1 pint; as before. Amber varnish is suited for all purposes where a very hard and durable oil varnish is required. The paler kind is superior to copal varnish, and is often mixed with the latter to increase its hardness and durability. The only objection to it is the difficulty of preparing it of a very pale colour. It may, however, be easily bleached with some fresh- slaked lime. Balloon Varnish.— See Flexible Varnish (below). Bessemer’s Varnish.—This consists of a pale oil copal varnish, diluted with about 6 times its volume of oil of turpentine, the mixture being subsequently agitated with about 1-30th part of dry slaked lime, and decanted after a few days’ repose. Five parts of the product mixed with four parts of bronze powder form (l Bessemer’s gold paint.” Black Varnish. — Prep. 1. (Black amber varnish.) From amber, 1 lb.; fuse, add of hot drying oil, \ pint; powdered black resin, 3 oz.; asphaltum (Naples), 4 oz.; when properly incorporated and considerably cooled, add of oil of turpentine, 1 pint. This is the beautiful black varnish of the coachmakers. 2. (Ironwork black.) From asphaltum, 48 lb.; fuse, add of boiled oil, 10 galls.; red lead and litharge, of each 7 lb.; dried and powdered white copperas, 3 lb.; boil for two hours, then add of dark gum amber (fused), 8 lb.; lio f linseed oil, 2 galls.; boil for two hours longer, or until a little of the mass, when cooled, may be rolled into pills, then withdraw the heat, and afterwards thin it down with oil of turpentine, 30 galls. Used for the ironwork of carriages, and other nice purposes. VARNISHES. 337 3. (Black japan, Bituminous varnish.) a . From Naples asphaltum, 50 lb.; dark gum anime, 8 lb.; fuse, acid of linseed oil, 12 galls.; boil as before, then add of dark gum amber, 10 lb., previously fused and boiled with linseed oil, 2 galls. ; next add of driers, q. s., and further proceed as ordered in No. 2. Excellent for either wood or metals. b. From burnt umber, 8 oz.; true asphaltum, 4 oz. ; boiled linseed oil, 1 gall. ; grind the umber with a little of the oil; add it to the asphaltum, previously dissolved in a small quantity of the oil by heat; mix, add the remainder of the oil, boil, cool, and thin with a sufficient quantity of oil of turpentine. Flexible. 4. (Brunswick black.) a. To asphalt, 2 lb., fused in an iron pot, add of hot boiled oil, 1 pint; mix well, remove the pot from the fire, and, when cooled a little, add of oil of turpentine, 2 quarts. IJsed to blacken and polish grates and ironwork. Some makers add driers. b. From black pitch and gas-tar asphaltum, of each 25 lb.; boil gently for five hours, then add of linseed oil, 8 galls.; litharge and red lead, of each 10 lb.; boil as before, and thin with oil of turpentine, 20 galls. Cheaper than the last, but inferior. Body Varnish.— Prep. 1. From the finest African copal, 8 lb.; drying oil, 2 galls.; oil of turpentine, 3I galls.; pro¬ ceed as for Amber varnish. Very hard and durable. 2. Pale gum copal, 8 lb.; clarified oil, 2 galls.; dried sugar of lead, | lb.; oil of turpentine, 3J galls.; proceed as before, and mix the product, whilst still hot, with the follow¬ ing varnish :—Pale gum anime, 8 lb. ; linseed oil, 2 galls.; dried white copperas, lb.; oil of turpentine, 3I galls.; the mixed varnishes are to be immediately strained into the cans or cistern. Dries in about six hours in winter, and in about four hours in summer. Used for the bodies of coaches and other vehicles. z 338 OILS AND VARNISHES. Bookbinder’s Varnish.— Prep. Take of pale gum san¬ darach, 3 oz.; rectified spirit, 1 pint; dissolve by cold diges¬ tion and frequent agitation. Used by binders to varnish morocco leather book-covers. A similar varnish is also pre¬ pared from very pale shell-lac and wood naphtha. Cabinet-maker’s Varnish. —French polish is occasion¬ ally so called. Carriage Varnish. — Prep. 1. (Spirit.) Take of gum sandarach, i| lb.; very pale shell-lac, f lb.; very pale transparent resin, \ lb.; rectified spirit of ‘8221 (64 o.p.), 3 quarts; dissolve, and add of pure Canada balsam, 1 1 lb. Used for the internal parts of carriages, &c. Dries in ten minutes or less. 2. (Oil.) a . (Best pale.) Take of pale African copal, 8 lb.; fuse, add of clarified linseed oil, 2 \ galls.; boil until very stringy, then add dried copperas and litharge, of each \ lb. ; again boil, thin with oil of turpentine, 5J galls.; mix, whilst both are hot, with the following varnish, and imme¬ diately strain the mixture into a covered vessel:—Gum anime, 8 lb.; clarified linseed oil, 2-J galls.; dried sugar of lead and litharge, of each | lb.; boil as before, thin with oil of turpentine, 5^ galls. Dries in four hours in summer, and six in winter. Used for the wheels, springs, &c., of coaches and other vehicles, and by house painters, decorators, and others who want a strong, quick-drying, and durable varnish. b. (Second quality.) From gum anime (“sorts”), 8 1 b.; clarified oil, 3 galls.; litharge, 5 oz.; dried and powdered sugar of lead and white copperas, of each 4 oz. ; boil as last, and thin with oil of turpentine, 5^ galls. Used as the last. Chinese Varnish. — Prep. From mastic and sandarach, of each 2 oz.; rectified spirit (64 o.p.), 1 pint; dissolve. Dries in six minutes. Very tough and brilliant. Copal Varnish. — Prep. 1. (Oil.) a. From pale hard VARNISHES. 339 copal, 2 lb.; fuse, add of hot drying oil, i pint; boil as before directed, and thin with oil of turpentine, 3 pints or q. s. Dries hard in twelve to twenty-four hours. b. From clear and pale African copal, 8 lb. ; pale drying oil, 2 galls.; rectified oil of turpentine, 3 galls. ; proceed as before, and immediately strain it into the store can or cistern. Very fine, hard, and durable. 2. (Spirit.) a. From coarsely powdered copal and glass, of each 4 oz.; alcohol of 90 per cent. (64 o.p.), 1 pint; camphor, oz.; heat the mixture, with frequent stirring, in a water-bath, so that the bubbles may be counted as they rise until solution is complete, and, when cold, decant the clear portion. b. From copal (which has been melted, dropped into water, and then dried and powdered), 4 oz.; gum sandarach, 6 oz.; mastic, 2 oz.; pure Ohio turpentine, 3 oz.; powdered glass, 5 oz.; spirit of 90 per cent., 1 quart; dissolve by a gentle heat. Dries rapidly. 3. (Turpentine.) To oil of turpentine, 1 pint, heated in a water-bath, add, in small portions at a time, of powdered copal (prepared as above), 3 to 4 oz.; dissolve, &c., as before. Dries slowly, but is very pale and durable. 4. (Japanner’s copal varnish.) From pale African copal, 7 lb.; pale drying oil, | gall. ; oil of turpentine, 3 galls. ; proceed as in No. 1. Dries in twenty to sixty minutes, and may be polished as soon as hard, particularly if stoved. ( See Japanning, p. 335.) All copal varnishes, when properly made, are very hard and durable, though less so than those of amber; but they have the advantage over the latter of being paler. They are applied on coaches, pictures, polished metal, wood, and other objects requiring a good durable varnish. Anime is frequently substituted for copal in the copal varnishes of the shops. 340 OILS AND VARNISHES. Crystal Varnish.— Prep. i. From genuine pale Canada balsam and rectified oil of turpentine, equal parts. Used for maps, prints, drawings, and other articles of paper, and also to prepare tracing-paper, and to transfer en¬ gravings. 2. Mastic, 3 oz.; rectified spirit, i pint; dissolve. Used to fix pencil drawings. Drying varnish.— Spirit copal varnish. Dutch Varnish.— Lac and toy varnishes are often so called. Etching Varnish. —White wax, 2 oz.; black and Bur¬ gundy pitch, of each \ oz.; melt together; add by degrees powdered asphaltum, 2 oz., and boil till a drop taken out on a plate will break when bent backwards and forwards several times. Next pour into warm water, and roll into small balls. Flexible Varnish.— Syn. Balloon varnish, Caout¬ chouc v., India-rubber v.— Prep. i. From india-rubber (cut small), 11? oz. ; chloroform, ether (washed), or bisul¬ phide of carbon, i pint; digest in the cold until solution is complete. Dries as soon as it is laid on. Pure gutta-percha may be substituted for india-rubber. 2. India-rubber, in shavings, i oz.; rectified mineral naphtha or benzol, i pint; digest at a gentle heat in a closed vessel, and strain. Dries very badly, and never gets per¬ fectly hard. 3 India-rubber, i oz. ; drying oil, i quart ; dissolve by heat. Very tough; dries in about forty-eight hours. 4. Linseed oil, 1 gall.; dried white copperas and sugar of lead, of each 3 oz.; litharge, 8 oz. ; boil, with constant agita¬ tion, until it strings well, then cool slowly, and decant the clear portion. If too thick, thin it down with quick-drying linseed oil. The above are used for balloons, gas-bags, &c. Furniture Varnish.—1. A solution of pure white wax, VARNISHES. 341 1 part, in rectified oil of turpentine, 4 parts, frequently passes under this name. ( See Body, Carriage, and Copal Var¬ nishes, &c.) 2. Olive oil, 9 parts; oil of amber, rectified, 9 parts; oil of turpentine, 9 parts; tincture of alkanet, 1 part; mix, and keep in a well-stoppered bottle. When using it, pour a little upon a pellet of cotton, apply it lightly to the wood several times, and then rub it dry with a cotton rag. If the polish of the furniture has only faded, it will be entirely restored. Of course, if the surface has been rendered rough, or has been scratched, it must first be restored to its former smoothness.* Gilder’s Varnish.— Prep. (Watin). Pale gum-lac in grains,gamboge, dragon’s-blood, and annotta, of each 12^ oz.; saffron, 3^ oz.; dissolve each resin separately in 5 pints of alcohol of 90 per cent., and make two separate tinctures of the dragon’s-blood and annotta, with a like quantity of spirit; then mix the solutions in the proper proportions to produce the required shade. Used for gilded articles, &c. Glass Varnish.- —-A solution of soluble glass. Used to render wood, &c., fire-proof. Gun-barrel Varnish.— Prep. From shell-lac, ij oz.; dragon’s-blood, 3 drs.; rectified spirit, 1 quart. Applied after the barrels are “ browned.” Hair Varnish. — Prep. From hog’s bristles (chopped small), 1 part; drying oil, 10 parts; dissolve by heat. Said to be used to give cotton or linen cloth the appearance of horse-hair. India-rubber Varnish.— See Flexible {above). Italian Varnish.— Prep. Boil Scio turpentine until brittle, powder it, and dissolve this in' oil of turpentine. Used for prints, &c. “ Year Book of Pharmacy,” 1883, 322. 342 OILS AND VARNISHES. Japan Varnish. —Pale amber or copal varnish. Used for japanning tin, papier-mache, &c. Label Varnish.*—Sandarach, 53 parts; mastic, 20 parts; camphor, 1 part; oil of lavender, 8 parts; Venice turpen¬ tine, 4 parts; ether, 6 parts; alcohol, 40 parts. Macerate for several weeks, agitating frequently until dissolved, and decant, or strain, from impurities. The varnish dries rapidly to a colourless, smooth, and glossy layer. Lac Varnish. — Prep. 1. Pale seed-lac (or shell-lac), 8 oz.; rectified spirit, 1 quart; dissolve. 2. Substitute lac bleached with chlorine for seed-lac. Both are very tough, hard, and durable, but quite indexible. Wood naphtha may be substituted for spirit. Used for pictures, metal, wood, or leather, and particularly for toys. Lac Varnish (Aqueous).— Prep. From pale shell-lac, 5 oz.; borax, 1 oz.; water, 1 pint; digest at nearly the boiling point until dissolved, then strain. Equal to the more costly spirit varnish for many purposes; it is an excel¬ lent vehicle for water-colours, inks, &c.; when dry, it is waterproof. Lac Varnish (Coloured). — Syn. Lacquer, Brasswork varnish. — Prep. 1. Take of turmeric (ground), 1 lb.; recti¬ fied spirit, 2 galls.; macerate for a week, strain, with ex¬ pression, and add to the tincture, gamboge, i\ oz.; pale shell-lac, f lb.; gum sandarach, 3! lb. When dissolved, strain, and further add of good turpentine varnish, 1 quart. Gold coloured. 2. Seed-lac, 3 oz.; turmeric, 1 oz.; dragon’s-blood, | oz.; rectified spirit, 1 pint; digest for a week, frequently shaking, then decant the clear portion. Deep gold coloured. 3. Spanish annotta, 3 lb.; dragon’s-blood, 1 lb.; gum * “ Handsel)au,” 1882, 686 ; “ Year Book of Pharmacy, 1 ” 18S2. ?2i. VA RNJSHES. 343 sandarach, si lb -5 rectified spirit, 2 galls.; turpentine varnish, 1 quart; as before. Red coloured. 4. Gamboge, 1 oz.; Cape aloes, 3 oz. ; pale shell-lac, 1 lb.; rectified spirit, 2 galls.; as before. Pale brass-colouied. 5. Seed-lac, dragon’s-blood, annotta, and gamboge, of each A ip. • gum sandarach, 2 oz.; saffron, 1 oz., rectified spiiit, 1 gall. Resembles the last. Lacquer. —A solution of shell-lac in alcohol, tinged with saffron, annotta, aloes, or other colouring substances. It is applied to wood and metals to impart a golden colour. Mahogany Varnish.— Prep. Prom gum anime (“sorts ’), 8 lb.; clarified oil, 3 galls.; litharge and powdered dried sugar of lead, of each \ lb.; proceed as for body varnish, and thin with oil of turpentine, 5 galls, or cp s. Maps, Varnish for. —A varnish for paper which pro¬ duces no stains may he prepared as follows:—Clear dammar resin is covered, in a flask, with four and a half to six times its quantity of acetone, and allowed to stand for fourteen days at a moderate temperature, after which the clear solution is poured off. Three parts of this solution are then mixed with four parts of thick collodion, and the mixture allowed to become clear by standing. It is applied with a soft camel’s-hair or beaver’s-hair brush in vertical strokes. At first the coating looks like a thin white film; but, on complete drying, it becomes transparent and shining. It should be laid on two or three times. It retains its elas¬ ticity under all circumstances, and remains glossy in every kind of weather.'"' Mastic Varnish.— Syn. Picture varnish, Turpentine v., Tingry’s essence v.— Prep. 1. Take of pale and picked gum mastic, 5 lb.; glass (pounded as small as barley, and well washed and dried), 3 lb.; finest newly rectified oil of * J. Soc. Cliem. Inti.’’ 1882, 180. 344 OILS AND VARNISHES. turpentine (lukewarm), 2 galls. ; put them into a clean 4-gall, tin bottle or can, bung down securely, and keep roll¬ ing it backwards and forwards pretty smartly on a counter, or any other solid place, for at least four hours, when, if the gum is all dissolved, the varnish may be decanted, strained through muslin into another bottle, and allowed to settle; if the solution is still incomplete, the agitation must be con¬ tinued for some time longer, or gentle warmth applied as well. Very fine. 2. (Second quality.) From mastic, 4 lb.; oil of turpen¬ tine, 2 galls. Dissolve with heat. Mastic varnish is much used for pictures, &c.; when good, it is tough, hard, brilliant, and colourless. It greatly improves by age, and, when possible, should never be used before it has been made at least a twelvemonth. Should it get “ chilled,” 1 lb. of well-washed siliceous sand should be made moderately hot and added to each gallon, which must then be well agitated for five minutes, and afterwards allowed to settle. Oak Varnish.— Syn. ’Wainscot varnish, Common tur¬ pentine v. — Prep. 1. Clear pale resin, 3J lb.; oil of tur¬ pentine, 1 gall.; dissolve. 2. To the last add of Canada balsam, 1 pint. Both are cheap and excellent common varnishes for wood or metal. Oil Varnish.—The finer qualities are noticed under Amber, Body, Carriage, and Copal Varnish. The follow¬ ing produces the ordinary oil varnish of the shops:—Take of good clear resin, 3 lb.; drying oil, | gall.; melt, and thin with oil of turpentine, 2 quarts. A good and durable var¬ nish for common work. Painter’s Varnish. — See Carriage, Copal, Mahogany, Oak, and other varnishes, the selection depending greatly on the colour and quality of the work. VARNISHES. 345 Patent Leather Varnish. —This is carefully prepared drying oil. The skins being stretched on a board, and every trace of grease being removed from them by means of a mixture of fuller’s earth and water, they are ready to receive the varnish, which is then spread upon them very thinly by means of a species of scraper. The first-coat varnish consists of pale Prussian blue (that containing some alumina), 5 oz.; drying oil, 1 gall.; boiled to the consistence of single size and, when cold, ground with a little vegetable black; it is stoved, and afterwards polished with fine-grained pumice. The second coating resembles the first, excepting in having a little pure Prussian blue mixed with it. The third-coat varnish consists of a similar mixture, but the oil is boiled until it strings well, and a little more pure Prussian blue and vegetable black are added. The last-coat varnish, or finish, is the same as the third, but must contain \ lb. of pure dark-coloured Prussian blue and | lb. of pure vegetable black per gall., to which a little oil copal or amber varnish is often added, each coat being duly stoved and pumiced before the next is applied. The heat of the stove or oven is commonly 120° F. for “ enamelled skins,” as those of the calf and seal, intended for “uppers;” and 175° to 180° for stout “ japan leather; ” the exposure in the stove is com¬ monly for six to ten hours. The skins are next oiled and grained. The “ graining ” of the “ enamelled skins ” is done by holding the skin in one hand, and with a curved board lined with cork (graining stick), lightly pressed upon the fleshy side, working it up and down until the proper effect is produced. Photographic Varnishes. —Mr. W. Bedford recom¬ mends the following negative varnish :—“ Button ” lac, ^ lb.; sandarach, 2 oz.; methylated spirit, \ gall. Shake up occasionally during a week, by which time the soluble por¬ tion will be taken up, but avoid heat, as it is better to filter 346 OILS AND VARNISHES. off the sediment. “ Button ” lac, though apparently browner than shell-lac, is recommended in preference, as it really gives a lighter coloured solution; but even seed-lac may be used if the precaution be taken, after filtration, of boiling the clear, but dark-coloured, varnish for ten minutes in a flask on a water-bath, with 4 oz. of freshly prepared animal char¬ coal. This treatment, followed by a second filtration, effec¬ tually removes the orange dye, which would otherwise tend to retard the printing. Another negative varnish is pre¬ pared from gum-juniper, 2 drs.; gum frankincense, 1 dr.; alcohol, 4 oz. Filter through paper, and use the clear solution. Varnish for Dry-plates * —Bed shell-lac varnish, \ pint; methylated spirit, about i| pint. Try a plate, and add or lessen spirit according to requirements. Varnish for Wet-plate Negatives* —White hard varnish, i pint; methylated spirit, about 1 pint. Try plate ; if too thick, add more spirit. A capital varnish for retouching purposes. Fritz Luckhardt's Retouching Varnish * —Alcohol, 300 parts; sandarach, 50 parts; camphor, 5 parts; castor oil, 10 parts; Venetian turpentine, 5 pai’ts. Varnish to imitate Ground Glass* —Sandarach, 18 parts; mastic, 4 parts; ether, 200 parts; benzol, 80 to 100 parts. Varnish for backing Positives. —Spirits of turpentine, 6 oz.; asphaltum, 2 oz.; white wax, 2 scruples; lampblack, i-t scruple. Dissolve in a warm place, and filter through flannel. Picture Varnish.— Several varnishes, especially mastic varnish, are called by this name. Pale copal or mastic varnish is generally \ised for oil paintings, and crystal, white hard spirit, or mastic varnish for water-colour drawings on paper. * “Year Book of Photography,” 1885. VARNISHES. 347 Resist Varnish. —Used in electro-plating for keeping off deposits where not required. Resin or copal dissolved in boiled linseed or oil of turpentine, and coloured with red lead, chrome yellow, or Prussian blue. Sealing-wax Varnish. —Black, red, or any coloured sealing-wax, broken small, with enough rectified spirit (or methylated spirit) to cover it, digested till dissolved. A most useful varnish for woodwork of electrical or chemical apparatus, for tops of corks, &c. Spirit Varnish. — Prep. i. (Brown hard.) a. Prom gum sandarach, 3 lb.; pale seed-lac or shell-lac, 2 lb.; rectified spirit (65 o.p.), 2 galls.; dissolve, and add of turpentine varnish, 1 quart; agitate well, strain (quickly) through gauze, and in a month decant the clear portion from the sediment. Very fine. b. Prom seed-lac and yellow resin, of each lb.; rectified spirit, 5 quarts ; oil of turpentine, i| pint; dissolve. Inferior to the last. 2. (White hard.) a. Prom gum sandarach (picked), 5 lb.; camphor, 2 oz.; washed and dried coarsely pounded glass, 3 lb.; rectified spirit (65 o.p.), 7 quarts; proceed as in making mastic varnish; when strained, add of pure Canada balsam, 1 quart. Very pale, durable, and brilliant. b. Prom gum sandarach and gum mastic, of each, picked, 4 oz.; coarsely powdered glass, 8 oz. ; rectified spirit, 1 quart; dissolve, and add of pure Strasburg turpentine, 3 oz. Very fine. 3. (Soft brilliant.) From sandarach, 6 oz.; elemi (genuine), 4 oz.; anime, 1 oz.; camphor, £ oz.; rectified spirit, 1 quart; as before. 4. (Scented.) To the preceding add some gum benzoin, balsam of Peru, balsam of Tolu, oil of lavender, or the essence of musk or ambergris. The first two can only be employed for dark varnishes. 348 OILS AND VARNISHES. Spirit varnishes are chiefly applied to articles of the toilette, as work-boxes, card-cases, &c., but are also suit¬ able for other articles, whether of paper, wood, linen, or metal, that require a brilliant and quick-drying varnish. They dry almost as soon as applied, and are usually hard enough to polish in twenty-four hours. They are, however, much less durable, and more liable to crack, than oil varnishes. Stopping-out Varnish. — Syn. Petit vernis, Fr.—Prom lampblack, made into a paste with turpentine. Used by engravers. Tingry’s Varnish. —See Mastic Varnish. Toy Varnish.—Similar to common spirit varnish, but using carefully rectified wood naphtha as the solvent. (See Lac and Spirit Varnishes.) Transfer Varnish. — Syn. Mordant varnish. — Prep. From mastic (in tears) andsandarach, of each 4 oz.; rectified spirit, ii pint; dissolve, and add of pure Canada balsam, i pint. Used for transferring and fixing engravings or lithographs on wood, and for gilding, silvering, &c. (See Crystal Varnish.) Turpentine Varnish. —See Mastic and Oak Varnishes. Universal Lacquer.- — Prep. Bleached shell-lac, 60 parts; Manilla copal (freshly powdered), 60 parts; gum mastic, 60 parts, are mixed with 1000 parts of alcohol (92 to 95 per cent.); a small quantity of coarsely powdered glass is added, and the whole left to stand for eight to fourteen days, frequently shaking; 1 part of boracic acid is then added, and the mixture filtered. This lacquer is said to he equally good for paper, metal, v/ood, glass, &c. It may be coloured with any aniline dye soluble in alcohol.* » “Chemist and Druggist,’’ Jan. 1885. VARNISHES. 349 “Wainscot Varnish. —See Oak Varnish. Waterproof Varnish. —Palmitate or oleate of alumina dissolved in petroleum, ether, or benzene. After the evapora¬ tion of the solvent, an impermeable varnish is left.* (See also Niin Oil, p. 33.) Wax Varnish. — Syn. Milk of wax, Emulsio cer^e spirituosa, L.— Prep. 1. Take of white wax (pure), 1 lb.; melt it with as gentle a heat as possible, add of warm rectified spirit, sp. gr. '830 (60 o.p.), 1 pint; mix perfectly, and pour the liquid out upon a cold porphyry slab; next grind it with a muller to a perfectly smooth paste, adding more spirit as required; put the paste into a marble mortar, make an emulsion with water, 3 A pints, gradually added, and strain it through muslin. Used as a varnish for paint¬ ings ; when dry, a hot iron is passed over it, or heat is otherwise evenly applied, so as to fuse it and render it transparent, after which, when quite cold, it is polished with a clean linen cloth. The most protective of all varnishes. 2. Wax (pure), 5 oz.; oil of turpentine, 1 quart; dissolve. Used for furniture. White Varnish. —See Spirit Varnish 2, a and b. * Engl. Patent 4921, 1S83. CHAPTER XI. TESTING RESINS. I. Mills’ Bromine Absorption Process. —Messrs. Mills and Muter* have applied their bromine method (see p. 251) to the examination of resins. The method of pro¬ cedure is as follows :—The finely powdered resin is placed overnight (together with the usual 50 c.c. of solvent) in the colorimetric bottles, and the next morning the bromine absorption is carried out. The following are some of the results:— Varnish Resins Absorp¬ tion. Remarks. Shellac, bleached Shellac. Gum benzoin ... Amber. Anirne . Gamboge. Copal, reduced to 5 by boiling... Copal . Sandarac . Dammar. Elemi . Mastic. 4-61 5 ' 2 I 38-90 53 *53 60 '22 71-56 84-52 89‘93 96-42 II 7-94 122-23 I 24-33 S.N. Chiefly insoluble. S.N. „ „ [given off. S.N. Partly soluble. Some hydric bromide S N. „ ,, Ditto. S.N. „ ,, Much hydric bromide. S.N. Chiefly „ Ditto. S.N. Partly „ Ditto. S.N. ,, „ Ditto. S.N. ,, „ Very much ditto. S.N. Wholly „ Much ditto. S.N. „ „ Very much ditto. S N. Partly „ Much ditto. * “ Journ. Soc. Chem. Ind.” 1885, 97. TESTING RESINS. 35i Tinctorial Resins. Absorp¬ tion. Remarks. Xanthorrhoea, New Hoi- land . 7 ' 11 T.H. Slightly soluble. Xantliorrhoea . 8'33 T.H. Insoluble. ^Calamus. X. hastilis (grass-tree), 8-37 T.H. „ Queensland . 9 ‘H T.H. Partially soluble. Xanthorrhoea, Australia ... io '35 T.H. Partially soluble. A little bydric bromide. * 0 ., Pnnjaub . .. io '45 T.H. Insoluble. *C., Ivew. ^Dracaena cinnabari, So- 11-97 T.H. „ cotra . 13-81 T.H. „ X. hastilis, Australia . 15-68 T.H. „ *C. draco, Bombay . 22-01 T.H. „ X. hastilis, Tasmania. 30'74 T.H. „ „ Sydney . *C. draco, Kew . 33-25 T.N. 55-24 T.H. Insoluble. Partly bleached by bromine. ^Sumatra. 66-39 T.H. Partly soluble. Partly bleached by bromine. *C. draco, Singapore . 73 -Si T.H. Partly bleached. ^Calamus, Menier & Co.... 7478 T.H. *Dutch E. Indies . 8 l -59 T.H. Insoluble ; bleached. ^Sumatra. 84-87 T.H. Partly soluble. Partly bleached. In the above experiments sometimes / 3 -naphthol was used for titrating back, more particularly—as in the case of the pale resins—when the bromine derivatives had but little tint. Sometimes the operation was finished with hyposul¬ phite and deci-normal iodine. All the results are means of at least three determinations. The letters S. and T. indi¬ cate that disulphide or tetrachloride was used respectively. The letters H. and H. indicate that the absorption was finally measured by / 3 -naphtliol or hyposulphite. The names marked with an asterisk represent commercial varieties of dragon’s- blood. 352 OILS AND VARNISHES . It will be seen that the extraordinarily low absorption of shellac gives it a unique position among resinous bodies, and amber is distinctly below all other substances of its class. As a rule, but not invariably, the more soluble a gum resin, the greater is its bromine absorption. II.—Hirscholm’s Process.* I. Alcohol (95 per cent.).f Benzoin Coniferous resins Dragon’s-blood Completely Soluble. Mastic (Alexandrian and Bombay) Sandarac Copal Dammar Elemi Gamboge Incompletely Soluble. Shellac Mastic (common) Lac (Sonora) Coniferous resins Dragon’s-blood Elemi Benzoin Copal Dammar 2. Ether. Completely Soluble. Mastic Sandarac Incompletely Soluble. Shellac Gamboge Lac (Sonora) 3. Ethereal Solution. With addition of Alcohol. Clouded. Copal (Brazilian) I Mastic (common) Dammar | Lac (Sonora) * “ Buss. Zeitschr. Pharm.” xvi. 1, 33, 65, 97; Watts’ “Diet, of Chem.” vol. viii. pt. ii. 3rd suppt. 1743. t This table is not extracted in full, but only so far as relates to the resins usually employed in varnishes. TESTING RESINS. Clear mixture. 3S3 Benzoin Conifer resins Copal Dragon's-blood Elerni Shellac Gamboge Mastic (Alexandrian and Bombay) Sandarac Benzoin Conifer resins Copal (Brazilian) Dammar 4. Chloroform. Completely soluble. Dragon’s-blood (not all varieties) Mastic Incompletely soluble, or not at all. Copal Dragon’s-blood ( Pterocarpus draco) Shellac Gamboge Sandarac Lac (Sonora) 5. Alcoholic Solution. Precipitate does not dissolve, Benzoin Conifer resins Copal Dammar (certain East Indian samples) only partially, on boiling. Dragon’s-blood ( Pterocarpus draco) Shellac Mastic (Bombay) Sandarac Lac (Sonora) on heating. Mastic (common and Alexan¬ drian) Precipitate disappears on heating. Dammar (certain East Indian samples) A. With addition of Lead Acetate, or No turbidity. Dammar | Elerni Dragon’s-blood (some sorts) j Gamboge A A 354 OILS AND VARNISHES. B. With addition of Ferric Chloride. A turbidity or precipitate which disappears on heating and dissolves in ether. Dammar (some Indian sorts) Precipitate does not disappear on heating, nor dissolve in ether. Copal | Lac (Sonora) No precipitate, but (a) Black, brown, or greenish- black. Gamboge Shellac solution coloured. (b) Dark-green. Benzoin The other resins are coloured either greenish, or brownish, or not at all. C. With addition of Aqueous Ammonia. Clear mixture. Conifer resins (some) Copal Dragon’s-blood (Pterocarpus draco) Shellac Gamboge Sandarac Lac (Sonora) Turbid mixture. The other (varnish) resins 6. Alcohol containing Hydrochloric Acid. (a) (b) Coloured. Blue to violet. Elemi Yellow, changing through red-brown to cherry-red. Benzoin (c) Yellow. Gamboge (d) Brown changing to various shades. The remaining (varnish) resins 7. Concentrated Sulphuric Acid. Dissolves. 1°. With cherry-red colour. 1 2°. Yellow. Benzoin (Siam) I Gamboge 3 0 . Brown, changing to various shades. Other resins 355 TESTING RESINS. 8. Sulphuric Acid Solution. A. With addition of Alcohol. 2°. Turbid, brown. 1 °. Clear violet. Benzoin (Siam and Sumatra) Other resins Violet. B. With addition of Water. Resins thrown down in flocks. 3 °. Yellow. Benzoin (Siam) Gamboge Dingy red-violet. 4 °. Brown. Benzoin (Sumatra) Other resins 9- Chloroform Extract. With addition of Bromine Solution. 2°. Brown colour—no flocks. Resin thrown down in flocks. Shellac Copal (Australian) Other resins Violet. Shellac Crimson. Lac (Sonora) Violet. Shellac Yellow. Benzoin Dragon’s-blood Sandarac 10. Sodium Carbonate Solution. E. At Ordinary Temperatures. 3°. V ellowish, or yellow-red. Dragon’s-blood ( Pterocar - pus draco') Gamboge 4 0 . Yellowish, brownish, or no coloration. Other resins B. At Boiling Heat. 3 . Yellowish, brownish, or no coloration. Other resins C With addition of Acetic Acid at Ordinary Temperatures. I . Flocks thrown down. I 2°. Nothing, or only turbidity. Conifer resins Gamboge Sandarac Other resins 356 OILS AND VARNISHES. ii. Petroleum Ether Extract. 1°. Deep yellow. Gamboge A. I 2°. Yellowish, or colourless. Other resins B. With addition of Iodine Solution. 1°. Clear violet. Benzoin Dragon’s-blood Shellac 2 °. Red-violet — clear, becoming turbid. Copal Dammar (some samples) Mastic Gamboge Sandarac 3°. Brown and turbid mixtures. Other resins C. Residue after Evaporation. (a) With addition of Sulphuric Acid. 1°. Crimson. I 2°. No coloration. | 3 0 . Yellow, or brown. Benzoin (Siam) | Shellac | Other resins (b) With addition of Chloral Reagent. (I.e., an impure chloral hydrate obtained by saturating alcohol with chlorine, mixing the product with 4 vols. strong sulphuric acid, stirring up the solid mass which separates with one-third of its weight of water and distilling.) 1 °. Yellowish, or greenish, chang¬ ing to red-violet. Conifer resins 2 °. Yellow. Gamboga 3 0 . Green. Dammar 4 0 . Greenish. Benzoin (Sumatra) 5 0 . No coloration, or faint. Other resins APPENDIX, COMPARISON of FAHRENHEIT and CENTIGRADE THERMOMETERS. To convert C. into F. temperatures +22 = F. 99 i° F. =0-555° C. i° C. = i*8° F. (F-- 3 2 ) x 5 _ c F. Degrees. c. Degrees. F. Degrees. C. Degrees. F. Degrees. C. Degrees. O = - 1778 70 = 21*11 145 = 62*77 5 - 1500 75 23*88 150 65'55 IO - 12*22 80 26 67 155 68*32 15 - 9'44 85 29-44 160 7I*II 20 — 6*67 90 32*22 I 6 5 73'88 25 - 3'88 95 34'99 170 76*66 3 ° - 1 *i 1 100 3778 175 79‘43 32 0*00 i °5 40-55 180 82*22 35 1*6 7 no 43'33 185 84*99 40 4'44 ii 5 46*10 190 8 777 45 7*21 120 48*89 195 9054 5 ° 10*00 125 51*66 200 9333 55 12*77 130 54'44 205 96*10 6o i 5'56 135 57 ' 2 i 210 98*88 65 i 8*33 140 6o*oo 212 100*00 358 OILS AND VARNISHES. PRICES. The prices quoted in the following lists are examples of those actually obtained in Mincing Lane for articles sold in bulk for cash :— Oils. £ s. d. £ s. d. Seal oil, pale . per tun 25 0 0 to 28 0 0 Sperm oil, body . 11 5 i 0 0 60 0 0 Cod oil . 11 per gall. 3 1 0 0 35 0 0 Cod-liver oil. o 3 0 0 6 0 Whale oil, S. Sea, pale ... per tun 19 0 0 26 0 0 Olive oil: Florence . half-chest 0 8 6 0 17 6 ) 5 . Lucca . square box 0 13 0 0 14 6 per gall. 0 4 0 0 6 6 Gallipoli, f.o.b. per tun 40 0 0 53 0 0 Sublime . 11 59 0 0 70 0 0 Extra ditto . . 70 0 0 — Cream . .. 80 0 0 82 0 0 Cocoa-nut oil: Cochin . per ton 29 10 0 34 0 0 Ceylon . 11 26 0 0 32 0 0 Palm oil: Fine Lagos . 1) 29 0 0 34 0 0 WhydalT . 11 28 0 0 34 0 0 Accra . 11 26 0 0 33 0 0 Palm-nut or copra oil . 26 0 0 30 10 0 Linseed oil . 19 5 0 22 10 0 Eape-seed oil: English refined . 11 22 15 0 27 15 0 Brown . 21 0 0 26 0 0 Lard oil, English. 11 34 0 0 4 i 0 0 Tallow and oleine oil . 25 0 0 45 0 0 Cotton oil: Refined. 17 15 0 26 5 0 Crude . 11 per gall. 15 15 0 21 10 0 Rangoon engine oil . 0 2 6 0 3 0 Castor oil, in tins. per lb. 0 0 3 0 0 4 Colza oil . per cwt. 1 4 0 1 8 0 Nut oil : French . 1 12 0 2 2 0 Gambia . 1 18 0 Sesame oil . I 14 0 1 16 0 Neat’s-foot oil . per gall. 0 3 0 0 3 6 APPENDIX. 359 Prices —( continued ). Oils. £ s. d. £ s. d. Petroleum oil: per gall. o o 6 to o o 7J Pennsylvanian. Water-white . 11 o o 7f o o ii Eussian ditto . 11 o o 6^ o o 8 Petroleum: Spirit . 19 o o 61 o o 7 i Beatified .. 99 007 0 0 8| Coal oil, refined . 91 0 0 sf 0 0 64 Lubricating oil, English and foreign . 500 15 0 0 per ton Paraffin: per lb. 0 0 i| 004 Scale. Wax. 11 004 006 Tallows. P.Y.C. per cwt. 1 15 0 200 Australian beef . 11 100 1 14 0 Mutton. 11 120 1 14 6 Town . 11 149 1 15 0 Yellow candle . 11 1 15 0 220 Melted stuff. 11 0 17 0 160 Rough stuff. per 8 lb. 089 0 13 3 Town fat . 008 013 Graves. Good dregs . per cwt. 11 090 0 16 0 040 — Turpentine, American spirits . 11 1 1 6 180 Rosin, American. 11 026 0 14 0 Waxes. Bees’: 6 15 0 800 Jamaica . 11 East India . 11 5 5 0 7 12 0 Vegetable, Japan . V 2 12 0 3 3 0 Spermaceti: per b. Refined. 010 — American.. 11 0 0 104 — Essential Oils. Almond. 11 1 15 0 — Anise-seed: 1 Star . 11 069 073 German, &c. 11 080 0 13 0 Bergamot. 11 056 079 360 OILS AND VARNISHES. Prices—( continued ). Essential Oils. £ 8 . d. £ s. d. Cajuput... per bot. o 3 3 to o 3 4 Caraway . per lb. o 5 3 o ii 0 Cassia . o 3 6 o 4 0 Cinnamon . per oz. o i 6 o 3 6 Cinnamon-leaf. o o 2 o o 2 f Citronelle. 99 per lh. o o I o o 2 Clove.. o 3 3 o 3 6 Juniper. o i 6 o 2 0 Lavender: Exotic . o 6 6 o 8 6 Mitcham . 2 o o 2 IO 0 Lemon . 9 9 o 3 6 o 6 0 Lemon-grass . per oz. 0 o I IT o o 2 Neroli . 5 9 o 7 o — Nutmeg . 9 9 o o 8 — Orange. per lb. o 8 o o IO 0 Otto of roses . per oz. o 13 o I 12 0 Patchouli . o i 4 o 2 0 Peppermint: American. per lb. o 12 o o 13 0 II. G. Hotchkiss . o 17 6 o 19 0 English. I 8 o I 12 6 German. 99 o 8 o o 14 0 Japan . o IO o o 17 0 Menthol crystals . 9 9 o 17 o 2 O 0 Rosemary. 99 o 2 6 o 3 9 Sassafras . o 2 6 Spearmint . 99 o 12 o o 14 0 Thyme . 99 o I 9 o 2 6 Mace expressed .. per oz. o O 2 — Resins. Anime: Fine washed. per cwt. 14 IO O 22 0 0 Scraped . II o O 18 0 0 Mixed . 3 o O 11 0 0 Copal: Manilla . o IS O 3 15 0 Angola, red . 7 5 O 7 12 6 Dammar, pale . 3 IO o 4 7 6 Dragon’s blood. 3 IO o 12 0 0 Gamboge, pipe... IO IO o 15 0 0 Mastic, picked. per lb. o I 6 o 3 3 Sandarac . per cwt. 3 o o 5 5 0 Shellac: Orange. 99 2 12 o 4 8 0 APPENDIX. 361 Prices —( continued). Resins. Shellac: £ s. d. £ s. d. Native and liver . per cwt. 2 12 0 to 3 12 0 Garnet and bronze . 2 14 0 3 10 0 Button sort . 91 3 10 0 4 6 0 Varnishes. Body. per gall. 0 16 0 0 18 0 Carriage . 0 12 0 0 14 0 Oak . 0 5 0 0 8 6 Crystal paper . 9 ) 0 7 0 0 8 0 Fine paper . 0 5 0 0 b 0 Spirit varnishes and French polish . 0 8 6 0 9 0 Gold size . 0 S 0 0 7 6 Black japan. 0 11 0 0 12 0 Brunswick black. 0 4 6 0 6 0 Terebine . 0 5 6 QUANTITIES and VALUES of OILS IMPORTED DURING 1882, X883, AND 1884. Oils. Quantities. Values. 1882. 1883. 1884. 1882. 1883. 1884. Cocoa-nut. cwt. 116,081 210,874 245, 6 95 £ 214,236 £ 365,716 £ 398,488 Olive. tuns. 23,190 3 °, 935 17,201 825,822 937,601 1,193,797 715,752 Palm. cwt. 801,54s 743 , 5 i 2 1,220,817 1,304,385 1,385,345 Petroleum. galls. 59 . 135,384 7 °,iS 5 , 5 6 3 52,808,436 1,704,753 2,156,235 1,705,773 Seed of all kinds. tuns. 14,620 io, 5 i 3 12,546 478,208 365,855 384,509 Train, blub¬ ber & sperm 15,924 16,899 17,525 526,862 596,721 531,421 Turpentine..., cwt. 357,878 350,138 462,134 639,685 555,902 559,973 AMOUNT and YALUE of EXPORTS of SEED OILS during 1882, 1883, and 1884. OILS AND VARNISHES. rJ-w'OOO WO OiOOOO 'tN N 00 1^0 co -vt- i-i vo VO vo O OOO O OnvO no co t}- vo co On 11 mvO m O S? of o'oT >-T t-C o’ voocT tCvcT ■vf;xfvo‘ I—I ■vt-o NNOroNvoOi-i ■Vj- M 1-1 1-1 H « 00 vO NO no vo 1 OOOOOO OOOOOO On N On VO N ro e> On C'l COCO MOO h O OncDNO O M h n lovO row •-( OOO rffOO GO MD W xJ-vO NCOwtJ-C^vOOM Nh n tJ-nO On hh hh O O fO On co On CO h 00 ^ hh On On co ■'3' CN S? rC rC rCc-* rf co of ro On ro On CD* ■^"00 O >-< ro rf r^CO >-1 'OCO NO i-N ON COOO O CO CO On CO ON W 10 INOO nOvoOnOOnONOh CO N*vO HH h incOONNN W O c^ On On cq O cOvO un co ^ OnvO 4 H of C continuing the Petroleum Act, 1871, had not been passed. c . 103. ADDENDA. Viscosity of Oils (p. 303).—New forms of apparatus for testing viscosity are described in “ Journ. Soc. Chem. Ind.” 1886, by Mr. Boverton Redwood (p. 121) and by Prof. Mills (p. 148). _ ^ aume ne’s Test (p. 233).—When a drying oil, or fish oil, is to be examined, Mr. C. J. Ellis has proposed (“ Journ. Soc. Chem. Ind.” 1886, p. 150) to dilute the sample, before addition of the acid, with a mineral oil the temperature reaction of which has been previously deter¬ mined, so as to moderate the action and lower the maxi¬ mum temperature attainable to below 6o° or even 30° C. In this way, it is said, the test may be made quantitative. INDEX, A Acids, table of, 4, 5 Acid, arachidic, 4, 8 behenic, 4, 8 Appendix, 357 brassic, 5, 10 butyric, 4, 5 B capric, 4, 6 Bailey’s pendulum friction test, 302 caproic, 4, 5 Balance, Westphal’s, 209 caprylic, 4, 6 Bell, constitution of butter fat, 12 cerotic, 4, 8 Bennett, cod-liver oil, 25 cocinic, 4, 6, 62 Bitumen, liquid, 171 doeglic, 5, 10 Bleaching, purifying, and refining elai'dic, 5, 10 oils, 192 erucic, 5, 10 almond oil, 193 glyceric, 3 castor oil, 193 glycerinic, 3 cocoa-nut oil, 194 * gynocardic, 62 fish oil, 195 lauric, 4, 6 linseed oil, 193 linoleic, 5, 10 nut oil, 193 margavic, 4, 7 olive oil, 193 melissic, 4, 8 palm oil, 194, 196 myristic, 4, 7 rape oil, 193 cenantliylic, 4, 5 tallow, 198 oleic, 5, 8 vegetable oil, 196 palmitic, 4, 7 Bosch, 17 pelargonic, 4, 6 Boulton, table of coal products, 167 ricinoleic, 5> IO Bromine absorption—oils, 251 stearic, 4, 7 resins, 350 sulpholeic, 61 action on shale and petroleum mmbellulic, 6 products, 288 valeric, 4, 5 ! Butter, 12 INDEX. 368 Butter, artificial, 17 fat, 16 Butterine, 17 Butyrin, 11 0 Carcel lamp, 314 Chemical tests for fixed oils, quali¬ tative, 218 quantitative, 236 Chemistry of oils, 2 fixed oils, 2 mineral oils, 14 volatile oils, 13 Coal products, table of, 167 Cohesion figures, 216, 259 Colour tests, 218 Comparison of Russian and Ameri¬ can petroleum, 179 Cost of light, comparative, 313, 314 D Destructive distillation, definite character of, 170 Difference between petroleum and shale products, 184 Distilled oils, 13 Driers, 42 Drying oils, 35, 36 Drying properties, methods of test¬ ing, 214 Dynamite, 4 E El^EOPTENE, 13 Ela'idin, 10 test, 234 Empyreumatic oils, 120 Enfleurage, 64 Erdol, 171 Essences, 63 Essential oils, 13, 64 Essential oils, classification, 70 preparation, 64 properties, 69 rectification, 68 uses, 71 Ethereal oils, 13 salt, 2 Export of seed oils, 362 F Falke’s tests for purity of mineral lubricating oils, 307 “ Eire ” test, American, 280 Fish oils, 16, 31 Fixed oils, 1, 2 animal oils, 16 vegetable oils, 34 “ Flashing ” point of petroleum, determining, 274 in tropical climates, 279 Fluidity of oils, Bailey’s apparatus for, 306 Fluorescence of mineral oils, 281 Free acid, determination of, 236 Fusel oil, 119 G Glyceric trinitrate, 3 Glycerides, 11 artificial, n Glycerin, 3, 11 H Henderson retorts, 158 Hiibl’s iodine absorption process, 248 Hydrocarbon oils, 153 I Illuminating equivalents of differ¬ ent light-givers, 313 INDEX. 369 Imports of oil, 361 Insect oils, 33 Iodine absorption process, Hiibl’s, 248 Iv Kieselgiiur, 3 Koettstofrer’s saponification or satu¬ ration equivalents, 346 L Lacquer, 343 Lamps, management of petroleum, 189 Lard, 19 Light standards, 315 Lubricating oils, characters of effi¬ cient, 292 Falke’s tests for, 307 M Management of petroleum lamps, 189 Medicated oils, 124 Melting points, methods of taking, 211 Mills’ bromine absorption process, 251, 35 ° Mineral oils, 153 Mixed oils, 130 N Neft-gil, 185 Niti’oglycerin, 3 Nitrous anhydride and nitrous acid, action of, on oleic acid, 10 Nobel’s dynamite, 4 Non-drying oils, 36, 45 0 Oils — Animal , 16, 23 ambergris, 31 ant-grease, 33 Oils— Animal: bank, 28 bone-fat, 22 castoreum, 24 civet, 24 cochineal fat, 33 cod-liver, 24 crocodile, 22 Dippel’s, 23 egg, 23 grey amber, 31 hartshorn, 23 Houlican, 31 lard, 19 Malabar, 31 manatee, 31 Menhaden, 28 neat’s-foot, 19 nerve, 19 niin, 33 Oolachan, 31 porpoise, 31 seal, 29 brown or dark, 29 pale, 29 refined, 29 shark, 30 liver, 30 sod, 31 sperm, 30 Straits, 28 tallow, 22 trotter, 19 whale, 30 Oils — Empyreumatic , 120 aloes, 120 amber, 121 oxydated, 121 animal, 121 birch, 122 boxwood, 122 brick, 122 cade, 122 B B INDEX. 370 Oils— Empyreum a t ic : guaiacum, 123 hartshorn, 123 paper, 123 rag, 123 soot, 123 tar, 123 tobacco, 123 wax, 123 Oils— Essential, 64 allspice, 89 almond, hitter, 80 factitious, 84 amber, 104 angelica, 92 aniseed, 92 hadian, 80 hay, 115 berry, 115 leaves, 115 bergamot, 72 birch, 104 buchu, 103 cajeput or cajuput, 75 camphor, 78 cananga, 71 caraway, 93 cascarilla, 113 cassia, 113 cedar, 105 wood, 105 cedrat, 72 celery-seed, 93 chamomile, 95 cherry-laurel, 84 cinnamon, 113 China, 113 citron, 72 cloves, 75 copaiba, 88 coriander, 94 cubebs, 116 cumin 94 Oils— Essential: dill, 93 ergot, 117 eucalyptus, 80 fennel, 94 galbanum, 95 gale, 115 gaultheria, 102 geranium, 79 ginger-grass, 79 goose foot, 104 grass, 119 green mint, 101 hop, 117 hyssop, 97 ilang-ilang, 71 jasmin, 96 jessamine, 96 juniper, 105 laurel, 84 lavender, 97 lemons, 73 limes, 73 lovage, 95 marjoram, 98 mignonette, 80 mint, 101 mugwort, 96 myrrh, 89 neroli, 73 nutmeg, 116 olibanum, 88 orange, 74 berries, 74 leaf, 74 flowers, 73 origanum, 98 partridge-berry, 102 patchouly, 101 pennyroyal, 102 pepper, 116 peppermint, 99 pimento, 89 INDEX. 371 Oils— Essential: rose, 85 rosemary, 101 rue, 103 sandal-wood, 117 sassafras, 115 savine, 106 spearmint, 101 spike, 98 spikenard, 79 spring grass, 119 star-anise, 80 sweet marjoram, 98 thyme, 102 turpentine, 106 vanillin, artificial, 77 wintergreen, 102 wormwood, 96 Oils —Fatty or Fixed, 16 Oils— Medicated, 124 adder’s tongue, 124 ant, 124 balsam apple, 124 belladonna, 124 cantharides, 125 capsicum, 125 chamomile, 125 colocynth, 125 earthworm, 125 elder flower, 125 leaves, 125 fenugreek, 126 foxglove, 126 garden nightshade, 126 garlic, 126 green, 126 hemlock, 126 henbane, 126 iodized, 127 juniper, 127 lily, 127 melilot, 127 mucilage, 127 Oil-;— Medicated: mudar, 127 opium, 127 ozonized, 123 pellitory, 128 pepper, black. 12S poison oak, 128 rhubarb, 128 rose, 128 rue, 128 St. John’s wort, 129 scammony, 129 stramonium, 129 tobacco, 129 tooth wort, 129 wormwood, 129 Oils— Mineral, 153 albertite, 181 Alsace, 175 American, 174 apyroetic, 182 Belmontine, 182 Californian, 176 Canadian, 176 caoutchouc, 166 cazeline, 183 coal naphtha, 165 colzarine, 183 dead oil, 165 Egyptian, 175 Enniskillen, 176 illuminating, 175 kerosene, 175 ligroin, 175 Mecca, 176 naphtha, 171, 172 Ohio, 176 peat, 164 Pennsylvanian, 176 petroleum, 171, 172 benzine, 174 ether, 174 petro-sperm, 203 INDEX. 37 2 Oils— Mineral: photogen, 163 primary, 203 rhigoline, 174 rock oil, 171 Russian, 177 solar, 163 tar, 171 Oils— Mixed, 130 acoustic, 130 black, 130 British, 130 camphorated, 130 carron, 131 Chabert’s, 131 Exeter, 131 furniture, 131 mahogany, 131 Marshall’s, 132 mixed, 132 Newmarket, 132 nine, 132 petre, 133 phosphorated, 133 quitter, 134 Radley’s, 134 Sheldrake’s, 134 spike, 135 Stanford’s, 135 sulphurated, 134 three, 135 turpentine, 135 acoustic, 135 sulphurated, 135 Ward’s, 136 Wedell’s, 136 white, 132 worm (canine), 135 Oils— Perfumery, 136 ambergris, 139 benzoin, 139 hair, 139 macassar, 140 Oils— Perfumery: marrow, 140 musk, 141 and ambergris, 141 styrax, 141 vanilla, 141 Oils— Vegetable, 34, 63 almond, 45 arachis, 51 hay, 47 beech, 47 nut, 36 hehen, 47 belladonna, 36 ben, 47 benne, 50 seed, 48 Brazil-nut, 48 brown, 60 butter of bay, 47 cacao, 48 castor, 37 chaulmoogra, 62 cocoa-nut, 48 butter, 48 colza, 50 cotton-seed, 39 cress-seed, 40 croton, 49 cyperus-grass, 36 daphne, 36 deadly nightshade, 35 dilo, 40 gingelly, 50 gold of pleasure, 40 gorgon, 53 gourd-seed, 35 grape seed, 40 stone, 40 ground-nut, 51 hazel-nut, 36 hemp, 41 seed, 41 INDEX. 373 Oils— Vegetable, : henbane-seed, 36 honesty, 35 horse-chestnut, 51 huile tournante, 62 infernal regions, 53 laurel, 47 linseed, 41 boiled, 42 Lukrabo, 62 madi, 35 mustard, 51 nut, 45 nutmeg (expressed), 52 olive, 52 droppings, 59 palm, 59 butter, 59 kernel, 60 nut, 60 parsley, 36 piney, 60 dammar, 60 tallow, 60 plum-kernel, 36 poppy, 44 rape, 50, 60 Scotch-fir seed, 35 salad, 52 sesame, 50, 61 silver-fir cones, 35 spindle-tree, 35 spruce-fur, 35 spurge, 36 sunflower, 44 sweet, 52 Tamanu, 40 teel or til, 50, 61 tobacco-seed, 45 Turkey red, 61 virgin, 52 walnut, 45 watchmaker’s, 62 Oils— Vegetable: weld-seed, 35 wine-seed, 40 Oleic acid, determination, 242 preparation and purification, 9, 10 Olein, 11 action of nitrous acid on, 10 Oleomargarine, 17 Oleometer, 20S Ozokerit, 185 testing, 291 P Palmitic acid, determination of, 245 Palmitin, 11 Paraffin scale, determination of oil in, 286 Paraffins, 14 Perfumery oils, 136 Petroleum Act, 1879, 364 and shale products, 184 as an illuminant, cost of, 313 as fuel, 180 jelly, 186 storage of, 189 Photometers. 311 Preparation of varnishes, 331 volatile oils, 64 by absorption, 67 distillation, 64 enfleurage, 67 expression, 68 maceration, 68 solvents, 68 Prices of oils, tallows, waxes, resins, and varnishes, 358 Production of oil shale during last five years, 363 Purification of oils, 192 374 INDEX. Q Quantities and values of oils im¬ ported, 361 of exports of seed oils, 362 R Recovering rancid castor oil, 197 rancid oils and fats, 196 Rectification of essential oils, 6S Refining oils, 192 petroleum, 201 wax, 199 Reichert’s process for butter, 256 Resin or rosin oil, 322 purifying, 205 Resins, 318 amber, 318 and varnishes, 316 anime, 321 annotta, 326 asphaltum, 330 benjamin, 321 benzoin, 321 colophony, 322 copal, 323 dammar, 324 dragon’s-blood, 328 elemi, 324 gamboge, 328 lac, 325 mastic, 326 mumia, 330 saffron, 329 sandaracb, 326 testing, 350 Mills’ process, 350 Hirscholm’s process, 352 turmeric, 329 Russian petroleum industry, 177 S Saponification test, 240 Scottish mineral oil trade, 168 . Seed oils, exports of, 362 Solubility of oils in acetic acid, 235 Sources of oils, 14 Specific gravities of oils, 2, 208 Spectroscopic classification of oils, 215 Spermaceti, 144 Spontaneous combustion test, 235 Standards of light, 315 Stapfer oil tester, 295 Stearic acid, determination of, 245 Stearin, 11 Stearoptene, 13 Steinbl, 171 T Table of acetic series of fatty acids, 4 acrylic series, 5 action of iodine pentabromide, 262, 263 bromine absorptions, 252, 255, 350 by shale and petroleum products, 291 coal products, 167 co-efficients of Iriction, &c., of lubricants, 301 colour reactions, Chateau’s, 221 essential oils, 264-267 Glossner’s, 233 Penot’s, 231 comparison of Russian and American lubricating oils, 309 Russian and American petroleum, 179 corrosive action of oils on cop¬ per and iron, 239 densities of fatty acids, 211 differences of petroleum and shale products, 184 INDEX. Table of drying oils, 35 eucalyptus oils, 91 exports of seed oils, 362 hydrocarbons from Menhaden oil, 29 imports of oils, 361 iodine absorptions, 249 melting points of fatty acids— Archbutt’s, 213 Bach’s, 56 Bensemann’s, 215 melting and solidifying points of mixtures of stearic and palmitic acids, 245 non-drying oils, 36 output of oil shale, 363 of Eussian petroleum, 177 physical properties of fixed oils, 219 prices of oils, &c., 358 results by Stapfer’s oil tester, 296, 298 rise of temperature with sul¬ phuric acid (Maumenfi), 233 solubility of salicylic acid in essential oils, 270 sp. gr. and optical properties of essential oils, 271 sp. gr. of paraffins, 184 specific viscosities, 305 Tallow, 20 bleaching of, 21 Chinese, 147 Terpenes, 13 Testing bees’-wax, 149 essential oils, 256 fatty oils, 209 illuminating efficiency, 310 lubricating qualities, 292 mineral oils, 272 ozokerit, 291 resins, 350 375 Thermometers, comparison of Fah¬ renheit and Centigrade, 356 Thurston’s friction test apparatus, 299 Trinitroglycerin, 3 V Varnish, amber, 335 balloon, 336, 340 Bessemer’s, 336 bituminous, 337 black, 336 body, 337 bookbinder’s, 338 Brunswick black, 337 cabinet-maker’s, 338 caoutchouc, 340 carriage, 338 Chinese, 33S copal, 338 japanner’s, 339 crystal, 340 drying, 340 Dutch, 340 etching, 340 flexible, 340 furniture, 340 gilder’s, 341 glass, 341 gun-barrel, 341 hair, 341 india-rubber, 340, 341 Italian, 341 Japan, 342 label, 342 lac, 342 aqueous, 342 coloured, 342 lacquer, 343 mahogany, 343 map, 343 mastic, 343 INDEX . 376 Varnish, mordant, 348 oak, 344 oil, 344 painter’s, 344 patent-leather, 345 photographic, 345 picture, 343, 346 resist, 347 sealing-wax, 347 spirit, 347 brown hard, 347 scented, 347 soft brilliant, 347 white hard, 347 stopping out, 348 Tingry’s, 343 toy, 348 transfer, 348 turpentine, 343, 344, 348 universal, 348 wainscot, 344 waterproof, 348 wax, 348 white, 347, 349 Varnishes, 316, 331 • application of, 334 formulae for, 335 preparation of, 331 Vaseline, 186 Viscosity, tests for, 303 Lamansky’s method of testing, 303 Viscosity, pendulum method of test¬ ing (Bailey’s), 302 Townson & Mercer’s (Sacker’s) apparatus, 306 W Waxes, 142 animal, 142 artificial, 147 bees’, 142, 149 Carnauba, 145 Chinese, 146 vegetable tallow, 147 factitious, 147 fossil, 147 Japan, 145 mineral, 147 modelling, 147 myrica, 147 palm, 147 pela, 146 sealing, 148 spermaceti, 144 sugar-cane, 147 vegetable, 145 white, 143 Y Young’s paraffin process, 154 PRINTED RY BALLANTYNE, HANSON AND COw LONDON AND EDINBURGH