Book >C/^ SMITHSONIAN DEPOSIT / TESTIMONIALS. From Rev. James Greeu, an experienced and most successful Teacher. I believe the introduction of Scientific and Practical Agriculture into our academies and high schools, as a regular branch of study, to be highly de- sirable. I am confident, too, that it would be highly popular, both with our farmers and their sons. As soon as a suitable text-book can be pro- cured, I wish to introduce the subject into my own course of instruction. From what I know personally of Professor Campbell, from what I have witnessed of his examinations of classes in agricultural science ; and from the general plan of his work on this subject, I have no doubt that it will meet the wants of teachers, and fill a vacancy now existing in our series of test-books. JAMES GREER, Prin. Brownsburg High-school, at Brownsburg, Rockbridge Co., Va. April 2d, 1859. From J. R. Jones, Esq., a?i eminent Lawyer and Agriculturalist of Brunswick County. ■"eofessor J. L. Campbell. Dear Sir, — I am gratified to hear that your " Manual" is now ready for the publisher. In every eifort to bring the great principles of Chemistry, Geology, and Physiology, to the clear and easy comprehension of practical and intelligent agriculturalists, I feel a very decided interest ; and the world of farmers will hail him as a great public benefactor who successfully ac- complishes that object. That portion of your manuscript which was submitted to me, as chairman of the Committee on Essuys at the last State Agricultui-al Fair, met my cordial approval ; and, so far as I am competent to judge of a work which treats of scientific subjects, of which I can claim but a very limited know- ledge, gave promise of success in your design. It is proper to state, in this connection, that your work was withdrawn from the committee, at my suggestion, that you might retain the copyright, which would have been forfeited, if it had obtained a premium from the Virginia State Agricultural Society. I will be obliged, if you will order five copies of your Manual to be sent to my address, care of Messrs. Mcllwaine, Son & Co., Petersburg, Va., as soon as it is issued from the press. I am, very truly and respectfully, yours, J. EAVENSCROFT JONES. (2) TESTIMONIALS. From Major Wm. Giliiam, rmfessor of Clifmisfri/ and Agricullure in the Virginia Military Institute. Virginia Military Institcte, 1 ,, , 10 i lom \ March iZth, 1859. Lexington, Va., J Professor J. L. Campbell. Dear Sir, — I have very carefully read the manuscript of your work upon Scientific and Practical Agriculture, and it gives me great pleasure to say that I think it eminently suited to the purposes for which it was intended. I have long felt that just such a work, combining, as it does, a complete outline of the principles of science which have a direct bearing upon agri- culture, together with full directions for the management and improvement of the soil ; the cultivation of the crops peculiar to our country ; their rela- tive value; the rotation of crops, &c. &c., was very much needed. I rejoice to see that you have succeeded so well, and have adapted your work — the first of its kind in our country — to meet the peculiar wants of the agricul- turalists of the South and West. Yours, very sincerely, WILLIAM GILHAM. The following is from some of (he Author s former pupils, most of whom are sons of farmers. Having attended Prof. Campbell's highly interesting and instructive Lec- tures on Scientific Agriculture, we were most favorably impressed with the author's accurate scientific attainments, which, combined with a practical knowledge of the subject, such as few possess, eminently qualify him for fur- nishing a work of rare excellence, both for the scientific and practical agriculturalist. ISAAC P. IIEISKELL, WM. T. WALKER, W. Y. CHESTER, GEORGE LIFE, JOHN D. BROOKS, J. W. M'COWN, GEO. G. JUNKIN, J. M'D. M'CLUNG, JAMES S. GREENLEE, HARVEY GILMORE, H. T. DARNALL, WM. F. WILHELM, WM. A. M'CUE, D. D. PENDLETON, WM. M. WILLSON, JAMES HAYNES, GEO. L. LEYBURN, M. H. HOUSTON, A MANUAL SCIENTIFIC AND PRACTICAL AGRICULTURE, THE SCHOOL AND THE FARM. J.^Lt>"CAMPBELL, A.M PnOFESSOR OP PHYSICAL SCIENCE, WASHINGTON COLLEGE, VA. Happy tho man, who studying Nature's laws, TUrough known effects can trace the secret cause. DrydEiN's Vmcit. PHILADELPHIA : LINDSAY & BLAKISTOK. 1859. Entered, according to Act of Congress, in the year 1859, liy LINDSAY & BLAKISTON, in the Clerk's Office of the District Court of the United States for the Eastern District of Pennsylvania. STEREOTTPED BY J. FAGAN PKINTED BY C. 6HEKMAN & SON. J^Mtittioi);. To the many young gentlemen whom I have had the honor and the pleasure of instructing in this important department of Applied Science, this little "Work is affectionately dedicated, as a token of the interest still felt in their success in life. The Authoe. (xi) PREFACE. There is a rapidly increasing demand for scien- tific information, reduced to such a form that it may be applied to the daily business of Agriculture. This makes the adoption of the study of Agricul- ture into our higher schools a matter of great im- portance. It has already led to the introduction of the subject into several of our best colleges, and into a few of the higher schools ; but those teachers who have undertaken the important task of giving to our farmers' sons, that kind of scientific training, which especially fits them for the intelligent pursuit of their future calling, have felt the want of a text-book of thQ right kind. One of the leading objects which the Author of this little work has kept in view, has been to meet this want, as far as possible. Another demand for some such work, comes from those already engaged in the cultivation of the soil. 2 (xiii) PREFACE, It comes from those who have been long employed as "tillers of the land," as well as from the younger farmers, who desire to improve upon the old system (or rather want of system) of culture, which has worn out so many of our best lands. It is hoped that this demand, also, will be met, to some extent, at least, by what is here offered to the agricultural public. Hence, the great purpose kept in view has been the preparation of a "Manual" adapted to the School and the Farm, to serve especially as a guide to the youthful mind in acquiring such knowledge and men- tal training as might lay a firm foundation for future and higher attainments. The only systeraatie books on this subject hereto- fore available, have been either foreign works, or compilations from these, modified to suit limited sec- tions of our country. Not one of them is at all adapted to the agriculture of our Southern and Western States. It is true that the leading princi- ples of science, as applied to the culture of the soil, are the same everywhere ; but the 2Jractical applica- tion of these principles is as widely difierent in differ- ent latitudes, as the numerous crops cultivated in the several sections of our wide-spread country. Their application to Southern Agriculture has been gene- PREFACE. XV rally left out of view, in all books of a general char- acter hitherto issued on this great subject. This little work will, therefore, come in competition with no other of like character. Some excellent productions, on specific subjects in Agriculture, have appeared from the pens of Southern writers, and will be found alluded to in the text, where they have been made available by the writer. But this is designed to fill a place before unoccupied. The following general plan has been pursued : — 1, A few preliminary definitions are given as an "Introduction." 2. The agencies, "Heat, Light, and Electricity," have such of their general laws discussed as are necessarily connected with other subjects afterwards introduced, and especially with reference to the rela- tions they bear to Agriculture and domestic afiairs. 3, The language of chemistry, so far as is neces- sary to a clear understanding of the subject, is briefly summed up and explained in the form of " Symbols and Nomenclature." 4. The most important elementary substances, both "Metalloids and Metals," with such of their inorganic compounds as are of interest to the agri- XVI PREFACE. culturalist, are described, and their properties illus- trated by simple experiments. 5. The leading principles of "Organic Chemistry" are concisely stated, and applied to the discussion of both "Vegetable and Animal" compounds. 6. The sources from which plants derive their nourishment are described. 7. Then, to show clearly the relation of the plant to its sources of nourishment, and to show what con- ditions are necessary for healthful and vigorous growth, the various organs of plants, and the func- tions they perform are given, under a general outline of "Vegetable Physiology." 8. The "Soil," as the only source of plant nourish- ment under our control, is then discussed, with refer- ence, /rsi, to its "Geological Origin" — showing how the quality of soils is influenced by the rocks from which they are formed ; secondly, with reference to its " Mechanical Management" — embracing the prin- ciples involved in "Plowing, Draining, etc.," with their practical application ; thirdly, with reference to its "Chemical Treatment" — showing what is neces- sary to fertility in a soil, and what constitutes any substance a good fertilizer. PREFACE XVU 9. "Special Manures" — their composition and che- mical relations to one another, and to the soil and crop, with the principles which should govern their "Application," are treated somewhat definitely. 10. The "Selection of Seed," and the leading prin- ciples to be observed in "Planting and Culture," are briefly discussed. These principles are then cvpi^lied to the planting and culture of "Indian Corn," "Wheat," "Clover and Grasses," "The Southern Pea," "Tobacco," and "Cotton." 11. The principles, with a few examples of "Ptota- tion of "Crops," are stated. 12. The "Value of different Crops, as Articles of Food," is briefly given. 13. Then, to show the relation between the animal and his food and habits, we have a brief outline of that part of "Animal Physiology" which is most in- timately related to the rearing, feeding, and general management of stock, followed by practical applica- tions. In every part of the work, the Author has endea- vored to blend principles and practice — first in a general way, then more specifically, as applied to particular cases in every-day exjierience. XVni . PREFACE. The reader must not suppose that this, or any other book alone, can make him a good farmer. Books, without practice, can no more make successful farm- ers, than they can make successful lawyers or physi- cians. The judgment must be exercised by close observation, and by varied experience, in farming as well as in other pursuits. The experience of others must be consulted, too, and carefully weighed. To do this, every farmer who expects to be intelligent in his profession, must secure the regular reading of some good Agricultural Journal, and such Essays as are from time to time presented before Agricultural Societies. Fortunately for our young farmers, many of our best agricultural writers are among the most successful cultivators of the soil. The results of their experience may be made familiar, by spending an occasional leisure hour with such papers in hand, as tell us what they have been doing, and how they have succeeded. But do not, by any means, try every man's experiments. Study this little book carefully, and it will aid you to decide on the probable value of any given operations. Examine into the causes and effects involved in what has been done, and you may see at once whether the experimenter has understood his own operations or not. PREFACE. XIX What is here offered is the result of the Author's labors of several years, in giving instruction to young men on the important topics discussed. The matter, of course, is not all original. It has been gathered up from various sources — partly from books, partly from Agricultural Journals and Essays, partly from observation, and partly from a limited practical experience. The Author is not an entire stranger to the plow-handle and the hoe, and therefore claims a higher position than that of mere "book-farmer." The experiments given for illustration are very simple, and may be performed by any ingenious youth, or by the teacher of almost any respectable school. The apparatus and chemicals required to begin with, can be bought for ten or twelve dollars. A list of them will be found in the Appendix. Prof. LuDWiG, of Lexington, deserves many thanks for valuable and friendly assistance in drawing some of the principal cuts given, and in copying several others. My young friend and pupil, H. T. Darnall, is the delineator of the cut in Chapter XV, which illustrates so clearly the system of side-hill irrigation there given. To my friend and neighbor. Prof. Gil- ham, of the Virginia Military Institute, I am under peculiar obligation for the labor he has undergone, in revising the whole of my manuscript, and in making PREFACE. some most valuable suggestions, which have been adopted, and which have done much to give clearness and precision to several of my scientific discussions. My indebtedness to various books and journals has been generally acknowledged in the body of the work. It is due the engravers, Messrs, Baxter & Harley, to add, that they deserve high commendation for their faithfulness in executing the various cuts with which the work is illustrated. The Frontispiece, especially, presents a rare specimen of artistic skill. J. L. CAMPBELL. Washington College, > Lexiugton, Va., June, 1859. j TABLE OF CONTENTS. CHAPTER I. Preliminary Definitions and Illustrations page 25 CHAPTER II. Heat, Light, and Electricity , 29 CHAPTER III. Chemical Symbols, Equivalents, and Nomenclature 49 CHAPTER IV. History and Properties of the Metalloids 55 CHAPTER V. History and Properties of the Metals 77 CHAPTER VI. Organic Chemistry — Chemistry of Plants 98 (xxi) • XSU TABLE or CONTENTS. CHAPTER VII. Mineral Constituents, or Ashes, of Plants 120 CHAPTER VIII. Animal Chemistry <... 125 CHAPTER IX. Sources from which Plants derive their Nourishment 189 CHAPTER X. General Principles of Vegetable Physiology 144 CHAPTER XI. Structure and Functions of the Organs of Plants 149 CHAPTER XII. The Soil — its Geological Origin, &c 168 CHAPTER XIIL Mechanical Management of the Soil 195 CHAPTER XIV. Chemical Treatment of the Soil 210 CHAPTER XV. History and Properties of Special Manures 227 CHAPTER XVI. Application of Fertilizers — Planting and Culture of Crops 255 TABLE OF CONTENTS. XXIU CHAPTER XVII. Culture of Indian Corn 268 CHAPTER XVIII. Culture of Wheat and Oats 280 CHAPTER XIX. Planting and Culture of Potatoes 287 CHAPTER XX. Hay Crops and Pasture 293 CHAPTER XXI. Beans and Peas — especially the "Southern Pea" 301 CHAPTER XXII, Culture and Management of Tobacco 311 CHAPTER XXIII. The Cotton Crop 330 CHAPTER XXIV. Rotation of Ci'ops 342 CHAPTER XXV. Value of Crops as Food 354 CHAPTER XXVI. Animal Physiology 363 XXIV TABLE OF CONTENTS. CHAPTER XXVII. Selection and Preparation of Food 405 CHAPTER XXVIII. Selection and Care of Stock 418 SCIENTIFIC AND PRACTICAL AGRICULTURE. CHAPTER I. INTRODUCTION. § 1. Agriculture may be viewed in the two-fold light of a science and an art. As a science, it embraces some of the leading principles of Chemistry, Geology, and of Ve- getable and Animal Physiology. As an art, it consists in the skilful application of science to the cultivation of the soil, so as to make it yield the largest crops at the least possible cost. It also embraces the proper management and feeding of such animals as belong to the farm. We shall first define the several branches of science in- volved in our general subject; then discuss each of them briefly, giving only such principles and illustrations as may be applicable to domestic and agricultural pursuits. 2. Chemistry treats of the composition and properties of all substances on the surface of the earth. Soils, manures, and all vegetable and animal substances, have their true composition determined by chemical research. Chemistry also explains the various changes which take place in the growth and decay of plants and animals. 3 (25) 2G INTRODUCTION. 3. Geology examines into the structure of the earth, the nature of rocks, and the origin of soils. 4. Pliysiology makes us acquainted with the various organs of plants and animals, and the part they act in pro- moting growth, nutrition, etc. 5. Chemical Experiment. — Take a few grains of iron filings, and mix them with an equal weight of finely- powdered sulphur. If you now examine the mixture, you find the particles of iron and sulphur still distinct from each other — the mass is a simple mixture. Place the mix- ture upon a piece of porcelain cup, and heat it over hot coals or a spirit-lamp, until the sulphur takes fire and all the surplus sulphur is burnt out. The resulting mass will be found to difiier entirely from both iron and sulphur. The two substances have united in one ; they have become a compound substance. While they were still in separate particles they were simple or elementary substances. The force which caused them to unite when heated, is called chemical affinity. 6. Definition. — A simple or elementary substance is one which cannot be separated into two or more parts, which dift'er from each other in their properties. Illustration. — Sulphur maybe ground to a fine powder, yet all the particles will possess the same properties. Sul- phur, then, is an elementary substance. Water may be separated by the galvanic battery into two gases, having the form and appearance of the air; but they difier very widely from each other in many of their properties. Water is not an elementary substance. But neither of the gases of which water is composed, can be again divided into parts having different properties. These gases are elementary substances, and are called oxygen and hydrogen. 7. Definition. — A compound suhstance is one formed by the combination of two or more elementary substances. INTRODUCTION. 27 lUusfration. — When iron and sulphur were heated together (§ 5), they united into one mass similar in all its parts. This combination of iron and sulphur is a chemical comjwxind. We call it sulphurct of iron. Oxygen and hydrogen, when combined, form water, which is a compound. 8. Definition. — Chemical affinity is the force which causes elementary substances to combine and form compounds, and compounds to combine with each other and form new compounds. Illustrations. — The force which causes iron and sulj)hur to combine is chemical afRnity. A piece of limestone or marble is composed of lime and a gas called carbonic acid. These are kept together by affinity. If the stone is heated red hot for some time, the gas is expelled, and the lime alone is left. The power of affinity between them has been over- come by heat, and the stone is said to be decomposed. Keeping before our minds the definitions of elementary and compound substances, and of affinity, let us now define Chemistry. 9. Definition. — Chemistry is the branch of science which treats : 1. Of the history and properties of elementary sub- stances ; 2. Of the formation and properties of compounds ; 3. Of the latvs icliich regulate the action of affinity. There are certain agencies which have a great influence over chemical affinity. These are Heat, Light, Electricity, and Vitality. We must here study some of their properties and eficcts, before we enter upon the study of chemistry in its more restricted sense. QUESTIONS ON CHAPTER I. \ 1. How ma/ Agriculture be viewed? As a science, what does it embrace ? What as an art ? 2. Of what does Chemistry treat? How is the true compositioa of all substances detei-mined ? 28 INTRODUCTION. 3, 4. What is Geology? Physiology? 5. What chemical experiment is here given? What is the product? 6. AVhat is a simple or elementary substance? Illustrate it. Is water simple ? Of what composed ? 7. What is a compound substance ? Illustrate. 8. What is chemical affinity ? Illustrate. 9. Define Chemistry. What agencies influence chemical affinity ? To Teachers. — The questions inserted at the end of each chapter are merely designed to be Buggestiye to young teachers. Every teacher should, of course, frame hi.s own questions, to suit circumstances. For my own part, I never use the questions given in any text-book; nor do I regard those given here as of much importance. Still, the young teacher, in the preparation of the lesson in advance of bis class, may get some good suggestions by reading the questions over, after he has studied the text. HEAT. 29 CHAPTER II. HEAT — LIGHT — AND ELECTRICITY. 10. The term caloric is often applied to tlie agency "whicli causes the sensation called heat ; but we shall use the word HEAT to denote both the cause and the sensation. Heat is a most important agent in pi'omoting, modifying, or destroying the force of affinity. Many substances which do not combine at ordinary temperatures, combine rapidly when heated. We had an illustration of this in the experi- ment witli iron and sulphur. In the burning of limestone (§ 7), affinity was destroyed, or at least overpowered, by heat. The action of affinity also produces heat, as in the burning of a lamp or fire. 11. Sources of lie at. — The sun is the greatest source of heat. Combustion, electricity, and friction are sources of heat on the earth. Heat is thrown out from its sources in straight lines. It is then said to be radiated. 12. When radiated heat falls upon the surface of a body, and, entering, pervades the particles of that body, it is said to be absorbed. If the heat is thrown off by the surface upon which it falls, it is said to be reflected. Experiment. — Take two tin vessels of the same form and size. Let one of them be bright, and paint the other with lampblack. Fill both nearly full of cold water, and set them in front of the fire. The water in the vessel with the black, rough surface will be heated most rapidly. The polished, bright surface reflects the heat, while the black, rough one absorbs it. Again, fill the two vessels with hot 3* 30 II EAT. water, and set them aside to cool. A thermometer in each will show that the black vessel cools off most rapidly. Black, rough surfaces radiate more rapidly than bright ones. A stove should be dark and rough — we wish it to radiate as much as possible. A coffee or tea-pot should be bright and smooth, that it may retain the heat. Dark soils are warmed more rapidly in the spring by the sun, than are those of light color. 13. Conduction of Heat. — Heat passes from particle to particle very rapidly in some bodies, while it passes very slowly in others. Hold a piece of iron and a piece of glass in the flame of a candle at the same time. The heat soon reaches the fingers through the iron, but the glass may be held in the flame for many hours without conveying the heat to the hand. Bodies through which heat passes freely are conductors. Those through which it passes very slowly are non-conductors. Metals are good conductors. Glass, charcoal, dry wood, and most liquids, are non-conductors. We clothe ourselves with non-conductors in winter, to con- fine the heat of the body. We surround ice-houses and refrigerators with non-conductors, to keep out the heat of the sun and earth. Experiment. — To show that water is not a conductor, PiQ, 1^ drop a little lump of ice into the bottom of a test-tube (Fig. 1), and fasten it down with a coil of wire. The water may then be boiled at the top of the tube, Avhile the ice remains unmelted in the bottom. EFFECTS OF HEAT. 14. Expansion. — Bodies of all forms, solids, liquids, and gases, are expanded by heat. Exps. — 1. Let the metallic bar (a) be made exactly to fit the frame (h) (Fig. 2), at HEAT. 31 Pig. 2. 'tn^-lWlflllj^ -3 Fig. 3. ordinary temperatures ; tlien, when heated, the bar will be too long for the frame ; and when cooled with ice, it will be shorter than the frame. 2. Fill the glass bulb and tube (Fig. 3) with water to the point a, and mark that point; then hold the bulb over a lamp, or dip it into hot water. The water in the tube will soon rise above a, by the expansion of the portion in the bulb. Alcohol will expand still more than water with the same in- crease of temperature. 3. Pour the ^ water out of the bulb and tube, and invert the tube, placing the mouth of it under water, in the tumbler (6). The tube and bulb will then be full of air alone, but if the bulb is clasped in the hand until it becomes warm, the heat will be communicated to the air within, and expand it to such ah ex- tent, that a portion will be expelled, and pass out in bubbles through the water. A lamp flame applied to the bulb will expel the air still more rapidly. As the bulb cools again, the air within contracts, and, oc- cupying a smaller space, allows the water to be forced upward towards the point c, by the pressure of the surrounding atmosphere. 15. Practical Applications. — When a blacksmith wishes to fit the tire upon a wagon-wheel, he guages it so that, when cold, it is a little smaller than the wooden rim of the wheel. He then expands it by heat, until it is larger than the wheel. It is then easily put on, and, to cool it, the wheel is turned on an axis, with the rim dipping into a 33 HEAT. Boiling. trough full of water, the workman, meantime, adjusting it properly with his hammer. As it contracts, the wheel is bound together with great force. The wheels of wagons often become loose in hot weather, partly by the drying of the wood of which they are made, but partly, too, by the expansion of the tii-e under the sun's heat. 16. We have a beautiful and useful application of the expansion of liquids, in the construction of the common thermometer (Fig- 4). •pjj,_ 4_ " Ordinary thermometers consist simply ^-~. of a glass tube of an exceedingly small bore, with a bulb blown at one extremity, and filled with mercury to about one-third the height of the stem. The air being expelled, the tube is hermetically sealed, and the freezing-point ascertained by hold- ing it a short time in water containing ice, and the boiling point by holding it in the same manner in boiling water. It is neces- sary that these two points should be accu- rately determined, in order that the indi- cations of diiferent instruments may be compared with each other. '' Having determiiied these points, the intervening space is to be divided into equal parts, called degrees ; and in fixing upon the proper number, regard to conve- nience alone would seem to be our guide. Unfortunately, there have been different opinions with regard to this point, and no less than three different scales are in use. In Fahrenheit's thermometer, which is chiefly used in this country and in England, the space between the freezing and boiling points of water is divided into 180 parts, and the zero is placed 32 degrees below the freezing point, so HEAT. 33 that the boiling point is at 212. In the Centigrade thermo- meter, which is generally used in France, the space is divided into 100 parts, zero being at the freezing point, and of course the boiling point is at 100. In Reaumur's thermometer the beginning of the scale, or zero, is at the freezing point ; but the boiling point is at 80. This thermometer is used in Germany and Russia." — Johnston's Turner. 17. Water follows the ordinary laws of expansion and contraction, only within certain limits. When cooled below the ordinary temperature, it contracts, until the temperature is brought down nearly to 89° F. It then begins to expand, and continues to do so until, at the moment of freezing, there is a sudden expansion, so great as to make ice consi- derably lighter than water, and thus cause it to float upon the surface. This property of water points us in a striking manner to the wisdom and benevolence of our Creator; for, if water had been so constituted as to follow the law of con- traction, as exhibited in bodies generally, it would sink as it freezes, leaving the surface always exposed; and thus, in cold climates, one portion after another would freeze and sink, till all the streams and lakes would become solid masses of ice. But as the ice floats upon the surface, it protects the body of water beneath, and prevents its too rapid fz-eezing. The expansion of frozen water in the pores of the soil, enlarges those pores ; thus rendering the soil easily culti- vated, and leaving it, in the spring, in condition to be readily penetrated by the roots of plants. 18. The expansion of air by heat serves many valuable purposes. Heated air, by becoming lighter, is forced upward by the mass of cooler air which surrounds it. Thus, the heated air in a fire-place or stove is made to pass rapidly up the chimney or pipe, and carries the smoke with it. So when some portions of the atmosphere become more highly heated than others, they rise, while the surrounding portions flow in 31 HEAT. to take their place. Thus, currents of wind are produced. In this way, the Creator has provided that our atmosphere shall be kept in a state of perpetual circulation, by the varying heat of the sun. FORMS OF BODIES. 19. Solids, Liquids, Gases. — All bodies on the earth have one of three conditions — they are solid, liquid, or gaseous. These conditions are determined chiefly by temperature. For example, water is solid below 32° ; liquid, between 32° and 212°; gaseous (steam) above 212°. Mercury is solid at 40° below zero; while between that temperature and 662° it is liquid. Heated to a still higher temperature, it assumes Yjq 5 the gaseous form. Boiling is the agitation produced by the rapid formation of steam or other vapor at the bottom of a portion of liquid, and the rising of the bubbles of the steam thus produced. The boiling of water may be beautifully exhibited by filling a glass flask (Fig. 5) half full, and placing a spirit-lamp under it until it boils. 20. Insensible or Latent Heat. — When the heat of a body is so modified as not to be felt by the hand, or so as not to afi'ect the thermometer, it is said to be rendered insensihle or latent. Heat becomes insensible when a solid is changed to a liquid, or when a liquid is changed to vapor. When ice is made to melt rapidly by mixing it with a substance like common salt, for which it has an affinity, the heat already in it becomes insensible, and the temperature falls rapidly. Experiment. — Reduce two pounds of ice to fine powder, and mix it thoroughly with one pound of salt. A thermo- meter inserted in the mixture will soon fall below zero. A little water in the bottom of a test-tube, immersed into the mixture, will be frozen in a few minutes. HEAT. Fig. 6. Tq freezing ice-cream, we have an illustration of a similar kind. But, in this case, a smaller quantity of salt should be used, so that the freezing may not be too rapid. The cream has a finer grain if frozen more gradually, and frequently agitated as it freezes. 21. When water is heated up to 212°, it begins to boil. A thermometer immersed into the water will cease to rise as soon as the boiling commences. Unless the water is confined by external pressure, it cannot be heated above 212°. The steam, as it rises from the water, has the same temperature as the boiling water. But after water has been heated to the boiling point, it still requires a great amount of heat to con- vert it into steam. This added heat becomes insensible in the steam. 22. The boiling point of a liquid, such as water, is greatly modified by outward pressure. The atmosphere at the surface of the sea exerts a pressure of about 15 jjounds on every square inch of surface. On the tops of high mountains, the pressure is much less, because a large portion of the atmo- sphere is beneath us. Here water will boil below 212°. If the pressure of the air can be dimi- nished in any other way, a similar result follows. Experiment. — Fill a glass flask half full of water (Fig. 6), and boil it a few minutes, till the air is all expelled by the steam. While still boiling, cork it tightly, and invert it into a glass tumbler or cup, with a little water in the bottom. Apply a cloth dipped in cold water to the top of the flask as now inverted, and the water will boil violently. This will take place even after the flask becomes cool enough to be held comfortably in the hand. If hot water is applied to the outside of the flask, instead of cold, the boiling will cease. To understand this 36 HEAT. beautiful and interesting experiment, we must remember that the air has all been expelled, and nothing but the vapor of water remains above the surface of the water in the flask. When cold water is applied, this vapor is rapidly condensed, and its pressure on the water diminished. Under this dimi- nished pressure, the water boils at a low temperature. Hot water, however, instead of condensing the vapor, tends to expand it; and thus the pressure is increased, and the boiling checked. 23. Distillation. — Two liquids, which boil at different temperatures, may be separated by distillation ; or a volatile liquid may be separated from involatile substances held in solution by it. Experiments. — 1. Put a mixture of equal parts of alco- hol, and water in the retort, a (Fig. 7). Insert the neck of Fig. 7. the retort into the receiver, h, kept cool by being placed in a basin of cold water. Apply a lamp to the retort, and regu- late the heat so that the boiling will go on slowly. As the liquid disappears from the retort, a portion of it will be found condensed again in the receiver. When about the half of it has thus passed over to the receiver, examine the two por- HEAT. 37 tions; and it ■will be found that what is left in the retort is much weaker than the original mixture, while that portion in the receiver is much stronger. The alcohol, being more volatile than water, has passed over more rapidly. 2. Empty the retort and receiver, and use clean spring-water instead of the mixture. The mineral matter, some of which is always found even in the purest springs, will remain in the retort; while pure water will be collected in the receiver. Water should be thus distilled before it is used in preparing solutions of chemical substances. 24. Atmospheric Vapor. — Water is continually evapo- rated from the surface of the earth, from rivers, seas, and oceans, and, ascending, mingles with the air in vast quanti- ties. It is found in the atmosphere in two conditions. (1) In a visible form, as clouds and fogs. (2) In the form of true vapor, which is entirely invisible. If the air were removed, that is, if the space above the surface of the earth were a vacuum (wnth reference to air), evaporation would go on much more rapidly than it now does, until the whole world would be surrounded by an atmosphere of vapor. The air checks evaporation. The quantity of vapor required to fill a given space, at a maximum density, varies with the temperature (below 212" F.), increasing as the temperature rises, and diminishing as the temperature falls. When the space is entirely filled, the vapor is said to have its " maximum density," for the tem- perature it then has. The vapor of water required to fill a cubic foot of space, at 32° F., weighs about 2 J grains; while that required to fill the same space, at 212°, weighs 258j grains. If the vapor were heated only to 100°, then 19 4 grains would fill the cubic foot of space. 25. Although the presence of the air causes evaporation to go on more slowly, yet the quantity of vapor which will ultimately be required to fill a given space, at any given 4 88 11 E A T. temperature, will always be the same, whether the air is present or not. And the vapor will not cease to rise till it has reached its maximum density. Whenever this takes place, the air is generally said to be " saturated with mois- ture." The temperature of the vapor mingled with the air varies with the temperature of the air. When the vapor has its greatest density at any temperature, and the air is cooled below that temperature, the vapor is also cooled. Less of it will then saturate the air (or fill the sjiace), and the remainder must be condensed into the form of water. When the air is cooled down until the vapor which it contains begins to be deposited as little particles of moisture, that temperature is called the " dew-point." 26. If the vapor in air has nearly its greatest density, the air is said to be damj) ; but if there is not vapor enough present to give it near its greatest density, the air is said to be dry. If damp air has its temperature reduced but a few degrees, a part of its moisture is condensed ; but if its tem- perature is elevated a few degrees, it becomes apparently dry ; that is, its vapor, with the increase of temperature, is no longer capable of filling the space it occupies. On the other hand, dry air may become damp by being cooled ; for the reduction of temperature may be sufficient to bring the vapor to its state of greatest density for that temperature. It is then readily deposited as moisture. When the temperature of air is reduced below the dew- point, a portion of the vapor present becomes condensed, and assumes a visible form, either like deic, on the surfaces of solid bodies, or like jh/s/, floating in the air. 27. Dew and Frost. — Experiments. 1. Fill a bright cup of silver or tin half full of water, and place a thermo- meter in it. Wipe the outer surface of the cup perfectly dry; then drop small lumps of ice into the water at short intervals. On a warm summer day, the moisture from the H E A T. 39 air will soon begin to dim the bright surface of the cup. The temperature indicated by the thermometer at that mo- ment, is the temperature at which the vapor of the air begins to be condensed: it is the dew-point. — 2. Put a mixture of ice and salt into the cup, instead of ice-water, and the moisture will be frozen as it collects upon the sur- face. It is then frost — frozen dew. After the sun, the great source of heat, has gone down, solid bodies on the earth radiate their heat rapidly into the atmosphere, while the atmosphere itself radiates but slowly. As these bodies radiate heat, their temperature gradually falls; and they cool down the particles of air which come in contact with them, and also the particles of vapor mingled with the air. Whenever the temperature is thus brought below the dew-point, dew begins to be deposited. When the receiving surfaces are below 32°, the dew is frozen, and becomes frost. 28. If the air is agitated by winds, dew and frost are not so readily deposited ; because no portion of the air is then allowed to remain long enough in contact with the cold sur- faces of bodies on the ground, to be brought down to the required temperature. In low valleys we very frequently find vegetation covered with dew or killed by frost, while the same efiects are not produced on the surrounding hills. This is owing to the fact, that the confined portions of air along the valleys remain tranquil, while those on the hills are disturbed by currents of wind. Clouds reflect the heat radiated from the earth's surface, and thus prevent the temperature from being reduced to the dew-point. Hence, there is no dew on cloudy nights. Surfaces which radiate most freely are cooled most rapidly at night, and consequently collect dew in greatest abundance. This is the case with green vegetable substances. Plants which especially need the dew, have thus been organized by 40 HEAT. an all-wise Creator, that they might collect it readily from the air. In some countries, the dews are almost the only source of moisture for plants for many successive weeks. 29. Rain. — When two equal portions of air at widely differ- ent temperatures are mingled, the resulting temperature will be a mean between the two. But if both portions were nearly saturated with moisture before they were mingled, this mois- ture can now no longer remain in the form of vapor; because the quantity of vapor required to fill the space occupied by the two bodies of air at their mean temperature, is less than was required when they had widely different temperatures. A portion of the vapor, then, must be changed to mist or dotid. Illustration. — 5000 cu. inches of air at 32° can contain only about 10 grains of vapor. 5000 cu. inches of air at 59° can contain only about 20 grains of vapor. 5000 cu. inches of air at 86° can contain as much as 40 grains of vapor. Now, suppose the first portion of 5000 cu. inches, at 32°, to be mingled with the third, at 86° : their mean tempera- ture will be that of the second portion (59°); but the re- sulting 10000 cu. inches, at this temperature, can contain only 40 grains, while they unitedly had 50 grains before they were brought together. The surplus 10 grains of vapor must now appear in a condensed form. When currents in the atmosphere meet and mingle in this way on a large scale, immense quantities of moisture are condensed in the form of minute hollow globules, which, uniting, form rain-drops, and fall to the earth. If, from great elevation, or any other cause, the drops become frozen before they reach the earth, they come down as hail or sleet. When the moisture is condensed at a temperature below 32°, it forms minute crystals, instead of globules; and these, Ainiting in clusters, form Jlakcs of snow. HEAT — L-I G II T. 41 30. Fogs are clouds formed near the earth's surface. This happens around islands and along the sea-shore, when the cool air from elevated land flows down and mingles with the warm, moist air over the surface of the water. The same phenomenon is witnessed in valleys, and especially along- large rivers, in spring and autumn, when the days are warm and the nights cool : the cool, dense air from the surround- ing hills flows down and mingles with the warmer air along the water. Whenever such a mingled mass of air has a temperature too low for all its moisture to retain the form of vapor, a portion of fog will make its appearance. Fortunate is it for our comfort, that the air plays so con- spicuous a part in regulating the evaporation of moisture. We can see the hand of a kind Providence in so constitu- ting the air, that it presents a perpetual impediment to eva- poration. If it had been so constituted that evaporation and condensation could go on as freely in it, as they do In vacuo, the atmosphere would be ever reeking with moisture : no sooner would a slight elevation of temperature take place, than a sudden rise of vapor from the earth would follow, and the vapor of the air be brought to the condition of maxi- mum density. Then, every portion of the atmosphere being in this condition, the least diminution of temperature would produce a cloud or a mist; and every object surrounded by the air would be drenched by a copious deposit of dew, whenever by any means its temperature happened to fall below that of the atmosphere. Drought and drenching would then be the alternate efiects of elevations and de- pressions of temperature. LIGHT. 31. We shall not stop to discuss the nature of light, nor any of its effects, except such as relate to our immediate subject. 4* 42 Lie. II T. 32. The great natural source of light is the sun. Artifi- cial light is generally the result of heat produced by chemical action ; by combustion. Whatever may be the source of light, it passes off from luminous bodies in straight lines; and is either absorbed by the bodies on which it falls j or is thrown back from their surfaces {i'( fleeted) ; or passes through them (transmitted^. Reflected light enables us to see the objects around us, by passing from them to the eye. The colors of objects are determined by the manner in which they reflect light. 33. Light has a remarkable effect upon the heat which accompanies it. This is seen in some of the peculiarities of the heat produced by the sun. The light seems to have the effect of making it pass freely through transparent sub- stances, such as air and glass, without affecting their tempe- rature to any considerable extent. If this were not the case, but little of the sun's heat would reach the earth. The heat of the sun accompanied by light, has the property of being absorbed more freely by dark surfaces, than heat without light. 34. The effects of light on chemical afiinity are remark- able. Some substances are decomposed by it, while others are caused to combine. Experiment. — Moisten a piece of white paper or linen with some solution of lunar caustic (nitrate of silver), and lay it for a few minutes in the sunlight. It will become dark — almost black. Here the light decomposes the nitrate of silver. Illustrations. — The effect of light upon chemical action is beautifully illustrated in the process of taking Daguerreo- types, ambrotypes, etc. Light is necessary to the healthful growth of plants and animals. Every one is familiar with the difference in the appearance and vigor of the same kind of plant, when ELECTRICITY. 43 growing in a shaded place, and in the full light of the sun. Very few plants will come to full maturity without a full supply of light. Animals, too, generally require light. The lower animals, as well as men, never attain to much vigor if they are shut up in the dark during the period of their growth. ELECTRICITY. 35. That form of electrical excitement produced by the galvanic battery, is one of the most powerful chemical agencies within our reach, and enables us to perform some of the most interesting and striking experiments. But our present purpose demands only a few of the leading facts and principles on this subject; such as are necessary to a clear and full understanding of the laws of chemical affinity. 36. *' When two solid conducting bodies are plunged into a liquid which acts upon them unequally, the electric equili- brium is also disturbed — the one acquiring what is called the positive condition, and the other the negative. Thus, pieces of zinc and platinum (or copper), put into dilute sul- phuric acid (oil of vitriol, with 5 or 6 parts of water), con- stitute an arrangement capable of generating electrical force : the zinc, being the metal attacked, becomes negative (above the liquid) ; and the platinum (or copper) re- p « 8 maining unaltered, assumes the positive con- ^ ^^ dition; and on making the metallic communi- cation in any way (as at a, Fig. 8) between the two plates, a discharge ensues, as when the two surfaces of a coated and charged jar are put into connection. " No sooner, however, has this occurred, than the disturbance is repeated; and, as these successive charges and discharges take place through the fluid and metals with inconceivable rapidity, the result is an appa- 44 ELECTRICITY. rently continuous action, to wliicli the term electrical current is given." — Fownes. 37. With a single pair of plates, as above described, the degree of excitement is very feeble; but if we arrange several pairs as in Fig. 9, having the zinc and copper in Fig. 9. contiguous cups connected by wires soldered to each other, and placing them so that the difl'crcnt metals shall succeed each other in the same order; then connect the first and last plate by wires (a, h), we have a compound circuit. This gives us the simplest form of the galvanic battery, ends of a and h are called the poles of the battery. one marked, -{-, is the positive; and the one marked, the negative. 38. Another very simple form of the battery is repre- sented in Fig. 10. It consists of a wooden trough with per Fig. 10. The The -, is pendicular grooves in the sides, and corresponding grooves across the bottom. Into these are fitted pairs of zinc and ELECTRICITY, 45 copper plates, soldered back to back, and having all the copper plates facing the same way. They are then to be carefully cemented into the grooves. The trough is thus divided into cells for holding the mixture of acid and water with which the battery is charged. At the extremities of the last cells, plates are to be inserted for the connecting wires : one of zinc, so placed as to be opposite to and facing the last copper; the other of copper, facing in like manner the zinc at the opposite end of the trough. 39. There are various other forms of the battery in use, among the best of which is Grove's. This is the one most commonly used on telegraph lines. We have not room for a description of it here. It is described in most of the larger works on Chemistry. 40. Whatever may be the form of the battery, if the poles are tipped with little strips of platinum foil, and immersed into water, to which a little sulphuric acid has been added, bubbles of gas will rise rapidly around both poles. The water is decomposed. The oxygen and hydrogen of which it is Fig. 11. composed are separated ; the oxygen collecting around the positive pole, and the hydrogen around the negative. These 46 ELECTRICITY. gases may be collected by filling test-tubes with water, and inverting them over the poles of the battery, by some such arrangement as that seen in Fig. 11. The tube over the negative pole, into which the hydrogen passes, will be filled twice as rapidly as the other; showing that the hydrogen of water occupies twice the volume of the oxygen. But if we could weigh the two gases, we would find the oxygen eight times as lieavi/ as the hydrogen. 41. Experiment. — Mix a few grains of starch with a spoonful of cold water; then add the mixture slowly to half- a-pint of boiling water, stirring as you pour it in. You will thus get a dilute solution of starch. When this has become cold, pour into it a little of the solution of iodide of potas- sium. Then put the mixture into a tumbler, and bend the poles of the battery over the opposite sides of the tumbler, so that the strips of platinum will dip a little way into the solution. If the battery is now put into action, the solution soon becomes of a deep blue color around the positive pole, while there is no change of color around the negative. The battery decomposes the iodide of potassium, which is com- posed of iodine and potassium combined. The iodine is collected around the positive pole, free from the potassium, which has gone to the negative pole. But so soon as the iodine is set free, it attacks the starch in the solution, and, uniting with it, forms a beautiful blue compound, called iodide of starch. The starch in the solution is not aifected by the battery: it is used in this experiment to show the presence of the free iodine around the positive pole. IMany other substances may be decomposed with the bat- tery; but the above will serve to illustrate, sufficiently for lOur present purpose, the action of this wonderful piece of apparatus. The influence of Vitality will be shown in connection with organic chemistry. QUESTIONS. 47 QUESTIONS ON CHAPTER II. § 10. How is the term "caloric" applied? In what sense is "heat" here used? Why is heat an important agency to the chemist? 11. What is the greatest source of heat ? AVhat are other sources? 12. When is heat said to be absorbed? When i-eflectcd ? Illus- trate. What kind of surface should a stove have? Why? Coffee- pot? Why? How does dark color affect soil ? 13. What bodies are conductors? Non-conductors? Is water a good conductor? How illustrated by experiment? 14. What is the influence of heat on the dimensions of a body? What experiments illustrate expansion of solids ? Of liquids ? Of gases ? 15. IG. How is a tire fitted to a wagon- wheel? Explain the struc- ture of the common Thermometer. What principle does its action illustrate ? 17, 18. To what degree of temperature does water contract when cooled? AVhat takes place at the moment of freezing? What would be the result if contraction should continue, with continued reduc- tion of temperature? Why does ice float? IIow does freezing affect the soil? What are the effects of expansion and contraction in the air? 19. In what conditions do all bodies exist? What determines these differences in form ? How illustrated ? 20. What is insensible heat ? Why does the temperature fall rapidly in a mixture of salt and ice ? Explain the preparation of ice-cream. 21. At what temperature does water boil? If a thermometer is immersed in it, will it rise above 212°? What becomes of the heat continually added ? 22. How does change of pressure influence the boiling point? How illustrated? AVhy does cold water applied to the flask increase the boiling, while hot water diminishes it? 23. What kind of substances may be separated by distillation? How are alcohol and water separated ? How is water purified ? Is not spring-water pure? Why not? 24. From what sources does the air receive moisture ? In what conditions does moisture exist in the air? What determines the 48 QUESTIONS. quantity of vapor required to fill a given space below 212° ? When has vapor its greatest density ? Illustrate. 25. Does the presence of air diminish the quantity of vapor re- quired to fill a given space? IIow does the temperature of the air influence the temperature of the vapor present? What is meant by the " dew-point"' ? 26. When is air damp ? AVhen dry ? What if the temperature of damp air be reduced? V/hat if it be elevated? How maj' dry air be made apparently damp ? When does the vapor become visible? 27. Explain the deposition of moisture on the surface of a cool cup. When does it become frost ? How arc dew and frost formed at night ? 28. Influence of winds on the formation of dew? Why is vege- tation frequently killed by frost in valleys, while it escapes on the surrounding hills? lIow do clouds prevent dew and frost? What surfaces receive most dew? Who made this provision? Why? 29. When do mingled portions of air form clouds ? How illus- trated? How ai-e rain-drops formed? Hail? Snow? 30. What are fogs? Where most frequently seen? Why? If the air did not regulate evaporation and condensation, what would be the consequence ? 31. 32. Great natural source of IJght ? Sources of artificial light? In what ways is light disposed of when it falls upon the surface of bodies? What determines color? 33. Influence of light on transmission of heat? How is the air heated? 34. What is said of influence of light on affinity? How illus- trated? Influence on vegetation? 35. 36. What is said of Electricity produced by the galvanic bat- tery ? What if two solid conductors are acted upon unequally by an acid liquid? Explain Fig. 8. What is called the "electric current"? 37, 38, 39. Effect of increasing the number of plates ? Explain Fig. 9. How is a battery constructed ? 40, 41. How is water decomposed by the battery ? What experi- ments are here given? SYMBOLS — E Q U I VA L E N T S . 49 CHAPTER III. SYMBOLS — EQUIVALENTS — NOMENCLATURE. 42. There are sixty-five elementary substances known to chemists (see § 5). These unite and form all the various compounds of v?hich we have any knowledge. Many of them, however, are rare and unimportant. We shall take time to describe only twenty-eight of the most important. These will be found in a table on the next page. SYMBOLS. 43. It is not always convenient to write the names of sub- stances in full; hence we employ what are called syvihols. These consist of the first letter, or some two letters, of the names ; thus, C is the symbol for carbon ; H for hydrogen ; Al for aluminum; Mn for manganese. When the substance has a Latin name, we use the first letter or letters of this as its symbol ; thus, K stands for potassium (from lialium, its Latin name). So Sb (from stlhiuiii) is the symbol for antimony ; and Fe (from ferrmn) for iron. EQUIVALENTS. 44. When elementary substances combine to form com- pounds (§ 5 and 6), they enter into the compounds in defi- nile proportions by weight. Hydrogen and oxygen are com- bined in water, in the proportion of 1 to 8 (§ 40). That is, the oxygen in water (in all pure water) weighs eight times as much as the hydrogen. When hydrogen and sulphur combine to form the disagreeable gas which rises from sul- phur springs, the proportion is 1 of hydrogen to 16 of sul- phur. And as hydrogen enters into combination in a less 5 50 EQUIVA LENTS. relative weiglit than any other elementary substance, we take its combining weight as 1 ; then that of oxygen will be 8 ; and that of sulphur 16. These numbers are supposed to represent the relative 7ceih. acid) = CaO^SOj -f HO -f CO,. 65. Natural Sources. — Combustion, respiration, and vol- canic action, are some of the chief natural sources of COj. It is formed abundantly in the burning of wood or coal — the carbon of the fuel combining with the ox;jgen of the air. During the decay of vegetable and animal substances, which is a slow combustion, this gas is abundantly generated. Hence its accumulation in old cellars and wells. During the breathing of animals, large quantities of CO, are thrown out into the air (see § 625). It also rises abundantly from many springs, ponds, lakes, etc. especially in volcanic regions. The air, thus continually receiving supplies of this poisonous gas (poisonous except in very small quantities), would soon be- come unfit to sustain life, had not Providence furnished one of those compensating arrangements so often met with in the study of nature. It is this : growing plants extract CO^ from the air. It is an important article of food for the plant. But while the plant consumes CO2, it gives out a fresh supply of oxygen. Combustion and respiration con- NITROGEN. 63 sume oxygen and generate carbonic acid, while vegetation consumes carbonic acid and generates oxygen; and thus the equilibrium of the air is preserved^ in respect to these gases. Carbonic acid is abundant in combination with different bases, as lime, potassa, soda, etc. forming a class of salts called carbonates. Fig. 21. NITROGEN, OR AZOTE (Sf/mhol, N; At. Wt. 14). 66. Preparation. — This gas, as before stated, constitutes about I of our atmosphere. From this source it is most conveniently procured. A little metallic capsule, or a flat piece of chalk with a cavity in the top, may be placed on a flat cork, and thus made to float on the surface of the pneu- matic cistern. Place on this a little lump of phosphorus, ignite it, and immediately invert a jar over it, as in Fig. 21. The burning phosphorus consumes all of the oxygen within the receiver, and leaves the nitrogen. The water rises to take the place of the oxygen. The vapor of phosphoric acid, pro- duced by the burning phosphorus, will subside in a few minutes, and leave the nitrogen as a transparent, colorless gas, a little lighter than air. For experiments, it may easily be transferred to bottles, by inverting the bottles, filled with water, over the hole in the shelf of the cistern ; then slipping the mouth of the jar of gas beneath the shelf, and gradually turning it up, till the gas can escape, and pass up into the bottle. Experiments. — 1. Immerse a candle into a bottle of ni- trogen, and it goes out at once, from the want of oxygen. 2. Place a small animal in a bottle of it, and it soon dies. G4 NITROGEN. The N is not poisonous to tlie animal, but death is caused by the absence of oxygen. The Atmosphere. 67. Besides the mixture of and N, which constitutes the chief part of the atmosphere, small quantities of carbonic acid and other gases are found at every point accessible to man. > The atmosphere is also a great reservoir of moisture, as we have seen (§ 24). It is the great agency, too, by which the circulation of water on land is kept up. The vapor of water is continually rising and mingling with the air, and, by the mechanical agency of winds, is carried from those parts of the earth where evaporation goes on most rapidly; to those parts where rain is most needed. 68. The atmosphere is one of the most important sources of nutrition for plants. If the air were deprived of moist- ure, all plants would wither, droop, and finally die. If car- bonic acid and ammonia were taken away, our crops would soon be starved. Carbonic acid, absorbed by the leaves, and taken up by the roots in rain-water, which brings down large quantities of it from the air, is the great source of carbon in plants. Ammonia, too, affords nutriment no less important. Nitrogen and Oxygen. 69. Nitrogen forms several interesting compounds with oxygen, but only one of these is important for our jDresent purpose. This is nitric acid (NO5). Preparation. — Put three or four ounces of saltpetre (nitrate of potassa) into a retort (Fig. 22), and pour upon it an equal weight of sulphuric acid ; then apply heat gra- dually, by means of a spirit-lamp or charcoal furnace. The neck of the retort must pass into a receiver or bottle, kept cool by being immersed in cold water, or by having a wet cloth spread over it, on which cool water is made to drip NITROGEN. 65 continually. Tlie apparatus will at first be filled with red vapor, which is hyponitric acid, formed by the decompositioa Fig. 22. of the first portions of nitric acid. This, however, will dis- appear after a while, and the nitric acid be distilled into the cool receiver, and there condensed as a liquid, colored by the presence of nitrous or hyponitrous acid. When nitric acid is pui-e, it is a colorless liquid, about once and a half times (1.52) as heavy as water. Exjieriments. — 1. Put a drop of it on a piece of colored cloth : it will destroy the color, and finally corrode the mate- rial of which the cloth is made. 2. Pour a little of the acid upon some powdered charcoal heated red-hot in a cup or crucible ; brilliant combustion takes place. It will also ignite hot spirits of turpentine. 3. Dilute a little nitric acid with an equal quantity of water, and drop a fragment of copper into it. The copper will gradually disappear. It decomposes one portion of the acid, by taking away a part of its oxygen. This decomposed acid rises and forms the same red vapor in the air which we saw in the retort, when 6* 66 NITROGEN. preparing nitric acid. After tlie copper has become oxidized at the expense of one portion of the acid, it at once combines with another portion, and forms nitrate of copper (CaO,N05). The solution has a green color. 4. Pour a little of this solution into some clear water in a saucer : the water will scarcely be colored ; but add some ammonia-water (spirit of hartshorn), and you will have a beautiful blue color. This is one of the best tests for the presence of copper in a solution. Nitric acid combines with a great number of bases, giving us an important class of salts called nitrates. Nitrogen and Hydrogen. 70. Ammonia (NH3). — This most valuable and interest- ing compound is not formed by the direct union of its two elements, under ordinary circumstances 3 but electricity will cause them to combine. This is supposed to take place high up in the air, u.nder the influence of lightning. By the sam agency, nitric acid is also formed by the union of N and 0; and this, combining with the ammonia, forms the nitrate of ammonia often found in rain-water. Prejyaration. — Put equal weights of slacked lime and Fig. 23. pulverized sal-ammoniac into a flask, and apply a gentle heat. A gas having a strong suffocating odor will be set free. The lime decomposes sal-ammoniac (NH4CI), thus : CaO + NH.Gl = CaCl + HO + NH3. It cannot be collected at the water-cistern, be- cause water absorbs it with great rapidity. A small cistern filled with mercury, instead of water, enables us to collect it readily; but if there is no mercury-cistern at hand, it may be collected, with tolerable success, in a bottle (Fig. 23) inverted over the neck of the flask where it is generated. N I T R a E N. QT The gas, being much lighter than air, rises to the upper part of the bottle, and displaces the air. Experiment. — By attaching a bent tube to the mouth of the flask in which ammonia is generated (Fig. 24), and Fig. 24, causing the end of it to dip into a bottle of cold water, kept cool by surrounding ice, or by being set into a larger vessel of cool water, we can obtain the solution of this gas called " aqua ammoniae" 71. Chemical Properties. — Ammonia is a strong alkaline base,* sometimes called "volatile alkali." It neutralizes the strongest acids, and, by its union with them, forms definite salts. But it is readily set free from its combinations by potassa or lime. Uxpcrimenf. — Eub a little sal-ammoniac and fresh lime together, and you may at once perceive the odor of the escaping ammonia. Ammonia is one of the most valuable ingredients in all animal manures, and every precaution ■? * An alkaline base is any compound -wliich has a strong aiBnity for acids, and -which, ■when combined with them, forms salts. Po- tassa, soda, and lime are alkaline bases. G8 s u L p n u R . should be taken to prevent its escape. Hence, fresli lime sJiouId never be mixed with animal manures, because it seta the ammonia free. During the decay of many organic substances, such as dead animals and animal manures, ammonia is generated chiefly as a carbonate (NH40,C02), which is volatile, and will escape, unless in some way prevented. If gypsum in fine powder (ground plaster) is mingled with such manures, and water sprinkled freely over the heap, the gypsum, which is sulphate of lime (CaO,S03), will act uj)on the carbonate of ammonia in such a way that both compounds will be decom- posed. The sulphate of lime wall become the carbonate, and the carbonate of ammonia will become the sulphate. The carbonic and sulphuric acids exchange places. The sulphate of ammonia thus formed is not volatile, and hence the am- monia is said to be " fixed." But this sulphate is soluble ; and hence the manure should not be exposed to heavy rains before it is applied to the soil, else much of the ammonia will be washed out and lost. Every farmer should be fami- liar with the properties of ammonia, and its relation to other compounds; hence, we shall have more to say about it under the head of " Fertilizers." SULPHUR (S^nihol, S; At. Wf. 16). 72. This is a well-known yellow, brittle solid, often called " brimstone." It is insoluble in water, but dissolves readily in hot spirits of turpentine. If heated in a test-tube to about 230°, it melts, forming a thin yellow liquid. When heated to a higher temperature, it gradually forms a thick, viscid mass, which will not run out of the tube when in- verted. At a still higher temperature, it again becomes more liquid, and may be poured into cold water. Thua cooled, it forms a soft, elastic mass, not unlike gum-elastic. At about 600° it begins to boil, and rises in the form of a SULPHUR. 69 dense brown vapor, which condenses in the upper part of the tube as a fine yellow powder (flowers of sulphur). Sulphur is found abundantly in some volcanic regions, mixed with clay, ashes, and other impurities. From these it is separated by being distilled into large chambers, where it is condensed on the walls in tufts or clusters of fine yellow powder : these clusters are the flowers of sulphur. When melted and cast in wooden moulds, it forms roll sulplmr. 73. Both plants and animals contain small quantities of sulphur. Plants find it in the soil in the form of sulphates. Animals derive it from the plants upon which they feed. It exists more abundantly in the hair than in any other part of the animal. It is the sulphur in black mustard and in eggs which tarnishes silver spoons — forming sulphuret of silver on the surface. Sulplixir and Oxygen. 74. When sulphur is burned in the open air or in oxygen, it unites with two atoms of oxygen, and forms an acid gas (SO2) of very disagreeable odor. Exp. — Hold a rose, or any colored flower, over burning sulphur, and it will lose its color. A yellow straw treated in the same way will be whi- tened. This gas is used extensively in bleaching. It is called sulphurous acid. 75. SuIpJiuric Acid This is the most important and valuable compound of sulphur and oxygen. It is a heavy, oily liquid, nearly twice as heavy as water. It was formerly obtained by heating sulphate of iron (green vitriol) to a high temperature, and distilling the oily acid from it; hence it derived its common name, " oil of vitriol." Its symbol is H0,S03. For the process by which it is now prepared, the reader is referred to the larger works on chemistry. Sulphuric acid has a strong affinity for water. This may be illustrated : 1. By leaving a weighed portion of it in an open glass vessel for a day or two. It will be found to haw 70 CHLORINE. increased in weiglit, owing to the moisture absorbed from the air. 2. Fill a large test-tube one-third full of water; then fill it up quickly with sulphuric acid : the tube will become too hot to be held in the hand. The rapid combi- nation of the acid and water produces the heat. 3. A piece of wood dipped for a few minutes into strong sulphuric acid, is blackened (charred). The acid takes out hydrogen and oxygen from the wood, in the form of water, while the car- bon is left in an uncombined condition. 7G. Sulphuric acid is used extensively in the arts. It is also valuable to the former. We shall hereafter (§ 378, <7) recommend its use for preserving ammonia in animal manures. With bases it forms sidpJiates. Gypsum is a sulphate of lime. Glauber's salt is a sulphate of soda. These are both valuable fertilizers. Sulj)hur and Hydrogen. 77. The disagreeable gas which rises from sulphur springs, is a compound, of sulphur and hydrogen (IIS). It is usually called sidpliuretted hydrogen, or liydrosulphuvic acid. It is produced during the decay of eggs, and of many animal substances. When bright silver is exposed to this gas, it is soon tarnished, by the sulphur from the gas combining with the silver. CHLORINE {Symbol, CI; At. Wt. 35.5). 78. Experiment. — Put an ounce of black oxide of man- ganese into a flask (Fig. 25), and pour upon it two liquid ounces (half a teaeupful) of muriatic acid. Stir up the mixture well, and let it stand a fevf minutes. A gentle heat from a lamp, or pan of coals, will cause a heavy green gas to pass over into the bottle (Z^).* This gas is nearly two «■ Mn02 + 2IIC1 = MnCl -f 2II0 -f CI. CHLORINE 71 Fig. and a half times heavier than air. It will, therefore, sink to the bottom of the bottle; and, by gradually filling it up, will dis- place the air entirely — ^just as water, poured into a bottle of oil_, would cause the oil to flow out, while the water alone would fill the bottle. 79. This gas is called " chlorine," because of its green color. It can- not be collected over water, because water absorbs it freely. But over a hot solution of salt it may be col- lected, as this does not absorb it. This gas should not be inhaled freely, else it will irritate the throat and lungs. Experiments. — 1. A burning candle let down into a bottle of chlorine gas, burns but slowly, and gives off a dense smoke. This is because the chlorine combines with the hydrogen alone of the flame, while the carbon (for which it has no afiinity) is set free in the form of smoke. 2. A frag- ment of phosphorus suspended in this gas takes fire sponta- neously. 3. Suspend in chlorine a moistened strip of paper on which there is writing done with common ink, and the writing will soon disappear. This is owing to the strong afiinity between chlorine and iron. The iron, which gives the black color to ink, is removed by the chlorine, and the color thus destroyed ; while the new compound of chlorine and iron is colorless. 80. Chlorine is one of the elements in common salt, which is chloride of sodium (NaCl). It is found in small quanti- ties in nearly all plants, and quite abundantly in sea-weeds. In the fluids of animals it is found in considerable abun- dance. The compounds of CI with the metals are called " chlorides." Chlorine and Hijilrogen combine and form a strong acid. When free, it is a gas ; but a solution of it is generally sold 72 i?nosrii ORU s. by druggists 'undei* the name of " mui'iatic acid." It is a cheap acidj and niay be employed in preserving manures (§378, cZ). Iodine, Fluorine, and Bromine resemble chlorine in most of their chemical properties and relations. PHOSPHORUS {Si/mhol, V ; At. Wt. 32). 81. This remarkable substance is obtained from bones. When freshly prepared, it is a transparent, waxy substance, generally bought in the form of round sticks. A stick of it, placed in a tube, covered with water, and exposed to the light of the sun a few days, becomes brown. The light seems to cause some rearrangement of its atoms, without any essential change of its properties. 82. Phosphorus has a very strong affinity for oxygen. If exposed to the air it undergoes slow combustion, gives off a white vapor, and in the dark emits a faint light. It takes fire from a slight elevation of temperature, or from friction ', hence its value in making friction matches. It must be kept under water, to exclude it from the air. It must be handled cautiously, lest it be ignited by the heat of the hand. Burns produced by it arc exceedingly painful. In its free condi- tion, as well as in some of its compounds, phosphorus is very 2ioisonous. 83. When ignited in the open air or in oxygen gas, phos- phorus combines with five atoms of 0, forming phosphoric acid (PO5). This acid forms a very important class of salts, called " phosphates." Phosphate of lime is the white sub- stance left when a bone is burned in an open fire. It forms a large proportion of the bones of all animals. Phosphates also exist in other parts of animals, and in different parts of plants, but especially in the seeds. For a more full description of the phosphates, we must turn to the bases with which phosphoric acid combines. V SILICON — BORON. 73 SILICON (^Symhol, Si; At. Wt. 21). 84- This substance possesses but little practical interest, except in its combination with oxygen. Silica (SiOs) is a very abundant mineral, found in nearly all the rocks and soils on the surface of the earth. We often find it in beautiful crystals, having the form of six-sided prisms with six-sided pyramids at the ends (Fig. Fig. 26. 26). Flint and sand are nearly pure silica, but /h. often colored with a little of the oxides of iron ^^-A^ and other metals. Agate, carnelian, amethyst, opal, and some other gems, are composed of silica. The strongest acids will not dissolve nor decom- pose silica. It is also so hard as to scratch glass readily, and is very infusible alone. Although silica is so very hard, insoluble, and tasteless, it is classed among the acich, and called " silicic acid." It is regarded as an acid, because, when heated to a high tempe- rature with potassa, soda, or lime, it combines readily with these bases, and forms a class of salts called '^ silicates." The stalks of grains and grasses contain considerable quantities of silica (§ 185). It must, therefore, be found in a soluble form in every fertile soil. BORON {Symbol, B; At. Wt. 11). 85. The only interesting compound of boron is boracio acid (BO3). In combination with soda, this acid forms the horax used in the arts : it is a borate of soda. Borax is used as a flux for cleaning the surfaces of metals, and for excluding the air in welding and soldering with hard solder. It forms a thin and very fusible film over the surface of the metal, and thus prevents oxidation, until the two surfaces to be united can be brought together. 7 74 QUESTIONS. QUESTIONS ON CHAPTER IV. §54. Subject of this chapter? Which are the metalloids of Table I? 55, 56. Symbol and atomic weight of Oxygen'? Is oxygen im- portant? Abundant? Where found? From what most conve- niently prepared ? Explain the process. Describe the apparatus in Fig. 12. Use of its different parts? What changes take place in KOjClOg in the preparation of oxygen ? 57. Detail the fii'st experiment here given; the second; the third; the fourth. What is the first conclusion drawn from these experi- ments? the second? the third? 68. AVhy is oxygen necessary in air? What advantage from being mixed with nitrogen ? What if our atmosphere were pure oxygen ? 59. Symbol and atomic weight of Hydrogen? In what comj^ounds is it found? How prepared? Explain formula HOjSOg -j- Zn =■ ZnOjSOg -|- H. Explain experiment second. How may a mixture of hydrogen and air be exploded ? Is hydrogen combustible? How illustrated ? Product of the combustion ? 60. First inference drawn ? second? third? 61. Of what is water composed ? Is it generally pure ? Its purest form? What does spring-water always contain? Sea-water? Ee- lation of water to the growth of plants? 62. Symbol and atomic weight of Carbon? AVhy important? Various forms? First experiment? What does it illustrate? Se- cond experiment ? third ? How may stagnant water be purified with charcoal? G3, 64. What is carbonic acid? First method of preparing it? Second method? Why collected over warm water? Why in open bottles ? How is lime-water prepared ? How affected by carbonic acid ? Experiment with a mouse ? Explain the chemical changes in its preparation from CaOjCOj. 65. What are the natural sources of COj? How formed by com- bustion? by decay? by breathing? Why is not the quantity in the air increased ? 66. Symbol and atomic weight of Nitrogen 7 Hoav much of it in QUESTIONS. 75 tbe atmosphere? How procured for experiment? Explain Fig. 21. Experiments first and second? 67, 68. AVbat are tlie constituents of tlie Atmosphere? How does the air cause circulation of moisture ? What relation does it bear to plants ? What does it provide for their nourishment ? 69. What is the most important compound of nitrogen and oxy- gen? How prepared? Its properties? First experiment with NOg? second? third? What is the product ? Fourth experiment ? What are nitrates ? 70. What compound does nitrogen form with hydrogen? Its sym- bol ? Do its elements generally combine directly ? How prepared ? Explain the process. Can it be collected over water ? Experiment illustrated in Fig. 2-1 ? 71. Chemical properties of ammonia? Its effect on acids? IIow is it readily set free ? Experiment. Why should lime not be mixed with animal manures? When is carbonate of ammonia generated? How is its escape prevented ? Explain the chemical action between carbonate of ammonia and gypsum. 72. Symbol and atomic weight of Sulphur ? Its form and proper- ties? Influence of heat upon it? What are flowers of sulphur? Where is sulphur found? How purified ? 73. Is it found in plants and animals ? Whence do they obtain it ? In what part of the animal is it most abundant? Why do eggs tarnish silver spoons? 74. Product of sulphur burnt in open air ? Experiment with SO2? What isSOa? 75. Describe sulphuric acid. Its symbol? AflSnity for water? First experiment ? second ? third ? 76. Uses of sulphuric acid ? What are sulphates ? Examples. 77. What compound of S and H is mentioned? AVhat is it called ? 78. 79. Symbol and atomic weight of Chlorine ? How prepared ? Why collected in an open bottle? Why called "chlorine" ? Expe- riment fii-st ? second ? third ? 80. Wh-At is common salt? What are chlorides ? What compound does CI form with H ? Its properties ? 81. Symbol and atomic weight of Phosphorus? Its source? Pro- perties ? Influence of light upon it ? 82. 83. Its aflinity for oxygen? How illustrated? For what 76 QUESTIONS. used? How is phosphoric acid formed? The most importaut phosphate? 84. Symbol and atomic weight of Silicon? Its only important compound with oxygen ? Forms under which it occurs ? Its pro- perties ? Why regarded as an acid? What are "silicates"? In ■what part of plants is silica abundant? 85. Symbol and atomic weight of Boron ? What valuable com- pound ? What is borax ? For what used ? Why ? METALS, CHAPTER V. METALS, 86. There are about fifty metals known to chemists, but only a few of these are important to our present purpose. These we will briefly describe. They are generally found in the earth, combined with other substances in the form of ores. A few of the metals, such as gold and silver, are often found uncombined, and are then called native metals. Oxygen, sulphur, chlorine, and some of the acids, are the substances with which the metals are generally combined in ores. With oxygen some metals form both oxides and aeids. Thus, FeO and FcjOs are both oxides of iron ; but FeOs is ''ferric acid." So, CrO and Cr02 are oxides of chromium; whilst CrOs has strong acid properties, and is called " chromic acid." With sulphur the metals form sulpliurets : FeS, KS, and SbS.2 are sulphurets of iron, potassium, and antimony. With chlorine they form such chlorides as NaCl (chloride of so- dium), AgCl (chloride of silver), etc. The oxides of the metals nearly all combine with acids, and form what are called "salts" of the metals. The pi'ot- oxide of iron combined with sulphuric acid forms the salt (FeOjSOs) called sulphate of iron. So, ZnO,S03 is sulphate of zinc ; KOjNOj is nitrate of potassa; and CaO,C02 is car- bonate of lime. 87. Alkalies. — Potassa and soda (KO and NaO) were formerly the only substances called alkalies ; but that term 7* 78 POTASSIUM. is now frequently used in a -wider sense, and applied to other bases whicli have a strong affinity for acids. Lime, magne- sia, and other compounds of similar character, are regarded as alkaline bases.* POTASSIUM {Si/mhol, K; At. Wt. 39). 88. This is a metal so soft that it may be moulded to any shape with the fingers, and so light that it will float on the surface of water. Exp. — Drop a little lump of potassium upon the surface of a cup of water : it will at once take fire, and float about over the surface until it finally disappears. The affinity of the potassium for oxygen is so strong, that the oxygen is rapidly taken from a portion of the water, while the hydrogen is set free. The heat generated by the rapid union of the potassium and oxygen is sufficient to ignite the liberated hydrogen. The flame thus produced is tinged by the potassium with a purple hue. The water will have oxide of potassium in solution. When evaporated to dryness, a white mass remains, which is oxide of potassium (potassa) combined with one atom of water (HO,KO). This combi- nation is called " hydrate of potassa." 89. Carbonate of Potassa (K0,C02) exists abundantly in wood-ashes. It is the substance which gives strength to lye. It is found in the ashes of nearly all plants ; hence potassa must be an abundant element in the vegetable kingdom. Exj). — Mix half-a-pound of ashes from wood, with a quart of hot water, and after stirring the mixture for a few minutes, pour it upon a paper filter (see Fig. 19) ; then evaporate the water to dryness in a saucer. The solid matter left in the saucer will be the carbonate of potassa, dissolved out of the ashes by the water. 90. Nitrate of Potassa (Saltpetre). — E:q). Pour a little * For an explanation of the term "alkaline base," see ^ 71, twle. SODIUM. 79 water upon tlie carbonate of potassa obtained by the last experiment; then add nitric acid, drop by drop. It will be seen that bubbles of gas escape as soon as the nitric acid mingles with the solution : these bubbles are carbonic acid. The nitric acid combines with the potassa, setting free the carbonic acid, and forming a new salt (K0,N05), nitrate of potassa. If the solution is again evaporated nearly to dry- ness, and set aside to cool, it will deposit crystals of nitre. This valuable salt is used extensively in making gunpowder, in the preservation of meat, and in preparing nitric acid. It is a powerful fertilizer on nearly all soils, but is too costly to be generally used in that way. 91. Sulphate of Potassa (KOjSOj) is formed when sul- phuric acid is added to a solution of potassa, or of carbonate of potassa. 92. Chlorate of Potassa is the salt we have used (see § 56) in preparing oxygen gas. There are many other salts of potassa which we must pass by for the present. SODIUM {Symbol, Na; At. Ys^'t. 23). 93. Sodium is very much like potassium in all of its pro- perties. It is a little heavier, but still light enough to float on water. It combines rapidly with the oxygen of the water, but gives out less heat. It will not cause ignition unless confined to one place on the water. Oxide of sodium (NaO) is the base of all the salts of soda. 94. Chloride of Sodium (NaCl) is our common table-salt, and is the most abundant, as well as the most important, of all the compounds of sodium. It is often found in beds of "rock-salt" in the earth, but is most commonly obtained from the water of salt springs, and of the ocean. 95. Sulphate or Soda is prepared on a very large scale by heating together common salt and sulphuric acid (NaCl -(- HOjSOs == HCl -f NaOjS jj. Hydrochloric acid is thus set 80 CALCIUM. free, and when collected in water forms "muriatic acid." Sulphate of soda often passes under the name of " Glauber's salt." It is a cheap article, and may be employed to great advantage as a fertilizer. 96. Carbonate of Soda (NaOjCOa). — This useful salt is prepared by decomposing the sulphate, by means of heat, and a mixture of sawdust and carbonate of lime. The hkarhonatc or supercm-bonate of soda is formed by passing a current of carbonic acid gas through a strong solution of the carbonate, or by passing the gas over a moist mass of the carbonate. The bicarbonate is used extensively in making bread. When mingled with a mass of dough, together with cream of tar- tar, sour milk, or some other acid substance, the carbonic gas is set free by the acid used, and little bubbles of gas are formed at all points throughout the mass of dough. In the process of baking, these bubbles are greatly expanded by the heat, and the bread is thus rendered porous, or " light." 97. Nitrate of Soda abounds on the coasts of Peru, and is exported to other countries, and employed in the manufac- ture of nitric acid. The acid is set free by the action of sulphuric acid (see § 09). The sulphate of soda, Avliich is generated by the operation, is a valuable fertilizer. 98. When soda salts abound in a soil, they often take the place, to some extent, of potassa salts, in plants growing upon that soil. The same species of plant near the shore, where the spray of sea-water is blown over the land, generally has more soda and less potassa than it has when it grows far in- land. We may often observe this fact in the different ana- lyses of ashes of the same grain from different localities. calcium {Si/mlol, Ca; At. Wt. 20.5). 99. Metallic calcium (the base of lime) is not easily pro- cured, and possesses no practical interest. But its compounds, known as lime and salts of lime, are of the highest import- CALCIUM. 81 ance, both, in the arts and in agriculture. It exists most abundantly as carbonate of lime (CaO,C02)3 in the forms of common limestone, marble, chalk, etc.; and as gypsum, or sulphate of lime. 100. Lime (CaO). — Exjjs. 1. Throw a few fragments of limestone or chalk into a fire of wood or charcoal, where they may be tept at a bright red heat for several hours. The carbonic acid will be expelled, and quick-lime will be left. 2. Weigh a few of these fragments of lime carefully, then pour over them slowly about one-third of their weight of water ; the water will be rapidly absorbed, the lime will be- come quite hot, and soon crumble to a dry, white powder. The water has combined with the lime, and assumed a solid form. This is called "hydrate of lime" (HO,CaO), with reference to its having water combined with it. It is said to be "slaked" with reference to the same fact. It is also called "' slacked lime " from the fact of being reduced to a fine powder. The term " caustic lime " is applied to it, because of its corroding influence on vegetable and animal substances. The water absorbed by lime in slack- ing, increases the weight by about one-third of the weight of the newly-burnt lime. This fact is of importance in buying lime by weight. 3. Expose a portion of stone lime (unslacked lime) to the open air for a few weeks, and it will absorb moisture from the air ; but in the meantime it will also absorb carbonic acid, and will be converted again into carbonate of lime. Such lime is said to be " air- slacked." It is also called " mild lime," or " weak lime," because the carbonic acid has destroyed its caustic character. When thrown into an acid, it effervesces. Caustic lime spread on a field, and left exposed upon the surface, soon becomes changed to a carbonate. 4. Rub a little caustic lime and sal- ammoniac together in a cup or mortar, and the odor of am- monia will at once be perceived. Such will be the case, too, 82 CALCIUM. if any other salt of ammonia, or even a little guano, is treated in the same way with caustic lime. This property of lime shows that it should never be mixed with manures which contain ammonia, because the ammonia, the most valuable ingredient, is thus expelled. The use of lime as a fertilizer will be discussed in a subsequent chapter. 101. Mortar. — "A mixture of lime and sand, on exposure to the air, gradually forms into a hard, stony mass. This consolidation is to be ascribed to three causes : 1st. The water evaporates, and the hydrate of lime remains behind as a co- hesive mass ; 2d. The lime attracts carbonic acid from the air, and there is formed a mixture of hydrate of lime and carbonate of lime, which possesses greater firmness than either body separately; 3d. On the surface of the sand a chemical combination is gradually formed of the silicic acid with the lime, both becoming, as it were, incorporated together. This explains the remarkable hardness of mortar in old buildings." — Stockhardt. 102. Carbonate of Lime constitutes the common lime- stones, marbles, and chalk so widely scattered over the earth. It is found in the various forms of marl, and is a constituent of all good soils. The carbonate may be distinguished from other salts of lime by its eflfervescing when an acid is poured upon it. Water charged with carbonic gas has the power of dissolving carbonate of lime : it then becomes '' hard water." The water which issues in springs from limestone rocks, always has carbonate of lime dissolved in it, and is called " limestone-water." When such water is boiled, the carbonic acid is expelled, and the carbonate of lime is set free as a white powder. This forms incrustations on the inner surface of tea-kettles, steam-boilers, and other vessels in which limestone-water is boiled. The stalactites which hang from the roofs of caves are carbonate of lime, which has been deposited by the water dripping from the roof. C A L C I U M. 83 Carbonate of lime is often beautifully crystallized in white or transparent crystals. 103. Gypsum (Sulphate of Lime) is an abundant mine- ral, found in extensive beds in many parts of the world. It often occurs in transparent, flat crystals, and is then called " selenite." When very compact and white, it is called " ala- baster." It is slightly soluble in water, requiring about 500 parts of water for its solution. Gypsum passes also under the name of '' plaster." Its composition is shown by this formula : CaOjSOg -f 2 HO. When heated to two or three hundred degrees, the two atoms of water are expelled, and it becomes CaOjSOs, which is " plaster of Paris," or " cal- cined plaster." Experiments. — 1. Heat a few ounces of ordinary ground plaster in an iron vessel, stirring it constantly, until moisture will not be deposited on a clean, cool piece of glass held over it; taking care not to let the heat rise much above oOO° F. You now have some calcined plaster. 2. Wind a narrow strip of paper around a piece of money, so as to make a little paper-box, of which the coin shall form the bottom. Mix your calcined plaster with water, so as to form a paste. Fill the paper-box with this paste, and set it aside for an hour or two : you will then find it to have become so hard, that you can unwrap the paper, and remove the coin. The face of the coin will leave a reversed impression on the plaster. This illustrates the formation of plaster casts. Calcined plaster is said to "set" with water. The water combines with it like water of crystallization, and thus forms a solid mass. Gypsum is well known as a valuable mineral fertilizer, to which we shall frequently allude hereafter. 104. Phosphate of Lime is found as a mineral in some parts of the world ; but its most abundant source is in the earthy matter of bones. When a bone is burned for a little while in a hot fire, it becomes white and brittle. This white 84 BARIUM JI A a N E S I U M. substance is chiefly phosphate of lime (oCaO^POj). For its use see § 405. 105. Nitrate of Lime is found with clay in the bot- toms of many caves. The soils in some places, too, abound in this salt. If lime is mingled with a mass of decaying animal and vegetable matter, it is converted into the nitrate of lime; The nitric acid is generated in the presence of a strong base, like lime, by the oxidation of the nitrogen of ammonia from the decaying matter, or the nitrogen of the air confined within the porous mass. Silicate of Lime. — This salt of lime is one of the consti- tuents of several varieties of rock, especially what are called " trap rocks." It is formed in variable quantities during the burning of lime. This process, and its value in the soil, are discussed under " Mineral Fertilizers." barium (Symbol, Ba; At. Wf. 68.6). 106. The oxide of barium (BaO) resembles lime in some of its properties. The chloride (BaCl) is used by chemists to detect the presence of sulphuric acid in solutions. Uxp. — Dissolve a few grains of sulphate of soda in water, pour in a few drops of muriatic acid, and then add a little of the solution of chloride of barium : a beautiful white precipitate of sulphate of barita will be formed. Sulphate of Barita, called " barites," has been used as a substitute for gypsum on grass lands, with some success. It is used also for adulterating white paints. MAGNESIUM {Symbol, Mg ; At. Wt. 12). 107. Magnesia (MgO) is the oxide of magnesium, and forms compounds, some of which resemble the corresponding salts of lime. Calcined magnesia is formed by heating the carbonate red hot, and thus expelling the carbonic acid. Carbonate of magnesia frequently occurs in combination with ALUMINUM. 85 the carbonate of lime, in limestone rocks. It is also found in nearly all soils. Epsom sails, so much used as a medicine, is the sulphate of magnesia. Silicate of magnesia forms the mineral called " talc," and enters largely into the composition of serpentine and other minerals. 108. Magnesia is found in the ashes of nearly all plants. It is, therefore, an important element of fertility in the soil. But soils generally have a sufficient supply of it, and hence its compounds are not often sought after as fertilizers ; though the sulphate has sometimes been applied with decided benefit. An excess of magnesia, in some forms, is regarded as inju- rious to soils. This is especially true of the caustic magne- sia, often formed in abundance, with caustic lime, from such limestones as abound in carbonate of magnesia. ALUMINUM {Si/mhol, Alj At. Wt. 13). 109. Aluminum has recently been separated from its com- pounds in considerable quantities, and is found to possess such properties as will probably make it a useful metal. 110. Alumina (AI2O3) is the only oxide of this metal known. In combinations with silica it forms clay, and also a large proportion of some of the most important minerals, such as mica and feldspar. 111. Clay is a silicate of alumina,* and possesses the highest interest with the farmer. Its purest forms are pipe- clay and porcelain-clay. In soils it exists in widely differ- ent proportions. Some sandy soils contain no more than 8 or 10 per cent of clay; and from this they vary to 50 per cent, and still have a sandy texture. As the quantity in- creases, the soil becomes more and more tenacious. 80 or 90 per cent of clay makes a stiff clay soil. Clay absorbs water freely, and retains it firmly. When * Formula for clay : AlgOjjoSiOg. 86 IRON. wet, it forms a compact, tenacious mass, and when dried "becomes very hard; hence the difficulty of cultivating stiflf soils. If sand be mingled with the clay in proper pro- portions, the texture of the soil is greatly improved (see §335). 112. Clay is found in many rocks combined with other silicates, such as the silicates of lime, potassa, and soda. Rain and frost reduce such rocks slowly to small fragments, and these again are decomposed by atmospheric action, and by the silicates of potassa and soda being gradually dissolved out. The remainder is clay. 113. Alum* is a double sulphate of alumina and potassa, combined with 21 atoms of water. The water may be driven off by heat, and the remaining porous mass is huTnt ahim. Exp. — Dissolve 5 ounces of alum in a half-pint of boiling water, and set it aside in a saucer to cool. When cold, the bottom of the saucer will be lined with a coating of beautiful crystals. IRON {Fcrrum), (Si/mlol, Fe; At. Wf. 28). 114. Although gold and silver are sought after with so much eagerness, they are not half so important to man as iron. Fortunately for our race, this most valuable metal is also the most widely diffused of all the metals used in the arts. Our Creator has so placed it, that, with the proper exercise of industry and skill, man, in all lands, may supply himself with it in abundance. Prof. Stockhardt says : " It is the only metal which is not injurious to the health — the only metal which forms a never-failing constituent of the body, especially of the blood — the only metal, finally, which is found everywhere on the earth, in all stones and soils, and in almost every plant. Although we are ignorant wherein * Alum = KOjSOa + AljOj^SSOg -j- 2-lHO. IRON. 87 consists the influence wliicli it exercises upon the life of ani- mals and plants, yet its universal diffusion must lead us to conclude that it has pleased the Highest Wisdom to invest iron with an importance for organic life, similar to that pos- sessed by comuion salt, lime, phosphoric acid, and some other substances." 115. We find the iron used in the arts under several dif- ferent forms. 1. Cast-iron is the crude iron obtained by heating in large furnaces a mixture of some ore of iron with coal and limestone. The carbon and lime together remove nearly all of the substances combined and mingled with the ore ; while the metal, set free in a melted condition, runs to the bottom of the furnace, and is there drawn off". In making the finer kinds of castings, the iron from the furnace is re- melted in foundries, from which it is poured into moulds of various shapes. Cast-iron is much more fusible than the purer bar-iron ; hence its value for making stoves, ploughs, and a thousand other articles. The fusibility of iron is in- creased by the presence of a small quantity of carbon. In passing through the furnace, the iron combines with a por- tion of the carbon used in separating it from the ore. This not only makes it more fusible than pure iron, but also makes it brittle. 2. When articles such as rakes and forks are made of cast- iron, and then kept red hot for several days in contact with an oxide of iron, the carbon is nearly all removed from them, and they become soft and flexible. The metal thus treated is called " malleable cast-iron." 3. Bar-iron is formed by burning the carbon out of cast- iron, in a forge-fire, and then hammering it into bars. It may then be passed between heavy rollers, and formed into slieet-iron; or drawn through holes in steel bars, and formed into wire. 4. Steel is prepared by embedding bars of iron in pow- 68 I R N. dered charcoal, and keeping it heated to redness for some time. Tlie iron combines with some of the carbon of the coal, and is thus rendered both harder and more fusible. "When bars thus prepared are melted and cast in moulds, they form cast-steel. 116. Iron and Oxygen. — At ordinary temperatures iron combines readily with the oxygen of the air, if moist- ure be present, and the result is " rust." At a red heat the surface of a piece of iron soon becomes coated with an oxide of iron. We have seen (§ 57) how rapidly ii'on may be con- sumed in pure oxygen gas. Ex^). — Sprinkle some fine iron filings into the flame of a spirit-lamp, or hold a piece of iron over the flame, and rub the metal with a file, so that the small fragments cut ofi" will fall into the flame : they will take fire, and burn with the appearance of bright sparks. 117. The protoxide (FeO) is the base of most of the salts of this metal. This oxide cannot be obtained in a separate form, on account of its strong affinity for an additional quan- tity of oxygen, by which it is changed to the sesquioxide (FcaOs). The sesquioxide is also the base of several im- portant salts of iron. The brown sediment we find about chalybeate springs is FszOg, with an atom of water (HO,Fe203). The sesquioxide of iron is often called "peroxide:" it is found in the earth in vast deposits, and is regarded as one of the most valuable ores of this important metal. It is the chief coloring matter in rocks and soils, except in cases where organic matter abounds, as in many limestones, and in dark alluvial soils. The red and brown varieties of clay are colored with this oxide. Oxide of manganese is, how- ever, frequently associated with oxide of iron. Black Oxide or Iron, called " magnetic oxide," seems to be a combination of protoxide with peroxide ; the formula being, FeOjFe.Os. The black, scaly particles which drop from the surface of iron, as it is wrought with the black- IRON. 89 smith's hammer, are composed of this oxide. When found as a mineral, it has the property of being attracted by the magnet; and many masses of it are native magnets, or " load-stones." 118. Salts of the Oxides of Iron are numerous, but we can notice only a few. 1. Carbonate of iron (FeO,C02) is one of the most valuable ores, and is often found beau- tifully crystallized ; and hence called " sparry iron-ore." 2. The sulphate (FeO,S03), called "copperas" and "green vitriol," is the most common salt of iron, and the one most extensively used in the arts. It is a crystalline salt of a green color, and very soluble in water. Its preparation is given in § 119. In the manufacture of ink, and in dyeing black colors, it is extensively used. Its use in agriculture will be mentioned in connection with fertilizers. 119. Iron and Sulphur. — When sulphur unites with a metal without oxygen, we call the compound a " sulphuret." There are several sulphurets of iron. The protosulphuret (FeS) is formed when sulphur and iron filings, or tacks, are heated together in a covered crucible (§ 5). It is used in preparing sulphuretted hydrogen. Bisulphuret of iron is commonly called "pyrites," or "iron pyrites" (FeSg). It is a very abundant mineral, and occurs in beautiful yellow crystals, in the form of cubes and octohedrons. Because so many people suppose, when they discover it in the rocks, that they have found gold, it has received the significant name of " fool's gold." When heated to a high temperature, the bisulphuret of iron parts with a portion of its sulphur, which may be collected in the form of " flowers of sulphur." The iron still remains combined with a portion of the sulphur ; and if exposed to air and moisture, the sulphur and iron both unite with oxygen. The sulphur becomes sulphuric acid, and the iron becomes prot- oxide of iron. The two combined, then, form sulphate of 8* 90 MANGANESE — ZINC. iron (copperas). Copperas is prepared on a large scale by exposing certain slaty rocks, abounding in pyrites, to tbe action of the air. The sulphuret of iron being converted, as we have just seen, into the sulphate, the impure mass is treated with water, which dissolves out the newly formed salt. When most of the water has been driven off by eva- poration, the copperas is deposited in a crystalline mass, as the concentrated solution becomes cool. MANGANESE (Sj/mhol, Mn ; At. Wf. 27.6). 120. This is a hard and very infusible metal, resembling iron in many of its chemical properties. It forms numci'ous compounds with oxygen ; but the only one of sufficient inte- rest to demand our attention now, is the jJcroxiVZe, or hIacJc oxide (Mn02). The principal use to which it is applied, is in the separation of chlorine from muriatic acid (§ 78). From its being employed in glass factories to remove the green color from glass, it has received the name of " glass- maker's soap." ZINC {Sijmbol, Zn; At. TTl 33). 121. We have learned something of the properties of zinc from its use in preparing hydrogen (§ 59). When polished, it is a bright metal of a blueish white color. It is brittle when cold ; but when heated to 250°, it may be rolled into thin sheets. Zinc is combustible. Exj:). Place a few frag- ments of the metal in an iron spoon, and cover them with a little plate of iron. Put the spoon into the fire till it be- comes red-hot; then remove the cover quickly, and the zinc will take fire. A white, flocculent substance will be formed, which is protoxide of zinc. Zinc Is used on a large scale in the manufacture of gal- vanic batteries. This makes it one of the most important of the metals. In the form of thin sheets, it is used for various COPPER — LEAD. 91 purposes ; being a cheap metal, and not so liable as iron to be destroyed by rust. Chains, wire, and other articles, are frequently coated with zinc, to prevent their rusting. They are then said to be '' galvanized." COPPER (Cuj)runi) (^Si/mbol, Cu; At. Wt. 32). 122. This is an abundant and useful metal, and is readily distinguished by its brownish red color. A bright surface of copper becomes slowly tarnished in the air, having a coat of red oxide formed on it. Blue vitriol is the sulphate of copper (CuO,S03), and is easily prepared by heating copper with sulphuric acid, in a glass or porcelain vessel. Experiments. — 1. Dissolve an ounce of blue vitriol in two ounces of boiling water, and set the solution aside in a saucer. As soon as it becomes cool, the saucer will be found to contain a quantity of beautiful blue crystals. 2. Pour off from the crystals the remaining solution, and add a little ammonia water to it; the color will be greatly deepened. Ammonia is a good test for the presence of copper in solu- tions. Acetate of copper is formed when copper is exposed to the action of vinegar and sour fruits. It is commonly called "verdigris," and is very poisonous, as are all the salts of copper. LEAD (Si/mlol, Pb; At. Wt. 103). 123. The external properties of lead, and the various uses to which it is applied, are familiar to every one. We will briefly notice some of its chemical properties, and some of its most important compounds. At ordinary temperatures, a bright surface of lead is almost immediately tarnished by the oxygen of the air, form- ing over it a thin coating of oxide of lead. This prevents 92 TIN further action of the air, and preserves the metal from con- tinued oxidation. The oxide thus formed is called " sub- oxide/' and has two atoms of lead united to one of oxygen (PbaO). An unmelted film of this oxide is generally seen floating as " dross" on the surface of melted lead. If melted lead is exposed to a free current of air, it rapidly combines with oxygen, and forms PbO, which is sold under the name " litharge." If kept at nearly a red heat, it combines wdth still more oxygen, and becomes red had (Pb304, or 2PbO,- PbO,). White Imd, used so extensively in painting, is the carbo- nate (PbO,C02). Sugar of lead is this metal combined with the acid of vinegar ; it is acetate of lead. Exp. Boil a quart of water, and dissolve in it a half-ounce of sugar of lead. Pour the solution into a bottle with a wide neck, and let it stand until it becomes clear; then suspend in it a lump of zinc attached to a thread (Fig. 27), and set it on a shelf where it will not be disturbed; iii a day or two, the zinc will be coated Fig. 27. with beautiful clusters of bright crystals of lead, which will soon form branches extending to the bottom of the bottle, like an inverted tree. This is the " leaden tree." It shows that acetic acid has a stronger affinity for zinc than it has for lead. Acetate of lead is decomposed, and acetate of zinc formed. Galena, the most common ore of lead, is a sulphuret (PbS). TIN {Si/mhol, Sn; At. Wt. 59). 124. Tin is a whiter metal than lead, and also much more fusible, melting at 442°. It is not readily tarnished by ex- posure to the air and moisture. Common tin icare is made of sheets of iron coated with tin. MERCURY — ANTIMONY — ARSENIC. 93 MERCURY {St/mhol, Hg; At. Wt. 100). 125. This is the liquid metal used in making thermometers and barometers. It boils at 662°, and freezes at 40° below zero. With oxygen, mercury forms the common and useful compound (HgO) called " red precipitate." Calomel is mer- cury combined with chlorine — tivo atoms of mercury being united to one of chlorine (Hg2Cl). Corrosive snhlimate, which is a dangerous poison, also consists of mercury and chlorine ; but it has only one atom of mercury united to one of chlorine (HgCl). If corrosive sublimate should, by any mistake, be taken into the stomach, the most sure and simple remedy is to beat up ten or twelve raw eggs, with a quart of water, and give the patient a tumbler full every two or three minutes, till he vomits. Common emetics should not be given. The beautiful red compound sold under the name of ^Ver- milion," is a sulphuret of mercury, HgS. ANTIMONY {Si/mhol, Sb; At. Wt. 129). 126. The dark powder sold by druggists as " antimony," or "crude antimony," is a sulphuret (SbSj). This compound is sometimes given by farmers to horses and hogs, as a remedy for diseases of the skin. The fourth of an ounce of crude antimony, mixed with the same quantity of flowers of sulphur, and an ounce of cream of tartar, forms a good alte- rative medicine for a horse. Tartar emetic is formed by boiling oxide of antimony and cream of tartar together. It is the double tartrate of potassa and antimony. Antimony is of great value in the preparation of printers' type. The type metal is an alloy of lead and this metal. ARSENIC (Symbol, As ; At. Wt. 75). 126 (a). Arsenic (or Arsenicum) is found in some rocks as a dark crystalline substance, which is very brittle, and 94 SILVER — GOLD. volatile at a high temperature. Its presence in iron is often injurious by rendering the iron brittle. The only compound of arsenic possessing much practical interest, is arsenious acid (AsOg), which is sold under the names "arsenic," " rats'-bane," etc. It is a terrible poison, and should be so kept that it may not be liable to improper use by vicious persons, and that it may not be used by mistake for other substances of similar appearance. For a more full description of this substance and its com- pounds, the reader is referred to works on chemistry. The best antidotes for arsenic are : (1) A powerful emetic; and (2) A free dose of hydrated oxide of iron (§ 117), or calcined magnesia. White of eggs, beaten and stirred into milk, should then be given promptly and freely. SILVER {Symbol, Ag; At. Wt. 108). 127. This is the whitest of the metals, and, when highly polished, gives a beautiful and brilliant lustre. In the form of coins, and of various useful and ornamental articles, it is well known. For the preparation of such articles, the pure metal is not used. It is too soft to be used alone. About ten per cent, of copper is added, to give it proper hardness and durability. Silver dissolves readily in nitric acid, forming " lunar caustic," which is nitrate of silver. The sulphur of sul- phuretted hydrogen, or of any soluble sulphuret, combines readily with silver, and gives it a dark surface. GOLD (Symhol, Au; At F?. 98). 128. Gold is the most beautiful of the metals, owing to its fine color and lustre ; but, like silver, it is too soft to be used in its pure form. The standard gold of coins contains tea per cent, of copper. ALLOYS QUESTIONS. 95 ALLOYS. 129. An alloy is a compound formed by the union of two or more metals, in any proportions whatever. Gold and sdver coins have been mentioned as alloys of 90 parts of gold or silver, with 10 of copper. T;yp€ metal is composed of 3 parts of lead, and 1 part of antimony. Brass contains about 1 part of zinc to 2 parts of copper. Pinchheck is also an alloy of copper and zinc. Bell metal, hronze, and gun metal, are alloys of copper with different quantities of tin. German silver has no real silver in it, but is a compound of copper, zinc, and nickel, in the proportion of 10 parts of copper to 6 of zinc, and 4 of nickel. The nickel gives whiteness to the compound, and also makes it malleable. Britannia is an alloy of 100 parts of tin, fused with 10 parts of antimony, and 2 of copper. Sometimes, instead of 10 parts of antimony, 8 of antimony and 2 of bismuth are used. Soft solder is formed by fusing tin and lead together. Pine solder has 2 parts of tin, and 1 of lead; coarse solder, 1 part of tin and 2 of lead. QUESTIONS ON CHAPTER V. 1 86. IIow many metals are known? Are they all important? What are ores? Native metals? What do metals form with oxy- gen? What are FeO, FejOg, and FeOj? AVhat are sulphurets? Mention some, and give their symbols. What are salts of the metals? Mention some. 87. What are alkalies ? What is the " volatile alkali " ? 88. Symbol and atomic weight of Potassium? Its properties? Experiment? Product of the combination? 89. Where is carbonate of potassa abundant ? How procured ? What is common lye ? 90. 91, 92. IIow can you form nitre? Explain the experiment. 96 QUESTIONS. Foi- •what is this substance used? What is said of sulphate of potiissa ? For what is the chlorate used ? 93. Symbol and atomic weight of Sodium? Properties? "What is the base of soda salts ? 94, 95. For what is chloride of sodium used ? Whence obtained ? How is sulphate of soda prepared ? What acid is liberated at the same time? Of what use is sulphate of soda in agriculture? 96, 97, 98. Preparation of carbonate of soda ? Of the bicarbon- ate? Use of the bicarbonate? How does it make bread light? Where is nitrate of soda found? What is said of soda salts when they abound in a soil ? 99, 100. Symbol and atomic weight of Calcium? Its most im- portant compounds ? What is lime ? How prepared ? Explain the process of slacking lime? What change takes place in the lime? How is the weight affected? What is air-slacked lime? How is it shown to be a carbonate? What influence has lime on a salt of ammonia? How illustrated? ES'ect of lime mixed with organic manures? 101. AVhat is mortar? Explain its consolidation. 102. What are common forms of carbonate of lime? How dis- tinguished from other salts of lime ? When does water dissolve carbonate of lime ? Explain the formation of stalactites. 103. Of what is gypsum composed ? What names are given to it under its several forms? Explain the first experiment with gypsum ; the second. Of what use in agriculture ? 104. 105. In what condition is phosphate of lime found? How obtained from bones ? What is said of nitrate of lime ? How formed in the soil? What is said of silicate of lime? 106. What does oxide of barium resemble? For what is the chlorate used? Illustrate. What salt of barium has been used in agriculture ? 107, 108. Sjanbol and atomic weight of 3Iagnesium? What is magnesia? How is calcined magnesia formed? Composition of Epsom salts? — of talc? Is magnesia found in plants? Is it im- portant in plants ? Is it ever injurious ? 109, 110, 111. Symbol and atomic weight of Aluminum? Is this a useful metal ? Composition of alumina? In what minerals is it found ? Composition of clay ? Purest forms of clay ? Absorbent power of clay? Are stiff' clay soils easily managed? QUESTIONS. 07 112, 113. How is clay combined in many rocks? How are such rocks decomposed ? AVliat is alum ? Burnt alum ? 114. Symbol and atomic weight oi Iron? Its importance? Its abundance ? Stockhardt's remarks about iron ? 115. Forms of iron used in the arts? What is cast-iron? How is fusibility of iron increased? How is malleable cast-iron pre- pared? Bar-iron? Sheet-iron? Wire? Steel? Cast-steel? 116. What is iron-rust ? How may iron be burnt ? Experiment. 117. Base of most of the salts of iron? Influence of air upon it? Sediment of chalybeate springs? Coloring matter of rocks and soils ? Magnetic oxide ? Load-stone ? 118. 119. What of carbonate of iron? Of sulphate? Its uses? Sulphuret of iron? Bisulphuret? Its uses? 120. Symbol and atomic weight of Manganese? What oxide is here mentioned ? Its uses? 121. Symbol and atomic weight of Zinc? For what have we used Zn? Properties? Experiment? For what used on a large scale? Galvanized iron ? 122. Symbol and atomic weight of Cojojoer .? Properties? What is blue vitriol ? Explain the experiments. "Verdigris"? 123. Symbol and atomic weight of ieatf.? External properties? How tarnished? Dross of lead? How is "litharge" prepared? Its composition ? "Red lead"? "White lead"? " Sugar of lead" ? Describe the leaden tree. Galena ? 124. 125. Describe Tin. What is "sheet-tin"? What is there peculiar a.ho\ii Blercury? For what used? What is "calomel"? " Corrosive sublimate " ? Antidote ? "Vermilion " ? 126. What is " crude antimony"? Uses? Tartar emetic ? Type- metal ? Describe Arseniaim. What is white arsenic ? Antidotes ? 127, 128. Describe Silver. Its uses? Why alloyed? "Lunar caustic"? What of Gold? 129. What is an alloy ? Type-metal? Brass? Bell-metal, bronze, and gun-metal ? German-silver? Britannia? Solders? ORGANIC CHEMISTRY. CHAPTER VI. ORGANIC CHEMISTRY. 130. If we examine closely a piece of wood, or a part of any plant, we find it consisting of fine fibres, and little tubes or cells of a peculiar form. Any part of an animal, when examined in the same way, is found to have a structure pe- culiar to itself. The plant has its roots, its leaves, its fibres, its sap-vessels ; the animal its stomach, its lungs, its muscles, its veins, etc. These are organs; hence the matter of which the diiferent parts of plants and animals are composed, is called '' organic matter." 131. The greater part of all organic matter is composed of four simple elements ; namely, carhon, hydrogen, oxygen, and nitrogen. These are, hence, often spoken of as " tlie organic elements." Sometimes they are all found in the same substance, as in a piece of cheese. At other times we find only three of them associated together, as in sugar, which is composed of carbon, hydrogen, and oxygen. Then again, only two may be found together, as in the oil of tur- pentine, where we find only carbon and hydrogen. Snlphtir and 2}^tos2)horus frequently enter into the compo- sition of organic bodies, in small quantities. The white of the egg contains some sulphur. The brains of animals con- tain phosphorus. 132. Mineral Part of Plants and Animals. — When we burn any portion of vegetable or animal matter, we always find something left, which we call " ashes." The organic elements, carbon, hydrogen, oxygen, and nitrogen, form ORGANIC CHE INI 1ST RT. 99 volatile compounds with each other, or with the oxygen of the air, during combustion, and disappear j but the ashes, being involatile, remain, forming what is known as the "inorganic part" of the burnt substance. In ashes we find a variety of substances. The bases, potassa, soda, lime, magnesia, oxide of iron, and oxide of manganese ; with the acidis, phosphoric, sulphuric, and silicic; also chlorine and fluorine, are found in the ashes of plants, and most of them also in the ashes of animal bodies. 133. Proximate Constituents. — The four principal organic elements of plants and animals (§ 131) unite in a great variety of forms, giving rise to compounds which exist together in the same body, but are distinct from one another, and may generally be separated without change. The com- pounds, then, which, united, form any part of a plant or animal, are its " proximate constituents." Illustration. — Take a little lump of flour-dough, and knead it on a fine sieve, or piece of muslin tied over the mouth of a bowl, while some one pours a small stream of water upon it (Fig. 28). Continue the ope- ration till the water passing through the sieve ceases to have a milky appearance. There will be a cohesive mass still left on the sieve : this is the gluten of wheat. Letthe water with which the dough was washed, stand a few hours, till it becomes clear : the white powder which settles in the bottom is starch. Gluten and starch are two of the "proximate constituents" of wheat. We will now study the composition and properties of the proximate and mineral constituents of plants and animals, Fig. 28. 100 VEGETABLE CHEMISTRY. separately, under the heads of " Vegetable Chemistry " and "Animal Chemistry." VEGETABLE CHEMISTRY. 134. Groups. — Many of the proximate elements found in different plants, or in different parts of the same plant, are very similar in composition, and may frequently be trans- formed into one another. When we find a number of such compounds, we may place them together in one gi-onp. 135. Starch Group. — There are a number of substances, composed of carbon, united with hydrogen and oxygen in the proportion in which they form water. Among these, starch is conspicuous ; and hence they constitute the " starch group." We shall notice a few of the most important. These are : 1. VegetaUe fibre or cellulose ^ 2. Gum; 3. Starch; 4. Sugar; 5. Pectose. 136. Vegetahle fibre is found almost perfectly pure in the fibre of cotton, and in clean white linen. It forms the solid, insoluble part of wood, and of the stalks of plants. In the stalks and leaves of green vegetable substances, it is soft, and, to some extent, digestible by animals. In dry straw, it is harder and less digestible. It forms the outer coating of grain — the bran. In the outer part of peach and plum stones, and in the shells of nuts, it is very firm and hard. The formula, representing a compound atom of cellulose, is C24H2o02o- If we multiply the atomic weights of the carbon, hydrogen, and oxygen, by the number of atoms of each found in this compound atom, we find them in the proportion of 144 parts of C, 20 of H, and 160 of 0. The great importance of vegetable fibre is evident, when we reflect for a moment upon the various purposes it serves. It is the frame-work of the vegetable kingdom; it is the chief component of fuel ; cotton and linen goods are made of it, in its purest natural form ; it is the principal constituent of all varieties of paper. SUGARS, 101 Pig. 29. 137. S'arch (C2,ILo02o). — Starch lias the same propor- tions of its elements as vegetable fibre, but these elements seem to be combined in somewhat diflferent form, so as to give different properties to the two substances. The cultivated grains are the most abundant source of starch. It is also obtained abundantly from the potato. It exists in greater or less quantities in numerous plants, espe- cially in their green state. To the naked eye, starch appears to be a very fine white powder, but when examined with a microscope it is found to consist of little granules, having an oi'ganized structure. Fig. 29 repre- sents the form of starch grains as they exist in the potato. Experiment. — Cold water will not produce any change on starch, but when the granules are first mixed up with a little cold water, and then poured into a much larger quantity of boiling water, they at once burst, and form an almost transparent solution, called '< starch water." If dry starch is heated to 300° or 400°, it becomes soluble in cold water. In this form it is sold as ■" British gum." 138. Starch water is rendered more perfectly fluid and transparent by being moderately heated with a little dilute sulphuric acid, or with an infusion of malt. The starch undergoes a slight change, and becomes what is called "dextrine." If the solution of dextrine with sulphuric acid is boiled for several hours, the dextrine is converted into grape-sugar. S UGARS. 139. a. Grape-sugar, Q2ji2S^u-\-^ (J^O'). — This variety of sugar is found in many ripe fruits, but especially in the sweet kinds of grape ; hence its name. Raisins are dried 9* 102 SUGARS. grapes, and the white sweet grains found amongst them are particles of this sugar. Starch will yield more than its own weight of grape-sugar by the process mentioned in § 138. By a somewhat similar process it may also be prepared from linen or cotton rags ! — (See Foivnes Chcmistrij, p. 335.) " Many unripe fruits, as the apple, contain a large quan- tity of starch, but no sugar. After the fruit is fully grown, the starch gradually disappears, and we find in its place grape-sugar. This change constitutes the ripening of fruits, and, as is well known, will take place after they are gath- ered." — SilUnian. 140. h. Cane-sxigar (C24H22O22) is obtained in immense quantities from sugar-cane, sugar-maple, and beets. It is also found in green corn-stalks, grass, and a variety of other substances. It is much sweeter and more soluble than grape-sugar. 141. c. Sugar of Milk {Lactose) C24H20O20 + 4 (HO) This is a variety of sugar found in milk. After the curd of milk is taken out, as in making cheese, the whey holds this sugar in solution. By boiling either cane-sugar, or lac- tose, with dilute sulphuric acid, grape-sugar is formed. 142. Gum (C24H20O20) has the same composition as starch, and vegetable fibre. One of its purest forms is seen in gum Arabic. It also exudes from the peach and cherry trees. In the seeds of many plants it is abundant. The mucilage of flaxseed is a form of gum. There is also a portion of it in all of our cultivated grains, and in almost all plants. Boiled in dilute sulphuric acid it becomes grape-sugar. 143. Pectose, or Pectine, is closely allied to gum. It is the substance which gives to the juices of many fruits the property of forming jellies. In such roots as the turnip and parsnip, pectine takes the place which starch occupies in the potato. As an article of food, it serves the same purpose as starch. PRODUCTS OF THE STARCH GROUP. 103 144. All the substances liere described as having a com- position similar to vegetable fibre, may be converted into that substance during the growth of plants, under the influ- ence of that mysterious principle which we call "vitality." NATURAL PRODUCTS OF THE STARCH GROUP. 145. Peat is the product of decaying vegetable fibre under water. In bogs, large quantities of vegetable matter are often accumulated. Then, difi"erent mosses grow upon the surface of the water, die, and sink to the bottom, there to undergo the process of decay. During the decay of such masses of vegetable matter, carbonic acid escapes, with some carburetted hydrogen (C2H4). The residue is chiefly carbon, a part of which is combined with a little remaining hydrogen and oxygen, forming a sort of bituminous substance. Long- continued pressure, and a little further advance in the decom- position of peat, would convert it into bituminous coal. 146. Peat bogs are found generally in latitudes north of 37°. In some countries, peat is used for fuel. It is also regarded as a valuable source of gas for lighting houses and cities. For agricultural purposes, it is valuable, especially as an absorbent of ammonia, when mingled with stable and barnyard manures. 147. Humus is another valuable product of the decay of vegetable fibre. The vegetable mould, which is produced so abundantly in forests, by the decay of leaves and twigs of trees is humus. So, the dark coloring matter of soils, abound- ing in organic substances, is humus. Its formation requires the presence of air and moisture. A mass of moist straw, leaves, or hay, lying upon the surface of the ground, so that the air can have access to it, soon begins to 7-ot, as we say. The change produced on the vegetable fibre is somewhat different from that which results in the formation of peat. It resembles a slow combustion. The oxygen of the air com- 104 PRODUCTS OF THE STARCH GROUP. bines with a part of the carbon, converting it into carbonic gas v.hich escapes into the air; but the hydrogen and oxygen of the vegetable fibre disappear much more rapidly than the carbon, and the large excess of carbon thus accumulated gives the dark brown color to the vegetable mould or humus. Humus is different in composition at different stages of its formation. It contains several distinct substances, some of which are acids. Of these, humic and ulmic acids may be mentioned as important. They have a strong affinity for ammonia, and combine also with other bases, forming soluble salts. In this condition, they are supposed to enter the roots of plants, and afford them nourishment. Experiment. — Dissolve an ounce of carbonate of soda in a quart of water ; then add two or three ounces of well de- cayed mould, and boil the mixture a few minutes. A brown solution of soda, combined with the humic and other acids of the mould, will be formed. If muriatic acid is now added till the solution becomes sour, the soda will be taken up by the muriatic acid, and the vegetable acids (humic, ulmic, etc.), being set free, soon fall to the bottom as a brown inso- luble precipitate. The value of humus in soils, and in the preservation of manures, will be mentioned under the composition of soils, and management of manures. 148. Alcohol (C4II6O2). — This is one of the important products of the starch group. It is generally produced from grape sugar, by a process which we call the " vinous fermen- tation." It consists in breaking up an atom of grape sugar into four atoms of alcohol, and eight atoms of carbonic acid. An atom of the sugar, C24H24O24 = 8 (CO,) + 4 (C^ITeO^). A solution of pure sugar will not undergo this change, even in the open air ; but if a little yeast, or white of e^g, be stirred into the solution, and the temperature be kept up to about 75° or 80°, little bubbles of gas will soon begin PRODUCTS OF THE STARCH GROUP. 105 to rise rapidly, and the odor of alcohol will become per- ceptible. It has already been stated that starch and cane sugar are readily changed to grape sugar by an infusion of malt. Yeast produces the same effect. This change is always sui>- posed to take place before starch and cane sugar can be con- verted into alcohol. 149. Alcohol is separated from the water, and other sub- stances with which it is mixed, by distillation (§ 23) ; but during the first distillation, a large quantity of water passes over with it, giving but a weak solution. By repeated dis- tillations, the temperature being reduced each time, the alcohol may be obtained so nearly pure as to contain only about 15 per cent, of water. This is " commercial alcohol." If absolutely pure alcohol is required, the common alcohol must be mixed with unslacked lime, or fused chloride of cal- cium, either of which will combine with the water, and not with the alcohol. The latter may then be distilled from the mixture in a pure form. Alcohol burns with a pale blue flame, without smoke, pro- ducing a high degree of heat. This makes it valuable to be used in lamps for heating purposes. The alcohol of wines is produced by the fermentation of the sugar of the grapes. So alcohol is generated in cider, and in the juices of many fruits containing sugar. 150. " Raisirtff Bread." — Flour contains some sngar. When yeast is added to a mass of dough, and the mixture set aside for several hours in a warm place, fermentation takes place throughout the mass ; alcohol and carbonic gas are generated. The bubbles of gas set free make the dough porous, and cause it to '' rise." During the baking, the heat expands the little gas bubbles, and this causes an increased l-ising. The vapor of alcohol generated within the dough 106 TRODUCTS OF THE STARCH GROUP. may aid in producing this result, but the alcohol is expelled by the heut before the baking is completed. 151. Acetic Acid (vinegar acid). — This is the most im- portant product of alcohol. It is produced by removing a part of the hydrogen from alcohol, and adding more oxygen. Pure alcohol, or alcohol diluted with pure water, will not undergo this change by exposure to the air ; but if a little yeast, or mother of vinegar, or some similar compound, be added to a solution of alcohol, the change to acetic acid soon begins. Thus alcohol is C4H6O2 ; if two atoms of its hydro- gen are removed, it becomes C4H4O2, which is called " alde- hyde." If two more atoms of oxygen combine with the aldehyde, it takes the form C4H303,HO,* which is acetic acid in its most concentrated form. 152. Vinegar. — The juices of fruits, such as cider and wines, contain enough of albuminous matter to cause their sugar to be changed first into alcohol ; and then, if air be freely admitted, acetic acid begins at once to be produced from this alcohol. If there is any dextrine (soluble starch) in the liquid, it will also produce, first sugar, then alcohol, then acetic acid. The strength of the vinegar formed from wine or cider, or from a solution of sugar or molasses, will depend upon the quantity of fermentable matter (sugar and dextrine) present, and the completeness of the fermentation. Free access of air is necessary to produce acetic acid, because the air is the agency by which part of the hydrogen is re- moved from alcohol, and an additional quantity of oxygen supplied. The very rapid fermentation of vinegar is some- times caused by passing it over a mass of beech or sugar- maple shavings placed in a large barrel, with holes near the bottom for allowing a free circulation of air. When vinegar is fermented in a half-filled cask (the common way), it should be frequently agitated, so as to cause the air to mingle with it. * Sometimes written C^H^O^ (see Silliman). PROTEIN E GROUP. 107 Acetates. — Acetic acid combines Tvitli bases such as potassa, soda, lime, etc., forming a class of salts called " ace- tates." Acetate of potassa (KO,C4H303) is easily formed by dissolving carbonate of potassa in vinegar until efferves- cence ceases. The vinegar loses its sour taste, being now a solution of acetate of potassa. A solution of acetate of soda may be prepared in the same way. Acetate of alumina is extensively used in dyeing, for the purpose of fixing the colors. Sugar of lead is the acetate of lead, with 3 atoms of water of crystallization (PbO,C4H303 + 3H0). Verdi- gris is acetate of copper. This, as well as acetate of lead, is very poisonous. When liquids containing acetic acid are heated, or kept for some time in copper or brass vessels, ace- tate of copper is formed to soijie extent. 153. Lactic Acid. — When sugar in solution is mixed with a little curd of milk, a peculiar kind of fermentation takes place, by which the sugar is converted into an acid different from acetic acid. The same acid is formed from lactose during the spontaneous souring of milk. From the fact of its being the natural acid of sour milk, it is called " lactic acid." PROTEINE GROUP. 154. We find in plants associated with the starch group, another very important class of compounds, which are known as jJi'oteine bodies. Besides carbon, hydrogen, and oxygen, they all contain nitrogen; hence the term '' nitrogenized" is often applied to them. They also contain small portions of sulphur and phosphorus. The most important of them are gluten, vegetable albumen, and vegetable caseine. They all resemble the white of eggs in composition. 155. Gluten. — When the starch is washed out of a piece of dough, by the experiment in § 133, the adhesive mass which remains is gluten. It has nearly the same composition 108 r R O T E I N E G R O U P . as the fibrous part of lean meat, and is hence called "vege- table fibrin." It is insoluble in water. 156. Vegetable Albumen. — If the water used in wash- ing the starch out of dough be allowed to stand till it be- comes perfectly clear, and is then poured off and boiled, it becomes turbid. It had removed from the flour a form of proteine matter, which was soluble until heated to a tempe- rature above 160° ; above that temperature it becomes inso- luble (coagulates), like the white of an egg dissolved in water, and heated to the same temperature. It is called "vegetable albumen," because of its similarity to the white (albumen) of the egg. 157. Vegetable Caseine. — This is a form of proteine matter found most abundantly in peas and beans. Exp. Crush some beans or peas in a mortar, or in any other way, to the condition of coarse meal, and soak them in water for several hours; then add a little vinegar to the clear solution. A white substance is set free and deposited, which, from its likeness to the caseine or curd of milk, has received the name we have applied to it. It is also called •" legumen." 158. These proteine compounds are of the highest im- portance in all vegetable substances used as food for animals. We shall hereafter learn that the greater part of the animal body is composed of proteine substances, similar to those we have found in vegetables. As all animals derive their nou- rishment either directly or indirectly from vegetable food, this food must possess a nutritive value somewhat propor- tional to the quantity of proteine matter it contains. 159. Our ordinary crops all contain some form of proteine, but the quantity is fovmd to vary considerably even in the same kind of plant. The grains, such as wheat, Indian corn, etc., contain from 8 to 20 per cent. Hay contains from 2 to 8 per cent. It is found also in the sap of ti'ees, and in various fruits. VEGETABLE OILS. i09 If proteine compounds are dried, they may be preserved for any length of time in that condition ; but when exposed to the united action of air and moisture, they very soon un- dergo decomposition — they become putrid. The result of their decomposition is the production of carbonic gas, water, and ammonia. The sulphur and phosphorus escape in com- bination with hydrogen, producing two gases of very dis- agreeable odor (sulphuretted and phosphuretted hydrogen). 160. The presence of proteine compounds causes rapid changes in other bodies with which they are in contact. The abundal^^ of albumen in the sap of trees causes the pap-wood to decay more rapidly than other parts of the tree. Animal matter, being made up largely of proteine substances, becomes putrid very soon after life is extinct. VEGETABLE OILS. 161. Oily matter of some kind is found in almost every variety of plant. It is found in the stalks, leaves, flowers, and seeds. Some vegetable oils are volatile; some on expo- sure to the air form a solid, dry film over the surface of any body upon which they are spread — these are "drying oils." Others are not readily changed by exposure to the air — these are " fixed oils." 162. Volatile or Essential Oils. — These are called ''essential" oils, because, when dissolved in alcohol, they form " essences." We can notice only a few of the most important. 163. Oil op Turpentine {Camphene') is prepared by distilling the crude turpentine which exudes from pine- trees. It is distilled with water (§ 23) ; and as the oil and water become condensed in the receiver, they at once se|>a- rate, the oil floating on the surfiice. After the first distilla- tion, it is called " spirits of turpentine," and still contains some resinous matter. To free it from this, it is distilled 10 no VEGETABLE OILS. again, and is then called "camphene." Its composition is represented by the formula : C5H4 (or, C,oHs). Camphene is a clear liquid, volatile and combustible. It burns with the production of a large quantity of smoke. The smoke consists of unburnt carbon. The hydrogen of the oil is more combustible than the carbon, and combines first with the oxygen of the surrounding air : the supply of oxygen not being sufiicient for both, the carbon is set free as smoke. There are lamps constructed so as to throw a strong current of air against the sides of the flame, and in this way oxygen enough is supplied to make the combustion complete. 164. Uses. — Oil of turpentine is extensively used as a solvent for varnishes, and in the preparation of paints; also for dissolving india-rubber and gutta-percha. But for no purpose is it so largely used as for producing light. It is frequently burnt alone in lamps constructed for the purpose (§163), but most largely consumed in the form of Burning Fluid. — We have already learned, that cam- phene alone has too much carbon in it to adapt it well for burning. Alcohol, on the other hand, has too little carbon in it to produce much light. The brightness of flame is caused by atoms of carbon suspended in it, and kept at a white or yellow heat until they reach the outer part of the flame, where they meet with the oxygen of the air, and are entirely consumed. If there is a deficiency of carbon, it is consumed too quickly to give much light, as in alcohol ; if an excess of carbon, smoke is the result, as in camphene alone. Now, when a portion of camphene is dissolved in alcohol, it supplies the deficiency of carbon ; and in this way the two liquids counteract the defects of each other. Such a solution is common " burning fluid." Oils of orange, lemon, citron, hergamot, peppei-, etc. are similar in composition, and in some of their properties^ to KESINS. Ill oil of turpentine. Camphor is also a volatile oil, obtained from a tree (laurus ca'^npliord). Drying Oils are obtained cbiefly from the seeds of plants. Among the most common and useful are linseed oil (from tbe seed of flax), hemjiseed oil, walnut oil, castor oil (used also in medicine and perfumery), and oil of cotton- seeds, whicli seems to have some drying properties, and is hence sometimes classed with drying oils. These oils are used for mixing paints ; and by the action of the air they are converted into a firm resinous substance, which adheres to the surface painted, and retains the particles of coloring matter, which were not dissolved in it, but simply mixed with it. 166. Fixed Vegetable Oils are such as retain their oily character when exposed to the air. They often absorb oxygen when exposed to the air for some time, and produce acids of strong odor : they become rancid. Olive Oil is one of the most common and useful of the fixed vegetable oils. It is obtained from the pulp of the olive fruit. It is used for food, for oiling machinery, and for various other purposes. Palm oil, from the fruit of the palm-tree, is solid at common temperatures. It is used ex- tensively for making soap. Almond oil, obtained from the sweet almond, is highly valuable in the manufacture of soap, and in the preparation of some ointments. 167. Oil is one of the necessary articles of food for ani- mals; and, in order to meet this necessity, the kind hand of Providence has made the crops produced by the earthy an abundant source of this, as well as the other elements of nutrition demanded by the animal kingdom. resins. 168. Some of the vegetable oils become oxidized by ex- posure to the air, and form solid bodies called "resins." 112 RESINS. Of these, yve find the one most common nncl most important, formed by the oxidation of oil of turpentine. As the crude turpentine collects in the wounds cut in the sides of trees for the purpose, it gradually absorbs oxygen, and becomes partially converted into resin. By distillation the oil of turpentine is removed, and an involatile resinous mass re- mains. This generally passes under the name of "rosin." 169. Uses of Rosin. — (1) It is frequently employed in the preparation of illuminating gases. (2) Mixed with ani- mal fats, it is used in the manufacture of " rosin soap." (3) A soap prepared from rosin is used for giving compactness and smooth surface to paper. It is mingled with the mate- rial in making the paper. (^Porter?) Copal, Lac, and Mastic are some of the resins commonly employed as varnishes. Lac dissolves most readily in alco- hol. Besides its use in varnishing, it is largely consumed in making sealing-ioax, which consists of lac (shellac) mixed with a little Venice turpentine, and some coloring matter. 170. Gum Resins are the products of plants in warm climates. They contain both gum and resinous matter. Of these, india-rubber and gutta-percJia are the most important. 171. India-rubber {CaoutcJiouc). — "This well-known substance is obtained by making incisions through the bark of certain trees of the fig or banyan species, which grow in S. America and the E. Indies : a milky juice flows out, which, upon evaporation, yields about 32 per cent of caout- chouc. The poppy, the lettuce, and other plants having viscid, milky sap, seem also to contain it. Caoutchouc, when pure, is white and transparent; its dark color being due to the blackening effect of the smoke in drying. It is highly elastic, and the freshly-cut surfaces adhere strongly, if pressed together. It is insoluble in water, alcohol, and acids; but dissolves in ether, naphtha, spirits of turpentine, and other essential oils. The solutions in ether and naphtha VEGETABLE ACIDS. 113 leave the caoutchouc in an elastic state. It is a simple hydro- carbon, containing no oxygen, and burning with a luminous sooty flame. Its uses are very various. Dissolved and applied to fabrics, it forms water-proof cloth : it is also used for shoes ; and when cut into thin shreds, and boiled with linseed oil (4 ozs. caoutchouc to 2 lbs. of oil), it forms a mixture used for making boots water-tight." — Youmans. Vulcanized India-rubber is that which has been exposed to the action of melted sulphur. The sulphur, uniting with it, makes it more firm, and less liable to be influenced by changes of temperature. GuTTA Percha is a substance obtained, like India-rubber, from the sap of certain trees. It is not so elastic as India- rubber, and has the property of becoming so soft, when im- mersed for a few minutes in hot water, that it may be moulded to any shape with the fingers. It becomes very firm and hard on cooling. VEGETABLE ACIDS. 172. Oxalic Acid is found in the different kinds of sorrel, and gives them their sour taste. It is easily pre- pared from sugar or starch by the action of nitric acid. Exjj. — Mix tlu-ec ounces of nitric acid with two ounces of water, and add half an ounce of sugar. Heat the mixture in a glass or porcelain vessel. Red vapor will soon begin to escape freely. Continue the heat until the solution is evapo- rated to one-half the original quantity, and then set it aside to cool. In a few hours the bottom of the vessel will be covered with beautiful, slender crystals of oxalic acid. Its composition is C203,HO. This acid is very poisonous, and if accidentally taken into the stomach, magnesia or lime-water should be given immediately. 173. Tartaric Acid is procured chiefly from grapes. During the preparation of wines, a hard crust is deposited 10* 11-1 VEGETABLE ACIDS. on tlic iruicr surface of the vessels ir> v.hicli the ■wine is fer- mented. This crust is an acid tartrate of potassa, and v,'hcn purified is called " Cream of Tartar." By mingling pow- dered chalk with cream of tartar in water, tartrate of lime is formed. This is again decomposed by sulphuric acid, which removes the lime in an insoluble form, leaving the free tar- taric acid in solution ; from this it is crystallized by evapora- tion. The composition of this acid is C8H40,o,2HO. Tar- taric acid is extensively used in the preparation of efferves- cing powders. With carbonate of soda or potassa it causes rapid effervescence. One atom of a base is not sufficient to neutralize an atom of this acid. It requires two atoms of any one base, or one atom of two different bases. Cream of Tartar consists of only one atom of potassa, luiited to each atom of acid, and is therefore an acid salt. If an additional quantity of potassa or soda were added to cream of tartar in water, the acid would unite with a second atom of either of these bases ; or if the carbonates of the bases were added, the same result would take place, and the carbonic gas u-ould he set free. This is what takes place when cream of tartar and carbonate of soda are mingled together in making bread. 174. Citric Acid is found abundantly in lemon juice, and in the orange. 3Ialic acid is the acid of apples, goose- berries, and many other fruits. It is also the acid oi garden rlinharl). 175. Tannic Acid is the astringent substance in oak bark, and in the leaves and bark of many trees. It is found in tea, to which it gives an astringent taste. When the skins of animals are steeped for some time in an infusion of oak or hemlock bark, the tannic acid combines with the skin ' and forms leather (see § 589). Inh is a compound of iron and tannic acid, or rather of peroxide of iron and this acid. For making ink, the tannic VEGETABLE BASES. 115 acid is obtained from nut-galls (a kind of excrescence found on tlie leaves of some species of oak). VEGETABLE BASES. 176. Plants often produce bases, as well as acids. These are not free, as they exist in the plant, but generally in com- bination with acids. They possess the property of neutral- izing acids, and are hence called '' vegetable alkaloids." They all contain nitrogen, and ai-e in some respects similar to ammonia. Many of them are valuable for their medicinal properties. We can notice only a few of the most important. 177. Quinine is obtained from Peruvian harh. It is this alkaloid, together with another called " cinchonine," which gives Peruvian bark its medicinal value. Ilorphine and Narcothie are the alkaloids of opium, and give that drug its peculiar properties. Strychnine is found in the nux-vomica, St. Ignatius's bean, and some other sub- stances. It is a most fatal poison. Theine, or caffeine, is a substance found in both tea and coflPee, having stimulating properties, which give these articles their value as beverages. Nicotine is a very poisonous alkaloid existing in tobacco. Taken in small quantities into the stomach, as it is by tobacco-chewers, or into the lungs, as it is by smokers, it produces a kind of mild intoxication, and on this account is esteemed a great luxury. COLORING COMPOUNDS (dye-stuffs'). 178. Indigo. — This common blue substance is obtained from plants. It is colorless in the juice of the plant, but when exposed to the air it becomes blue. Its use in dyeing is well known. Madder is the root of a plant cultivated in different parts of the world. The root i« dried and ground to a powder, 116 COLORING COMPOUNDS. from wliich the coloring matter is extracted for dyeing purposes. Logwood is found as a common tree in Central America, and is sold either in the form of wood, or an extract from the wood, and used as a coloring substance. 179. Colors of Flowers, Leaves, &c. — The beautiful colors of flowers are caused by some transient compounds, seldom permanent enough to be separated, or even to survive the drying of the bodies in which they exist. Chlorophyll is the name given to the green coloring matter of leaves, and other green parts of plants. It " is one of the most widely diffused substances in the vegetable kingdom, since it occurs in all parts of the plant which pos- sess a green color. As found in plants, it is a mixture of wax and of several coloring matters not well known. It need hardly be said that it is not soluble in water ; for if it were, the water would become green on flowing over meadows. The expressed juice's of the herbs are indeed green, but it is obvious from their turbidness that the leaf-green is only mechanically mixed with the liquid. We become still more fully convinced of this by the separation of the coloring matter which takes place when the juices are boiled, or allowed to remain for some time in repose. If, on the other hand, alcohol, ether, or weak lye, is poured on the green leaves, we obtain green solutions ; hence all the tinctures of pharmacy which are prepared from leaves or stalks have a green color. The green color appears only in those parts of the plant which are exposed to the light ; it is obvious from this, that the chemical compound which we call chlorophyll is only generated with the cooperation of light. When sepa- rated from plants, this coloring matter is very soon decom- posed ; it is, therefore, not at all suited for a coloring sub- stance, except, perhaps, for cordials and other liquids. In the autumn it is converted in the leaves themselves, into QUESTIONS. 117 leaf-yellow and leaf-red, probably by a process of oxidation." — Stockhardt. Chlorophyll contains nitrogen as well as carbon, hydrogen, and oxygen ; and the importance of nitrogen in fertilizers may give to this compound a value in green crops, of which we are not fully aware. QUESTIONS ON CHAPTER VI. ^ 130. What do we find peculiar in a plant or an animal? What is organic matter? 131. Of what elements are organic bodies chiefly composed ? What example is given of a substance containing all of them ? of one con- taining on\y three? containing oriiytwo? What two elements are less abundant in organic bodies ? Examples ? 132. What is always left when an organic body is burnt? What elements disappear? What is the inorganic part of a body? What substances are found in ashes ? 133. What is said of the compounds formed by the union of the organic elements ? What are proximate constituents? How illus- trated ? 134. 135. When may we group substances together? What sub- stances constitute the starch group ? 186. Where is pure vegetable fibre found? In what other form is it abundant ? What formula represents its composition ? The pro- portions by weight of C, H, and ? What shows the great import- ance of vegetable fibre ? 137,138. Composition of /S'/'arcA ? What does it resemble in com- position? Most abundant sources? How does it appear under the microscope? Effect of cold water ? Ofhotwater? "British Gum?" Effect of dilute sulphuric acid on starch water ? What is the starch then called ? If boiled several hours with the acid, what change takes place ? 139, 140, 141. Composition of (Jra/e^Si/^ar.? Where found? How formed from starch? Explain the ripening of fruit. Formula of Cane Sugar ? From what chiefly obtained ? Its qualities ? What is sugar of milk ? How prepared ? 142,143,144. Composition of (?t«?! .? Examples mentioned? How 118 QUESTIONS. converted into grape sugar? Vf hhi is Pectose ? What change may vitality produce in any member of the starch group? 145, 14G. AVhat is Peat? Describe its formation. How converted into coal? Where are peat-bogs generally found? Uses of peat? 147. What is //i/7n!;s .? In what forms does it exist? Conditions necessai-y to its formation? Explain the chemical changes which take place during its formation. Its influence on ammonia? What experiment is mentioned? 148, 149, 150. Torm\x\n. 0^ Alcohol? From what produced ? Ex- plain the chemical changes in its formation. What is necessary to produce vinous fermentation in sugar ? How are starch and cane sugar converted into alcohol ? Explain the distillation of alcohol. How does it burn? Alcohol of wines? Explain the raising of bread. How does baking increase its liglitness ? 151,152. What is the acid of vinegar? How produced? Explain its formation. How is vinegar formed ? What determines its strength ? Why is air necessary to its formation? Methods of pro- moting its fermentation? What are Acetates? Examples given? Uses? 153. What is the influence of curd on a solution of sugar? Why called lactic acid ? 154. What elements are contained in the proteine group ? Most important compounds in this group ? 155. 156, 157. Describe Gluten. Why called vegetable fibrin? What is vegetable albumen ? How obtained from flour ? Why called albumen? From what is vegetable Caseine produced? What expe- riment shows its properties ? 158, 159, 160. What of the importance of these? Why necessary in animal food ? Are they present in all crops ? How may they be preserved unchanged? Effect of air and moisture? Products of their decomposition ? Their influence on the decay of other bodies? Why do animal bodies readily decay ? 161, 162. Where is oily matter found? What are drying oils? Fixed oils? Essential oils? 163, 164. How is Oil of Turpentine formed? When called spii-its of turpentine? Camphene? Its formula? Describe camphene. Why does it smoke when burning ? How is this prevented ? Its uses ? What is bui-ning fluid ? What are the advantages of com- bining camphene and alcohol ? What other oils are similar to oil of tm-pentine ? QUESTIONS. 119 165. From what are drying oils obtained ? Give examples. For ■what are they used ? Explain the drying of paint. 166, 167. What are Fixed Oils? How do they become rancid? What is olive oil ? Palm oil ? Almond oil ? Why are all forms of vegetable food provided with oil? 168,169. yf hat are Besins ? Which is the most important ? Uses of rosin ? AVhat of copal, lac, etc. ? 170, 171. Where is I?idia Rubber obtained? What other name has it? Its properties ? Uses? How vulcanized ? Whatofgutta percha ? 172. Where is oxalic acid found? How prepared artificially? Give the experiment. Formula of its composition? Effect on the stomach ? Antidotes ? 173, 174, 175. How is Tartaric Acid procured? Explain the col- lection of cream of tartar. How is tartaric acid prepared? Its uses ? Does one atom of a base neutralize it ? What is cream of tartar? Why used in bread-making? What of citric and malic acids? Sources of o obtained ? Madder? Logwood? What of the colors of flowers, the leaves, etc. ? What is Chloi-ophyll ? Where found ? Is it soluble in water ? On what part of the plant does the green color appear? AVhat of the influence of light upon it ? Of what is chlorophyll composed ? 120 MINERAL CONSTITUENTS OF PLANTS. CHAPTER VII. MINERAL CONSTITUENTS (ASHES) OF PLANTS. 180. In § 132 the ashes of plants have been defined, and the substances generally found in them have been mentioned. The mineral constituents of the same species of plants differ but little, no matter where the plant may grow. The ashes of the oak have very nearly the same composition all over the world. AVheat cultivated in America differs but little, in the cjuantity and quality of its ashes, from that which is cultivated in Europe. Local causes may produce slight vari- ations, some of which will be hereafter noticed. 181. Quantity of Ashes. — 1. Different parts of the same plant yield different quantities of ashes. For example, 100 pounds of the dry grain of tcheat yield, when completely burnt, about two pounds of ashes; while 100 pounds of the straw yield about 6 pounds of ashes. So the grain of corn yields about IJ per cent, of ashes, while the stalk yields about 5 per cent. ; and so of other crops. 2. Different plants yield different quantities of ashes. The oak, for example, gives about 2^ pounds of ashes from 100 pounds of the wood well dried ; but hickory gives about 4 or 5 pounds of ashes from 100 pounds of the dry wood. 182. The relative quantity of ashes from different parts of the same plant, as well as from diff'ercnt kinds of plants, will be seen at once, by examining the following table : MINERAL CONSTITUENTS OF PLANTS. 121 TABLE II. 100 ft)S of dry Oak* yield about 2 J lbs f ashes, (I " Ash or Hickory 4 or 5 " (( <( (( Pine 1 <( (C <( (( Wheat Straw 6 (C ii « (< Stalks of Indian Corn 6 (( <( (( <( Grain of Wheat 2 (( <( « (( " Corn 1^ (< « « « Potato (sliced and dried) 4 (( (( « <( Potato Stalks 12 << (( « (< Tobacco Leaves 20 to 23 (( [agnesi xide of hospho ulpburi ilicic A -• o ? f /3 B ■a d ^•5 b^ > -i o 5'o .—V O > -5 3 I-" o^ nt ;:;^ o p5 p c--. t3" s- << i-j ' ~r-0 o o it>. _-i o 53 o — ' — ' CO ;o to 05 in — ZJ^ o 05 -1 51 00 -■ -~l S-o o* o ^ _^ hS q2.o O o p w 31 o -~1 M ■li. OS -1 to S c2. ^ »«>■ to o o o to Oi to V\ OS CO -" w 05 Zn ■^ ai o to rf^ •" B a* !_, 1 ^ o 3> 05 w M h-i Ol -1 to o ^2.3 2.§ 00 o iO O LO o w ^1 o r- ^ g" 1 Kl o si So™ ">£ o§ h- 1 -4 o -^I O 05 GO ■~D 30 o-i o M ^ CO 05 CO 05 05 c* ,_, CO o » tt^ 2 3 B o p to o r(^ CO LO o 05 Ol o to o o 2.2 4^ o hl^ C5 o ^1 o CO ^ o !_, !_, CO !_, o ^1 o 00 o 1— ' 05 o 03 kP>. 2,0 M M o no 1— 1 CO CD CJi Cn OT en '-' Ot OT CO 05 00 ^ !_, 1 — 1-1 o CO r-0 1—1 m* ^ •^t o o U) ^I ;0 C5 1— ' Ol to IsS CO "-1 ;^ s° o o -1 o —J -^ <» CO to -(- "^ ■-* 1^ 1 s o )_a i_j H-l CO t 1 ° o Hi. t^S —I I-" o O to ^I a\ H- 1 (_l ^_i CO rs ,_l t_l C5 — 1 8 Oi OT >f- c: »4^ to CO o ? 1 i-ij ^ o o )— ( N3 *- o-S o -J bO t^ 05 to o o Oi o ■ S OT 1_> >;i^ C.T o rf^ --1 CO I—" r-B 2,8 o (JO OT o CJi ^ OT Oi o< 1 o ^_, Oi 1 llfp o to •^1 03 OS o OT CO 000 hen ried CO Oi OI -■1 •-4 00 C5 h;^ CO ' W H w >■ W o tr^ hd bJ O h- 1 ^ l-H o hi 124 QUESTIONS. growth, as we learn: 1. From its being present in the same plant, in about the same proportions, wherever that plant may grow, provided it has come to full maturity; and, 2. From the fact that a plant will not grow in a soil destitute of the mineral matter peculiar to the ashes of that plant. 187. The mineral ingredients of plants, being involatile, cannot constitute any part of the atmosphere ; hence, they must find this part of their nourishment altogether in the soil. Of this part of the subject, a more full discussion will be given in a subsequent chapter. QUESTIONS ON CHAPTER VII. § 180. What are the ashes of plants? What is said of their com- position in the same plant, wherever found ? Examples. 181, 182, 183. What of different quantities in different jwar^s of the same plant? Examples. Quantities yielded by different plants? Examples. What does Table II. represent? Influence of soil and climate on the quantity of ashes? 184, 185, 186, 187. What of the composition of ashes in different parts of the same plant ? How illustrated ? What of ashes from different plants? Illustration. Explain Table III. What do the numbers at the top of each column represent ? From what source do plants receive their mineral ingredients ? ANIMAL C H E M I S T R if. 125 CHAPTER VIII. ANIMAL CHEMISTRY. 188. In studying the organic elements of plants, we have found the " starch group " most conspicuous. Vegetable fibre and starch make up the greater part of all ordinary ci'ops. But when we examine the composition of animals, we find a different group holding the first place. The '' proteine group " aids in the formation of almost every part of the animal system. These nitrogenized compounds con- stitute the greater part of the skin, the muscle, and the tendons. 189. Let us now examine the composition and properties of the most important elements found in the animal kingdom. Proteine Group. — Several substances under different names, but very similar in composition, constitute this well- defined group. They are Fibrine, Albumen, and Caseine. 190. Fibrine is the fibrous part of lean meat or muscle of animals. Exjieriments. — 1. Cut a few ounces of lean beef into small particles, and pour over the mass a little cold water; after allowing it to stand a few minutes, press the water out of it in a linen rag. Repeat this two or three times, and what is called ''flesh fluid" will be all washed out. Then boil the meat in a small quantity of water, and again press it as dry as possible in a cloth. The solid residue will be nearly pure y?&?-/?ie. 2. Heat the cold water, with which the meat was first washed, nearly to the boiling point ; a frothy mass will separate from it. This is albumen, which is soluble in cold water, but coagulates when the water is heated to 160° or 170°. 3. Set aside the small quantity of water, in which the meat was boiled, until it becomes cool, 11* 126 ANIMAL CHEMISTRY. and it will form a gelatinous mass. This is owing to the presence o^ gelatine extracted from the flesh by boiling water. Gelatine is soluble in boiling water, but when the water be- comes cold it becomes insoluble, and forms ^' jelly." 191. Albumen is found in its purest form in the white of the Qg^, which consists of a solution of this substance in water. In a boiled e^^ the albumen is coagulated, and ren- dered insoluble. A solution of corrosive sublimate will co- agulate albumen, hence the value of raw eggs as an antidote for this dangerous poison. 192. Caseine is most abundant in milk. When the cream has been removed from milk, the remainder is chiefly a solution of caseine. Exp. — Pour a little vinegar, or very dilute muriatic acid, into a tumbler of milk, and the caseine will be set free from solution, in the form of " curd." When milk becomes sour, through the formation of lactic acid, it curdles spontaneously. When the inner coating of a calf's stomach (rennet) is steeped in water, the solution has the property of separating the caseine from milk. When sweet milk is taken into the stomach, it is at once curdled by the acids of the gastric juice. Caseine pressed into cakes forms cheese. The oily matter (butter) from the milk is mingled with the curd, in making cheese from milk which has not been skimmed. 193. The composition of these three principal proteine bodies of the animal kingdom is presented in the following table, according to Mulder's analysis : TABLE IV. In 100 parts. Fibrine. Albumen. Caseine. Carbon 54.56 54.84 54.96 Hydrogen 6.90 7.09 7.15 Oxygen 22.13 21.23 21.73 Nitrogen 15.72 15.83 15.80 Sulphur 0.36 0.G8 0.36 Piiosphorus 0.33 0.33 ANIMAL CHEMISTIIY. 127 It will be seen that tliese substances closely resemble each other in composition, with the exception of the absence of phosphorus in caseine. 194. Gelatine is a nitrogenized substance, already men- tioned (§ 190) as extracted from animal muscle by boiling water. It may be obtained much more abundantly from the bones, skin, tendons, and some other parts of the animal, by boiling them for some time. In the bones of young animals there is a large quantity of this compound, and compara- tively little mineral matter. Hence, calves' feet are a source of gelatine in the preparation of jelly. Common glue is a form of gelatine; it is dried jelly. Isinglass is dried gela- tine. One of its purest forms is found in the dried air- bladder of a species of fish. The gelatine from other animal substances is often dried and sold under the name of *' Isinglass." 195. All animal, as well as vegetable compounds, con- taining ?NVro^c», pass very readily into a state of putrefaction, and emit a strong, disagreeable odor. This is especially the case with fibrine and albumen, which contain both sulphur and phosphorus. These form sulpJmretted a.ndi 2Jliosplmrettcd hydrogen, two gases which give the disgusting odor to rotten eggs and decaying meat. Carbonate of ammonia is also set free in large quantities by the decay of animal matter con- taining nitrogen. These bodies also induce decay, or fer- mentation, in other substances with which they are in con- tact. CooJdng coagulates albuminous substances, and makes their decay less rapid. Hence, cooked meat may be pre- served longer in warm weather than the same meat in a raw state. 196. Gelatine forms an insoluble compound with tannic acid (§ 175), which may be kept an indefinite time without decomposition. Leather is such a compound. The gelatine, of which the skins of animals are chiefly composed, com- 128 ANIMAL FATS. bines with tlie tannic acid of the bark used in tanning. Exp. — Dissolve a Uttle glue or isinglass in boiling water, and, before the solution gets entirely cold, pour into it a little water in which oak bark has been steeped. A pre- cipitate will be formed, which has the same composition as leather. 197. Hoofs, horns, hair, and feathers, are similar in com- position to gelatine, having the addition of some sulphur. ^ These forms are not converted into jelly by boiling, but they swell and become soft. They decay very slowly. ANIMAL FATS. 198. The fats of ordinary animals used for food, consist chiefly of two compounds, called "Stearine" and '' Oleine." Another called "Margarine" is abundant in olive oil, and exists to some extent also in animal fats. Stearine is solid at ordinary temperatures, while oleine is fluid (oily). Mar- garine holds a medium place, being less solid than the former, and less liquid than the latter. Expi. — Take several pieces of thick wrapping-paper, six or eight inches square. Spread over one of them, with a knife, a thin layer of beef or mutton tallow. Lay a second piece of paper upon this, and give it a similar layer of tallow. Continue this, until several pieces are treated in the same way. Place the whole mass between two smooth boards, a little larger than the pieces of paper, and lay a heavy weight on the upper board. After an hour or two, separate the pieces of paper, and they will be found coated with a substance apparently drier than tallow. This is almost pure stearine. The oleine has been absorbed by the paper. Tallow and lard are both mixtures of steai'ine and oleine. Tallow has a larger proportion of stearine, and less oleine, than lard ; and is consequently more solid. 199. Stearine and oleine arc compounds of two acids COMPOSITION OF PARTS OF ANIIMALS. 1C9 called '^ stearic and oleic acids," combined with a compound base called " glycerine." When animal fats are boiled with caustic solutions of potassa or soda, these bases unite with the stearic and oleic acid, and form soaj^s. The potassa com- pound is soft soap, and the soda compound hard soap. The glycerine is set free, and remains partly mingled with the soap and partly in the refuse liquid. Lime and lead, with these fatty acids, form insoluble soaps. COMPOSITION OF DIFFERENT PARTS OF ANIMALS. 200. Besides the substance above described, there are others which enter in small quantities into the various parts of the animal; and, where they seem important to a general view of animal chemistry, they will be mentioned in their appropriate connections ; but many of them must be passed over unnoticed. 201. Skin, Hair, Horns, etc. — These have already been mentioned (§ 197), as being composed chiefly of gela- tinous matter. In the outer coating (epidermis) of the skin, a little sulphur is found ; and still more in the hair, horns, and hoofs, which may be regarded as appendages to the skin. The tendons, ligaments, etc., have a composition analogous to that of the skin. 202. Flesh. — The solid part of the muscle, or flesh, has been described in § 190 as being composed of a proteine substance called '' fibrine." It has an organized structure, and is insoluble in water. In acetic acid, or strong vinegar, it dissolves to some extent. If potassa solution be added to the acetic acid in which a piece of flesh has been digested for some time, the dissolved fibrine will be precipitated, and give the liquid a turbid appearance. 203. There is some fat mingled with the fibrine in the muscular part of nearly all animals; but about 80 per cent of the weight of fresh, lean muscle, consists of a fluid called 130 COMPOSITION OF PARTS OF ANIMALS. ''flesh -fluid." It holds albvmen in solution; but when heated nearly to the boiling-point of water, this albumen is coagulated. The flesh-fluid also contains an acid, and some other substances, which give peculiar flavor to meats, and to soups prepared from them. If the water in which fresh meat is to be cooked, is heated to the boiling-point before the meat is put into it, the albumen near the outer surface is at once coagulated ; and other portions, as they come near the surface, or as the heat penetrates the mass, are also coag- ulated ; and in this way much of the highly flavored and nutritious juice of the meat is prevented from escaping. But if the object is to get a broth or soup containing as much as possible of the richness and flavor of the meat, the heat should be very gradually applied to the water after the meat has been placed in it. The most abundant mineral matter in flesh-fluid consists of salts of potassa ; but the potassa is not sufficiently abun- dant to neutralize all the acids of the fluid, for it is found always to be acid in its character. 204. Bones form the framework of the animal. They contain an organized form of (jclatinous matter, associated with a large quantity of mineral matter, which is chiefly phosjjhate of lime, with a little carbonate of lime; and in some parts of the bones, a trace of fluoride of calcium is found. Experiments. — 1. Boil a fresh bone for some hours in water. Evaporate the water to a small quantity, and set it aside in a cool place. The solution soon becomes jelly. 2. Throw a bone into the fire, and let it remain some time, and it will become white when cool. The gelatinous matter will then be burnt out, and the remainder (bone-earth) is chiefly p1ioq)]iate of lime (oCaOjPOs), with some carbonate of lime, and a little of other salts. 3. Burn a bone in a covered cru- cible, or small iron pot. The air being thus excluded, the COMPOSITION OF PARTS OF ANIMALS. 131 heat will char the organic part without consuming it ; and the result will be hone-blach (ivory-black). 4. Pour dilute muriatic acid over a bone, and set it aside for a day or two ; the phosphate of lime will be dissolved out by the acid, and the gelatine will be left as a soft elastic mass, having the same form as the bone. When washed and boiled, this gela- tine will be dissolved, and form glue. Bones possess a very high value for fertilizing purposes, as we shall learn in another chapter. According to Berzelius, 100 parts of the bones of an ox consist, — of animal matter, 33.30; phosphate of lime, and a little fluoride of calcium, 57.35; carb. of lime, 3.85; phos. of magnesia, 2.05; soda, with some chloride of sodium, 3.45. 205. Nervous Matter, of which both the brain and nerves are composed, is a mixture of albuminous matter with some peculiar oily substances. 206. Blood. — If fresh blood is stirred for some time with a bundle of small rods or twigs, a fibrous substance will be found adhering to the rods. When washed in clean water, this substance becomes nearly white. It is animal fihrine, having the same composition as muscle. But if blood is allowed to stand for a short time without being stirred, it coag- ulates, or forms a clot. After standing for some time, a color- less liquid separates from the clot. This liquid is called the " serum," and is a solution of albumen. When heated to a boiling temperature, the albumen is coagulated. The coloring matter of blood consists of small globular bodies, called " blood corpuscles," which are diffused all through the blood when in the veins ; but, after exposure to the air for a short time, these corpuscles are separated, and, becoming entangled with the fine threads of fibrin e, form the clot. The chief constituents of blood are water, Jibrine, albu- men, and corpuscles. 132 COMPOSITION OF PART 8 OF ANIMALS. 207. Mineral salts are found in the blood; chiefly common salt and phosphate of soda, with some sulphates of soda and potassa. Iron is found in considerable quantity in the color- ing matter. The different conditions of the blood, effects of respira- tion, and the functions performed by the blood, will be found under the head of Animal Physiology. 208. Digestive Fluids. — These are the saliva, gastric juice, pancreatic fluid, and hile. 209. Saliva is a slightly alkaline fluid, secreted by the glands of the mouth. It is water holding*in solution a little organic matter, with some alkaline phosphates and chlorides. Gastric juice is secreted from the inner coating of the stomach (mucous membrane). It contains a little hydro- chloric acid in solution, also some lactic acid. These give it an acid character. There is a peculiar organic substance found in gastric juice, called '^pepsin." * This substance, obtained from the stomach of the ox, is often employed as a medicine, in cases of dyspepsia. The gastric juice holds common salt in solution, with small portions of other salts. The acid character of this fluid gives it the power of dis- solving (digesting) fibrine, albumen, and other forms of pro- teine matter. 210. Pancreatic fluid is an aJkaline secretion, from a peculiar organ near the stomach called the " pancreas." This fluid is mingled with the food as it passes out of the stomach into what is called the " duodenum." It has the power of digesting starch and oily compounds. 211. Bile is a secretion from the liver, and is alkaline. It is thrown into the duodenum with the pancreatic fluid, but physiologists difibr as to the office it performs in diges- tion. It is supposed to aid especially in the digestion of fatty substances. * From pepto, " digest." MILK. 133 JM ILK. 212. Milk has been mentioned (§ 192) as the chief source of caseine. Besides caseine, it contains little globules of o% matter (butter'), and a peculiar kind of sugar, called " sugar of milk," or " lactose." The method of separating caseine has been already given. If the clear ivhei/, left after the caseine is removed, be evaporated to dryness, a mass of crystalline sugar will be obtained (see § 141). When milk becomes sour, this sugar is converted into lactic acid. Churning consists in simply agitating the milk so as to cause the little globules of butter to unite into masses of sufficient size to be easily separated from the liquid. Butter is com- posed chiefly of two fats : olcine, which is oily at common temperatures, and margarine, which is solid. When exposed to the air for some time, butter becomes rancid, by a portion of volatile acid being generated in it, which gives it a dis- agreeable taste and odor. It may be again sweetened, at least to some extent, by boiling it several times in two or three times its own volume of water, or by careful washing with fresh milk. 213. Ashes of Milk. — When milk is evaporated to dry- ness, one hundred ounces of it will yield about 12J ounces of solid matter. About 87 2 ounces of water have disap- peared, while caseine,- butter, sugar, and mineral matter are left. If you now burn this 12 5 ounces of solid matter to ashes, the caseine, butter, and sugar, will disappear, being all decomposed and expelled by the heat. The ashes left will weigh about a half-ounce. That is, one hundred ounces of milk contain about a half-ounce of mineral matter. Nearly the half of this mineral matter is plios^jhate of lime, a little more than one-fourth of it is chloride of potassium, while the remainder is made up of phosphate of magnesia and salts of soda and iron. Milk contains just those elements best 12 134 EXCREMENTS. fitted to promote tlie growth of the young animal for whose nourishment an all-wise Creator designed it. EXCREMENTS. 214. The refuse portions of the food, and the waste matter of the animal system, are thrown oif partly in a solid and partly in a liquid form. The solid excrements (faeces) con- sist, for the most part, of those constituents of the food which are not dissolved in the stomach — not digested ; in the her- bivorous animals, they consist principally of vegetable tissue, chlorophyll, wax, and insoluble salts; in the carnivorous animals, dogs for instance, frequently almost wholly of inor- ganic substances, as phosphate of lime, magnesia, &c., mixed with but a very small quantity of organic matter. The bene- ficial influence of solid excrements on vegetation is princi- pally owing to the inorganic compounds contained in them (lime and magnesia, phosphoric acid and silicic acid). 215. By the urine, which is separated in the kidneys from the arterial blood, the soluble salts contained in the food, and also the nitrogen compounds, no longer necessary for the vital process, are removed again from the body; it is natural, there- fore, that the constituents of it, as likewise of the faeces, should correspond exactly with the food consumed. If this is rich in soluble salts, the urine will- also be rich in them j if this contains only a few soluble, and many insoluble salts, the urine will be poor in soluble salts, while the foeces will be rich in insoluble salts. Consequently the amount of inorganic substances in the animal excrement, or manure, may be just as accurately ascertained from the food which the animal con- sumes, as from the manure itself. The food has only to be burned, and the remaining ashes examined ; those parts of it which are soluble in water, correspond with the salts of the urine; those which are insoluble, to the salts of the EXCREMENTS. 135 fseces. We find in the urine of cows and horses principally alkaline carbonates, muriates, and sulphates of potassa, soda, and ammonia ; in the urine of men, moreover, some alkaline phosphates. 216. ^'Nitrogen is contained in the urine, either in the form of urea, uric acid, or hippuric acid. Urea occurs iu the greatest abundance in the urine of the higher animals, especially the carnivorous quadrupeds In a practical point of view, that decomposition which urea undergoes in urine, when the latter putrefies by long standing in the air, is of great importance. During this decomposi- tion, the urea combines with the constituents of two atoms of water, and becomes thereby carbonate of ammonia; from Urea = Carbon, Oxygen, Nitrogen, Hydrogen ; and Water = Oxygen Hydrogen are formed, ""p; — r -. r^ , ""^^'^T^""" "^""^ Carbonic acid and Ammonia. 217. " Uric acid (lithic acid) predominates in the urine of the lower animals. The white excrements of birds and snakes (a mixture of fasces and urine,) consists chiefly of urate of ammonia. In the pure state it consists of fine white crystalline scales, which are dissolved in water only with extreme difficulty. On account of this difficult solu- bility, it sometimes separates spontaneously from the urine, as gravel and urinary calculi. If the excrements, which are rich in uric acid, are allowed to remain for some time exposed to the air they will absorb oxygen, and afterwards contain oxalate of ammonia; but if the latter takes up more oxygen, it passes over into carbonate of ammonia. Thus is explained the cause why we frequently find in some sorts of guano only traces of uric acid, but in place of it, large quantities of oxalates. 218. ^^ Guano, which in recent times has been in such demand as a manure, owes its efficacy chiefly to the iiric acid 136 EXCREMENTS. (as urate of ammonia) contained in it ; or, in as far as this lias already undergone decomposition, to the ammoniacal salts formed from it, and in part also to inorganic salts (sul- phate, phosphate, and muriate of potassa, soda, lime, magne- sia, &c.) present in it. On account of the great difference in the article, it is indispensable that the firmer should test it before its application. This is done with sufficient accu- racy for agricultural purposes in the following ways : Experiments. — a. Pour some strong vinegar over guano; no perceptible eff'ervescence should ensue. A brisk effer- vescence would indicate an admixture of carbonate of lime. h. Heat half an ounce of guano in an iron spoon, over an alcohol lamp or over glowing charcoal, till it is burnt to white ashes ; good guano should only leave behind, at most, one dram (l ounce) of ashes. How much alkaline salts this ashes contains, may be ascertained by extraction with hot water; what remains (undissolved) are lime and magnesian salts. The inferior sorts of guano often yield, after burning, three-quarters of ashes, c. Treat an ounce of pulverized guano several times with hot water, and decant the liquid after it has become clear on settling; then dry and weigh the muddy mass which finally remains ; it should not weigh more than half an ounce. 219. "Sijyjmn'c Acid. — This azotized acid always occurs in the urine of herbivorous animals : it crystallizes in long, white needles, and is difficultly soluble in water. On the putrefaction of the urine, it is converted into benzoic acid and ammonia. " Human urine contains the above-named compounds (rich in nitrogen) — urea, uric acid, and hippuric acid; the first (urea) in the largest quantity. 2!Z0. 'MVhen urine remains for some time exposed to the air, it undergoes a decomposition, by which volatile sub- stances having a disagreeable odor are formed : it passes QUESTIONS. 137 into i^utrefaction. It is obvious, from what Las been stated, that carbonate of ammonia is to be regarded as the principal product of this decomposition This change takes place when the urine is collected in manure heaps, or is poured upon the soil. To prevent the escape of the volatile carbonate of ammonia, it is best to add gypsum, dilute sul- phuric acid, etc." — Stochhardt. See also §378. QUESTIONS ON CHAPTER VIII. § 188, 189. What group of proximate constituents did we find most conspicuous in the chemistry of plants? What group is most conspicuous in animal chemistry ? The most important substances of the proteine gr»up ? 190. What is /6?en€ .^ First experiment? second? third? 191. What is albumen? Influence of heat upon it? 192. Where is caseine most abundant? How separated? Effect of rennet on milk ? Of the acid juices of the stomach? AVhat is cheese ? 193. What does Table IV represent ? IIoav do these substances differ ? 194. 195, 1 96, 197. What is gelatine ? What of the bones of young animals? What is glue? Isinglass? What of the putrefaction of animal bodies? What substances are set free ? Influence of decay- ing animal matter on other substances? How does cooking prevent putrefaction? What is the chemical process in tanning? IIow illus- trated? AVhat of hoofs, horns, etc.? 198, 199. Of what are fats of ordinary animals composed? Pro- perties of stearine and olcine? How separated? Of what are tallow a,nd lard composed? How do they differ? What is the chemical composition of stearine and oleino? How are soaps formed? Soft soap and hard soap ? Soaps of lime and lead? 200, 201. Of what are skin, hair, and horns composed? What of sulphur in these? Tendons and ligaments? 202, 203. Of what is the flesh of animals composed? Its struc- ture? Effect of acetic acid upon it? How precipitated? What is mingled with fibrine in the muscles ? What constitutes the greater part of the weight of fresh lean meat ? Composition of flesh fluid ? 12* 188 QUESTIONS. What of cooking meat? — making soup? Most abundant mineral substance in flesh fluid? 204, 205. Describe the bones of animals. First experiment? se- cond? third? fourth? For what are bones valuable? Composition of an ox-bone? What is nervous matter? 206, 207. IIow may fibrine be separated from fresh blood? AVhen does blood coagulate? Wliat is the serum? Coloring matter of blood ? Chief constituents of blood ? Mineral salts ? 208, 209, 210, 211. What are the digestive fluids ? Describe saliva. Gastric juice ? For what is pepsin used ? Describe the pancreatic fluid. What substances are digested by it ? Secretion of bile ? Its office? 212, 213. Chief solid constituent of milk? What is butter? How is sugar of milk obtained? Explain the souring of milk. What is churning? How does butter become rancid ? How may it be sweet- ened ? How much solid matter in milk ? How much ashes in milk? Chief mineral constituent? For what is millc peculiarly fitted? 214, 215, 216. Office of the urine? How is its composition in- fluenced by food ? Chief salts in the urine of cows and horses ? What substances in urine contain nitrogen? What changes take place in the putrefaction of urine ? What are the products ? Ex- crement of birds ? 217, 218. Properties of uric acid? Result of the decomposition of urate of ammonia? Most valuable ingredient in guano? j\Iine- ral salts of guano ? Experiment a ? Experiment b ? Experiment c ? 219, 220. AVhere is hippuric acid found? What of human urine? Its putrefaction ? How may its carbonate of ammonia be preserved ? SOURCES or PLANT K O U U I S II .^I E K T. 139 CHAPTER IX. SOURCES FROM WHICH PLANTS DERIVE THEIR NOURISHMENT. 221. It has been stated (in §132) that plants are com- posed of two sets of elements : (1) The " organic elements," which are volatile, and disappear during combustion ; (2) The " inorganic or mineral elements," which are incombus- tible, and constitute ashes. These two classes seem equally necessary to the healthy growth and full development of the plant. They constitute the food of the plant, as they are taken up by it while growing. 222. Sources of Plant Food. — Plants do not get all their food from the soil on which they grow, as many persons suppose. The soil and the air both furnish nourishment to the growing crop. Through its roots, the plant is in constant contact with the soil, and through its leaves it is in constant contact with the air. The roots are so con- structed as to be able to absorb from the soil such food as is required from that source, whenever it is found there in a proper condition. But all substances taken up by the roots must be first rendered soluble, as these organs can absorb matter only in the liquid form. 223. The mineral elements, being involatile, are not found in the air ; hence, they must be derived from the soil alone. Besides these, the soil must have a sufficient quantity of water to dissolve whatever is required by the plant. The soil also contains, generally, a considerable quantity of or- ganic matter, the use of which we shall see in the next section. 110 SOURCES OF PLANT NOURISHMENT, 224. Wheyice do ]il«nts get their organic demerits? These have been stated to be chiefly four — carbon, hydrogen, oxy- gen, and nitrogen. The carbon of plants is derived chiefly but not entirely, from carbonic acid. This gas is one of the constituents of the atmosphere, and is found to make about the j-soo part of the weight of air, whether this air be col- lected in the lowest valley or on the top of the highest mountain. Plants have the power of collecting carbonic gas from the air through their leaves. As the organic matter in the soil undergoes decay, this gas is freely generated, and, being absorbed by the water of the soil, is conveyed abun- dantly to the roots of the growing plant. As rain descends through the air, it absorbs a considerable quantity of car- bonic gas, and conveys it to the soil. Thus we find both the atmosphere and the soil to be sources of this carboniferous food. Whether the carbonic acid be absorbed by the roots or by the leaves, it circulates through the plant in solution in the sap; and under the influence of light it is decomposed, the plant retaining the carbon, and throwing oif the oxygen through the leaves. This action goes on chiefly by day, and most rapidly under the direct rays of the sun. Hence, plants grow more rapidly by day than by night. If light be ex- cluded entirely, the plant soon dies. The hnmus of the soil, or rather some of its constituents, become soluble in certain combinations. In this form, too, carbon is doubtless taken up by the roots, and conveyed through the sap to the diff"erent parts of the growing plant. 225. Hydrogen and Oxygen are supplied to plants in the form of loater. If you look back over the vegetable com- pounds which we have studied, you will find a large part of them containing H and in the proportions in which these exist in water. Take, for example, starch (CuHioOio). Here we find the elements of ten atoms of toater. In the forma- tion of such a compound as starch, twelve atoms of carbonic *Also written (Cj^IIjoOjg), SOURCES OF PLANT NOURISHMENT. 1-41 acid must be decomposed, and tlieir carbon combined with ten atoms of water, to form one atom of starch. The leaver absorb yfdXGV from the air ; the roots absorb it from the soil. 226. Nitrogen is not so abundant in plants, as the other three organic elements; but it is not less important, and even essential, to their growth. Ammonia (NH3) is no doubt the chief source from which plants get their nitrogen ; and some chemists believe it to be the only form in which nitrogen is taken into the growing plant. But nitric acid (in the ni- trates), and several other nitrogen compounds, are doubtless sources from which this important element is often derived. Prof. Johnston says : '' There seems, indeed, very little solid foundation for the opinion held by some, that the plants in our cultivated fields derive the ichole of their nitrogen from ammonia and nitric acid together — still less, that they obtain it from ammonia alone." Still, ammonia is the great source .of nitrogen to the vegetable world. 227. Ammonia is found both in the atmosphere and the soil. From the atmosphere it is carried down by rain and snow. In the soil it is generated by the decay of such animal and vegetable compounds as contain nitrogen. It is retained by the clay, as well as by the humus of the soil (see § 367). Some plants are believed to absorb it from the air, through the leaves ; but in most cases it enters through the roots from the soil. Although nitrogen is so abundant as the chief constituent of our atmosphere, it rarely (perhaps never) enters directly in its pure, gaseous form, into any of the combinations in which it occurs in organic substances. In contact with decaying organic matter in the soil, and in other closely confined localities, nitrogen from the air unites with nascent hydrogen, forming ammonia. The ammonia formed in this way, as well as that which is set free by the decay of proteine matter, may be again decom- posed in the presence of strong bases, such as lime and alka- 142 QUESTIONS. lies ; the nitrogen of NH3, becoming oxidized, forms nitric acid (NO5), "while the hydrogen, combining with an addi- tional quantity of oxygen, becomes water. The nitric acid thus generated combines with whatever bases may be present, forming nitrates. " Nitre (nitrate of potassa) is often gene- rated in arable land, whence it passes into the juice of plants ; thus it is known that beets and tobacco, growing upon very strongly manured soil, and also those rank plants growing on manure heaps, such as henbane, thorn-apples, etc., are frequently so rich in nitre, that when dried they emit sparks, if burnt on charcoal. " Nitric acid is also naturally formed, and in some coun- tries probably in large quantities, by the passage of electricity through the atmosphere. The air consists of oxygen and nitrogen mixed together; but when electric sparks are passed through a quantity of air, minute portions of the two gases unite together chemically, so that every spark which passes forms a small portion of nitric acid. A flash of lightning is only a large electric spark; and hence every flash that crosses the air, produces along its path a sensible portion of this acid. Where thunder-storms are frequent, much nitric acid, and probably some ammonia, are produced in this way in the air. They are washed down by rains — in which they have been frequently detected — and thus reach the soil, where the acid combines with potash, soda, lime, etc." — {Johnston.^ 228. The soil and the air, then, are the great fountains of nourishment for the vegetable world. The soil provides mineral matter, carbonic acid, humus, water, ammonia, and nitric acid. The air, too, provides all these except mineral matter and humus. QUESTIONS ON CHAPTER IX. 221, 222, 223. Of what two classes of elements are plants com- posed ? Are they equally necessary ? Do plants get all their food QUESTIONS. . 113 from the soil ? From -what other source? How are plants brought in contact with their sources of nourishment ? Are the mineral elements found in the air? In what condition must they be when taken up by the roots ? 224. Whence do plants get their Carbon? Is carbonic acid abun- dant in the atmosphere? How collected by plants? How does organic matter in the soil furnish food to plants ? AVhat change takes place on carbonic acid in the organs of the plant? What if light be excluded from a plant? How does Humus furnish food for plants? 225. In what form are Hydrogen and Oxygen supplied to plants ? Do they constitute a large proportion of vegetable compounds? What is the composition of starch ? 226. Is Nitrogen as abundant as other organic elements ? Chief source of nitrogen? From what other source may it also be derived? 227. 228. Where is Ammonia found ? How does it reach the roots of plants ? How generated in the soil ? How retained ? Is nitro- gen ever absorbed dii-ectly from the atmosphere? How may ammo- nia be converted into nitric acid? What plants contain nitrate of potassa ? How is nitric acid generated in the atmosphere ? What do the soil and air respectively provide for the plant ? 1 U V E r, E T A B L E T 11 Y S I O L O G Y. CHAPTER X. VEGETABLE PHYSIOLOGY. 229. Plants and animals constitute the two great depart- ments of organic nature. They all consist of those organs necessary to sustain life, to promote growth, and to repro- duce their own species. Plants, as well as animals, are en- dowed with vitalif//; hut they differ from animals in not possessing sensation. In some plants there seem to be some evidences of sensation, as in the sensitive plant (^Mimosa')', and it may be that all plants have some kind of sensation, which is so obscure as not to be ordinarily perceptible. Still we generally regard plants as destitute of this property. 230. Botany is the science of plants. It gives us a know- ledge of their names, classification, structure, the functions of their various organs, and the uses to which the}^ are applied. 231. Vegetable Physiology is that department of Botany which treats of the organs of plants — their structure, and the part they severally perform in promoting life and reproduction. A distinction is drawn between vegetable Anatomy and Physiology; the former treating of the struc- ture of the organs, and the latter of their functions. But we shall embrace both of these in the term Physiology. An intelligent vicAV of this subject is of high importance to every one engaged in the cultivation of the soil. 232. Skilful cultivation always increases the productive- ness of plants; and, in many cases, improves their quality to VEGETABLE P II Y S I L O O Y. 145 such an extent as to render what was once worthless, now highly valuable. The apple, the potato, and the tomato, are examples of plants reclaimed from a wild and almost worth- less state, to one of the highest value and importance. 233. Germination. — The plant is first found as an cm- hryo in the seed, from which it springs. Exp. Place a bean in warm water, and let it remain a few hours, until it becomes swollen. Then separate the two lobes of which it is formed, and you will discover, near what is called the '' eye" of the bean, the embryo, consisting of two parts, one to be deve- loped into roots, and the other into the stalk and leaves of the plant. When a seed is placed in a moist, warm soil, it soon begins to absorb water, and also oxygen from the air mingled with the soil. A chemical change begins at once within the seed, by which the material of the grain is so modified as to be- come the food of the embryo plant. Seeds consist chiefly of starch and gluten; but these being insoluble, cannot be taken up by the germ in their present form. Under the combined influence of air, water, and heat, the gluten becomes diastase, and begins to act as a ferment (§ 138) ; and, under its influ- ence, the starch is soon converted into dextrine, and then into sugar. Being thus rendered soluble, it enters the cir- culation of the embryo, which begins to expand, and soon bursts the seed. It " sprouts," sending forth two branches, one of which turns downward, and puts forth roots ; this is called the radicle. The other turns upward to seek the light and air; this is thep?wmif?e, and is soon developed into the stalk and leaves. Exp. Put grains of corn into several cups or bowls filled with fine soil, and place them in a warm place for three or four days, keeping the soil moist. At the end of this time examine one of them, and observe the change the grain has undergone. Then examine one on each successive day, and you will see the radicle and idumide 18 14G VEGETABLE T II Y S I O L O O Y. in their various degrees of development, until the one he- FiG. 30. comes roots, and the other rises to the sur- face, and sends forth a green blade. Mean- while the grain has been consumed, and will soon disappear entirely; the plant being now able to get nourishment from the soil through its roots, and from the air through its blades or leaves, no longer requires the store of nourishment which an all-wise Providence had laid up for its inflmcy. Fig. 30 will give some idea of the appearance of a grain of Indian corn, in one of its stages of germi- nation. The covering of the seed is called the integument (the bran); the starchy part within the integuments, and surrounding the embryo, is known as the albumen. The albumen and integuments together form what is called the cotyledon, or seed-lobe. When a seed consists of only one lobe or cotyledon, the plant producing it is said to be monocotyledonous : Indian corn is an example of a monocotyledonous plant. If the seed has two lobes, as the bean, the plant is dicotyledonous. 234. The stems of plants whose seeds have only one coty- ledon, increase in size by internal growth. Such plants are called Endogens. The dicotyledonous plants, on the other hand, generally grow by the formation of new layers on the outer part of the stem, and immediately beneath the bark. They are hence called Exogens. The grasses (including wheat, corn, etc.), the palms, and plants generally having the veins of their leaves parallel, are endogens. Beans, peas, and the trees and shrubs of our forests, are exogens. 235. Tissues of Plants. — The various organs of plants are composed chiefly of several kinds of structure, called VEGETABLE PIIYSIOLOOY. 147 Fig. 31. m tissues. These are made up of Jibres or membranes, or both together. There are five kinds of tissue: 1. Cellular tissue; 2. Woody tissue; 3. Vascular tissue; 4. Vasi/orm tissue; 5. Laticiferous tissue. 236. Cellular tissue is composed of minute cells, resting upon and pressing against each other, so that the sides where they meet become flattened, and give to the cell a some- what regular form. Fig. 31 (a) is a section of cellular tissue from pith of elder, as viewed with the microscope. 237. Woody tissue has a fibrous structure — the fibres being in the form of slender tubes overlapping each other at their extremities, as in Fig. 31 (b). It is this structure which gives strength to wood, and the various kinds of fibrous material used in the arts, such as flax, hemp, cotton, etc. 238. The vascidar tissue resembles the woody in external form, but difiers in having a long slender fibre coiled within it from end to end. 239. The vasi/orm tissue consists of tubes much larger than those of the woody fibre. These tubes may be seen in a cross-section of oak-wood. It is chiefly through these that the sap passes in ascending from the roots to the leaves. 240. Laticiferous tissue consists of very small tubes and cells, found most abundantly in the bark and leaves. After the sap has been prepared in the leaf for nourishing the plant, it is called latex. Those vessels of the leaf in which this preparation or elaboration goes on, and those which 148 QUESTIONS. afterwards convey the latex to the part of the plant to be nourished by it, are formed of the latieiferous (latex) tissue. These various kinds of tissue hold and transmit the fluids of the plant, the different tubes and cells having no com- munication with each other, except through minute pores. These vessels are sometimes charged with liquid matter, and sometimes with gases. Let us now examine the structure and functions of the various organs so beautifully constructed out of these several forms of tissue. QUESTIONS ON CHAPTER X. § 229, 230, 231. In what respect are plants and animals similar? How do they differ? What is Botany? Vegetable Physiology? 232, 233, 234. How does cultivation influence plants ? Examples. Where is the germ of a plant found ? Experiment. When a seed is placed in moist, warm soil, what change takes place ? How does the material of the seed nourish the embryo plant? What is the radi- cle? Plumule? Experiments with a grain of corn? The integu- ments of seeds ? The albumen ? Cotyledon ? What plants are called Undogens ? Exogens ? Examples ? 235 — 240. Of what are the organs of plants composed? How many kinds of tissue? What are they? Describe cellular tissue? Woody tissue. Examples. Vascular tissue. Vasiform tissue. Where seen? Latieiferous tissue? What part do these tissues perform ? OEGANS OF PLANTS. 149 CHAPTER XI ORGANS OF PLANTS. 241. The chief organs of the plant are the Barh, Roof, Stem, Leaf, and Floiccr. 242. Bark. — The hark is the external covering of the plant; and, in the widest sense, may be regarded as enve- loping every other part of it, except the extremities of the roots, and the stigma of the flower. It consists of three layers. The outer one, called the Epidermis, is a thin, and often transparent integument, which covers every part of the plant, with the exceptions above mentioned. It may be easily separated from the surface of the leaves and green stems of many plants. On trees of many years growth, it becomes thick and rough, forming an uneven, scaly surfoce. The inner layer of the bark, which is in contact with the surface of the wood, is called the liber. It is generally thin, and often strong enough to serve many valuable purposes of art. The ancients used it as we use paper (hence, liber, a book) ; while in more modern times it has been used in the manufacture of mats, and of cloth of various qualities, from the coarsest coflFee-sack to the finest Irish linen. Between the epidermis and liber is the cellular integument, which in many trees is quite thick. In the bark of the cork-tree {Quercus suber,') it forms the material of which corks are made. The epidermis and cellular integument are both composed chiefly of cellular tissue. The liber consists of cellular and woody tissues. 13* 150 BOOTS. There are little openings in the epidermis, called stomata (mouths). These are very minute, requiring the aid of the microscope to see them. They are most numerous on the surface of the leaves, and on parts of the plant of recent growth. These stomata perform important offices, which will be discussed in connection with the leaves. 243. Glands are minute masses of cellular tissue, of various forms, and situated in different parts of the plant. Their office is to elaborate and discharge the peculiar secre- tions of the plant. The gums, oils, &c., are secreted by glands. Hairs, stings, and prickles, are protuberances of the epi- dermis, or of the cellular integuments, covered by the epidermis. ROOTS. 244. The roots serve the double purpose of sustaining the plant in its proper position, and of absorbing from the soil appropriate nourishment. Their office is somewhat similar to that of the mouths of animals. They take in both food and water. 245. Variety of forms. — Roots have a great variety of form, but we have room to notice only a few of the most common and conspicuous varieties. (1.) The ra- mose, or branching rooty is one which sends off branches of various size in every direction. It is the kind of root common to all trees and shrubs. (See Fig. 32, a). (2). The spindle root tapers from the top downward, often branching near the lower end. It sends off little branches, or rootlets, all along the sides. Fig. .32, a. ROOTS, 151 V Fig. 32, c. We have examples of this form in the radish and parsnip (Fig. 32, J). The tiirnijy, or naivfortn root, differs from the spindle root, only in swelling out consider- "' ' ably, just at the surface of the ground. (3.) The tuberous root consists of fleshy masses con- nected together by fibres. It closely resembles the potato, which was formerly regarded as a tuberous root; but the proper tuberous root has no buds (eyes), while the potato has, and it is, therefore, classed with underground stems. I ^ ■■ M ('^■) The fibrous root is one [iW_:S which consists of nume- rous thread-like divisions, or fibres, extending out from a common head near the base of the plant. Wheat, corn, and most of the other grasses have fibrous roots (Fig. 32, c). Other varieties we cannot now stop to notice. The student should collect the different varieties of roots, and wash them carefully, so as to preserve every part un- broken, that he may become familiar with them as they actually grow. 245. Floating, or aquatic roots, are such as belong to plants which float upon the surface of water, without having any connection with the soil. 246. Aerial roots are such as shoot forth in the air. (1.) Sometimes they remain suspended in the air, without attach- ing themselves to any other substance, except so far as may be necessary to sustain the plant to which they belong. Their ofl&ce, then, is to absorb nourishment from the air, and the rain which falls upon them. Of such plants are the pendent mosses, which festoon the trees so remarkably in 152 ROOTS. some of our Southern States. (2.) They sometimes attach themselves to the bark, and even penetrate the tissues of other plants, from which they get their nourishment. The mistletoe is an example of such beggar-plants. They are aptly called "jmrasites." (3.) The roots which shoot forth from the joints of some prostrate plants, as the tomato, are regarded as aerial roots, but these soon penetrate the soil. (4.) Another variety of aerial roots are such as spring from the stems of erect plants, at some distance above the surface of the ground, and extending downward into the earth, stand like a circular row of braces around the base of the stalk. We have a beautiful example of this kind of root in the Indian corn, when growing on a good soil. These are often called brace-roofs. They serve to support the plant, and prevent its being prostrated by winds; and, at the same time, collect nourishment from the soil. 247. Parts of the root. — Whatever may be the shape of the root, it generally has several distinct parts worthy of notice : (1.) The Caudex is the main body of the root, generally descending vertically into the soil. It is frequently called the tap-root. (2.) The Fibrils are the branches sent off from the caudex, often passing into many sub-divisions. (3.) Sjionffioles are the soft, pulpy points of the fibrils, through which the plant gets its nourishment from the soil in a liquid form. 248. Structure. — The root has a structure similar to that of the stem to which it belongs. The bark of the root is more soft and spongy than the bark of the stem. Its epi- dermis terminates near the spongioles, leaving them un- covered. The fibrils are composed chiefly of vasiform tissue, covered with the epidermis. The extremities of the fibrils THE STEM. 153 consist of this vasiform tissue in very soft and delicate form, spongy in structure, and hence called " spongioles." 249. Functions of the Root. — These have several times been alluded to. The, first is the mechanical office of attach- ing the 2ilcint to the soil, and Tceeping it in its proper position. The second is the ahsorp>tion of food and moisture from the soil. THE STEM. 250. The stem originates in the plumule. The ascending of the plumule and descending of the radicle, seem to be owing chiefly to the mysterious influence of light. When seeds are planted in a box of soil, with a few stalks of hay or a little moss spread over it, and then some narrow strips of wood placed over all, so that the contents of the box will not fall out when it is inverted ; and the box then turned with its open side downwards, over a mirror, a bright sur- face of tin, or even over white paper, so that the light will reach the soil only from below : the seeds will germinate, and the plumule descend towards the light, whilst the radicle will ascend into the dark soil above it. 251. Stems are aerial when they grow above the surface of the ground, and suhterranean when they grow beneath the surface. Erect stems continue to grow in a vertical direction. Creeping and trailing stems are such as grow along the surface of the ground. Many of these have tendrils (coiling fibres) by which they sustain themselves on the branches of other plants; as we see in the grape- vine. 252. Subterranean stems generally grow just below the surface of the soil. They ai'e distinguished from roots in having buds, from which aerial or other subterranean branches may be sent forth. The roots of many plants have the power of developing buds, and thus sending up " shoots" from their 154 THE STEM. surfiicc ; but still buds are the chief mark of distinction be- tween roots and stems. 253. Forms. — Some of the most general forms of sub- terranean roots are : (1) The tuber, a familiar example of which wc have in the potato. Its buds (eyes) arc the germs of new stems, to be developed the next year. (2) The bulb, which consists of concentric layers surrounding one or more germs or buds, from which stems spring up, developing new bulbs at their base during the succeeding season of growth. Examples — the tulip and onion. 254. Stems are further distinguished by the terms ligneous and licrhaceous. A ligneous stem is one which has a woody structure, such as wc see in ordinary trees and shrubs; and is composed of pith, loood, and hark. An herbaceous stem is composed of tissues similar to those of the ligneous stem (the cellular predominating), but less compact, softer, usually of a single year's growth, and without the distinctions of pith, wood, and bark. Ligneous stems are usually distin- guished, in temperate climates, by concentric layers of wood, marking the annual growth, and thus enabling us to deter- mine the age of the tree. Plerbaceous stems usually grow but one season : in many cases coming to maturity and dying with the ripening of the seed. 255. Physical Structure of Exooens. — The exogens (outside growers), when they first spring from the seed (and abo branches, during their first year's growth), have a soft, spongy centre of cellular tissue, called pith. This is covered by a thin layer of vascular tissue, having its spiral vessels connected with the leaves, and called the medullar^/ sheath. Surrounding this is the bar/i: Such is the structure of the infant plant; but this condition lasts but a short time. The sap, carried up by the pith, and elaborated in the leaves, descends through the vessels of the liber, and soon forms a layer of wood around the medullary sheath. This layer THE S T E M. 155 Fig. 33. consists, first, of ducts or sap-tubes, formed during the early part of the season ; then of a more compact kyer of woody and vasiform tissue. Such a layer is added every year, giving to a cross-section of oak or ash an ap- pearance similar to that represented in Fig. .3.3. 2.5G. The pith soon ceases to be the channel through which the sap ascends — the newly-formed ducts performing this office. Again the laj'ers of wood become gradually hard, the sap-tubes partially obstructed by the deposition of matter, which gives a reddish or brown color to the wood, and the sap ceases to ascend through them. They then form the red-wood, called the duramen, on account of its compact- ness and strength. For several years the newly-formed layers continue to circulate the sap, and retain their light color : they form the cdburuum (white-wood — sap-wood_). The duramen is the most valuable portion of the tree, on account of its strength and durability. The aThurnum is softer, and decays readily, on account of the albuminous matter present in it (see § IGO), 257. Passing from the centre of the trunk or stem to the bark, and cutting the annual layers at right angles, are many plates formed of fine fibres. These are called the medidlary rays. They are conspicuous in a piece of split wood of oak or maple. 258. Physical Structure op Endogens. — "In the endogenous stem, there is no distinction of pith, wood, and bark; nor does a cross-section exhibit any concentric ar- rangement of annual layers. It is composed of the same tissues and vessels as that of the exogen ; that is, of cellular tissue, woody fibre, spiral vessels, and ducts — the first exist- 153 T II E L E A P. ing equally in all parts of the stem, and the rest imbedded in it in the form of bundles. Each bundle consists of one or more ducts, with spiral vessels adjoining their {yiner side next the centre of the stem, and woody fibres on their outer side, as in the exogens." — Wood's Botany. Most of the endogenous herbaceous stems are hollow, and have hard joints at nearly regular intervals. A bladed leaf is usually attached at each one of these joints. The joints give strength to the stem. Examples are seen in many of the grasses. Some stalks, like those of the Indian corn, are jointed, but not hollow. 259. Functions of the Stem. — These are, Jirst, to convey the sap from the roots to the leaves, where it is prepared for the nutrition of the plant, and thence to carry it to the various parts to be nourished by it; secondly, to sustain the leaves, flowers, and fruit, so as to expose them properly to the action of air and light. Where it is necessary that a very large surfoce of leaf should be exposed, the plant is constructed with numerous branches, forming a spreading top, such as we see on trees generally. In a tree, that part of the stem below the branches is called the trunk. The trunk is the most valuable part of those trees used for timber. THE LEAF. 260. Buds. — Tlants have two kinds of buds: (1) The Icaf-huds, the first of which is the plumule as it bursts from the seed. This is developed into the stalk and leaves, and is itself perpetually renewed on the summit of the stalk. Just above the base of each leaf, a new bud makes its ap- pearance J and in ligneous plants it is subsequently devel- oped into leaves alone, or into a branch and leaves. (2) The flower-bud, which has a difi'erent structure, generally having enveloped within it the germs of both leaves and flowers. In cold climates, buds are protected in winter by a scaly THE LEAF. 157 covering, wliicli opens and frequently drops off soon after the bud begins to swell and grow in the Spring. 261. The leaf combines, in a striking manner, the useful and beautiful, in its structure and color. The almost count- less shapes, from the straight and slender blade of grass to the deeply lobed oak leaf and the broad palm, present to the eye a wonderful variety of Nature's most delicate handiwork. The green color, the most pleasant to the eye, seems to have been provided by a kind Providence to soften the bright glare of the summer's sun, and thus to promote the comfort of his creatures. To the plant itself the leaf bears the most important rela- tion. It is the hreatliing organ of the plant — its lungs. It is the digestive organ, too — its stomach. 262. Structure. — The leaf consists of several parts worthy of distinct notice. The leaf-stem, or that by which it is attached to the branch or stalk to which it belongs, is called the '■'■Petiole!^ Some leaves have no petiole, but are connected by their base directly with the branch or stem. They are then said to be Sessile. The broad expansion of the leaf is called the " blade." The framework consists of numerous veins and veinlets. The mid-vein is the extension of the petiole, running through the centre of the leaf. The other veins either branch off from the base of the mid-vein, or run parallel with it. The branches of the veins are called veinlets. 263. A leaf is said to be (1) " JVet-veined," when the vein- lets so intersect and cross one another as to form a sort of net-work. The leaves of exogens, such as our forest trees, peas, beans, etc., are net-veined; (2) ^' Parallel' veined," when the veins run parallel with the mid-vein, and the vein- lets parallel with one another, as in grasses, and most of the endogens; (3) " Porlc-veined," when the veins and veinlets Vixc forked, as in the fern leaf. 14 158 THE LEAP. 264. Forms. — The form of the leaf is determined by the direction and extent of the veins and veinlets, and the deve- lopment of the intervening tissue. It may be orhicular, round; ovate, egg-shaped; cordate, heart-shaped; lanceolate, lance-shaped, etc., according as the outline of the framework assumes one or other of these imitative forms. 265. Physiology of the Leaf. — The veins and veinlets may be regarded as a prolongation of the medullary sheath, and are composed of the woody and vascular tissues. The thin, membranous part of the leaf, or lamina, is formed of cellular tissue, and generally consists of two layers; that which forms the upper side of the leaf differing somewhat in structure from that which forms the lower side. In some cases, the plane of the leaf is nearly or quite vertical when in its natural position. In such cases, both sides being equally exposed to light, have the same structure. 266. The cells, which abound in the lamina, have their inner surface lined with little green globules of chlorophyll (§ 179), which give the green color to the leaf. The differ- ent shades of green are produced by the greater or less com- pactness of the cellular tissue, and consequent compactness of the chlorophyll (leaf-green). 267. Every part of the leaf is enveloped in the epidermii (§ 242). Beneath the epidermis, and among the cells, we find many open spaces, especially near the lower surface of the leaf. These are called air-cham- pm. 34, hers, and have communication with the air through openings (stomata) in the epidermis, which are too small to be seen with the naked eye, but with the aid of a powerful microscope, they may be seen in great numbers. Fig. 34 represents a magnified view of some of the stomata, as seen in the leaf of the lily. They are so numerous on most leaves, FUNCTIONS OF THE LEAF. 159 that many thousands of them are embraced within the space of a single square inch of surface. The stomata are chiefly confined to the lower surface of the leaf; but in leaves whose natural position is vertical, exposing each side alike to the sun, they are found on both sides. FUNCTIONS OP THE LEAF. 268. When the sap ascends from the root to the leaf, it carries with it in solution a portion of the material necessary for the nourishment of the growing plant. But this nourish- ment is still in a crude form, and too dilute to be adapted to the purposes for which it is designed. It must, therefore, undergo certain modifications. These take place chiefly in the leaves, as described in the next three sections. 269. Exhalation. — The sap must be condensed ; that is, the surplus moisture must be thrown ofi". This takes place through the stomata, and is similar to the perspiration of animals. It is generally called ^' exliajation" and occurs chiefly under the influence of light, and to a great extent independent of temperature. The stomata are open in the light, and closed in the darh ; but the direct rays of the sun are unfavorable to their action. 270. Respiration. — Plants derive a large proportion of their nourishment from the air, through their leaves, in the form of carbonic acid gas. They also absorb small quanti- ties of oxygen from the air, but throw ofi" a much larger quantity into the air. This inhalation of carbonic gas, and exhalation of oxygen, we shall call ^'respiration." In one respect it is the reverse of respiration in animals, inasmuch as animals inhale oxygen and exhale carbonic gas (§ 65). The respiration of plants goes on chiefly by day, the stomata being opened under the influence of light. As the carbonic gas enters the leaf, it is at once dissolved by the sap, and carried through the circulating vessels of the leaf, where it 160 FLOWERS AND FRUIT. is decomposed, its carbon being retained, and its oxygen thrown back into the air. 271. Digestion. — The food taken up by the roots, and car- ried by the sap to the leaves, there meets with the gaseous food from the air, all together forming, by their solution, " crude sap." This is greatly modified during its circulation through the leaf, if an abundant supply of light be present. The changes which the plant-food thus undergoes, we call " digestion," because of its resemblance to the changes pro- duced on animal food by animal digestion. When the sap has thus been prepared for nourishing the plant, it is called " latex" or true sap. It is then conveyed by the circulating organs to the various portions of the plant, and in some mysterious way, under the guiding finger of Omnipotence, assumes various forms of organic structure, producing stems and leaves, flowers and fruits. Here we have a beautiful analogy between the circulation of sap in plants, and the circulation of blood in animals (§ 612). FLOWERS AND FRUIT. 272. Growth, decay, and death, mark the history of every individual upon our globe, whether plant or animal. If, then, organized beings possessed not the power of reproduc- tion, our world would soon become a bleak and barren waste. But the Creator has wisely ordained that the earth shall bring forth '* grass, and herb yielding seed after his kind, and the tree yielding fruit, whose seed was in itself, after his kind." 273. Rrjyrodiictive onjans. — The reproductive organs of plant^s are found in the flower, which is the expansion of the floicer-hud (§ 260). These, by their combined influence, bring the seed to maturity, and thus produce the embryo of a new plant. FLOWERS AND FRUIT. 161 274. Structure of the Flower. — As a general rule, flowers have sevei'al distinct organs or parts worthy of note : (1.) Many flowers are attached to the plant by a stem, called the ''flower-stalk" (Fig. 35, a). When the flower rests upon the stem, or branch of the plant, without a flower- stalk, it is said to be *' sessile." Fig. 35. Stamen (2.) The head or top of the flower-stalk on which the other organs rest, and to which they are usually attached, is called the "receptacle" (6). (3.) The "calyx" is the external c^/p which surrounds the flower at its base. It is generally green, but sometimes colored like the other parts of the flower. It is sometimes in one entire piece, having its edge notched. At other times it consists of a whorl of separate leaves. These divisions of the calyx are called "sepals" (c). (4.) The delicate and beautifully colored circle of leaves, forming the inner coating of the flower, is the " corolla." Its divisions are called "petals" (d^. (5.) The "stamens" are the slender organs of thread-like 14* 1G2 FLOWERS AND TRUIT. structure, situated within the corolla, and generally (though not always,) equal to the petals in number (e). The three divisions of a stamen are : the filament, or slender stem ; the anther, which is a little two-lohed organ at the extremity of the filament; and the pollen, or fine yellow dust found in the anther. The pollen, when viewed with a microscope, is found to consist of minute membranous sacks filled with a fluid substance (Fig. 35,/, (7, /i). (6.) Within the circle of stamens are the "pistils." These occupy the centre of the flower. Some flowers have but one pistil, others have a great many (Fig. 35^ i). 2,1b. The pistil has three divisions : the ovary, which is the enlarged part of the pistil at its base, and contains the germs of the future seeds j the style, the slender part of the pistil rising above the ovary; the stigma is the top of the pistil, and usually consists of one or more rounded lobes. The ovary is often simple, consist- ing of a single cell, or carpel; but more frequently it is compound, having two or more carpels. When the ovary is simple, it has but one style and stigma ; when compound, it has a style and stigma for each carpel; unless the style is wanting, as sometimes happens. In that case, the stigma rests upon the ovary, and has one division for each carpel. (Fig- 36, a, shows a simple pistil with its diff"erent parts; h, one of compound form.) 276. Stamens and p>ist!ls are essential organs for the pro- duction of seed in any plant. But they are not always found in the same flower. (1.) They often grmo in different fiowers vpon the same stalk. In such cases, the flowers containing the stamens arc called " staminate," and those containing the Fig. 36. FUNCTIONS OP THE FLOWER. 1G3 pistils are called " pistilate." For example, Indian corn lias its stamens in the tassel, and its pistils in the ear-shoot. The tassel then is the staminate flower, while the shoot, with its silk, forms the pistilate flower; the tassel, with its beauti- ful, pendulous stamens, and the shoot with its fine glossy silk, present interesting objects of study. (2.) The staminate and •pistilate floxoers sometimes grow on sejjarate plants. Of this, we have an example in common hemp>. A little exami- nation will enable the student to distinguish between the staminate and pistilate plant. The staminate is barren — the pistilate produces seed. FUNCTIONS OF THE FLOWER 277. The corolla is the breathing organ of the flower; but, unlike the leaf, it absorbs large quantities of oxygen, and exhales corresponding quantities of carbonic gas. The same process is carried on to some extent by the stamens and pistils. 278. The end to be accomplished by the stamens and pistils, is to fertilize the seed. Pollen is produced in the anthers ; and by them is so discharged at the proper season, that portions of it fall upon the stigma. The little granules of pollen then burst, and their contents are absorbed by the stigma, and carried through the style to the ovary, where they take part in the formation of the seed. If the pollen is cut oft' from the stigma entirely (as may be done in an isolated stalk of corn, by destroying the tassel before the silk makes its appearance), no seed can be produced. But if other tassels are near at hand to provide pollen, the stalk may produce an ear without a tassel of its own. There are certain periods in the growth of crops, when the pollen, and even the stamens, may be beaten ofi" by vio- lent rains and hail, to such an extent as greatly to diminish 104 FUNCTIONS OP THE FLOWER. the quantity of grain which would otherwise have been produced.* 279. By a wise provision of the Creator, the flower is so constructed that the pollen is readily transferred from the anther to the stigma. When the flower grows erect, like the tulip, the pistil is shorter than the stamen ; and the anther rising above the stigma, readily discharges its pollen where it is wanted. So, when the flower droops, as the lily, the pistil is longer than the stamen, in order that the pollen may still fall upon the stigma, (see Fig. 35). When the staminate and pistilate flowers are on difier- ent plants, the pollen is sometimes carried from the one to the other by the wind; sometimes by bees, and other insects. 280. Fruit. — When the ovary is fully developed, it forms the fruit. The fruit consists of two parts : (1) The 2)crir carp, which surrounds the seeds ; and, (2) The seeds, which contain the germs of new plants. In the apple, peach, etc. the pericarp is the most valuable portion of the fruit. In cereal or grain crops, the seed is of chief value — the pericarp being the chafi" or husk. 281. The seed may be divided into: (1) The integuments (bran), which consist of several layers, forming the outer coating of the grain ; (2) The albumen, which is the white, starchy mass within the integuments ; and, (3) The emhryo, or germ of the new plant, which is also within the integu- ments, and generally surrounded in part by the albumen. The albumen constitutes the larger part of cereal grains, and serves not only as food for the embryo plant, but also constitutes a large proportion of the food of man and beast. * The wheat crops, in the summer of 1858, were seriously damaged, in some places, by the heavy rains which fell while the grain-fielda were in full bloom. QUESTIONS. 165 DURATION OF PLANTS AND THEIR ORGANS. 282. When a root or stem lives through only one summer, it is said to be annual. When it lives through hco, it is said to be biennial; and when it lives through three or more, it is said to be perennial. (1) The root and stem are often hoth annual, as in flax, hemp, Indian corn, cotton, and tobacco. (2) The root may be biennial, and the stem annual. In such cases the stem does not usually make its appearance until the second season. Examples — the common thistle and winter wheat. (3) The root may he perennial, and the stem, annual, as in most varie- ties of grass. (4) Both root and stem may be perennial, as we see in trees and shrubs. 283. Leaves are deciduous when they die and fall at the close of summer, or as soon as the plant has reached matu- rity. They are evergreen, when they endure until the new leaves of the next growth have made their appearance. It is, properly speaking, the plant, and not the leaf, which is evergreen ; for the old leaves of evergreen plants, like the pine, drop off in the spring, as the new leaves come out to take their place ; and thus the succession of leaves keeps the plant ever green. Climate modifies the duration of the leaf. A plant may be ever green in a warm climate, while its leaves become deciduous when removed to a colder region. QUESTIONS ON CHAPTER XI. I 241, 242, 243. What are the chief organs of a plant ? What is the bark ? Its divisions ? Describe each. Of what kinds of tissue composed? What are stomala? What are glands? Their office? Hairs, stings, and prickles ? 244, 245, 240, 247, 248, 249. Purposes served by the roots? Va- rieties of form? Describe the branching root. Spindle root? Tur- nip root? Tubei'ose root ? Fibrous root? Aquatic roots ? Aerial 166 QUESTIONS. roots ? How do they grow ? When called brace roots ? The caudex of a root ? The fibrihs ? The spongioles ? What does the root re- semble in structure? How does it differ from the stem? The two principal functions of the root? 250, 251, 252, 253, 254. Where does the stem originate ? Influence of light? How illustrated ? Aerial stems? Subterranean stems? Creeping stems ? What are tendrils ? Where do subterranean stems generally grow ? What are tubers ? Examples ? Bulbs ? Exam- ples ? What is a ligneous stem ? Herbaceous stem ? 255, 256, 257. Describe the structure of exogeus ? How do they grow ? Changes in the layers of wood ? Duramen ? Alburnum ? Medullary rays ? 258, 259. Give the structure of endogens. What kind of stems have they? What form of leaf? Use of joints? First function of the stem ? second ? Use of branches ? 200, 261, 262, 263, 264. What does the leaf combine? Variety of forms? Its color? Its use to the plant? How many kinds of bud? Describe each. How protected in warm climates? What is the petiole of a leaf? Blade? Describe the frame-work. When is a leaf net-veined ? Parallel-veined? Fork-veined? What are some of the forms of leaves? 265, 266, 267. How may the veins and veinlets be regarded? Describe the lamina. How do the two sides of a leaf generally differ ? Where is the chlorophyll found ? In what is the whole leaf enveloped? Describe the air-chambers. The stomata. 268, 269, 270, 271. What does the sap carry up from the roots? How is the sap condensed ? When are the stomata open, and wheu closed ? What do plants absorb from the air by their leaves ? Do- scribe the process of respiration. How is sap modified in the leaf? What is it then called ? How does it promote growth ? Analogy ? 272, 273. If organized bodies had not the power of reproduction, what would be the consequence ? Where are the reproductive organs found ? What is the flower ? 274, 275, 276. What is the flower-stalk? When is a flower "ses- sile " ? What is the receptacle ? The calyx ? Sepals ? Corolla and petals? Stamens? Its parts ? Pistil and its parts ? Simple and compound ovary? Describe Figs. 35 and 36. What organs are essential to the production of seed ? Are they always in the same flower? Example? Are they always on the same plant? Example? QUESTIONS 107 277, 278, 279. Hotv is the respiration of the flower carried on? Functions of the stamens and pistils ? How is the seed fertilized ? What if the pollen is cut off from the pistil ? Illustrate. Effects of violent storms ? What provisions are made to secure the transfer of pollen to the stigma ? What if the pistilate and staminate flowers are on different plants ? 280, 281. What is the fruit? Its parts? What is the valuable part of apples, peaches, etc. ? Of cereal grains ? Divisions of the seed ? 282, 283. What is an annual root or stem ? A biennial ? Are the root and stem ever both annual ? Examples ? Can a root be bien- nial and a stem annual? Examples? INIay the root be perennial and the stem annual ? Examples? May both be perennial ? Exam- ples ? When are leaves deciduous ? When is a plant evergreen ? Influence of climate ? 168 AGRICULTURAL GEOLOGY. CHAPTER XII. THE SOIL. 284. Having before us the composition of the plant and its organic structure, we may now study more minutely its nutrition and cultivation. We have given some attention to the sources from which crops get their nourishment. These are the atmosphere and the soil. We can exercise no con- trol over the condition of the air. Our Creator has esta- blished laws by which its chemical composition is made almost invariable. The quantity of moisture, too, which it brings and pours out as rain upon our farms^ is a matter en- tirely beyond our influence. The management of the soil alone has been committed to our hands. Then, leaving the atmosphere in the hands of that all-wise and beneficent Being who has made it an inex- haustible source of food for plants, and of fertility to the soil, let us turn our attention to those principles and laws which will guide us to a knowledge of the origin and nature of different soils, and to the means by which they can be best cultivated and improved AGRICULTURAL GEOLOGY. 285. "Geoloread and grow freely ; (2) Tlicy must permit a free circu- lation of air ; (3) The water ichich falls upon them must he readily ahsorhed, and have, at the same time, such free circu- lation, that any swplus moisture loill p)ass off, without hecom- ing stagnant, and icithout ivashing away the surface. To accomplish these objects, several methods may be pur- sued, one or all of which may be employed, as the condition of the land, or other circumstances seem to require. Those means best adapted to the farming operations of our own country will be described in this chapter. 335. (a) Mixing soils may be resorted to, where those of widely-different classes are sufficiently near each other to admit of transportation. For example, the best and most durable remedy for a stiff clay is the application of sand ; while, on the other hand, the best remedy for a very loose, sandy soil., is the application of clay. If a farmer has both kinds of soil on contiguous portions of his land, he may often find it profitable to haul sand upon his stiff clays, and, for each load of sand, bring back a load of clay to be applied to the loose, sandy surface. This method is extensively and most successfully employed in Holland. Clay soils may also be greatly benefited by being mixed with peaty soils, or, still better, by applying pure peat. So, those of peaty character, 196 MECHANICAL TREAMENT OT SOILS. being often too porous, may be improved with clay, or clay and sand together. 336. (6) Plowing is the most common, and most econo- mical means of giving a soil its proper mechanical condition. All past experience proves that, without the plow, or its , equivalent, successful agriculture is impossible ; while the history of the world shows that nations have generally been prosperous (other things being equal,) just in proportion to the skilful use they have made of this most important of all instruments. If two men, with equal force and capital, are placed upon contiguous farms of equal size and fertility, they will 2'>>'osper very much as they plow. The one who scratches the surface to the depth of only three or four inches, will soon find both his farm and himself growing poor; while the one who is not satisfied with breaking and cultivating less than twelve inches in depth of his land, will, most probably, soon find it necessary to " pull down his barns and build greater." 337. (c) Repeated p)lowin(j during the growth of many crops, not only cleans the land, by destroying weeds and gi'ass, but also serves another most important purpose not to be overlooked, even if the land is already clean : that is, it keeps the soil in a proper condition for the growing roots, and for the free circulation of air and moisture. These ad- vantages are seen every season, where corn, tobacco, and cotton crops are properly cultivated. 338. ((7) Deep plowing is absolutely necessary on almost every farm, in order to get the highest profit from the soil. The reasons for this may be rendered plain enough for any mind, in a few sentences. (1.) The space in depth, to which the roots of crops penetrate, and from which they derive nourishment, is limited chiefly by the extent to which the plow has run. Beneath that point, especially in clay soils, the roots make but little progress. (2.) The unbroken sub- MECHANICAL TREATMENT OF SOILS. 197 soil, when composed of clay, is not easily penetrated by rain. Hence, after the plowed mass has become saturated, the sur- plus water escapes from the surflice, frequently carrying off valuable portions of the fertility, and leaving unsightly gullies behind it. Deep plowing tends to prevent icashhig. (3.) A deeply-broken soil is a sort of store-house for moisture, holding a portion always in reserve for periods of drought. When the sun, the air, and the growing crop have taken up the surface moisture, some of the roots are still deep down in the earth, where the supply is abundant. Then, again, this moisture from below constantly rises toward the top during drought, by the force of capillary attraction, thus keeping up the supply to those roots nearer the surface. Besides this, it brings with it some elements of fertility in solution, and as the evaporation at the surface goes on, these are left to aid in enriching the surface-soil. Drought may thus improve land which has been properly plowed. 339. Sub-soiling. — The sub-soil plow is designed to follow the ordinary or surface-plow, in the furrow left by the latter. By this means the bottom of the furrow is broken and pulverized, without being turned up. The surface-plow then throws its next furrow upon this loosened portion of the sub-soil ; and, again, the sub-soil plow following, breaks another portion beneath ; and so the process is continued till the whole field has its surface stirred to a depth which cannot ordinarily be reached by any one plow operating alone. One of the simplest and best sub-soil plows is constructed upon the following plan : It has a strong, sharp coulter, extending about fifteen inches below the beam, having a share, or wing, on one side of it, about two-thirds as wide as the share of the surface-plow (Fig. 42, a). The hind part of this share-wing should be elevated about three inches, so as simply to raise the clay, and let it fall back in a pulverized 17* 198 MECIIANICA.L TREATMENT OF SOILS. MECHANICAL TREATMENT OF SOILS. 399 condition behind the coulter. The bar forming the point, should extend backward from the heel of the coulter four or five inches, to give steadiness to the plow, and enable the plow-man to regulate its depth (Fig. 42, h). If the plow is to be worked by two horses, which it gene- rally requires in a stiff soil, one of the horses should walk in the furrow, and the coulter must then run with its share directly behind him. In order to throw the coulter thus more nearly in the track of the furrow-horse, than of the one on the unbroken land, the beam may be made crooked. The accompanying figure will give a good general idea of the parts and structure of this implement. It can be made by any ordinary plow-maker, at a cost of three or four dollars. A straight beam will do, if the point of the coulter is inclined towards the furrow. But the handles are then thrown too far out of the line of draught. 340. Benefits. — The benefits of sub-soiling are very similar to those of deep plowing, already given (§ 338). It opens up a new source of fertility, for the sub-soil always contains many of the substances demanded by the growing crop. It gives a deeper space for the circulation and reten- tion of air and moisture, and thus serves as an antidote to drought. Again, if the soil is level, and of such a character as to retain too much of the water which falls on it, and thus becomes swampy, the broken sub-soil lets it pass ofi" more freely from the surface-soil, and the sub-soiling thus becomes akin to draining. But, on horizontal lands, in case there is still a stratum of impervious clay beneath the broken sub- soil, there will be no outlet for the surplus water, which will then be confined in the level field, as in a shallow basin. In such a case, draining must precede sub-soil plowing, else the latter will be of no avail. If land is level, then subsoiling will be of little service to it, unless it be either naturally or artificially drained. 200 MECHANICAL T R E A T M I-: N T OF SOILS. But one peculiar advantage which sub-soiling has over ordinary deep plowing, is that it gives a deeply-pulverized mass, without exposing upon the surface that portion which is often unfit for such a purpose. If, for example, the sub- soil is a tenacious clay, which would readily form a hard crust on the surface, it had best not be turned up; or if it is of a lighter color than the surface-soil, it would not absorb heat so freely, and would hence be, in that respect, injurious. Sub-soiling need not be resorted to in all cases. In very deep loamy and sandy soils, it is sometimes better to run two ordinary plows, the one after the other, in the same furrow — the second being set deeper than the first. In this way the surface and sub-soils are inverted, to some extent, or, at least, completely mingled • and where the surface has been exhausted by long-continued tillage, its place is thus supplied by fresh soil. This is called " trench-plowing." The sub-soil plow serves a valuable purpose, when run through meadows and grass-lands which have become too compact. The soil beneath the sod is loosened to a great depth, without the sod being seriously broken. This plow may also be used for loosening the earth beneath the roots of corn, or cotton, before the plant has attained any consid- erable size. The Harroio and Cultivator are important auxiliaries to the plow, in reducing the soil to a more completely pulve- rized condition; in mixing fertilizers more entirely with it ; in giving a smooth surface ; and in covering the seeds of some crops. The cultivator is especially useful in stirring the soil between corn-rows, when the roots have become too much extended to allow very deep tillage ; and in covering wheat, when sown broad-cast. The Roller is an important instrument on many soils. Where clods are too hard for the harrow to reduce, the roller DRAINING. 201 affords the best means of crushing them. Wlien very light soils are cultivated in wheat or grass, the roller is frequently wanted to render the surface sufficiently compact. DRAINING. 341. The chief object of draining is to carry off the sur- plus moisture from the soil. In our countiy, especially in the South and West, where land is abundant, it is confined almost entirely to sAvamps, and to such lands as (by their level surface and impervious sub-soil, or tenacious strata beneath) collect and retain stagnant water. Thousands of acres of swamp-lands have by this means been reclaimed from a worse than worthless condition, and rendered ex- tremely fertile; while millions lie yet unreclaimed, in our Southern States, fit now to produce nothing but loathsome reptiles and insects, together with fatal malaria, which often make much of the surrounding country almost unin- habitable. 342. Will/ are swampy lands mfertile? (1) The stagnant water excludes the air, and causes the organic matter so abundantly accumulated to be converted into vegetable acids, such as the humic and ulmic, in large excess, with small but sometimes very perceptible quantities of acetic and tannic acids. Such soils are said to be '^ sour," and produce no- thing but coarse, worthless vegetation. (2) The air is also necessary to keep up the proper chemical activities in the soil, in order to produce the required changes in its mineral ingredients. Stagnant water prevents this, by excluding the air. (3) Swampy lands are cold. Water neither absorbs nor conducts heat so freely as soil ; hence lands covered, or even saturated with water, are not readily penetrated by the heat of the sun. Besides this, the constant evaporation which goes on from the surface of such lands, carries off heat rapidly. 2C2 DRAINING. 343. Draining, then, by admitting the circulation of air, promotes the proper kind of chemical changes in both or- ganic and inorganic substances, and thus sweetens a sour soil ; and, by admitting heat and checking evaporation, brings the ground under the warming influence of the sun. The decay of organic matter, and consequent generation of gases in drained lauds, has the mechanical effect of ren- dering their soils more porous, in a short time after the sur- plus water has been withdrawn. The winter frosts greatly aid in bringing about the same result. As soon as drained lands have become sufficiently dry for the plow, they should be treated with a free dressing of quick-lime or unleached ashes, to neutralize the excess of vegetable acids, and then be broken up to as great a depth as possible, in order to aid the circulation of air. 344. Modes of Draining. — There are two modes of draining in common use. The one by surface (or opai) drains; the other by hUnd (covered) drains. 345. I. The open drains consist (1) of one or more main channels, or ditches, as deep as they can conveniently be made, running through the lowest part of the field. A natural channel often serves the same purpose. (2) The spaces between the main channels are traversed by the smaller drains, leading into these, and situated at distances apart, varying from 25 to 100 feet, according to the nature of the soil. The depth of each cross-drain, if the ground is level, should vary — increasing towards the main channel, in order to give some ''fall" to the water in that direction. (3) The spaces between these have to be cultivated as sepa- rate strips or beds. 346. Advantage. — The only advantage this kind of drain- ing can claim, is its 2^i'<'seiit cheapness. Disadvantages. — (1) It is not a tliorougli method. The drains cannot be made very deep without endangering the D U A I N I N O . 203 safety of horses and otlier animals ; and the soil can only be drained to the depth of the ditches. (2) It wastes land, by occupying considerable spaces which might be cultirated, if the ditches were covered. (3) Heavy rains carry away much of the valuable matter of the soil, through such drains. (4) They are very much in the way of convenient tillage. 347. II. The covered drains. — These are in every respect preferable to those above described. They are constructed by digging deep ditches parallel to one another, and leading into a larger main channel, like the open drains. But, in- stead of being left open, a tube or pipe, formed of tiles, is laid in the bottom to carry off the water, and the ditch then filled up. 348. The following figures, with their descriptions, taken from the ''Patent-Office Reports" for 1856, will give a good idea of the construction of covered drains. " Draining tiles are made of clay, similar to brick-clay, moulded by a machine into tubes, usually 13 inches long, and burnt in a kiln or furnace to be about as hard as what Fig. 43. « a ^ Q' are called hard-burnt bricks. They are of various forms and sizes. Some are round, with a sole or flat bottom moulded with the tile, and are called " sole tiles," as shown in figure a ; others are of a horse-shoe form, open at the bottom, to 204 DRAINING. be laid on the hard bottom of the ditch without a sole, or in soft places with a sole or flat bottom of the same material with the tile, made separate from it, as shown in figure h. For some localities, pipe-tiles, merely of round tubes, as re- presented in figure c, are preferred." The tiles are generally laid end to end, and the water always finds its way in, readily and freely, at the joints. " Where there is danger of displacement, by reason of the soft condition of the ground at the bottom of the trenches, pipe-tiles are often kept in position by means of collars of the same material as the tiles themselves, made loosely to fit over the joint, as represented in the following cut: Fig. 44. c ex '' The size of tiles to be used varies from 2 to 6 inches calibre, according to the quantity of water to be conveyed. It is a question of expediency whether to use very large tiles, or to lay two or more courses of smaller size, side by side, when the flow of water is very great. 349.* "A glance at the following diagrams will give a cor- rect idea of the general process of opening and finishing the drains with the pipes laid : Fig. 45. DRAINING. 205 " Figure o roprescnts a trench cut in clay, ready to receive pipe-tiles; and figure h, a section of the same drain finished. Figure c represents a section of a finished drain, with a sole tile, as usually constructed in common soil." 350. Where stones can he conveniently procured, the fol- lowing method, as described in ''Norton's Scientific Agricul- ture," is cheap and simple. " The ditch should of course be wedge-shaped, for conve- nience of digging, and should be smooth on the bottom. "Where stones are used, the proper width is about six inches at the bottom. Small stones should be selected, or large ones broken to about the size of a hen's egg, and the ditch filled in with these to the depth of niiTe or ten inches. The earth is apt to fall into the cavities among larger stones, and mice or rats make their burrows there ; in either case, water finds its way from above, and washes in dirt and mud, soon causing the drain to choke. With small stones, choking from either of these causes cannot take place, if a good turf be laid grass-side down above the stones, and the earth then trampled in hard. Cypress or cedar shavings are sometimes used, but are not quite so safe as a good sound turf. The water should find its way into the drain from the sides, and not from the top. The accompanying figure (46) represents the arrangement of the stones : a is the turf on top; if the water enters at the sides, h, h, it ^^' ' comes in clear, having filtered through the soil, and deposited everything in the way of mud, which might tend to choke the drain. In very swampy, soft ground, it is sometimes necessary to lay a plank or slab on the bottom of the drain before putting in the stones. This is to prevent them from sinking, and making an uneven bottom, before the soil becomes dry enough to be firm." 18 20G DRAINING. Unbroken stones have been very successfully used in con- structing drains. The method of laying such stones, in ditches, two feet wide at the top and one foot at the bottom, is very clearly stated by Mr. P. Slaughter, in his Premium Essay on this subject, submitted to the Virginia State Agri- cultural Society in 1854. He says : "A careful hand, in choosing suitable stones, places them on each side of the ditch as side walls, treading upon them as he goes along, to be assured that they are firm in their places. A second hand follows, placing flat stones upon these side walls. A third fills the spaces with small stones. Another levels the surface with still smaller fragments, upon which, straw, leaves, grass, of even shavings, are laid in thin layers to ex- clude the earth from remaining crevices." Timbers — even unhewn poles — have been frequcTitly substituted for the stones. Two lines of poles are laid in the bottom of the ditch, and a third over the space between them. These have been found to last many years, and are especially applicable in swamps, where stones or tiles would sink. 351. There are several points to be observed in the con- struction of covered drains. (1) What should be their direction, with respect to the slope of the ground ? If the land is nearly level, the main or cross channel should run along the lowest part of the space to be drained by the small channels, and should have as much fall as possible towards the final outlet of the water from the field. The side drains should run at right angles (or nearly so) to this, with as much fall as can be given them. If the drained land is a hill-side, the large cross drain should run along the base of the hill, but have sufficient fall to carry off water freely. The smaller drains should run directly down the slope into the cross drain. DRAINING. 207 352. (2) How far apart should the drains be placed? This depends upon the nature of the soil.' If the soil is a very impervious clay, it may be best to place them not more than twenty-five feet apart. But if the soil is gravelly or peaty, they may often be separated by a space of 50 or 100 yards. A large field, with a sandy or pebbly sub-stratum, may be drained by a single ditch. In hilly regions, there are frequently very narrow valleys, where the bases of hills come nearly together, form- ing strips of land more or less swampy, or at least too wet to be productive. The meadows in the Valley of Virginia abound in such localities. A single drain, run from end to end along each one of these, would generally make them productive of either good grass or grain crops. Where they are wide, short side drains may be required. 353, (3) How deep should drains be laid '! At least so deep, that the top of the line of tiles M'ill be several inches below the lowest depth to which the sub-soil plow can be made to run. If the sub-soiling reaches fifteen inches, short of which no farmer should be satisfied, and which can easily be attained in a few years, by increasing the depth at each successive plowing, then the ditches should be at least thirty inches. But the great object of draining is to remove the surplus water, and give free access of air to as great a dejith of soil as possible. Hence, if drains can be economically laid at a depth of five or six feet, so much the greater will be their benefit. The roots of crops run to a great depth in soils which are in a proper physical condition to be pene- trated by them, and in a proper chemical condition to give them nourishment. Indian corn has been known to send its roots to the depth of five or six feet. At a place where an opening had been made for the foundation of a house, to the depth of about five feet, and afterwards filled up, a most 208 DRAINING. luxuriant buncli of clover was found growing. I had it carefully dug out, and found the main root extending to a perpendicular depth of forty-two inches. It will generally be found that the tops of plants vary nearly in proportion to their roots, and by furnishing a deep rich soil for the roots, we will ultimately reap an abundant reward from the harvest which they j^roduce. 354. When swampy lands have been drained, they will not generally be at once productive. Time must be allowed for the proper chemical changes to take place, but these changes may be greatly hastened by artificial means. (1) Ploicimj, as soon as the ground is sufficiently dry, will aid in giving the air free circulation, and this we know to be one of the great chemical agencies by which soils are improved. (2) The application of caustic lime, or unleaclied ashes, will help to neutralize the excess of organic acids generally present, and thus sweeten the soil. Draining in clay soils is one of the best preventives of drought. Stiff soils are generally very wet during the winter and spring, and, by their own weight, settle down into a compact mass ; and, although the surface-soil may be broken up and pulverized, the sub-soil may still be left in its com- pact form ; or, if broken up, there will still be a layer below, to prevent the free escape of surplus water. In wet weather the whole will become like a bed of mortar, and will tend to settle down again into its original compactness. Then, in a drought, the small quantity of water, which the few remain- ing pores can hold, will soon disappear. But, if the surjjlus water is let off by drains as soon as it collects, the surface and sub-soils will retain their porous character — the larger pores being filled with air, and the smaller ones with moist- ure, which will be held by capillary attraction, in readiness Jor future drought. QUESTIONS. 209 QUESTIONS ON CHAPTER XIII. § 334. In reducing soils to their proper mechanical condition, what three points arc to be kept distinctly in view? 335. When may mixing soils be adopted ? Best remedy for stiff clay? Best remedy for loose sand? How may the mixing be adopted ? 336-338. Most common means of reducing the soil ? Is the plow indispensable? What connection has its use with the prosperity of an individual, or a people? Repeated plowing? Deep plowing? Its first advantage? Second? Third? IJow docs it cause moisture to circulate ? How docs it increase fertility ? 339, 340. What is the subsoil? Use of a sub-soil plow? Describe the plow represented in Fig. 42. Why is the beam made crooked? What is said of the benefits of sub-soiling? When should draining accompany sub-soiling? AVhat peculiar advantage has sub-soiling over common deep plowing? When is sub-soiling not needed? Use of sub-soil plow in grass lands ? What is said of the harrow and cul- tioalor? The roller? 341-343. The chief object of Draining? To which liind of land is it chiefly applied iu this country? Why are swampy lands itifer- tile ? Influence of stagnant water? How does draining promote circulation of air in tlie soil ? IIow does it render the soil wai'mer? Effect of dccajing.organic matter? What dressing should be applied to drained lands ? 344-340. IIow many ?7!0(fes of draining? Describe the open drains. Advantage of this method? First disadvantage ? Second? Third? Fourth ? 347-350. IIow are covered drains constructed ? How are draining- tiles made? AVhat does Fig. 44 represent ? Size of tiles? Explain Fig. 45. How are drains made with broken stones ? Explain Fig. 4G. IIow have unbroken stones been used? Timbers substituted for tiles ? 351-354. First point to be observed in the construction of drains? Second point? How may narrow valleys be drained? How deep should drains be made? Objects to be aimed at? Depth to which roots run ? Will swampy lands be immediately productive after draining? What means may be adopted to hasten their productive- ness? IIow does draining prevent drought in clay soils? 18* 210 CHEMICAL TREATMENT OF THE SOIL. CHAPTER XIV. CHEMICAL TREATMENT OF THE SOIL. 355. A SOIL may receive all the attention possible, in tlie ■way of plowing, draining, &c., and still not be productive. It may yet lack some of the proper chemical elements neces- sary to supply the wants of the growing crop. By referring back to Tabic III. (p. 12.3), we see that the mineral ingre- dients taken from the soil by different crops are nearly iden- tical in hind, but vary considerably in the j^^oportio^is in which they enter into the constitution of the ashes of differ- ent plants, or different parts of the same plant. 356. That a soil may be fertile for a particular crop, several chemical properties are essential. (1) It must con- tain a sufficient excess of the mineral elements required by the crop, to allow the roots to find an abundant supply within the limited spaces which can be reached by the rootlets. Of course, this would require in the whole mass of the soil, much more of each clement than could be removed by a single crop. (2) The 2^^(^nt-food must he in the proper che- mical and physical condition to he tahcn vp) and appropriated hj the jilants. Silica, in the condition of sand, cannot act as a fertilizer, because of its insolubility; but, in such combina- tions as render it soluble, it is one of the most important elements of nutrition for plants. (3) The soil must he free from an ivjurioiis excess of any of the elements of fertility. Too much magnesia, or even too much carbonate of lime, may be injurious ; as in the chalk lands of England, Avhich are among the least productive of that country. The acids in humus are useful to a certain extent, but in large excess CHEMICAL TREATMENT OF THE SOIL. 211 they become injurious (§ 342). (4) Organic matter is essen- tial to a high degree of fertility. In a soil having the proper mineral elements alone, a plant may come to maturity, and hear seed, obtaining the necessary organic food from the air, through its leaves and roots ; but a full crop cannot be ex- pected in such a case. The soil, to be fertile, must contain both humus and ammonia. 357. The analysis of a soil is not always sufficient to de- cide the question whether it is fertile or not. The per cent of some ingredients taken from the land, by even several successive crops, is so extremely small, that the most delicate chemical tests would barely indicate traces of their presence. Far less than one per cent of phosphoric acid, or chlorine, or potassa, or lime, would be sufficient for all the crops that could be cultivated on a soil for many successive years. Even one-hunched fh of one per cent is more than sufficient to sup-^ ply many crops. But chemical analysis can detect far less than this, and yet not be able to say positively whether the soil is fertile or not for a particular crop ; for the substance may be present in sufficient quantity, but not in the proper condition to be used by the plant. Chemistry is not able, in every case, to say in what combination elements exist in soils, where the proportions are extremely small ; much less has it been able to tell us in what combinations the plant takes up its mineral food. Still, this valuable science has thrown much light upon the relation subsisting between the soil and the crop. Analysis tells us, in the first place, that productive soils always contain the same mineral matter found in the ashes of the plants which grow upon thciu. In the second place, it tells us which elements of fertility exist in very minute quantities, and which in abundance, and then points to the sources from which we may supply those in which the soil is deficient; but it cannot ahvays predict the influence which 212 CIIEIMICAL TREATMENT OF THE SOIL. a particular fertilizer is to have upon the crop to which it ia applied. It frequently tells us, too, when an injurious excess of any substance is present, and what applications are to be made, to counteract the influence of such substance. 858. We shall place side by side, in the following table, the analyses of three soils, difi'ering in quality. The first is fertile for all ordinary crops, without manure. The reason of this will be seen in the presence of an abundance of those substances found in the ashes of plants. The second is a soil Avhich produces well, with the apjilication of gtjpsum (furnishing lime and sulphuric acid) and ashes (furnishi)ig potassa, lime, etc.). The deficiencies in the table are thus filled up. The tldrel is a poor soil, requiring much manuring. Observe in how many ingredients it is deficient. TABLE V. In 100 lbs. of soil. Fertile. ^^■i'.,","'' "'",'.. „""'* Infertile. Fertile ivith ashes and f:ypsum. Organic matter 10.00 5.00 COO Potassa 0.40 0.01 (clef.).... Deficieut. Soda 0.20 0.20 Deficient. Lime 5.90 1.80 0.50 Magnesia 0.80 0.70 0.80 Oxide of iron 2.10 4.10 8.00 Oxide of manganese. ... 0.10 0.30 1.00 Alumina 10.70 25.60 25.30 riiosplioric acid 0.40 0.20 Deficient. Sulphuric acid 0.30 Deficient Deficient. Carbonic acid 5.20 1.40 0.50 Silica 63.90 60.00 58.00 Chlorine 0.02 0.07 Deficient. 359. It will be seen, from the first column of the above table, that even a fertile soil may have but a small percent- age of several ingredients which are absolutely necessary in the production of every crop. No crop, for example, can be be produced without potassa and phosphoric acid ; and yet these form a very small proportion of any ordinary soil. A CHEMICAL TREATMENT OF THE SOIL. 213 single crop takes away but little of any one element of fer- tility; but still, reiDcated cultivation of similar crops for many years, must greatly diminish the supply of those mineral ele- ments found in the ashes of such crops. Every bushel of wheat, every hogshead of tobacco, every ton of hay, and every bale of cotton sold, carries with it a portion of potassa, lime, phosphoric acid, and other mineral matter. Every fatted ox carries with him to market a good many pounds of phosphate of lime, which came from the soil on which his food was produced. 360. If every article of produce sent to market carries with it a portion of the mineral fertility of the farm, this must in some way be restored, else the land must become poor. Some soils may contain all the mineral elements of fertility in such abundance, that even centuries of cultiva- tion would not exhaust them entirely; but such is not gene- rally the case. Some of the fields in the central and north- ern parts of Kentucky, have been cultivated for more than half a century without manure, and are still fertile. Some of the James river bottoms, in Virginia, have been cultivated for more than a century without manure, and still produce well. But we must not draw general conclusions from a few extraordinary cases. The general experience of the world is, that lands become exhausted hy lowj tillage icithout manure. 361. The organic, as well as the inorganic, matter is ex- hausted by improper cultivation. The humus of the soil is decomposed, and gradually disappears; and unless fresh por- tions are supplied from time to time, a deficiency must be the result. The ammonia is still more rapidly exhausted. The natural supply of ammonia in soils is not generally abundant, while its volatility and chemical activity, cause it to be con- stantly escaping, or undergoing changes of form and combi- nation. Hence, we see the necessity for artificial fertilizers. 21-1 FERTILIZERS, FERTILIZERS. 362. A fertilizer is any substance which, ajyplicd to a soil, will preserve or increase its productiveness. 363. From what has been said of the origin of soils, and of their -^^xo^ex p)]ii/sical and chemical condition, we infer that they may demand fertilizers : a. From original infertility. If the rocks* from which the soil is formed have not the required elements of fertility, they must be supplied from other sources, before the land can become productive. Exs. Granite soils generally require lime. Limestone soils are often deficient in potassa. h. From the presence of some substance inncholesome to crops. We have seen that too much water is injurious. The remedy in such a case is draining. Organic acids we have also found to be injurious, when in excess, as is generally the case in swampy lands. c. From exhaustion by long-continued cultivation. The reasons for this have been already given; and we have illus- trations of it in all countries where the lands have been tilled for many years without proper application of manures. d. From too lo)ig application of the same fertilizer. If a soil is deficient in only one or two of its proper elements, and these are supplied, its fertility may be at once restored. But if the application of these same substances alone, be made for several successive years, they will be found in many cases to cease having their former influence, and will appear to prove injurious rather than beneficial. Such has been the case with many a field in the Valley of Virginia, under the influence of oft-repeated applications of gypsum alone. To understand the reason of this, we have only to remem- ber, that, while we are applying one or two elements of fer- *By "rocks" we mean all solid mineral matter wbich, by disin- tegration, helps to form soils. FERTILIZERS. 215 tility to the soil, we are taking away many others. Gypsum can suj^ply lime ami sulphnric acid, but it cannot supply potassa and phosphoric acid. By applying gypsum, then, year after year, we may accumulate a large excess of its own elements, while the soil is becoming poor from the exhaus- tion of something else equally necessary, such as potassa or phosphoric acid. 363. Whether, then, we would enrich a barren waste, neutralize some unwholesome ingredient of the soil, restore exhausted lands, or supply neglected fertilizers, we must re- sort to the proper artificial means. To do this intelligently requires some knowledge of the various fertilizers; their composition, mode of application, influence, etc. 364. Classification. — Fertilizers naturally form two general classes, yforihy 0^ woiQ : (1) Organic manures ; that is, such as have a vegetable or animal origin. Barn-yard and stable manures, crops plowed down upon the soil, guano, etc. come under this class. (2) Mineral manures are such as are obtained from the earth, from water, or by burning out the organic matter of plants and animals. Gypsum, common salt (NaCl), ashes, and bone-earth are examples of mineral manures. We may with propriety subdivide organic manures into : (1) Those which, by their decay, produce chiefly Immus. These we shall c^Al ^'•liumlfcrous." * (2) Those which, by their decay, produce much ammonia, we shall call " ammo- nifero^is." * Illustration. — When leaves, straw, and such like substances decay, the product is chiefly humus; hence, these are hunii- ferous. When the flesh and urine of animals decay, they * So far as I know, these terms have not been employed before ; but every student of Agricultural Chemistry will see, at once, that they are needed in our vocabulary, conveying ideas vrhich could not be otherwise expressed without circumlocution. 210 FKRTILIZERS. set free large quantities of ammonia; liencC; these are am- moniferous. 365. Influence of Organic Manures. — They increase the supply of organic matter in the soil, and generally have a ftivorable influence on both its mechanical and chemical condition. (1) If the soil is a stiff clay, the particles of humus, mingling with the particles of clay, prevent their forming a cohesive mass. The soil being thus rendered more loose and porous, is more easily cultivated, absorbs and retains moisture better, and is more easily penetrated by the roots of plants. The carbonic gas set free during the decay of humus, no doubt aids in rendering soils porous. The gas being liberated in all parts of the soil, as it is throughout a loaf of bread, becomes entangled among the particles, and forces them asunder. (2) The increase of organic matter gives a darker color to the surface, and thus renders liicarmer and earlier. This influence may be readily perceived, by observing how much more quickly corn, or other grain, ger- minates in those parts of a field where the soil is darkened with humus, than it does where the surface is lighter in color. In such places the crop generally starts more promptly, and at first grows more rapidly, but often fails to be as heavy in the end as that which started more slowly ; because, while the soil is in a bettter physical condition, its chemical con- dition may, in some important particulars, be less favorable. 366. (2) Organic manures improve the cJicmical condition of the soil, by keeping up the supply of humus, which be- comes gradually exhausted by repeated tillage. The humi- ferous manures do this in part ; but it may, to a great ex- tent, be accomjilished by the roots and stubble left upon the ground. The other class of organic manures — the ammoni- ferous — are still more important. Reasons have been already given for the rapid disappeai'ance of ammonia from the soil. It is also true of all ammoniferous compounds, that they un- FERTILIZERS. 21T dergo spontaneous decay with great rapidity, under the in- fluence of air, moisture, and heat ; and are, hence, not very durahle. They must, therefore, be frequently applied. Then a supply of such substances being essential to the vigorous growth of almost every valuable crop, we readily perceive their great value. In fact, the value of organic manures may be estimated chiefly by the quantity of ammonia they are capable of yielding. 367. (3) Besides furnishing organic food in the form of carbonic gas, the acids of the humus combine with liberated ammonia in the soil, and prevent its escape ('' fix it"). Such compounds, being soluble, are probably absorbed directly by the roots of the crop, and yield both carbon and nitrogen compounds to the sap. These are afterwards elaborated in the leaf, and fitted to promote the subsequent growth of the the plant. A proper admixture of humus, by fixing ammo- nia as it is generated, makes the influence of ammoniferous manures more durable than they would otherwise be. 368. (4) The organic manures do more than simply supply organic food to crops. They bring back much of the mine- ral matter which they have previously collected from the soil. They return this, too, in the form best adapted to meet the wants of the plants to be nourished ; for they have already been subjected to the modifying influence of vitality in one set of plants, and will most probably require very slight changes to adapt them to another set. Reasoning from analogy, we may conclude that plants take up most readily those substances having the form required in their new com- bination. The phosphates from the stable and the barn-yard are certainly in a better condition to nourish a crop of wheat or tobacco, than is the phosphate of lime in bone ashes. 369. Forms of IIumiferous Fertilizers. — (1) Dri/, undecayed vegetable substances, in the form of straic, corn- stalks, forest leaves, etc. are often plowed down into the soil. 19 218 FERTILIZEKS. These gradually undergoing decay, produce a fresh supply of humus. From a little albuminous matter which they usually contain, a small portion of ammonia is also generated. The decay of such substances is slow, and hence an imme- diate effect is not to be expected; but the ultimate influence is always beneficial, unless there is already an excess of or- ganic matter in the soil. If straw, leaves, etc. are thrown up in heaps (compost heaps) with other substances, such as the scrapings of stables and barn-yards, which will hasten their decomposition, and allowed to lie in that condition until partial decay has taken place, their benefit to the soil will be more immediate. After the process of decay has commenced, it will continue to go on rapidly in the soil ; and there will be less loss from the escape of volatile matter, than if the decay is completed in the heap. 370. (2) Green Crops, plowed down into the soil upon which they have grown, make one of the cheapest, as well as most efficient, means of enriching land. They possess Beveral advantages over dry substances of similar charac- ter. In the first place, they are already spread upon the soil, without the inconvenience of hauling. Secondly, they decay more quickly, and sooner become food for other crops. Thirdly, they contain a larger quantity of ammoniferous matter. The albuminous substances gradually diminish in the stalks and leaves of plants, as they approach their period of decay, or as their seeds ripen. In this country, clover, grasses, buckwheat, peas, oats, and some other crops, are plowed down as green manures; but of all these, clover is probably the best, especially on lime- stone lands. Clover not only produces a good crop above the surface, but it produces one still more valuable beneath, in the form of roots. The large, fleshy roots of the clover, as they decay in the soil, yield both humus and ammonia, in considerable quantities. Peas are, perhaps, next in value. FERTILIZERS. 219 The increase of organic matter added to the soil, by plow- ing down crops, comes, of course, from the air. Carbonic acid and water are taken in by the leaves and roots, and converted into vegetable tissues, which by their decay be- come hnnius; while ammonia, collected from the air, forms the albuminous parts of the plant, and these again generate ammonia in the soil. Such roots as run deep, like those of clover, bring up mineral matter from a considerable depth, and accumulate it near the surface, so that it becomes more available for the use of other crops. This is an advantage, arising from this process of manuring, not to be disre- garded. Sub-soiling aids in this elevation of the mineral ingredients of the soil, by allowing the roots to descend "to a greater depth. There are some soils too light, or too far exhausted, to produce clover or grass, which will produce buckwheat or peas. By planting and plowing down a few of such crops as these, the land may be greatly recruited, and may afterwards be treated with clover, if desired, in order to give it still greater fertility, or to keep it up to its improved condition. 371. (3) Peat (the half-decayed vegetable matter col- lected in swamps), when thrown up in heaps, and exposed to the air for some time — when mixed with lime or ashes, and applied to the soil, is a valuable source of humus; and when dried and thrown into stables and barn-yards, it forms one of the best means of absorbing the liquid parts of animal manures, and of fixing their ammonia. The spent-bark of tanneries, the scrapings of wood-yards, and the muck formed in forests by the decay of leaves, may all be treated in the same way. Charcoal and soot (finely-divided carbon) im- prove the physical condition of clay soils. 372. Forms of Ammoniferous Manures, and best Means of preserving them. — These are chiefly of ani- mal origin, consisting of the excrements of animals, and 220 FERTILIZERS. such refuse niattev as accumulates about slaugliter-liouses and fisheries ; also the ammoniacal liquids of gas-works. The reasons for attaching a high value to manures of this class, have been given (§ 366) ; but to impress a matter of so much importance still more deeply upon the mind of the reader, the following paragraph is given from Norton. " Manures containing nitrogen in large quantity ai"e so exceedingly valuable, because this gas is required to form gluten, and bodies of that class, in the plant : this is parti- cularly so in the seed, and sometimes also in the fruit. Plants can easily obtain an abundance of carbon, oxygen, and hydrogen from the air, the soil, and manures. Not so with nitrogen. They cannot get it from the air [in its free form] J there is little of it in most soils ; and hence manures which contain much of it produce such marked effect. Not that it is more necessary than the other organic bodies, but more scarce, at least in a form available for plants." 373. Excrements. — Under the term " excrement," we shall include both the fseces and urine of animals. The fseces, or solid excrements contain : (1) Some portions of proteine compounds, which soon undergo putrefactive decay, and set free ammonia. The quantity of ammonia from this source, except in the faeces of hogs, is but small, compared with that from the urine. (2) Vegetable fibre iu considerable quantities, being the undigested portions of the food. This is an abundant source of humus; and on account of its predominance over that portion which forms ammonia, the fo3ces might with propriety be classed as humiferous manure. (3) Portions of mineral substances from the food, too valuable to be overlooked, are found in solid excrement. Among these, the most abundant are those which are least soluble, such as the phosphates of lime and magnesia. 374. Urine contains about twice as much ammoniferoua matter as the same wciuht of fajccs. 'J'hat of horses and FERTILIZERS. 221 sheep is especially rich in ammonia. Some farmers are sufi&- eiently careful not to lose the solid portions of the manures of their stables and yards, while they take but little pains to make provision for having the liquid portions absorbed, and thus preserved. They may not be aware that a pint of urine from a horse is equal in value to at least three pounds of his solid excrement. The next most valuable ingredients of urine are the salts of potassa and soda. These being soluble, naturally pass more readily into the urine, while less soluble phosphates are car- ried oif with the solid excrements. There are several advantages arising from having these two forms of excremcntary matter mixed. Fii'st, it gives a pi-oper supply of both humiferous and ammoniferous sub- stances. Secondly, it gives the necessary variety of mineral matter — phosphoric acid, silica, lime, and magnesia from the fasces, with suli)hurie acid, chlorine, and the alkalies, from the urine. Thirdly, the presence of ammoniferous matter causes rapid fermentation, and consequent decomposition of the humiferous matter; and the whole mass is thus more quickly brought into the proper state to furnish nutriment for the crop. 375. Fixing Ammonia. — During the fermentation of a mixed mass of animal manure, large quantities of ammonia escape in the form of a volatile carbonate. This must result in great loss of value, unless the escaping substance can be arrested, and rendered^ involatile (''fixed"). It becomes a question, then, of the highest importance to the farmer, how this can best be done. Before we consider the properties of the different kinds of animal manures, we must examine a little more fully the chemical relations between ammonia and certain means which may be employed for its preserva- tion (§ 71). and the principles upon which this preservation depends. 19* 222 FERTILIZERS. 376. Arresting Fermentation. — What is usually termed "fermentation" in heaps of organic manures, is a form of spontaneous combustion, which takes place most readily and most rapidly in a mass of matter containing con- siderable quantities of ammoniferous compounds. The con- ditions necessary to this decomposing process are (1), a temperature not below 45° ¥.; (2) the presence of a consi- derable amount of moisture ; (3) a full supply of air. The chief products are carbonic acid gas, water, and ammonia, which are volatile; and humus, which is involatile. The rapidity of the fermentation (after the three conditions above mentioned are fulfilled), depends upon the accumulation and retention of the heat always developed by the process. When the chemical changes commence in a moist mass of manure, which is sufficiently porous to admit the air, the result is similar to that which follows the igniting of a mass of com- bustible material; while the combustion increases the heat, this increase of heat makes the combustion still more rapid. But if the burning material is spread out, so that the heat will be dispersed, the rapidity of the process is greatly checked. So, if a mass of fermenting manure is spread over a wide surface, the accumulation of heat is prevented ; and if the weather is dry, the moisture is evaporated, and thus two of the conditions aifecting the rate of fermentation are partially removed. Hence we see how sjyreading manure iqwn the surface of land, may to a great extent arrest the fermentative process, and thus prevent the escape of the most valuable of its con- stituents — ammonia and carbonic acid. When manures are hauled out and scattered during the Fall and Winter, upon clover and grass, or as preparatory to Spring crops, there is but little danger of serious loss, except from washing rains, which may run over the surface, and carry oif the soluble portions of the manure. The extent of the risk in this re- FERTILIZERS. 223 spect must be judged of from the steepness of the land and the structure of the soil. If the weather of Winter is favorable to the removal of stable and yard manures as they accumulate, the cheapest, and ordinarily the most convenient way of preserving them, is to spread them as soon as possible upon the fields for which they are designed. This plan is especially applicable to porous lands which are not very steep. The rain then carries the soluble portions down into the soil, while the fer- mentation of the insoluble portions goes on but slowly, and the loss of ammonia is but trifling, compared with what it would have been in heaps; unless the heaps had been treated with some of the absorbents of ammonia hereafter to be mentioned. For something more on this subject, see § 430. 377. Plowing Down. — If it is found convenient to apply animal manures to the soil as soon as they are collected, they may at once be spread upon the land, and buried with the plow, provided a crop is to be planted very soon. The fer- mentation then goes on beneath the soil; and as the volatile matter (of which the ammonia is the most valuable part) arises, it is absorbed by the clay, the humus, and the mois- ture, with which it immediately comes in contact, and is soon found by the roots of the crop. The fertilizing action is slow in this case, but is long continued ; and the eifects are often more marked in the second crop, than in the one imme- diately following the application of the manure. An illus- tration of this is very common where farmers are in the habit of applying to their corn crop, in the Spring, the fresh ma- nures collected during the Winter. Such manures are un- fermented, and frequently have no great influence upon the corn crop ; but if the corn is followed by wheat, the eff'ects of the manure upon it are very conspicuous. 378. It is not always convenient to apply manures to the soil as soon as they are collected ; they must, therefore, re- 22-1: FERTILIZERS. main for some time in heaps, subject to fermentative decay. By this decay their action is rendered more prompt, and the farmer can sooner reap their beneficial effects ; but to prevent serious loss, something must be mixed with the fermenting mass to fix the ammonia. The following are some of the best substances to be used for this purpose. (o) Clay and humus, either separately or mixed, have the property of rendering large quantities of ammonia involatile. Clay alone is generally too tenacious to be conveniently mixed with manures ; but when mingled with a large quan- tity of decayed vegetable matter, it forms a rich mould which may be conveniently used in compost heaps. Humus, under the form of peat, muck, etc., contains organic acids which readily combine with ammonia, forming involatile compounds. Qj) Gypsum is valuable as an absorbent of ammonia. Its action is chemical, and has been given in § 71, which the student is requested to read in this connection. (c) SuJpliate of iron (copperas) acts in a manner similar to gypsum. It gives up its sulphuric acid to the ammonia, forming an involatile sulphate of ammonia., while the iron becomes first a carbonate, then an oxide. The copperas must be applied in solution. One pound to four gallons of water is sufiicient. It may be sprinkled over the difiierent portions of manure as they are thrown upon the heap, or sprinkled over the whole before it is thrown up. (cT) Acids. — Sulphuric and muriatic acids both have a strong afiinity for ammonia. If either of them be diluted with twenty parts of water, and sprinkled over a fermenting manure heap, the escape of ammonia will be at once arrested in every part of the mass to which the acid liquid has access. (e) Caution. — Avoid the use of caustic lime with all ma- nures containing ammonia. It will expel ammonia from any and all of its compounds. Sulphate of lime, on the other hand, is beneficial ; carbonate of lime has no effect, while QUESTIONS. 225 caustic lime is ruinous when mingled with ammoniferous fer- tilizers (§ 100). Such a mixture may still possess consider- able value, and often produces decidedly beneficial effects upon growing crops ; but this benefit is independent of the presence of ammonia, and is to be attributed either to the lime, or to such organic matter as the lime has not removed. These circumstances sometimes lead farmers into the mistake of supposing that stable and yard manures are improved by the lime, while in reality the most valuable ingredient has been exjielled from them. QUESTIONS ON CHAPTER XIV'. § 355. Why may a -well-plowed soil still be unproductive ? What do we learn from Table III ? 356, 357, 358, 359, 360, 361. That a soil may be fertile, what is the first property required ? Why ? Second property required ? Illustrate. Third? Example? Fourth? What forms of organic matter must a fertile soil contain? What is said of atiali/sis of soils? What relation does it show between the ashes of the crop and the soil ? What does Table V illustrate ? Explain it. Is a large per- centage of every mineral ingredient necessary? AVhat does every article sent to market carry with it? What effect will this ultimately have upon the soil ? May not soils be cultivated for many years without manure? What does general experience decide? AVhat becomes of the organic matter of soils? Which escapes most rapidly ? 362, 363. What is a fertilizer? First cause which renders fertili- zers necessary ? Second? Remedy? Third? Reasons? Fourth? Explain this. Knowledge required on this subject ? 364. lloyr ATQ fertilizers classified? Organic manures? Mineral manures ? Illustrations ? Subdivisions of organic manures ? Illus- trate each. 365, 366, 367, 368. Influence of organic manures? How do tliey influence a stiff clay ? Explain. IIow do they render a soil warmer? Illustrate. How do they improve the chemical condition ? Why must ammoniferous substances be frequently applied ? How does humus fix ammonia? What mineral substances do organic manures add to the soil ? 22G QUESTIONS. 3G9, 370, 371. First forms of humiferous fertilizers? How do they form humus? Influence of stable manures upon humiferous mat- ter? y^^hsii of green crops? Their first advantage ? Second? Crops most commonly ploughed down? Which are most valuable? How do they increase the organic matter of the soil ? Influence on the mineral ingredients? What is peat? How does it form humus? Spent-bark ? 372, 373, 374. Chief source of ammoniferous manures? AVhy are these so highly valued ? What are included under the term " excre- ments " ? First constituent of fceces ? The second ? The third ? In what does urine abound? Best from what animals? Illustrate its value. What minerals does it contain? Should humiferous and ammoniferous manures be mixed ? The three reasons given ? 375. What is meant by ^^ fixing" ammonia? AVhy is it important? 376, 377. Explain fermentation in manure heaps. First condition necessary? second? third? What are the products? What deter- mines its rapidity ? How does spreading check it ? How does spread- ing imxnwvQ preserve it? When is there danger of loss from washing? What generally becomes of the soluble matter of manures spread oa the soil ? What is said of plowing down manures ? What then be- comes of the ammonia ? Is the fertilizing action rapid ? How illus- trated ? 378. Why must manures be sometimes thi-own in heaps? What advantages from this ? What of clay and humus, as means for fixing ammonia? Of gypsum? How does it act (§ 71) ? Sulphate of iron? How applied? How does it act ? What acids are mentioned? How applied ? What caution is given ? Do the sulphate and carbonate of lime act like caustic lime ? Into what mistake do farmers some- times fall ? SPECIAL MANURES. 227 CHAPTER XV. SPECIAL MANUKES. 379. The stable manure collected from the stalls of horses, is highly valued by all farmers. But the readiness with which it undergoes fermentation, and sends off ammonia, together with its abundant supply of soluble organic and mineral matter, makes it necessary to exercise care in its collection and preservation, so as to avoid loss. The urine must be kept from running off. (1) This is sometimes done by keeping the horses on close plank floors, sloping backward from the trough. At the lower edge of the floor, a trench or gutter is so constructed as to receive the liquid. This trench is kept constantly supplied with some absorbent substance, such as dry peat, muck, or spent- tan, which will take up the fluid, and, during the subsequent decay, will fix the volatile part, and prevent its loss. A little gypsum strewed in the trench every day, would make the preservation of the ammonia more certain, and also add to the value of the manure. The trench should be cleaned out, and filled with a fresh supply of the absorbent very fre- quently. (2) Another method is to have a firm clay floor (which is better for the feet and legs of horses than a plank floor), and to keep it well supplied with litter of straw, leaves, muck, etc., which will absorb the liquid part of the manure. The wet portions of the litter should be removed every morn- ing, and, as they are thrown out into the manure-shed, should have a little gypsum, humus, copperas-water, or other absorb- ent, sprinkled over them, to arrest the ammonia, which will begin to escape in a few hours. 228 SPECIAL MANURES. 380. It must never be forgotten by the farmer, that how- ever well he may succeed in rendering the most valuable portion of his compost, or manure heaps involatile, it is still very soluble ; and evei'y rain which passes through the mass, carries off much of its value. The loss sustained on many of our farms, in two or three years, by exposure of manures to the influence of rain, would, if saved, be quite sufiicient to cover the cost of a few sheds, which would shelter all the manures of the farm for twenty years or more. The labor of collecting the manure from cattle-pens into sheds, is, perhaps, generally too great to make that an eco- nomical method of preserving it. Whenever this is the case, it should be hauled out and spread upon the soil, before it undergoes fermentation, and before its soluble ingredients have been washed away by the rain. 381. JExcremcnts of coivs, sheep, and hogs require no less care for their proper preservation than those of horses. Simi- lar means may be adopted. The urine of cows is not much inferior to that of horses in value. That of sheep is more valuable than either; while that of hogs, though abundant, is less valuable than any of those above mentioned, but still too important to be neglected. Of all domestic animals, the hog gives the most valuable solid excrement, which compen- sates for the want of value in his urine. The solid excre- ment of the sheep is next in value; then that of the horse stands next; while that of the cow is inferior to either. Still, all are sufficiently useful to be worth preserving. 382. Human Excrement requires special attention : (1) Because of its high fertilizing value ; and, (2) Because of the little regard paid to it by the majority of families. When compared with the exeremcntary matter from other animals, that of man stands above all, except perhaps that of well-fed sheep and fowls. The urine has a much higher value than the faeces. " Very accurate analyses have shown that the SPECIAL MANURES. 229 amount of urine contains double the quantity of phosphoric acid, four times as much azotizcd [ammoniferous] substances, and six times as much alkalies and alkaline salts, as the solid faices. Hence, therefore, it follows that the former possesses a far higher value than the latter, and deserves to be most carefully collected " From the preceding observations it may be incidentally perceived what an immense capital is lost in large cities, where the greater proportion of urine runs into the sewers and drains." — Stockhardt. Arrangements may easily be made about every country dwelling for the careful collection and preservation of this valuable kind of fertilizing matter. The simplest methods are, to have, in the first place, a compost heap of vegetable mould, the scrapings of wood-yards, &c., at some convenient place, under shelter, upon which all the slop from chambers may be thrown. Let the heap receive occasionally a fresh layer of material, and a free application of gypsum. This will keep down all disagreeable odor. Then, in the con- struction of privies, let the vaults be above ground, large, and so arranged that they can be kept constantly charged with such absorbent substances as are used in the above compost heap. This should be renewed frequently, and what is removed from time to time be thrown upon the compost heap. A little dilute acid, copperas water, or gypsum, should be applied to the vaults frequently, to keep down unpleasant odors and preserve ammonia. 383. GrUANO. — This fertilizer, which is now so extensively used, is the excrement of birds which feed chiefly upon fish, and have their habitations upon rocky, desolate islands and coasts. It has been stated (§ 217) that the urine of birds is solid. Guano, then, is a mixture of the urine and faeces of birds. From the quality of the food upon which these live, we would naturally expect to find in their excrements large 20 230 SPECIAL MANURES. quantities of ammoniferous compounds and phosphates. Ana- lysis shows that these are the most abundant and most valu- able ingredients of guano ; while experience proves that the most valuable varieties are those which contain the largest per cent of salts of ammonia. The best guano is found in localities where rain seldom falls — where the ammonia salts have not been washed out. Parts of Peru, and the islands lying along the coast of that country, are seldom visited by rains. Here immense beds of guano, which must have re- quired thousands, and probably tens of thousands of years for their accumulation, are found in great numbers. The deposits of guano are vast stores of ammonia, which a kind Providence has been treasuring up through many centuries for the use of man. While the rivers have been carrying off the ammonia from the land in vast quantities, either in solution or in the form of dead animals and insects, the sea- birds have been bringing it back in the form of fish ; and thus we have another of those compensating arrangements, by which the balances of nature are kept properly adjusted. The reader must be struck, too, with the analogy between these deposits of agricultural wealth, and the great deposits of mineral wealth laid up in past ages, in the extensive coal- beds found all over the world. In Peru and her adjacent islands, there are supposed to be many millions of tons of this rich fertilizer yet undisturbed. The African, Chilian, and Mexican guanoes are not so valuable as the Peruvian, because of their having been more exposed to rains. 884. The following table gives about the average compo- sition of several varieties of guano. SPECIAL MANURES. 231 TABLE VI. In 100 parts of Guano are found Peruvian. Chilian. African. Water 9 12 20 Salts of Ammonia and other organic matter 60 50 38 Phosphates 20 28 26 Salts of Soda and Potassa 5 6 10 Carbonate of Lime .^ 4 2 3 Sand and Clay 2 2 3 100 100 100 385. The ammonia of guano is combined chiefly with or- ganic acids, such as the uric and humic, forming urate and humate of ammonia. These, by exposure to air and moist- ure, are gradually converted into the volatile carbonate of ammonia, the presence of which is readily perceived on opening a bag of Peruvian guano. Hence, if it is to be kept on hand for some time, a dry, close place is best for its security. 386. Application. — In applying a manure so costly as guano, the greatest economy should be carefully studied. All real economy in such cases, consists in such management as will realize the largest income from the least expenditure of money and labor. The economical use of guano demands, (1) the application of the smallest quantity required to accomplish the object in view; (2) such treatment of it as will secure it against loss, either before or after it is applied; (3) a judicious regard to the ultimate improvement of the soil. The quantity varies with the quality of the soil, and the kind of crop. For wheat and corn, from 100 to 300 pounds per acre is generally a sufficient quantity ; but every farmer should decide questions like this for his own soils, by nume- rous experiments. Small quantities may often be most eco- nomically used, by being mixed with other manures. This is especially the case where the guano is to be brought di- rectly in contact with the seeds in the soil. But the labor of mixing thoroughly is, in many cases, greater than the advantages Grained. 232 SPECIAL MANURES. The most common method of applying guano to wheat, is to sow it upon the wheat, and harrow or plow both into the soil together; or, when the wheat is drilled, to drill the guano with it. To make such applications safe to the grain, very minute portions only must be allowed to come in con- tact with each separate grain of wheai?^ When applied in the hill with corn, cotton, potatoes, or any other crop, it is best to '* dilute " it with other substances. The following general directions may be of use to guide the young farmer to successful experience. 387. (a) As soon as the bags are opened, the lumps should be carefully pulverized by the use of any convenient instru- ment, such as a pestle with a broad base. To separate such parts as may not be fully reduced to powder, a sieve may be used. This should be done just before it is to be applied, so that it may not be long exposed. If the lumps are very hard, it is best to moisten them, and let them lie in a heap several days. (6) When the guano is to be mixed with something else, some form of humus, or rich vegetable mould, serves well for this purpose. Spread a layer two inches deep, of moist mould, upon a floor of boards or earth, and over this a layer of guano half an inch or an inch thick, with a free sprink- ling of plaster. Then add another layer of mould and an- other of guano and plaster, in the same order, until as much has been employed as is wanted for use. Mix the whole mass carefully with a shovel ; or, if a more perfect mingling is desired, pass it through a coarse sieve. Such a mixture preserves the guano, and puts it in a good condition to be applied to almost any crop. * A conveuient method of moistening the hiraps, is to dip the un- opened bags into a large tub of hot water for 5 or 10 minutes, and then lay them up in piles, or stacks, for two or three days, till they arc thoroughly penetrated by the moisture, and incipient fermenta- tion takes place. This will relax the lumps completely. SPECIAL MANURES. 233 (c) The effects of guano have been found to be more ener- getic, when it is dissolved in dilute sulphuric acid. About twelve or fifteen pounds of acid, and ten gallons of water, poured upon 100 pounds of Peruvian guano, would decom- pose the organic salts of ammonia, and form the sulphate of ammonia, which is a most energetic fertilizer; and, at the same time, another portion of the acid would so act upon the phosphate of lime present, as to convert it into the more soluble super-phosphate (§§ 395 and 406). (rZ) In whatever condition guano may be employed, it should be thoroughly incorporated with the soil. This will tend to preserve its ammonia, and will so distribute its par- ticles, that some of them will be found by the roots of the crop in every part of the soil. 388. Action of Guano. — Some formers say that guano, while it produces fine crops for a few years, ultimately ex- hausts the soil. In the opinion of many, this results from a kind of stimulating influence which it produces upon plants, causing in them a kind of artificial or forced growth, by which they take away from the soil more fertilizing matter than the guano has brought into it. This influence has been compared to the influence of alcohol on the human system. But, as guano contains nothing which is not an appropriate article of nutrition for plants (real food), such a comparison is rather absurd. It has also been satisfactorily shown, that an ordinary application of guano gives more mineral matter to the soil than the resulting crop takes away,* at least so far as some of the mineral ingredients are concerned. But when we remember that guano continues its influence through several successive crops, the quantity of some of the mineral substances of the soil may, in the meantime, be diminished more than they have been pre- * See Dr. P. B. Pendleton's "Essay on Guano." — Proceedings of Virginia State Agricultural Society, Vol. III., p. 39. 20* 234 SPECIAL MANURES. viously increased by the guano. This is especially true of potassa, lime, and sulphuric acid. In such cases, the long- continued application of guano to some soils may exhaust their supply of mineral fertilizers, at least the supply of those in the proper condition to be taken up by the roots of plants (§ 356). The long-continued application of guano exhausts the humus of the soil. While guano has an excess of ammonia, it has but little humiferous matter in it; and, while the caustic character of the ammonia hastens the decomposition of humus already present, the loss is not made up from the guano. But if we mix with it leached ashes, plaster, and humus, there can be but little danger of injury ever resulting from its application ; while a corresponding im- provement will be the general reward. 389. The best method of using guano for the permanent improvement of soils, is to employ it in connection with green manures. It greatly increases the growth of clover, peas, &c. ; and when these crops are plowed down, they not only carry back with them the mineral matter of the guano, but add largely to the supply of humus and ammonia in the soil. The guano thus has the power of causing plants to convert the carbonic acid and water of the air and soil into humife- rous compounds, much more rapidly than they would have done if the guano had not been applied. It also causes the same plants to thrust their roots more deeply into the sub- soil, and thus bring up an increased supply of mineral matter in the proper condition to feed succeeding crops. 390. A great deal of swindling has been practised in the sale of guano. The best safeguard against being imposed upon, is to buy only from i-cUahle men, regularly engaged in the business of selling it. But in case the quality is sus- pected, one or two simple tests may be useful in removing or confirming suspicions. Exps. — Burn 100 grs. to ashes in a ANIMAL COMPOUNDS. 235 crucible, or iron spoon. The remaining ashes should not weigh more than from 35 to 45 grs., and should be nearly all soluble in dilute muriatic acid 2. Hub a little of the guano with a few grains of freshly-slacked lime, and if a strong odor of ammonia is not given off, the quality is not good. 391. Domestic Gnano may be collected about hen-roosts, and, although not equal in value to the same weight of the Peruvian, it is still the most powerful fertilizer produced upon our farms. It should be carefully collected, and treated in the same way as guano. ANIMAL COMPOUNDS. 392. The refuse of slaughter-houses and fisheries consists of blood, entrails, hair, and other animal compounds, all of which contain the elements of ammonia in large quantities, and also a considerable amount of soluble mineral salts. Hence they possess a high agricultural value. They should be mixed with humus, and kept under shelter till they can be applied to the soil. If an animal dies on the farm, it may be made less offensive by being buried in a mass of humus and clay, which will soon be highly charged with ammonia from the decaying animal, and will serve to enrich some poor spot on an adjacent field. Fish are caught in many places, and used for manure. They soon decay, and set free ammonia abundantly. Insects of various kinds make their habitations in the soil. By eating vegetable substances, they help to collect and con- centrate the ammoniferous portions of their food ; and when they die, their remains add something to the fertility of ground in which they are buried. 393. Bones yield ammonia by the decay of their gelatinous substance (§ 204), which makes them a valuable source of this important element of fertility. We have also learned 23G A N I M A L C O JI I' O U N D S . that their mineral part is chiefly phosphate of lime, which is well adapted to almost all ordinary crops. 394. Value. — Bones, when dried and ground to powder without burning, are inferior only to good guano, in agricul- tural value. They yield about half as much ammonia, about f7cice as much phosphoric acid, and about three times as much lime. Hence, their value in the form of bone-dust is more than half that of guano. When applied alone, their effect is much slower than that of the guano, but much more durable. This is owing to the fact that the gelatine undergoes decay more slowly than the ammonia salts in guano. In fact, the ammonia of the latter is already, to a large extent, ready to afford food for the plant, while the ammonia of the former is yet to be gene- rated from the decaying gelatine. The phosphate of lime, too, seems to require thne to adapt it to the nutrition of crops (§429,.). 395. If bone-dust is treated with an excess of sulphuric acid, the phosphate gives up a portion of its lime to the acid;, forming sulphate of lime, and a superphosphate of lime is thus left, which is much more soluble than the ordinary bone-earth, and is hence a much more energetic fertilizer. The gelatine of the bones is at the same time reduced to a pulpy mass, which soon undergoes decay in the soil, and generates ammonia. While the gelatine is not injured, the phosphate is greatly improved by being thus treated. 396. Preparation. — " To every 100 pounds of bones, about 50 or 60 of acid are taken ; if bone-dust is used, from 25 to 45 pounds of acid are suflBcient. The acid must be mixed with two or three times its bulk of water, because if applied strong it would only burn and blacken the bones, without dissolving them. " a. The bones are placed in a tub, and a portion of the previously-diluted acid poured upon them. After standing ANIMAL COMPOUNDS. 237 a day, another portion of acid maybe poured on; and finally, the last on the third day, if they are not already dissolved. The mass should be often stirred." " h. Another good way is to place the bones in a heap, on any convenient floor, and pour a portion of the acid upon them. After standing a day, the heap should be thoroughly mixed, and a little more acid added : this is to be continued so long as necessary. It is a method which I have known to prove very successful Application. — '' A convenient method, in most cases, is to thoroughly mix the pasty mass of dissolved bones with a large quantity of ashes, peat-earth, sawdust, or charcoal dust. It can then be sown by hand, or dropped from a drill-machine. Two or three bushels of these dissolved bones, with half the usual quantity of yard manure, are sufficient for an acre."— Norton. Some who have tried this method, contend that it will not succeed well, unless the bones are first broken into fragments, then boiled in water — the sulphuric acid being added while the water is still hot. The bones and boiling water must be thrown together into a large wooden vessel before the acid is added, as the acid would rapidly corrode the kettles used in the boiling process.* * " To DISSOLVE Bones. — If no mills are accessible, bones may be dissolved in sulphuric acid. For 100 pounds of bones take about 30 pounds of acid (2 gallons), and mix with it say 32 pounds of water (4 gallons). First put the water into a strong wooden-hooped cask or barrel, and add the acid slowly, stirring it, as added, with a stick. Crack the bones or not, as may be convenient, and put them in and above the fluid. Punch them down, and stir them occasionally with a stick. Let them stand four, six, or eight weeks, until softened and mostly dissolved. Many assert that they cannot dissolve whole bones, but they do not take time enough. From repeated trials, we know they ivill dissolve. The time will depend upon the dryness of the bones, and their freedom from fat. After standing two months, 2S8 MINERAL FERTILIZERS. MINERAL FERTILIZERS. 397. While the mineral fertilizers are less important thaa the organic, they still serve valuable purposes on many soils. A soil may contain even a large excess of some mineral sub- stance required by a particular crop, and yet that crop be benefited by the application of that same substance under some other form. Granite soils, for example, contain potassa in abundance, and yet the productiveness of these soils is generally increased by the application of potassa in any solu- ble form. The reason of this is obvious : the potassa of granite is locked up in its insoluble mica and feldspar. In hornblende granite (syenite) there is an abundant supply of lime, potassa, and silica. Now, these are the chief ingre- dients of value in ashes, but these soils are generally very much benefited by the application of ashes alone. The sye- nite yields its mineral matter but slowly, in a soluble form ; while the ashes supply the same ingredients, just ready for the plant. 398. Besides providing food directly for the crop, the mineral fertilizers often exert a beneficial influence upon mineral and organic substances already in the soil, and also absorb the organic food contained in the air. Of the chief mineral manures employed in our own coun- try, we must take some special notice. Their forms quid conditions, the best methods of applying them, and their effects, will be the principal points to be noticed. more or less, mix the mass thoroughly with six or eight times, or more, its bulk of muck, or even with common soil, if need be. This makes an excellent fertilizer, worth anywhere all it costs, and more. Sulphuric acid, in carboys of 120 to 160 pounds, costs from 2 to 3 cents per pound, according to distance from the manufactory. It needs to be handled with care, as it is corrosive to the flesh and clothing." — AinciKOii AyrkiiUurial. LIME. 239 LIME. 399. Lime is found in every crop, and must, therefore, exist in every cultivated soil. And in order to be of service to the crop, it must not only be present, but must be in a suitable condition to be taken up by the roots, and made available to the growing plant. If there is not a sufficient excess of available lime present, or if it should be wanted to act upon something already in the soil, it may be applied in several different forms. 400. (a) Caustic Lime, prepared from limestone or oyster- shells, should be slacked before it is applied, since the pul- verized condition makes it more easily spread. It is better, ordinarily, to apply it frequently in small portions, than to apply large quantities at one dressing. The quantity must be determined by the character of the soil. Every farmer should make experiments for himself, beginning with from 20 to 50 bushels per acre, uniformly spread, and increasing the quantity as he may find necessary. Recently-drained, swampy lands require larger doses. 401. Effects. — (1) Caustic lime combines with free or- ganic acids in the soil, and thus sweetens sour soils. With these acids it is supposed to form soluble salts, which are valuable as food for crops. (2) It hastens the decay of vegetable fibre in the soil, and reduces it to a nutritious form — changes it to humus. (3) It sets free ammonia, which may exist in some inert condition in the soil, and thus indirectly hastens its absorption by the crop. (4) It decomposes some mineral substances already present^ and makes their elements more available to plants. 402. Cautions. — It must' not be forgotten that the too frequent application of lime, especially to clay soils, may so far exhaust the organic matter, as to cause a deficiency in this important part of every fertile soil. Its efiects upon 240 LIME. manures containing ammonia, make it unsuitable to be mixed with such manures, or even to be applied near the same time. 403. (h) Mild Lime. — When caustic lime has been exposed to the air for some time, it gradually combines with carbonic acid, and loses its caustic character; it becomes mild lime. Ux^y. Pour a little dilute acid or strong vinegar upon lime which has lain a good while in the open air : a brisk eflPer- vescence will take place, showing that it has become a car- bonate. It has the same composition as ordinary limestone, but is much superior to the latter, because it is reduced to an extremely fine powder, and hence more readily dissolved by rain-water containing carbonic acid gas (§ 102). 404. Effects. — Besides affording nutrition directly to the growing crop, it has an effect upon the stronger organic acids, similar to that of the caustic lime. These acids are capa- ble of removing the carbonic acid, by taking its place iu combination with lime ; and thus the organic acids become neutral. 405. ((') Phosphate of Lime. — The phosphate obtained by burning bones has been alluded to (§ 204). Besides being the chief source from which the quantity of phosphoric acid in the soil is increased, it also adds to the supply of lime. When the organic matter has been burnt out of bones, they are easily reduced to a fine powder, by pounding or grind- ing; and may be sown by hand, or mixed with other ma- nures. Bone-earth seldom has an immediate effect upon cereal grains. Its chemical condition seems to require some modifications, before it is well fitted to nourish such crops. Hence, the effects are often more marked upon the second or third crop, after the application is made, than upon the first. If treated with sulphuric acid, as prescribed for un- burnt bones (§ 396), the action is much more pi'ompt, and a smaller quantity will serve for a single dressing. LIME. 241 406. SiqyerjjhospJiafe of Lime. — By mixing bone-dust and guano together, and treating the mixture with sulphuric acid, a mixture of sulphate of ammonia from the guano, and of superphosphate of lime from both the bones and the guano, is formed, ■which has proved to be a most energetic manure. Such mixtures are frequently sold under the name of " improved sixperphosphates." Guano of inferior quality, containing a large percentage of phosphates, and but little ammonia, is now extensively employed, by mixing it intimately with some good Peruvian guano. The mixture is called " manipulated guano." There is so much room for imposition in all such artificial manures, that farmers should be cautious as to the source from whence they come. Buy only from reliable men. 407. When bones have been burnt in a close vessel, they form hone-hJack, or animal charcoal. In this, the animal matter has been reduced to carbon in extremely fine division. This greatly increases its absorbent power while dry ; and when mixed with decaying organic manures, it takes up a large c{uantity of ammonia. 408. (d) Gypsu:m. — This is a source of both lime and sul- phuric acid. Its composition and properties have been so frequently alluded to already, that a very few additional remarks will be sufficient. Effects. — (1) It furnishes both of its ingredients (lime and sulphuric acid) in a soluble form ; and, as these are re- quired by nearly all crops, its direct influence would be to supply them (one or both), if deficient in the soil, in an available form. It is especially applicable to the grasses, including corn and wheat, and to potato and tobacco crops (see Table III). (2) Its effects on most crops may be attri- buted, perhaps, chiefly to its property of collecting and fixing ammonia. 409. (e) Marl. — The terra ''marl" is used somewhat 21 242 LIME. indefinitely. In the valley of Virginia, as well as in many other places, the porous masses of carbonate of lime deposited by limestone springs, are called marl. These are known in mineralogy as calcareous tufa. Mixtures of carbonate of lime with clay, sand, and other impurities deposited in a loose form by water, are also called marl. When such deposits are composed largely of shells, infusoria, and organic matter, they are generally known as '' shell-marl." Alkaline salts are common in shell-marl; and among the organic matter, some ammonia may generally be detected. They also con- tain some sulphate and phosphate of lime. The presence of such a variety of valuable ingredients, makes this species of marl a very cifective fertilizer. The marls found in the ter- tiary strata of the tide-water region of Virginia, as well as those found in other localities, have proved very beneficial as manures. In some sections they have formed the hasis of a system of improvement, which has done much to reclaim many exhausted farms. — (See Riiffiiis Essai/ on Calcareous Ilamtres.') 410. (/) Silicate or Lime. — This compound probably plays a more important part as a fertilizer, than many per- sons suppose. It is found to some extent in almost all soils. As one of the constituents of hornblende and trap rocks, it has been already mentioned. In the process of burning lime, some portions of it are formed by the silica (almost always present to some extent in limestones) uniting with lime. Effect. — By the combined influence of moisture and car- bonic acid, the silicate of lime is slowly changed into the carbonate, while the silica is set free in a wlahlc form, so that it can be taken up by the roots of plants. The groat value of soluble silica will be perceived, when we reflect upon the extent to which it enters into the composition of the ashes of the stalks, cspcciallv of the cereal grains and Lay (see Table III). MAGNESIA ASHES. 243 MAGNESIA. 411. Magnesia is essential to fertility in a soil; but there are very few lands which are not already supplied with an abundance of it for meeting the demands of the growing plant. In a few soils where it is deficient, it may be supplied with advantage in connection with lime. Limestones fre- quently contain a large per centum of carbonate of magnesia, which is reduced to caustic magnesia, just as the carbonate of lime is reduced to caustic lime, in the process of burning. This mixture of magnesia and lime must be applied more lightly than simple lime, because large quantities of caustic magnesia are injurious to the soil. Magnesia will not serve, so well as lime, the various secondary purposes of " sweetening sour soils," of " decom- posing organic and mineral compounds," etc. It is some- times applied in the form o^ pliosjpliate or sulphate; but the beneficial results from these are generally to be attributed more to the influence of the phosphoric and sulphuric acids, than the magnesia with which they are combined. ASHES. 412. Ashes, consisting of the mineral matter derived from the soil by plants, might be esjDCcted to form one of the best fertilizers to be found; and such is really the case. The mineral bases, as they are found in ashes, are not in the same combinations which they have in the plant. Those which in the plant were combined with difi'erent organic acids, become carbonates by burning. Some others, too, such as the phos- phates, may be considerably modified by the heat during combustion. But they are still in a favorable condition to afibrd nourishment to new plants. 413. The ashes used for fertilizing purposes are derived chiefly from the fuel consumed in our dwellings, and in the mechanic arts. Near the sea-coast, farmers often avail them- selves of the rich mineral manure which may be procured 244 ASHES. by burning- sea-weeds. These are gathered, dried, and then burnt in shallow pits, which prevent the ashes from being blown about by the wind. Soda and chlorine, obtained from sea-water, are among the most abundant constituents of these ashes. They were formerly employed largely, as a source from which soda was prepared; but better and cheaper methods are now adopted (§ 96). 414. The average quantity of ashes produced by the vari- ous kinds of wood commonly used for fuel, is about 3 pounds from 100 pounds of well-dried wood. Where much pine is used, this average is too great, since pine yields only about 07ie per cent of ashes. The quantity from sea-weeds varies to some extent with the different varieties of plant ; but we may take seventeen per cent as about the average, which shows that these plants are very rich in mineral matter. 415. The following table gives a general view of the value of ashes, as determined by their constituents. The Jirst column gives the composition of those obtained by burning a mixed fuel, consisting of about one-half oak, and the re- mainder beech, ash, hickory, and maple in about equal pro- portions. The second column gives the composition of the ashes of sea-weeds. TABLE VII. 3000 Pounds of Dry Wood give 100 Pounds Mixed Wood Sea Weed of Ashes, containing Ashes. Ashes. Potassa 9.3 lbs. 17.4 lbs. Soda 2.5 " 27.1 " Lime 41.2 " 7.2 " Magnesia G.2 " 8.0 " 0.^ides of Iron and Manganese 1.6 " 0.1 " Sulphuric Acid 1.5 '• 17.0 '« Phosplioric Acid 4.3 " 3.0 " Silica 3.2 " 1.3 " Carbonic Acid 30.7 " Omitted. Chlorine 0.5 " 18.2 lbs. Iodine 0.7 " ASHES. 245 When we compare the above table with Table III, which gives us the mineral constituents of various crops, we find ashes rich in those substances most largely demanded by plants ; and when we refer to Table V, we see that these substances are not always abundant in the soil. The bases — that is, the potassa, soda, lime, etc. — are chiefly found as carbonates in ashes, while smaller portions of them are com- bined with th-e phosphoric, sulphuric, and silicic acids. The chlorine is most probably combined with sodium. The salts of potassa and soda being soluble, are more apt to be lost by exposure to rain than are the salts of lime and magnesia. Some of the silica in ashes is in combination with potassa, and in a soluble condition. This soluble silica, for most soils, is one of the most valuable fertilizers which can be em- ployed. We have already learned that its presence is neces- sary to the full and healthful growth of the stalks of plants ; and its influence may be frequently seen on the clean, strong and healthy straw of wheat growing upon soils recently dressed with ashes. The effects of ashes upon grass and corn crops are almost always highly favorable. 41G. Ashes. are caustic in their character, from the pre- sence of carbonates of potassa and soda. They also contain a large per cent of carbonate of lime. These qualities make them a most appropriate manure for sweetening sour soils, such as those which have been recently drained. They serve a good purpose, too, in hastening the decay of organic matter in compost heaps. But newly-burnt ashes should not be mixed with guano, and other manures containing ammo- nia, because there is generally caustic lime enough produced by the fire, to set free considerable quantities of ammonia. After ashes have been exposed for some time to the air, however, the caustic lime becomes a carbonate, and these effects will not then be produced by it. 417. Leached ashes are much inferior to the unleachcd in 21* 246 ASHES. their fertilizing value, a large quantity of the soluble matter having been carried oflf in the lye ; but still they are valuable on account of having some potassa and soda left in them, and from the large quantity of lime they have retained, to- gether with most of the phosphoric and some of the sulphuric acid and silica. They should be applied much more largely than unleached ashes, to produce a like effect. 418. The soap-suds used about the farm-house, contain not only the soluble matter taken out of the leached ashes in making lye, but also a considerable quantity of valuable animal matter employed in making soap. If these were care- fully preserved, and thrown upon a compost-heap, which would absorb them, they would be found to reward the labor bestowed, in adding their fertilizing value to the soil. A sheltered compost-heap, formed of wood-yard scrapings, turf, weeds, and enough of vegetable mould to prevent the suds from passing through the mass too quickly, should be con- structed near every wash-house, with a trough leading to it, to convey all the spent suds to the top of it. Coal-ashes should not be neglected. They consist, it is true, chiefly of alumina and silica, and, in some varieties, lime is abundant ; but all of them contain enough of the salts of potassa and soda, and of sulphates and phosphates, to make them well worth the trouble of applying them to the soil when near at hand. 419. Ashes and Plaster. — These make a favorite mixture with many of our best farmers. They are applied with great success to corn, by being dropped with it in the hill, or being sprinkled over it soon after it comes up. Some prefer sowing the mixture broadcast before planting, so that the rains may carry it down into all parts of the soil, where it will be found by the roots as they spread out during the growth of the crop. The gypsum thus spread out is supposed, too, to be in a more favorable condition for combining with ammonia SALTS OF SODA. 247 from the air and the soil. Sown upon clover fields and meadows, this mixture has sometimes a remarkable effect, and is, in almost every case, beneficial. It contains the ele- ments of fertility most largely demanded by grass crops. Lime, potassa, sulphuric, and phosphoric acids, and espe- cially soluble silica, are all taken up freely by the grasses. A special advantage arises from mixing ashes with plaster, when the mixture is to be applied to a soil in which sul- phuric acid is very deficient. The ashes, or rather the car- bonate of potassa in the ashes, so acts upon the sulphate of lime, that mutual decomposition takes place if the mixture is in a moist condition. The lime and potassa exchange places, so that we have carbonate of lime instead of carbonate of potassa, and sulphate of potassa instead of sulphate of lime. This change goes on with considerable rapidity, if the mingling of the two manures is complete, and the mass is kept moist and warm. The sulphate of potassa is much more soluble than the plaster, and is, hence, diffused through the soil at once by the rains, and made immediately available by the roots of the plant. . SALTS OF SODA. 420. Common salt is a very valuable fertilizer for many crops, but especially for those requiring considerable quan- tities of chlorine. Mixed with ashes and plaster, it has proved highly beneficial to crops of potatoes, hay, and corn. Four bushels of unleached ashes, and one bushel of plaster, with a gallon of salt, make a most valuable preparation for potatoes or grass. I have found twelve bushels of this mix- ture to bo suSicient for an acre of potatoes planted in the ordinary way. Grass lands would require a greater or less quantity, accoi'ding to the nature of the soil. Every farmer should make experiments for himself Asparagus beds re- 248 NITRATES BURNT CLAY. quire abundant and frequent applications of salt. The most convenient way to apply it is to dissolve the salt in water, and sprinkle the solution over the bed with a common water- sprinkler. 421. Sulphate of soda is now a very cheap article, being produced in large quantities in the manufacture of muriatic acid (§ 80). It has been advantageously used as a fertilizer. This substance, as well as common salt, may be beneficially mixed with other fertilizers. 422. Silicate of soda is easily prepared by fusing sand and carbonate of soda together. If two parts of carbonate of soda are fused with one part of sand, and a little powdered charcoal, the mass is soluble in water. The solution has been applied to wheat with very marked benefit. Soluble silica is so much needed on many soils, that it is to be hoped that means will be devised for preparing it at a moderate cost. N ITRATE S. 423. Nitric acid is one of the sources from which plants obtain nitrogen ; hence, the nitrates have proved to be valu- able as manures. The nitrates of potassa and soda have both been used with great success. Dilute solutions of these salts may be sprinkled upon the soil ; or, if sprinkled over compost-heaps, they find their way to the soil in mixture with other manures. BURNT CLAY. 424. Burning sometimes has a very remarkable influence in making a soil more productive. There are several causes which probably combine to produce this effect. (1) A part of the organic matter mingled with the soil is reduced to ashes, and thus made at once effective in providing its mine- ral matter in a free form to nourish the next crop. (2) Part of the organic matter is only charred, and left as finely RUNNING WATER A FERTILIZER. 249 divided carbon in tlie pores of the soil, where it serves as a valuable absorbent of ammonia, carbonic acid, and water. (8) The mineral matter already in the s(fil is frequently im- proved by heat. Some substances, such as protoxide of iron, are more highly oxidized; and others are disintegrated, and rendered more soluble. (4) The mechanical condition is often improved by the soil being made more loose and porous. RUNNING WATER A FERTILIZER. 425. The water of springs and streams is never pure. It contains, as has been stated (§ 61), both mineral and organic matter of the proper kind, and in the proper condition to nourish a growing crop, or to add fertility to the soil through which it passes. The fertilizing matter is conveyed by the water partly in solution, and partly in minute particles, which are mechanically transported and left upon the surface. In sections of country where the land is rolling, and running streams are numerous, a portion of every farm, through which one of these streams passes, can be not only watered, but enriched by watering, if properly managed. The purest spring-water has always portions of mineral matter from the soil and rocks through which it has passed. Decaying organic substances in the soil yield ammonia, which is also found, in some form of combination, in almost all springs. In streams which have received the water from the sewers of towns and cities, ammonia exists in verj' con- siderable quantities, and so do soluble and insoluble mineral ingredients. A careful farmer, although he may have no town or city above him to send down to his meadows, water freighted with fertility, will generally find that he has some careless neighbors up-stream, who will let him have the benefit of the "wash" from their barn-yards, hog-pens, and other like places j and not complain of his turning it into 250 R I" N N 1 N O WATER A FERTILIZER. hay aud grain, instead of lotting it run on to the ocean, to be forever lost. 420. Aj)2ili(:athn. — Running water can, of course, be ap plied only to those portions of land which are lower than the point where the water is turned out from the streaiu. By means of ditches conducted along the hill-sides, with just foil enough to give the necessary motion to the water, many acres of a farm may often be completely irrig-ated. In order to accomplish this thoroughly, with as little waste of water as possible, some attention must be given to the coustructiou aud arnuigemeut of the ditches. The principal ditch, or conductor (*l, A, Fig. 47), should wind around the hills nearly upon a level, so as to carry the water along the high- est possible line. Openings, from 10 to 20 feet apart, must be made, as at a, a, a, to let out small streams from the main conductor. Small shallow channels should lead off from these openings to the right and left, nearly parallel with the main conductor; for the purpose, in the fii-st place, of properly diffusing the water; and, in the second place, to prevent the little stream from cutting for itself a channel deeper than is wanted. These are seen at ?>, b, h. If the space to be watered extends far below the main ditch, other smaller ditches, as ^, B, C, C, and i>. D, should be run parallel with A, A, and at distances varying from 30 to 50 yards. These may vary in size as they are more or less distant from ^1. ..4, because a portion of the water conveyed by -4, ^4 will be ab- sorbed by the soil before it reaches B, B ; and when it reaches C\ G, the quantity is still less. Then, these secondary con- ductors are not designed so much to convci/ water from one part of the meadow or field to another, as they are to redis- tribute what has run down from ^1, J^. Finally, if there is not a natural channel at the base of the hill, as E, E, to carry off the surplus water, an artificial one should be dug for that purpose. RUNNJNO VVATLR A FKKTILIZER. 251 Fig. 47. 2r)2 RUNNING WATER A FERTILIZER. 427. The kind of soil most suitable for irrigation is one with a porous sub-soil. The water can then penetrate to a greater depth, and surplus water can escape as it does in a drained soil. If the sub-soil is an impervious clay, a system of covered drains should be constructed beneath the surface before the ditches are made ; or, if this cannot be done, and the land is to be kept in grass, it should be cultivated to the greatest possible depth with the sub-soil plow, before the grass is sown. When the soil is thus rendered porous, one portion of it may be completely saturated with water, and the stream then be turned upon another, while the former is left free to be acted upon by the air. By alternating in this way, a small stream may be made to water a large surface. If the land is under cultivation with corn, it may be watered, when necessary, by the same system ; but the water should be turned out upon the soil less frec^uently, in this case, than in the case of a grass crop. 428. Effects. — The prcaent crop is provided by the stream of water : (1) With an abundant supply of moisture, which is of great importance, and the land is thus made indepen- dent of drought;* (2) With mineral and organic manure al- ready in solution. Subsequent crops are, moreover, benefited by surplus fertility left in the soil by the water, and by de- caying roots, stalks, and blades, of which some portions always remain after every crop that has been removed. After a hay-crop has been removed, the meadow should be watered, in such a way as not to allow the water to pass off through the soil, or to run freely over the surface ; for, in that case, it will carry off fertilizing matter, which had better be re- tained. To prevent this, the quantity must be so regulated that all, or nearly all, will be absorbed, and afterwards eva- porated from the surface, or thoroughly filtered before it runs off from the field ; thus the fertilizing substances will be left in the soil. But if the water contains a considerable quan- QUESTIONS. 253 tity of organic and sedimentary substances, it should be allowed to pass freely and abundantly over the surface. QUESTIONS ON CHAPTER XV. §§ 379 — 382. AVhat is said of Stable Manure? How must the urine be preserved? First method given ? Second? AVhat else must be done besides rendering ammonia involatile ? If manures cannot be put into sheds, what should be done with them ? What of the urine of cows, sheep, and hogs? Of their solid excrements? Is human excrement valuable ? How does it compare with that of other ani- mals ? Is much of it wasted ? What arrangements may be made for its preservation ? 383 — 391. What is Guano? Why so rich in fertilizing matter? Its most abundant and most valuable ingredients? Where is the best guano found ? Analogy between these deposits and those of coal ? What of the African, Chilian, and Mexican guanos ? What does Table VI represent? With what is the ammonia of guano com- bined ? How do they become volatile? Why is the application of guano important? AVhat three things are required in its economical use? AVhat quantity is to be applied? Advantage of mixing with other manures? Most common method of applying it? AVhen should it be diluted? First thing (o) to be done in preparing guano? How mixed with humus (b)t Use of sulphuric acid (c)? AVhat effect does the acid produce ? AVhy always to be thoroughly min- gled with the soil {d) 1 AVhat do some farmers think of the exhaust- ing effects of guano? Does it really exhaust a soil? AVhy not? May its use exhaust some elements? Illustrate. AVhat cases men- tioned ? How prevented ? Best method of using guano for perma- nent improvement? How does it act when applied to green crops to be plowed down? AVhat precautions necessary in buying? How tested ? Domestic guano ? 392 — 396. AVhere are anfniaZ substances collected? AVhat gives them agricultural value? How preserved? AVhat offish? Insects? AVhat gives value to Bones ? How do they compare with guano ? Why is their influence slow ? How does sulphuric acid render bones more energetic ? How is the acid used ? 397,398. Is i/2ne?ai J/a«i«e important ? AVhy? Illustrate. AVhat indirect influence does it often produce ? 22 254 QUESTIONS. 399 — 410. Why must Lime exist in every soil ? In what condition must it be? (a) In what condition should caustic lime be applied? How much? On drained swamps? Why? First eifect of caustic lime? Second? Third? Fourth? Cautions? {b) What is mild lime? Experiment? Its effects? (c) Phosphate of lime obtained? What does it supply? Has it an immediate effect? lioyt la super- phosphate of lime prepared ? What is manipulated guano ? Bone black ? [d) What does Gypsum provide for crops ? Effects ? To what crops is it especially applicable? AVhy ? (e) How is the term marl, used? What is shell-marl? Marls of the tertiary strata? (/) Why is silicate of lime important? Explain its action. 411. Is J/aywfsia valuable in soil? Why? Is it valued as a fer- tilizer? AVhy not? Will it not take the place of lime? What salts of magnesia are sometimes applied to land ? 412 — 418. Why might we expect Ashes to form a good fertilizer? Are their constituents modified in burning ? Chief source of ashes? On the sea-coast? Average quantity produced by wood? What does Table VII represent? What do we learn by comparing it with Tables III and V? What portions of ashes are most readily lost by exposure? Why suited for "sour soils"? Influence on organic matter? Value of leached ashes? Value of soap-suds? Why? How collected ? Coal ashes ? 419. 'Row are plaster and ashes used together? Modes of apply- ing them ? Why especially adapted to clover and grasses ? What chemical changes do they produce on each other ? 420 — 424. What fiocTo! compound is first mentioned? What does common salt furnish to crops ? On what crops is it most beneficial ? What is said of sulphate of soda ? How is silicate of soda prepared ? What gives the Nitrates their value ? Influence of burnt clay ? First cause of this? Second? Third? Fourth? 425 — 428. Is rnnni7ig water ever pure ? What substances are found in it? How does it fertilize a soil? Where do springs get their mineral and organic matter ? How is the water of streams furnished with fertilizing substances ? To what lands can this water be applied? Describe the ditching in Fig. 47. 'What kind of soil is best suited for irrigation? How should clay soils be prepared? How may a small stream be made to water a large surface ? APPLICATION OF FERTILIZERS. 255 CHAPTER XVI. APPLICATION OF FERTILIZ E RS — PLANTING AND CULTURE OF CROPS. 429. It may be well to sum up, in review, some of the general principles and rules to be observed in applying fer- tilizers to the soil. (a) Manures may be applied either in a liquid or solid form. The liquid form has the advantage of producing the most speedy effects, thus returning its profits most quickly to the pocket of the farmer; but, in this country, liquid ma- nures are not much used, except on gardens and small lots. In older countries than ours, in some parts of our older States, in the vicinity of cities, and in all places where land is costly, and where a convenient and high market brings a prompt return for manure and labor, the liquid fertilizers are found frequently very economical. The manures of the solid form are most commonly applied, and have the advan- tages, generally, of requiring less trouble in their prepara- tion and application, of affording a much greater variety of ingredients, and of being much more durable; and hence, requiring less frequent application. (h) Solid manures should be as well pulverized as possible, so that they may be thoroughly mingled with and diffused through the soil. In this condition, a smaller quantity serves for a single application ; and the farmer gets back again, in a shorter time, the capital and labor invested in the manure and the land. (c) Manures of every kind should be as thoroughly incor- 25G ATPLICATION OF FERTILIZERS. porated with the soil as possible, so that the roots of the crop may find some portions wherever they run. If a ma- nure is heavy, like lime or plaster, it is best to apply it on the surface after the land has been broken up. It may then be stirred into the soil, and, by its weight, it will gradually sink towards the bottom during the cultivation. Soluble ingredients, such as the alkaline salts in ashes, will soon be carried down into the earth by rain-water, even when they are applied only on the surface. (fZ) Fermented manures have their ammonia already in a volatile form ; and unless they have been composted with other substances, much of the ammonia will escape, by exposure on the surface. Hence they should be speedily covered or mingled with the soil. The tendency of all vola- tile matter is towards the surface. Especially is this the case in porous soils ; hence guano, and other forms of manure which have passed through the process of fermentation, are frequently most effective and most durable in their influence when plowed down. (e) The crop should find the required fertilizers present in the soil, and in the proper condition to be absorbed, as soon as the roots are sufficiently developed to take them up as food. Organic food is required at every period of the plant's growth, and should therefore be present at the time of plant- ing. Of the mineral ingredients, silica and lime are taken up most abundantly during the growth of the stalk, while potassa and the phosphates enter most abundantly into the grain ; but in both cases it is best to apply the fertilizers, either at or before the time of planting. Important chemi- cal changes are often necessary, before a manure becomes fit for plant food. Bone dust, for example, has frequently, perhaps generally, a more decided effect upon a wheat crop, the second or third season after its application, than it has during the first. It doubtless undergoes, in process of time, APPLICATION OP FERTILIZERS. 257 changes in the soil, either from having a portion of its lime abstracted by lime-feeding plants, or under the influence of other substances, by which it is reduced to a more soluble, and hence more available condition. Unfermented manures applied to corn, or to a clover sod to be fallowed for wheat, generally have a better eflFect upon the succeeding wheat crop, than when applied directly to it at the time of sowing. 430. Top-dressivg is more extensively practised now than it was formerly; but, like all other modes of application, it must be resorted to only under certain circumstances. There is no mode which can ever be universal in its applications ; and where we find one particular method very successful in two or three experiments, there is always danger of some one drawing the general conclusion that this is, finally, to be the only method of operating. Top-dressing is doubtless favor- able to grass and clover crops in the Winter and Spring Organic manures thus applied have their soluble ingredients carried down by the rain into the soil, where the roots will find them at the very beginning of their Spring growth. The unrotted portions of manure, remaining upon the sur- face, are soon covered by the leaves and stalks that spring up through them, and decaying, form a rich, warm mould about the roots. Top-dressing for corn will do well, if it be done with the newly-collected manures from the stables and barn-yards during the Winter. The urine, and other por- tions soluble by the Winter and Spring rains, are carried down, and become very thoroughly incorporated with the soil ; while the remaining portions are turned down after- wards by the plow, and are gradually converted chiefly into humus. Manures may always be applied to the surface during the Autumn or Winter without serious loss, and fre- quently with decided advantage. It is always better to have stable and yard manures exposed to rains itj)on the field, than around the ham. 22* 258 PLANTING. 431. Mixing AND Composting Manures. — When the farmer wishes to have a great variety of fertilizing ingre- dients provided for his crop, and applied at the same time, he may mix several kinds of manure together; but, in doing this, he must weigh carefully all the advantages and disad- vantages involved. Besides giving a variety of food to the crop, some of the most obvious advantages arising from mixing manures, are : (1) That one may render another involatile, of which we have examples in the effect of humus or gypsum in " fixing ammonia;" and (2) That one may make another more soluble, as in the case of sulphuric acid poured upon bone- dust. 432. Corresponding disadvantages are seen : (1) In a volatile substance, especially ammonia, being expelled by another, such as caustic lime; and (2) In the addition of something which may make valuable ingredients, already present, more insoluble. Sulphate of iron (copperas), for instance, added to manure containing phosphate of potassa or phosphate of ammonia, will produce the very insoluble phosphate of iron ; thus rendering the phosphoric acid much less soluble than it was in its former combination. But it will only require a little reflection to avoid these difficulties. PLANTING. 433. The general principles have been given which should govern the farmer in both the mechanical and chemical preparation of the soil. By plowing and draining, it ig opened up, and ready to be acted i\Y>on by air and moisture, to receive such chemical appliances as will improve its com- position, and also to be penetrated by the roots of cultivated crops. By appropriate manure, it is supplied with an abun- dance of all the food wanted for the nourishment of these crops. PLANTING. 259 When the ground is thus made ready, the next object of attention, before we bring the seed and the soil together, is to know that we have seed of the best kind and quaUty. 434. Selection of Seed. — This is a matter of the highest importance to good farming. "As a man soweth, so shall he reap," is one of the sacred proverbs, no less true in the physical than in the moral world. The farmer is apt to reap, not only the same kind, but also the same quality, as that which he has sown. A little shrivelled grain, with a poorly-developed embryo, will generally send up a weak and sickly stalk, able to bear only such grains as that from which it sprung; while, on the other hand, the vigorous germ, found in the full, plump grain, forms at once a strong foundation for a healthful future growth. 435. If the farmer has seed of the right hind, he may, with a little care and trouble, improve its quality very con- siderably in a few years. In wheat, the first portions that ripen are usually the best. These should be first cleared of rye, cockle, and other foreign plants ; then cut as soon as ripe, and kept apart from the general crop, for seed. If this process is repeated for several years, the effect will be seen in the improved quality, and earlier ripening of the wheat. Seed corn should be selected in the field. The largest ears, from those stalks which bear two ears, are believed by many of our best farmers to be most desirable for ,seed, be- cause they are thought to be most likely to yield twin-bearing stalks for the next crop. There is good reason for this belief, from the fact that the ordinary varieties of Indian corn, when well cultivated on good soil, and not too much crowded for full development, generally yield at least two ears from every stalk; and, where only an occasional stalk has an opportunity of attaining its fullest growth, this is indicated by the production of two ears. In selecting the 200 PLANTING. best ears, then, from such stalks, we have the product of the most vigorous and full growth in the crop. Those who have tried this method of selecting their seed, testify that the number of double-eared stalks can thus be greatly mul- tiplied in a few years. It is a subject worthy of further careful experiment. Every one who has not the proper kind of seed on his farm should at once make a change, even if he should be compelled to pay what he may regard as a very high price for seed of good quality. Changes of wheat and other grains, from one soil to another of different character, and from one climate to another, seem in many cases to prove beneficial. Wheat from the shores of the Mediterranean, and even from Central and Northern Europe, is generally more free from disease, and often escapes the ravages of insects more entirely, than the varieties which have been long culti- vated in our own country. Grains transported from latitudes in which the season is short, to those in which it is much longer, ripen early, at least for a few seasons; but they finally appear to adapt their period of growth and maturity to the new climate. Our Government, through the agency of the Patent Office, is doing our agriculturists good service, by giving them an opportunity of trying various kinds of seeds from all parts of the world. 436. In determining the variety of wheat or corn to be planted, two circumstances should have their influence. (1) The productiveness of different varieties should be, as far as possible, ascertained. The difierent kinds of wheat and corn often vary in their relative products per acre, so much as to make this an important point of attention. The labor of cultivating an acre of land in a variety of corn which yields 80 bushels, is no gi'eater than that of cultivating the same quantity of land in another variety which yields only 50 or 60 bushels ; and the same is true of wheat, or any PLANTING. 2G1 other grain. (2) The difference in the marJcet valve per bushel must not be disregarded. Twenty bushels of white wheat, at $1.25, are equal in value to twenty -five bushels of red wheat, at $1.00. The mitritive value of corn to be used in feeding farm stock, should be estimated, in selecting the kind to be planted. Yellow corn is regarded by stock-raisers as superior to the white, in its fattening properties. For bread, the white variety, with a clear, flinty grain, is most highly esteemed. 437. The oat grain {Avena Stafiva') degenerates, to some extent, in the Southern States, after a few years' cultivation. The stalk may still grow with all the luxuriance desired, but the grain gradually becomes less full and heavy. For this reason, Southern farmers who wish to cultivate oats, should frequently (at least once in four or five years) renew their seed by importation from a more northern latitude. 438. Preparation of Seed for Planting. — All kinds of seeds should be tlioronghhj clear of everything which can spring up and grow at the same time with the cultivated crop. Indian corn is easily separated from every other kind of seed, by the peculiar manner of gathering it; but not so with wheat. Everything that grows with wheat must be gathered with it; and everything that ripens about the same time, will be still represented by its seeds, when the grain is threshed. Hence the great difficulty of keeping seed-wheat clean. Spring wheat is liable to become polluted with oats, because it has the same season of growth, while oats sown with winter wheat are killed by frosts. Winter wheat is most apt to have rye, cockle, and cheat (chess) mixed with it, as these, like the wheat, arc biennial, and ripen simulta- neously with it. 439. In order to estimate properly the importance of hav- ing clean seed, it must be remembered that these foreign grains do not simply injure the quality of the flour produced 2G2 PLANTING. from the crop, but they also diminish the quantity of the grain, just to the extent of their own presence. This may not be entirely true of oats and rye, for they are not entirely worthless ; but of cockle and cheat it certainly is true ; for the same ground which produced a stalk of either of these plants, would have produced a stalk of wheat, if wheat had been sown in their stead. A few bushels of wheat may be carefully picked out, head by head, and sown on a piece of clean and good soil ; and a supply of clean seed, sufficient for the whole of the next sowing, be thus obtained. 440. Steeping Seed-Grain. — A more prompt and vigor- ous germination, and a more rapid early growth, may be brought about, in almost all kinds of grain, by steeping the seed in suitable solutions. If the soil is then good, the early growth, thus urged forward, will continue ; but steeping the seed in a solution of one substance, can never make up de- ficiency in other elements of fertility in the soil ; nor can it compensate for defective ploicing, or negligence in other modes of tillage. The solutions used for steeping sometimes have the effect of destroying the eggs of insects, and the germs of injurious fungi, such as smut. Or, if these are not destroyed, their influence may be, to a great extent, counteracted by the in- creased vigor given to the young plant by the fertilizing salts in which the grain has been soaked. 441. Several salts may be used in the same solution, so as to give a variety of such food as the plant may require. The salts most frequently employed for this purpose are those containing potassa, soda, and ammonia, combined with such acids as are wholesome for plants. The ammonia salts, like the ammoniferous manures, are generally more powerful in their influence than the salts of the other bases. The sul- phate of ammonia and sal-ammoniac arc the cheapest salts PLANTING. 2G3 of that class ; but urine may be used with like effects, on account of its ammonia, and at much less cost. Nitrate of potassa (saltpetre), nitrates and sulphates of soda and mag- nesia, phosphate of soda, and common salt, may all be em- ployed in the preparation of steeping liquids. Some of these are within the reach of every farmer, and may be used at a trifling cost. The collection of urine requires only a little management, while saltpetre and common salt are found in every wayside store throughout the whole country. 442. The following receipts may be useful as general guides in preparing solutions. They are suitable for any of the cereal grains. a. For every bushel of wheat or corn, take 45 gallons of water, and dissolve in it one pound of saltpetre and one pound of common salt.* Pour the solution upon the grain in a tight vessel, and set it aside in a warm place to soak for 24 or 36 hours. Then drain off the surplus water (preserving- it), and mix with the grain, while wet, as much plaster as will adhere to it, or, rather, as much as will keep the grains from adhering to one another in planting. About half-a- bushel of plaster is sufficient for a bushel of grain. Caustic lime, used in the same way, is believed to prevent smut. The water may be used a second time, for about half as much grain, by dissolving a little more saltpetre and salt in it. h. A better solution than the preceding is formed by dis- solving, in 4^ gallons of water, for each bushel of grain to be soaked, -^ lb. sulphate of ammonia, ^ lb. saltpetre, ^ lb. Epsom salts, and \ lb. common saltj and, if phosphate of soda can be obtained, add \ lb. of it. Soak the grain and mix with plaster, as in the first receipt. * A strong brine of salt tends to retard germination, by preventing decay in the albumen. 2Gi PLANTING. c. To 4 5 gallons of urine, add a half-pint of sulphuric acid (oil of vitriol), J lb. saltpetre, I lb. Epsom salts, 2 lb. common salt. The solution is to be used as before directed. In this case the sulphuric acid unites with the ammonia of the urine, and forms sulphate of ammonia. This solution is improved by standing a day or two before it is used. Other solutions may be used, as the convenience or che- mical knowledge of the farmer may suggest. A strong de- coction of manure, formed by passing water through a barrel or box compactly filled with Iresh stable-dung, or that col- lected from hen-roosts, with the addition of a little sulphuric acid, nitre, and salt to the liquid, after it has passed off, will give a solution closely resembling the one last mentioned (c). When the quantity of grain to be prepared at one time is large, it may be more convenient to use a smaller amount of liquid, and apply it in a different way. The following plan will be found convenient; For every bushel of wheat provide I2 gallons of water, and in this dissolve the salts as above given. Spread the grain upon a close floor, to the depth of 5 or 6 inches, and with a common water-sprinkler apply about one-third of the solution. Let it stand two or three hours, stirring the mass occasionally. The grain will in the mean- time have absoi"bed most of the moisture ; then sprinkle over it another third of the solution, and let it stand 24 or 3G hours. Just before it is to be sown, let the remaining third of the solution be applied ; and while the grain is still wet, mix it with plaster or caustic lime, or any fertilizer you may wish to sow with it. If no pulverized fertilizer is to be used, all the liquid should be applied as soon as the grain can absorb it, so that it may stand at least 24 hours after the last portion has been applied. The grains will then be sufficiently dry upon the surface to prevent their adhering to each other in sowing. 444. Time of Planting. — This must vjiry widely, even PLANTING. 265 for the Fame crop, under variations of climate ; and also, to some extent, with variations of soil and exposure, even in the same climate. It is, therefore, difficult to lay down any rules, except those of the most general character. Crops planted in Autumn, such as wheat and rye, should have time to form a good strong root, before Winter sets in. The ex- perience of the most successful farmers in any particular section of country, is the best guide for the young farmer, at least until his own experiments have been tried sufficiently often to result in experience. Cold, clay soils, and those having a northern exposure, require earlier sowing than such as are warmer, from their composition or southern exposure; for the Fall growing season is shorter in the former than it is in the latter case. 445. In the Spring, oats and Spring-wheat crops may be sown as early as the ground can be conveniently prepared. This will give the force of hands and horses an opportunity of making preparation for planting other crops, especially corn, which always demands thorough cleaning and breaking up of the soil, in order to secure a good crop. Corn should be planted late enough to escape the frosts of Spring. It is a crop which requires much light and heat to cause a rapid growth, and will, therefore, make no great progress so Ion"- as the days are short and cool. Hence, we find in the lati- tude of Virginia that corn, planted about the first of April, has grown very little more by the last of June, than that which was not planted till the first of May. The planting season for corn has, then, a tolerably wide range. Good crops are made from plantings ranging over the whole period between the first of April and the middle of May. Farther south the planting period is still longer. 446. The chief advantages of early planting for corn are, in the first place, that, in tobacco-growing regions, tlie ''working" (tending) of the corn, may be as fiir advanced as 23 2GG QUESTIONS. possible before the planting of the tobacco crop requires attention ; and, in the second place, in wheat-growing regions, that the tending of the corn crop may be pretty well com- pleted before wheat harvest begins. 447. For jpf^tatoes there are two favorable seasons for planting. The first, very early in the Spring; the second, late in June, or, in more southern latitudes, the first of July. The potato is not capable of bearing very hot weather while at its highest stage of growth. The weather, at that time, should be moist and mild. When potatoes are planted about the last of March or first of April, the tubers are formed chiefly during the month of June; and, although this is a warm month, the ground has not become so hot, nor usually so dry, as it is in July. Hence, they are tolerably well ma- tured before the scorching weather of midsummer sets in. If they are planted in the early part of summer, they come up and pass through the stage of growth proper for cultiva- tion, by the time the very hottest weather has passed. Then, if they get good rains during the latter part of August and early part of September, fine tubers are formed, and a fair crop is realized. QUESTIONS ON CHAPTER XVI. § 429. In wliat two forms may manures be applied (a) ? A Jvan- tage of the liquid form ? Which form is most common ? (i) How should solid manui'es be prepared? Why? (c) Why should manures be perfectly incorporated with the soil? How accomplished? [d) Should fermented manures be exposed? Tendency of all volatile matter? (e) How should the crop find the fertilizers in the soil? When are silica and lime taken up most abundantly? What are potassa and the phosphates? Is time required for some manures? Illustrate. 430. AVhat of top-dressing ? Can any mode be imiversally employed ? To what crops and what seasons is top-dressing especially suited ? Why? Why are the Fall and Winter suitable for applying organic QUESTIONS. 267 431, 432. How may great variety be obtained in a manure? Other advantages of mixing? The first? The second? First disadvan- tage ? Second ? 433. Means used for reducing the soil to its proper mechanical condition? How is its chemical condition improved? When the ground has been prepared, what is the next step ? 434, 435. Why is the selection of seed important? Effect of plant- ing a little, shrivelled grain ? How may the quality of seed be im- proved ? In wheat ? Of corn ? Why do ears from stalks bearing double produce the same kind ? Advantages of importing seed ? 436, 437. Circumstances to be noted in determining the variety of seed ? Productiveness ? Why ? Market value ? Nutritive value ? Why should oat-seed be frequently changed ? 438,439. First step in jcirejt)a7-(7?eo« of seed? Cleansing seed-wheat? Spring-wheat? Influence of clean seed upon the quality of flour? Means of procuring clean seed-wheat ? 440-443. Advantage of steeping seed-grain ? Influence on insects, &c. ? Salts used in the solution ? Which are most powerful in their influence ? (a) First recipe ? (6) Second ? (c) Third ? Other solu- tions ? 444-447. What of time of planting? Of crops planted in Autumn? In Spring ? Time for planting corn ? Advantages of early planting ? Seasons for potatoes ? First ? Second 1 208 INDIAN CORN. CHAPTER XVII. INDIAN CORN {MAIZE). t 448. Preparation of Soil. — Principles have already- been given, which were designed to be of general application in reducing soils to their proper mechanical and cheuiical condition. A few special directions on this subject may be useful, as applicable to the culture of particular crops. 449. The most important point in the preparation of land for corn is deep, tliorourjh ploicinrj. For this, more than for any of our grain crops, the sub-soil plow is demanded — pre- ceded by draining, where this is necessary. Corn roots run deep enough to avail themselves of the benefit of all the soil which the plow can break. The earing-season of corn, too, is a period of frequent droughts; but we have shown, in Chap. XIII., that draining and sub-soiling are the best safe- guards against such contingencies. 450. The time of plowing should be determined by the quality and condition of the soil. The winter frosts are of great service to stiff clay and slaty soils ; hence, the advan- tage of plowing them in Autumn or early Winter. When the field is covered with a clover sod, or grass which is easily killed, or with litter easily rotted, it is considered a good plan to break up with the surface-plow alone, in the Fall or Winter, so as to cover the sod or litter, and let it lie in that, condition until near planting-time. It will then be suffi- ciently rotted to become readily mingled with the soil. The same plow should be again used, and be followed by sub- soiling. The decayed sod and litter will, during this second plowing, be partly turned up to the surface, and partly INDIAN CORN. 2G9 mingled with the surface-soil, giving it both a warm and meliGW character ; while the sub-soil plow will open the way for the roots to run far down, in their search for food and drink. 451. There are some grasses which are not easily killed with the plow, and which form a very tenacious sod. The varieties of blue grass, common on limestone lands, are of this character. A favorite method of treating such a sod, when broken up for corn, is to turn it down during the Winter, or very early in the Spring, and, at planting-time, run the harrow or cultivator over the top, so as not to dis- turb the sod, but leave it with its grassy surface still more completely concealed, and pressed down upon the bottom of the furrow. The rows for planting are then opened by a small bar-share plow, run so shallow as not to turn up the sod, but only to cut through the upturned part of it. The corn is thus planted in the inverted sod. The early culture is shallow, still not breaking the sod to any considerable extent. Such preparation, when accompanied by sub-soiling, is almost certain to produce a good crop. The advantage of leaving the sod so long undisturbed, is, that it may have time for complete decay, and thus become food for the crop at the period of its most rapid growth. Alluvial, and all loose soils containing much organic matter, need not be broken until near the time for planting. Weeds and grass will not then have an opportunity of commencing their growth much in advance of the corn. Soils cannot often be made too mellow for corn, nor be kept too mellow during its growth. 452. The distance apart at which corn should be planted, should vary with the richness and physical properties of the soil. A very fertile soil can of course sustain a greater number of stalks than one which does not equal it in strength. But of two soils, both equally fertile, the one of stiff clay and the other of dark loam, the latter will bear closer planting than 23* 270 INDIAN CORN. the former, because it absorbs more freely the light and heat of the sun. Yet in every case, there is a limit to the number of stalks to be left upon the ground ; and young farmers are more apt to err in having their corn too thick, than in having it too thin. The crop demands more than simply an abundance of nutrition from the soil ; it demands a full supply of both liijlit and heat, with free circulation of air. Corn, more than any other grain crop, is injured by being so much crowded as to exclude the free access of light and heat from the sun, or prevent ready circulation of air. 453. Modes of Planting. — There are two modes of planting practised by the best farmers, both of which have their advantages under peculiar circumstances. By one of these modes, the ground to be planted is marked off with furrows all running in the same direction, and parallel to one another, and at the proper distance apart for the rows. If the land is level, or nearly so, the rows are generally made straight; but if the land is hilly, they are made to wind around the faces of the hills, in such a way as to be nearly horizontal. The v,'idth of the spaces between the rows varies from three and a half to five feet. The corn is then dropped into the furrows, at from one to three feet apart, and covered with the hoe or plow to a depth which should not exceed two inches, unless the soil is very dry. "When the hills are so near as one foot, only one stalk should be left in each hill ; and even then there will be too many stalks in the rows for any but the best lands. If the hills are two and a half or three feet apart in the rows, two stalks may be allowed to grow together. The only advantages arising from having the hills wide enough apart for two stalks, are the greater convenience in hoeing, and the more free access of light and heat to the soil. But, for the absorption of food from the INDIAN CORN 271 soil, thei'e is some advantage in having the plants equally distributed in the row, each standing alone. 454. The other mode of planting differs from this, in the method of arranging the rows. The land is laid oif in two directions, at right angles to each other, so that one set of furrows run lengthwise, and another set run across the field, dividing the whole into little squares. At the corners of these, where the furrows cross each other, the corn is planted. The rows must be wide enough for the plow to be conve- niently run both along and across the field. In the large varieties of corn, which are almost exclusively cultivated in the Southern States, two stalks are as many as will grow to full vigor in one hill. 455. The principal advantages of this method are : (1) That the quantity to be cultivated on the field may be per- fectly regulated by the width of the rows. Each square, formed by the intersections of the rows, will correspond with the space occupied by each hill of corn ; or, in other words, there will be just as many corn-hills in the field as there are squares marked off by the rows, provided we reckon the margins along the fences as divided into half-squares. If, then, the rows are three feet apart each way, there will be two stalks (or one corn-hill) for every square yard of surface. If the land is tilled to the depth of a foot, each corn-hill will have the third of a cubic yard (equal to nine cubic feet) of soil to sustain it. When the soil is light, the number of stalks may be regulated to suit it, either by thinning to one stalk in each hill, or by increasing the distance between the rows, and leaving two stalks in the hills. (2) The plowing may be made more complete in the future culture of the crop, when there are two systems of rows crossing at right angles. Two successive plowings may be made to cross in the same way, and thus the soil is broken on all sides of the hills. The stirring of the soil is thus very complete and 272 INDIAN CORN. the grass and weeds are more thoroughly eradicated than they can be by the plow running only in one direction. (3) The sun has free admission to the soil. This method cannot be conveniently practised on steep land. 456. Quantity or Seed. — Each hill should have two or three times as many grains as there are stalks to be left grow- ing. By this means, if the seed has been carefully selected and kept in a dry place, and the ground is in a good condi- tion, the trouble of re-planting may be avoided. Another great advantage arising from an abundant application of seed is, that however perfect the grains may seem to be when planted, some will produce vigorous and healthful plants, while a few, at least, will produce only such as are feeble and sickly, and can never by any subsequent culture be made vigorous and productive. Five or six grains in a hill will almost always secure enough of the best quality to be left, while those of less promise may be pulled out. The trouble of thinning out in this case, will be amply rewarded in the future crop. Corn is often planted by machines constructed for the pur- pose. These should be so made that the distance between the hills, and the quantity of seed dropped, can be regulated to suit the soil. 457. Experiments. — Every farmer should test the capacity of the different parts of his land for corn, by actual experi- ment. He should, on different parts of the same quality of soil, try the cultivation of one, of one and a half, of hoo, and of ftt-o and a ZiaT/" stalks for every square yard of surface, until he finds out the number best suited to that soil. He will then know how thick to plant his corn on different parts of his farm, and will establish rules for himself far superior to any he can find in books. 458. After-culture. — The points of first importance in the culture of corn, after the planting has been properly exe- INDIAN CORN. 2,6 cutcd, wee, first, to keep the ground clear of everything •wliich- has the same period of growth, except the crop; and second/^, to stir the soil thoroughly, and to as great a depth as possi- ble, during the early stages of the corn's growth. In clay soils on which a strong grass sod has not been turned down (§ 450), a good plan is to run a coulter, made like that of the sub-soil plow (§ 339), about twice on each side of the row, soon after the corn comes up. The middle spaces may be stirred with the shovel-plow or cultivator. The process of hoeing and thinning may then follow. After this, another deep plowing will generally be sufficient. Many fiirmers, especially in the South, prefer the plan of running a small mould-board plow as near the rows as possi- ble, at the first Avorking, in such a way as to throw the earth off from the corn; following with the hoes, to cover again any roots that may be too much exposed. This is followed by a second use of the same plow, run in an opposite dii'ec- tion, so as to throw the earth back again towards the row. This method has some advantages, and is adopted in the cul- tivation of some other crops. In the first place, it gives free access of air to the soil about the roots of the crop, and gives the portion turned twice with the plow a complete stirring. Secondly, it destroys completely the first weeds and grass which spring up near the rows. As corn approaches the period of tasselling, the roots spread with great rapidity, after which deep tillage will, by breaking the roots, generally result in a degree of injury greater than any benefit arising from stirring the soil. All work, after the corn has grown to the height of four or five feet, should be done with the cultivator and hoe. The land may thus be kept clean, while the roots are left free to run out on all sides in quest of food, until they form a net-work entirely across the spaces between the rows. 459. Harvesting. — The harvesting of Indian corn has 271 INDIAN CORN. reference to two points; (1) the preservation of the fodder, and (2) the preservation of the grain. For securing the fodder, there are two methods adopted extensively in almost all parts of our country, both of which are so familiar to every one living in a corn-growing region, that a very brief notice of each, with its advantages and disadvantages, will be all that is necessary. {a) Blading and tojiping are performed where the securing of the fodder within the smallest compass, and in the most portable form, is desired. The blades below the ear, with the first one above, are stripped from the stalks with the hands, and placed in handfuls between stalks standing close together, until they are sufiiciently cured to be tied up in small bundles, and secured in stacks or under shelter. The blades are in order for being tied, or in any way handled, only in the mornings and evenings, and on cloudy days. If they are handled in dry weather, especially if it is windy, there is always considerable loss from their breaking into fragments. Topping consists in cutting off the portion of the stalk above the ear. The tops thus cut are allowed to lie in small heaps, until they are partially cured. They are then tied into bundles, and several of these put together so as to form shocks. In this condition they stand till they are perfectly cured ; that is, until the stalk, as well as the blade part, has become dry enough to prevent moulding when placed in larger bulk. The next step is to secure them against the weather by stacking, or putting them under a shelter. In parts of the country remote from high markets, and where provender is abundant, the blades are usually regarded as not worth gathering. The tops, being much more valu- able, are frequently cut, while the blades are left ungathered. Both blades and tops, when secured without much expo- sure to rain, are about equal in value to the same weight of INDIAN CORN. 275 good hay. But to secure the full forage value of tops, they must be cut into small fragments, so that the animals to which they are fed may be able to masticate them easily. I have found, when com tops are finely cut, and mixed with a little meal, and water enough to make the meal adhere to them, that my horses consume almost every fragment, and thrive remarkably well. After topping, the corn is left upon the stalks until it is sufficiently dry for the crib. It is then either pulled off with the shuck (husk)* still on it, and taken to the barn to be stripped and thrown into a well-ventilated crib, else shucked upon the stalks, the shucks and stalks being left together upon the ground. (6) The second method is to cut the stalks off at the sur- face of the ground, as soon as the ears have become hard, and set them up in small stacks (or shocks), to be cured by the air which circulates freely through them. In this con- dition the ci-op stands till the grain is dry enough to be put into cribs. It is then shucked, generally without being pulled off the stalk. The fodder, including the shucks, is then most commonly fed to cattle without cutting. The blades, shucks, and a little of the slender part of the stalk are eaten, while the remainder is trodden down, and forms valuable litter. (c) A third method is that of allowing the whole plant to stand untouched until the corn is ready to be gathered. Then after the crop has been removed, cattle are allowed to gather what they will of the standing fodder. In this case, the fodder is of little value. (cZ) In the Western States, where much larger crops are cultivated than could be secured by either of the methods above given — where the market is distant, or the great abun- dance of corn makes the price low, and where the object is to concentrate the crop into the more portable form of beef * "Shuck" is the word in common use in the South and South-west. 27() INDIAN CORN. and pork, the beef cattle are turned into the field of standing corn to eat as much as they choose, and tread down at plea- sure. Hogs are next made to follow and gather up the re- mainder. Sometimes hogs alone are allowed to gather the crop. Of course this wasteful method can only be practised whore the price of corn is low iu comparison with the price of labor. 460. Advantages and Disadvantages. — These several me- thods of harvesting corn have their advantages and disad- vantages; and the one to be pursued must be determined upon by each farmer for himself, according to the circum- stances by which he is surrounded. The method (a) has the advantage of securing the fodder in the most portable and most valuable form; and if the locality is one in which such provender commands a high price, this is no inconside- rable part of the crop. It is especially desirable in places where hay is not easily made. But it has the disadvantage of making a lighter crop of grain than either of the other plans given. The reason of this is, that the growth of the corn ceases almost entirely as soon as the blades and tops are removed. Although the grains may have become firm enough for the crop to be fully dried at gathering time, they shrink more, and will be found to be more loose upon the cob, than in the case in which the whole plant has been left standing for the same length of time, showing that it is not the more complete drying in the one case which makes the grains appear lighter than in the other; for in these two cases the opportunities for shrinkage, under the influence of drying, are the same. 461. The rule given in §468 for cutting wheat, is not so fully applicable to corn. Wheat has its highest value before the stalk is fully ripe ; but corn has not reached its highest value until the grains have become fully hardened, and glazed upon the surface. This is not generally completed INDIAN CORN. 277 until the blades below the ear are nearly all dead, the shuck partially brown, and the upper blades beginning to die ra- pidly. In that state the corn may be topped without injury, or may be cut off and removed from the ground. But the value of the fodder is then greatly diminished. The bran of corn does not, like that of wheat, increase much in thickness from being allowed to stand until it is " dead ripe." The method (i) has the advantage of securing the whole stalk for both fodder and litter, while the corn is well se- cured, provided the stacks are made small, so that the air can circulate- freely, and prevent moulding. If the corn is to be immediately succeeded by a wheat crop, this method has the additional advantage of clearing the land for the plow. In fact, it is the only method by which the ground can be brought into a good condition to be seeded down with wheat. The chief disadvantage attending this plan, is the heavy labor of cutting and stacking the corn, and the incon- venience of managing the bulky mass of fodder which it gives. The advantages of (c) are, first, the saving of labor, in case it can be more profitably expended on something else than the gathering of fodder; and, secondly, the securing the heaviest product of grain which the soil, culture, etc. could produce. The disadvantages are, first, the almost en- tire loss of the fodder; and, secondly, the greatly inferior value of the stalks for improving the soil, below what would result from using them for litter in the barn-yard. The lat- ter objection to both a and c plans, may be removed by gathering the stalks after the corn has been removed, and using them as litter. Labor-saving is the only advantage the last (r7) method can claim. It saves the labor of gathering the crop, and leaves the manure produced in feeding spread upon the land, 278 QUESTIONS. ■without the labor of hauling. Its disadvantages are too ob- vious to require even to be mentioned. 462. Cribbing. — The crop should be allowed to become as thoroughly dry in the field, as the season and the time required for gathering will justify. Every experienced far- mer knows how readily corn becomes musty, when thrown into a large bulk in a damp condition. This often takes place around the cob, when the external condition of the ear indicated entire dryness. The cob parts with its moisture very slowly, and generally contains a great deal when the corn is cribbed. To guard against damage from this source, cribs should be well ventilated. The walls should have numerous openings for the free admission of air. The floor should be elevated at least a few inches (or, still better, a foot or two) above the ground. If the floor is made close, strips should be put across it which will hold uj) the corn sufticiently to allow a free circulation of air. If the body of the crib is large, poles or laths extending across from side to side, at various points, especially for the first few feet above the floor, will aid in the circulation of air, and conse- quent drying of the corn. QUESTIONS ON CHAPTER XVII. 448 — 452. Wh.at is the most important point in preparation of soil for corn? Why is sub-soiling important? How is the time of plow- ing determined? Treatment of clover-sod? Its second plowing? Treatment of stiff grass-sod? Planting on such sod? Preparation of alluvial and sandy soils ? How is the distance between corn-rows and hills determined ? Danger of planting corn too thick ? 453 — 457. First mode of planting mentioned ? Describe it. Width of spaces? Distance between the hills ? Second method ? Laying off the ground? First advantage of this method? To determine the space appropriated to each hill ? Second advantage ? Third ? How many grains to the hill ? Why? Use of machines in planting corn ? How should every farmer test his soil ? QUESTIONS. 279 458. First point in after-culture of corn? Second? What if the soil is stiff sod ? What, if not ? Plow to be used ? Hoeing and thinning? Method of turning the mould from the row? Advan- tages ? When should deep tillage of corn cease ? 459 — 462. The two points to be noticed in harvesting Indian corn? (ff) How are blading and topping conducted? Value of blades and tops? [b) Process of cutting up corn? How is the fodder used ? (c) Third method? {d) Method in the Western States? Advantages of method (a) ? Is corn injured, like wheat, in becoming " dead- ripe"? Advantages of method (6)? Methods (c and d)t Condi- tion of corn befoi-e cribbed? Why? Construction of cribs? Ven- tilated how? 280 WUEAT AND OATS. CHAPTER XVIII. WHEAT AND OATS. 463. Preparation op Soil. — Deep plowing is not so important for wheat or oats, as it is for corn, because their roots do not naturally run so deep ', nor does their season of growth so frequently subject them to drought. But a point of great importance in the preparation of land for wheat especially, is that it shall be as dean as possible at the time of sowing. Grass and other green substances, whether they are plowed down just before sowing, or left strewed over the surftice after the sowing is completed, are often injurious, and seldom beneficial, to the crop of wheat. So when straw, or litter of any kind, is spread over wheat in Autumn or early Winter, more harm than good generally results from the application. The injury is supposed, by some judicious formers, to be owing in part to the fact that the litter serves as a harbor for chinch-bugs and other mischievous insects, and in part to the fact that the shading caused to the green crop makes it too tender near the root to stand the severities of winter so well as it would without such covering. (^Jour- nal State Agricultural Society, vol. ii. p. 69.) 464. When green crops or unrotted manures are plowed down for wheat, it should be done in the summer, that they may be well decayed, and ready to feed the newly-planted crop In the first stages of its growth. Clover, peas, and other leguminous plants having considerable quantities of nitro- genized matter in them (§370), undergo speedy decay; and may, therefore, be plowed down at a later period than would WHEAT AND OATS. 281 be suitable for most other crops. The time for this kind of fallowing of grass and clover-fields, must of course vary, to some extent, with variations in climate, soil, and exposure. 465. The cultivation of such crops as tobacco and potatoes, is found to be one of the best means of preparing a soil for wheat. The benefit in these cases seems to arise chiefly from the clean condition in which they leave the soil. There is also a probability, at least, that these, as well as some other crops, leave the soil in a favorable chemical condition for wheat. The rotation of wheat after corn is regarded, by our best Valley farmers, as affording but a doubtful chance for a good crop. The chances after oats are regarded as much more favorable, especially if the oat stubble is turned down early, that it may rot, while the scattered grains left upon the ground may spring up, and be destroyed during the seeding of the wheat. 466. Manuring. — Some farmers put off the application of their stable and yard manures to wheat, until winter or spring. When this is done, they are usually but poorly compensated for their labor. Winter wheat has two periods of growth : the first in Autumn, and the second during the following Spring and Summer. The vigor of the crop, in its second period, generally depends very much upon the healthful development of those parts of the roots, which are natural to the first, or Autumn period. If, then, manure is incorporated with the soil at the time of sowing, the impulse given to the wheat plants in Autumn is almost certain to continue until the crop is matured — unless some phi/sical cause come in to prevent it, such as drought, or the depre- dations of insects. But when manure is spread upon feeble wheat in Winter or Spring, it comes too late. The basis of a good crop is not there. As well might you expect to make a great ox from a stinted calf, as to make a good crop in such a case as this. 24* 282 WHEAT. 467. Modes of planting Wheat. — There are two plans pursued very largely in the planting of wheat. (1) The old method of sowing broadcast with the hand is still kept up on nearly all of the small ferms, as well as many of the larger ones, throughout the Union, but especially in the South. The slovenly method of sowing the grain among the standing corn crop, and covering it with shovel-plows or cultivators, is fast passing out of flivor. The custom of breaking up the ground, whether fallow or corn and oat stubble, &c., with the large plow, then sowing and covering with the harrow, cultivator, or shovel-plow, is still extensively prevalent, and is well suited to many soils, particularly the tenacious clays, which retain the roots of wheat firmly, during the frosts of winter. (2) Drilling has, within a few years past, been rapidly gaining favor among our progressive agriculturalists. The majority of those who have tried this method would be entirely unwilling to give it up. The annexed figure (48,) Fig. 48. will assist those who have not seen the " drill," to form a tolerably correct idea of its mode of operation. The drawing WHEAT. 283 is taken from the " Southern Planter," and represents Bickford and HuiFman's Iron-cylinder Drill. This Instru- ment has "attachments" for sowing guano and grass seed. A glance at the machine will enable any one to see that the lower part of each of the tubes, which extend downward from the axle to the ground, will open a small furrow as it moves forward. Through an opening near the bottom of the tube, and immediately behind it, the grain is discharged so as to fall into the open furrow. Then, as the machine moves forward, the soil falls into the furrow behind the tube, and covers the grain which has been deposited there. A contrivance within regulates the quantity discharged. With- out attempting any further description of this apparatus, let us see what are some of the most important results of its operation. (o) The quantity of seed may be regulated to suit the quality of the soil, the climate, and the time of sowing. Some soils bear heavier seeding than others. In climates where the winters are severe, some of the plants almost always perish, and for this some allowance must be made in deter- mining the quantity of seed applied. So northern exposures require more seed than those inclining to the south and east. Late sowing, if it be near the beginning of Winter, requires an increase of seed, because the roots, not having time to gain much vigor before Winter, will send up fewer stalks in the Spring than they would have done, if more time had been allowed for their first stage of growth ; hence, a greater number of roots will be required to yield a full crop. (6) A smaller quantity of seed is required than is used on the same soil in broadcast sowing, partly from the uniformity with which they are distributed, and partly from the increased .vigor given to the plants by the admission of light and air between the rows. These circumstances cause the roots to send up a large number of stalks. The drill is supposed 281 WHEAT. to save about one-third of the seed. On a farm of even moderate size, this saving would very soon amount to the cost of the machine. (c) The depth is uniform, and may be suited to the soil. Heavy soils require more shallow planting than light, porous soils. The covering, too, is complete, the grains never being left exposed on the surface, as is often the case where the plow or harrow has been used. The crop stands the winter frosts better, from having the roots of the diiFerent plants interwoven, and so matted together, as to prevent one from being thrown out by the freezing of the soil, without the mass being elevated together. This advantage is seen espe- cially in light and porous soils, from which wheat is so often entirely frozen out. (f?) The plants shade the soil less completely in drills than they do when more uniformly dispersed over the ground. The effect in this case is similar to that mentioned in con- nection with the planting of corn. Two stalks of corn grow- ing in the same hill, throw a shadow upon the ground very little larger than that of a single stalk standing alone. So, if the stalks of wheat are confined to narrow spaces, and even crowded in those spaces, the soil in which they grow gets the benefit of more light and heat, and of a more free circu- lation of air, than it could if the same number of stalks were more uniformly spread over the surface. The result is a more vigorous growth, and consequently a better crop. (e) Small quantities of such fertilizers as guano, plaster, ashes, &c., can be applied more directly to the wheat, and with more uniformity by the proper kind of "attachment" to the drill, than in any other way. The economy of fer- tilizers is hence very great, when they are applied in this way. Every one who farms on a sufficiently-lai'ge scale should have this valuable implement, and, moi-e especially, if his WHEAT. 285" soil is not such as to hold wheat strongly in winter. The cost (from $80 to $100,) may possibly deter one who farms on a very limited scale, but this obstacle may be very readily overcome by two or three, who have small farms near to- gether, uniting in the purchase of a drill which will, if care- fully used, serve all of them for many years. 468. Harvesting. — The time of wheat-harvest must be determined by the condition of the grain. The cutting should be done before the crop appears fully ripe. As soon as the grains have passed out of the ''milk state" — that is, as soon as the inner part has become firm, but is still soft enough to yield readily to the thumb-nail when pressed into it — the crop has its greatest value. The straw is then of a greenish-yellow, and there is still a green tinge about the head. If the wheat is allowed to stand two or three days after it reaches this stage, the straw and head assume a brown appearance — the crop has become dead ripe. The grain and straw have then both become less valuable. A portion of the starch of the grain has been converted into bran ; and, according to the testimony of the best millers, it will not make so much nor so good flour, as that which has been cut when less perfectly ripe. When cut in that condition which gives the best grain, the straw has more starch, and more albuminous matter in it, and is therefore more nutritious, than it would be if allowed to become dead ripe. Long exposure to rains has an injurious effect on both grain and straw. The dark color thus produced is owing to partial decay on the surface. When this takes place on the surface of the grain, the decayed particles become min- gled with the flour in grinding, and give it a dark shade. At the same time, repeated wetting and drying destroys the nutritive substances in the straw. Wheat should, therefore, be placed under shelter or carefully stacked, as soon as it has become suflliciently dry to prevent moulding, or heating in bulk. 286 OATS — QUESTIONS. OATS. 469. Soil. — The best chance for a good oat crop is to sow it upon corn or wheat stubble of the previous year. A freshly-turned sod seldom yields a full crop of this grain; but any land of tolerable fertility, which has been under cul- , tivatioa the previous year, will produce a fair crop of oats. 470. Planting. — The land should be plowed up in the Spring, or latter part of the Winter, and the sowing be done as early in the Spring as the weather will permit. It is a grain sufficiently hardy to endure quite severe frosts after it has come up in the Spring. Some varieties may be sown in the Fall, and will not only live through the Winter, but come forward more rapidly in the Spring, and ripen earlier than the ordinary oats. These are called " Winter oats." Their early progress often enables them to escape droughts, by which the spring varieties are cut short. This gives them an advantage in localities where early droughts are common. QUESTIONS ON CHAPTER XVIII. 32 4()3 — 4GG. Is deep plowing important in preparation of soil for v?heat and oats? Why not? What point is of great importance? Effect of straw or litter spread over wheat in Winter? The cause? When should green crops be plowed down? What crops prepare land well for wheat ? AVhy ? What of rotation of wheat after corn ?. What of manuring wheat in Winter? When should manure be ap- plied to wheat? Why? 4G7. First mode of planting? How conducted? Second mode? Describe the drill. Advantages from its use ? (a) Quantity of seed regulated? (6) Economy in seed? (c) Depth? Protection against frost? (rf) Admission of light? (e) Economy in fertilizers? 468. Time of harvesting? When is the grain fit for cutting? In- jury from standing too long? Explain this. Effect of long expo- sure to rain? 469, 470. Best preparation of soil for Oals? Season for sowing? Winter oats ? POTATOES. 287 CHAPTEK XIX. POTATOES. 471. Soil. — The potato will grow upon almost any soil, with good management and a favorable season ; but a loose, moist, and cool soil is most suitable. Well-drained swamps sometimes produce the potato with great luxuriance of growth. North-lying slopes of loose rich mould, gravelly and sandy loams, etc., are all favorable to the production of this important crop. 472. Preparation.— The ground should be prepared by a thorough plowing in the Autumn or Winter. But if the land has a clay sub-soil, this should not be turned up to the surface; it should, however, be well broken with the sub-soil plow. In the Spring, at the time selected for planting, ma- nure should be applied either immediately before planting, or in the drills with the potatoes. If manure is abundant, the best method of applying it is to spread it broadcast over the soil, and stir it completely into the loose mould, to the depth of four or five inches, by plowing and cross-plowing as many times as may be necessary. If manure is not abun- dant, it is more economical to use it in the drills for covering the tubers at the time of planting. 473. Manures. — The best manure for potatoes is fresh stable, or hog-pen scrapings, mixed with a large portion of broken straw, leaves, or other litter.* From ten to twenty tons per acre, as the soil is more or less fertile, should be * The horses and hogs can be made to do the mixing. 288 POTATOES. applied, in case it is spread upon the surface. A smaller quantity will be sufficient when applied in the drills. When only a light application of this kind of manure can be afford- ed, a little guano may be mixed with it, very much to the advantage of the crop, especially on light, thin soils. 474. Planting. — In our southern climates, the great enemy of the potato crop is the hot sun, and particularly when accompanied by drought. Our planting should, there- fore, have special reference to protection against excessive heat. The best means of accomplishing this is by mMlching. If the manure has been previously stirred into the soil, the crop should then be planted in drills, at distances varying from one to two feet from each other, according to the soil and variety of potato. The stronger soils will bear closer planting than those of less fertility; and those varieties of the potato which produce their tubers within a small space around the base of the stems, as we see in the Mercer va- riety, may be planted much more thickly than such as the Long Red, which sends its tubers off to a considerable dis- tance. 475. After the soil has been thoroughly prepared, I have found, in my own experiments, that the most convenient method of planting is to open a furrow along one side of the ground (along the lower side, if not level) with a shovel-plow or small bar-share, and drop the tubers in this furrow, at distances varying from eight to twelve inches. Then, with the same plow, another furrow is run close to the row thus prepared, and the soil thrown upon the potatoes, so as to cover them about two inches deep. If the soil and variety of potato will allow of very close planting, another row of tubers may be dropped in this second furrow, and the soil from a third be thrown over upon it; the third may then be supplied with potatoes, and be covered with the soil from a fourth, and so the operation be continued till all the ground POTATOES. 289 is planted. If the soil is not very fertile, or the potatoes of the spreading varieties, the planting should be done only in every second or third furrow, as the judgment of the planter may dictate. When this process of planting has been com- pleted, a large harrow may be passed over the ground, so as to leave it with a smooth and even surface. It will be well to sow a mixture of ashes, plaster, and salt over the ground, either before or after harrowing. The mixture should con- sist of four bushels of leached or two of unleached ashes, with one bushel of plaster, and one gallon of salt; and should be applied at the rate of ten or fifteen bushels per acre. Then the whole surface is to be covered to the depth of six or eight inches with broken straw, forest leaves, or some other form of litter. This covering (mulching) protects the crop against the severe heat of the sun, prevents rapid eva- poration, and thus secures both a cool and moist soil. Be- sides this, it prevents the growth of weeds, while the potato- shoots readily find their way to the surface. The shading of the ground hastens the decay of the manure which has been applied, thus increasing its efficiency, and also promotes other beneficial changes in the soil. Potatoes planted in this ■way require no subsequent culture. If a few weeds find their way through the mulching litter, they can be readily pulled up by hand. At digging-time the tubers will be found very near the surface, and many of them even- lying upon the surface of the soil. When potatoes are cultivated in the ordinary way, in drills three or four feet apart, such manure as that recommended above should be spread upon the tubers in the drills, so as nearly to fill the furrow, then a light covering of soil be added. 476. Culture. — If the methods of planting are adopted which require future culture, all plowing and hoeing should be done during the early stage of growth. No working, 25 290 POTATOES. whicli will disturb the roots, should be done after the flower- buds begin to make their appearance; because the period has then come for the rapid growth of the tubers, and they should not be disturbed. If weeds still prove troublesome, they may be removed by very shallow hoeing, and by hand. Deep covering at the time of planting, or heavy earthing in future culture, are injurious to the crop, especially in heavy clay soils, or in very damp localities. 477. The flower-buds of the potato should be plucked off as soon as they make their appearance. The nutrition, ex- pended in the production of seeds, is almost identical in kind with that which promotes the growth of tubers. Hence, if eeeds are produced, it must be at the expense of food which would otherwise nourish the tubers. The plucking of the flower-buds prevents this abstracting of starch, gluten, &c., from the crop. Topping the vines, when they are too rank, has sometimes a like efi'cct. 478. Digging. — As soon as the tops of the potatoes die, it indicates full maturity of the tubers, and the crop should then be gathered. For if the weather sliould become warm and moist, there is danger of a second growth, which makes the potato watery, from the conversion of a portion of its starch into dextrine. The same injury results, as is well known to arise from the "sprouting" of potatoes in the Spring. After being dug, they should be dried in the open air, and laid away in a cool, dry cellar. If they are to be buried in the earth, a dry and elevated spot should be selected for this purpose, and so prepared that the water cannot collect and stand in the bottom of the bed. They should not be buried until near the beginning of Winter, as there is then but little danger of heating, and consequent rotting under the influence of warm weather. Before the weather becomes warm enough in the Spring for the sprout- ing of the tubers to commence, they should be taken up, POTATOES. 291 and returned to the cool, dry cellar. If tliey are damp when taken from the ground, they should be spread out where they will be exposed to the sun for a few hours. They may be kept in good condition for eating much longer, by being spread on a dry floor in a cool situation, than in any other way — the great object being to prevent germination. 479. Selections for planting. — Those designed for seed may be conveniently selected, either at the time the crop is laid up in the Fall, or when spread out in the Spring. For planting, those tubers of medium size are best, because their buds (eyes) are generally more vigorous than those of the very large or very small ones. The object in planting this, as well as all other crops, should be to secure plants which are healthy and vigorous at the very beginning of their growth. It is well known that the part of the potato tuber, most remote from the point where it is attached to the root, has a greater number of eyes than any other part. These eyes are less vigorous than those more sparsely scattered over the parts nearer the root-cud, and will consequently give more feeble plants. A single tuber, of average size, has too many eyes for a single hill, and should, therefore, be cut in two. In doing this, attention should be given to what has just been said about the eyes. The tuber should be so split as to have some of the best buds on each piece. This is done by dividing lengthwise, or from the root-end through to the opposite part. 480. Degenerating. — Potatoes are found to degenerata in the hands of a great many farmers, and hence an impres- sion prevails extensively that the same variety naturallt/ de- teriorates, when cultivated in the same soil and climate for several successive yeai's. This is true to some extent, if it is planted too frequently on the same land, even when the best modes of culture are pursued. It is also true when, 292 QUESTIONS. year after year, the little worthless tubers are selected for planting; and when careless preparation of soil, careless planting, and careless culture, are bestowed upon the feeble plants which spring from little, half-developed tubers. Corn, wheat, rye, and every other kind of crop, degenerates under similar treatment. ]jet any farmer try the rules and princi- ples above given carefulli/, for a few years in succession, and it is most probable that he will find the quality of his crop advancinr/ gradually, instead of retrograding. Such, at least, has been the writer's own experience. QUESTIONS ON CHAPTER XIX. §471-473. Best soil for Foiatoes 9 How should the soil be pre- pared ? Application of manure ? If manure is abundant, how ap- plied ? Best manure for potatoes ? Quantity? 474, 475. Thing to be guarded against in planting in southern cli- mates ? Best means? Distance of rows and hills? Convenient methods of planting? If the soil is not fertile, how should the dis- tance be regulated ? Application of ashes, plaster, and salt ? Ad- vantages of jnulching? Ordinary mode of planting? 476, 477. AVhen should the culture of potatoes be performed ? Why ? Effect of plucking off the flower-buds ? 478, When should digging commence? What injury from second growth? Suitable locality for burying potatoes? Proper time for burying? When should they be taken up? IIow treated? AVhy? 479, 480. When should selections be made for seed? Which tubers are best for seed ? Why ? In what part of the tuber are eyes most numerous ? Where most vigorous ? Why should tubers be cut ? How? AVhy do potatoes so often appear to degenerate ? How may this be prevented ? HAY CROPS. 293 CHAPTER XX. HAY CROPS. 481. Clover. — From the three divisions of its leaf, clover is called "Trifolium." There are several varieties cultivated in different countries, but the best for our climate is the common rod clover (^Tri/oJium pratensc^. This is a biennial plant. If sown early in the Spring, and not too much shaded by other crops, it produces a few blossoms the first season. When allowed to grow the next year to full maturity, with- out cutting, it dies ; but if it is cut or pastured, so as to pre- vent it from coming to full maturity, it lives through a third or even a fourth summer, and retains vigor enough to pro- duce a tolerably fair crop. But its heaviest product is always in the second season after sowing. 482. Some farmers believe that red clover is, by a myste- rious process, converted, by close pasturage, into another species called "white clover," from the color of its bloom. There is no doubt that the red clover soon disappears from a closely-pastured field, and that white clover (^TriJoUum repens,) springs up in its place ; but this is easily explained, without the necessity of supposing the change, above men- tioned, to take place. Red clover is naturally biennial, and, if left to its full course of development, will die at the end of the second season ; and by artificial cutting or cropping by cattle, can seldom be made to grow well longer than to the end of the third or fourth season. White clover, on the other hand, \^ perennial. Its seeds are almost always mixed to some extent with those of the red variety, and when sown together, the latter, being of a much more rapid growth, and 25* 294 II AY CROPS. a much larger plant, takes possession of the ground, while the smaller white variety is too much shaded to be distin- guishable beside its more prosperous companion. But the short-lived red crop soon runs its course and dies, while the white, more tenacious of life, remains in possession of the field, with more room to display itself as the prominent owner of the soil. 483. Soil. — Clover grows best on clay loams, having a good supply of lime, in some available form ; but almost any soil (not swampy) may be made to produce a good crop, by frequent application of ashes and gypsum. The roots of clover run deep (§353), and hence require a deeply-broken soil. The sub-soil should be well broken in the cultivation of some preceding crop, when it cannot be done at the time of sowing the crop with which the clover is mixed. If, for example, corn is to precede oats, and clover is to be sown with the oats, a good sub-soiling for the corn crop will also be of great service to the clover, since the strong roots of clover will penetrate even a stiff clay sub-soil, if it has been well broken within a year or two. It is then less apt to be frozen out in Winter, than it is when cultivated on a soil less deeply broken. 484. Sowing. — The Spring is undoubtedly the best sea- son for securing a good stand of clover, while March and April are most probably the safest months for sowing it, in our latitude. It may be successfully sown upon wheat or rye, but there is more certainty of getting it to stand well with oats — the ground being in a better condition for the seed to become covered, and for the roots to get a good hold upon the soil. 485. When sown on a field of wheat, if the surface is a loose mould, a large harrow should be passed over the soil, about the last of March or early in April, and about six quarts of seed per acre sown immediately afterwards. li' the HAY CROPS. 295 surface is somewhat liard, the clover may be sown before the harrowing is done, as there is then no danger of coA'ering many of the seeds too deep ; and the slight covering given by the harrow on such a soil, will protect the young plant from injury in the rapid drying of such surfaces. To secure uniformity in sowing, the seed should be mixed with some- thing which will increase the bulk. The seed for an acre may be thoroughly mixed with a bushel of ashes and a half bushel of plaster. The quantity to be applied can then be easily regulated by the hand, as in sowing wheat, while the ashes and plaster will fertilize both wheat and clover. The harrowing, which is to precede or follow the sowing, will not injure the wheat; but is thought by many persons to be of service to it. The wheat-gleaner, now so extensively used, is a good instrument for covering clover-seed, if the surface is not too hard. 486. If clover is to be sown with an oat crop in the Spring, the seed should be prepared as above directed, and then applied immediately after the last harrowing of oats. The harrow passing over the ground, after the clovcr-sccd has been applied, would cover it too deep. The first rain that falls will cover it sufficiently. 487. Cutting, etc. — If the clover crop is designed for hay, it should be cut at the period of its growth at which it has the greatest nutritive value. This occurs when about one-third or one-half of the heads have commenced turning brown. After this period, the sugar and starch which abound in the green stalks are rapidly converted into woody fibre, while the proteine matter speedily disappears. The first crop of the season is most valuable for hay, but the second, and sometimes even the third, may be cut for this purpose. The cutting should be so managed as to form long and regular swaths, for the convenience of hay-making. 488. The leaves of clover are very abundant, and consti- 206 IIAY CROPS. tute a very valuable part of the hay; but when the hay is dry, they are very hriitle, and liable to be wasted in making and stacking the crop. To prevent this loss, as far as pos- sible, is an important point. It is best done by letting the swath lie until the top is tolerably well cured, and then turning it over Avith a fork, without any additional tossing. The hay may be safely packed away in mows, or stacked, before it is entirely cured, if a layer of dry straw a few inches thick is spread over the mow or stack for every foot in depth of hay. The straw tends to absorb the moisture of the hay, and also to admit the air. If there is much greenness in the hay when put up, a little salt spread over it will not only assist in preserving it, but will make it more palatable to stock. The straw used in packing will be greatly improved in flavor by contact with the clover. (See Mr. Ruffin's method, § 50G.) 489. GrATHERiNG Seed. — The second crop is generally best for seed; because, in the first place, the heads are usually better filled than those of the first crop; and, in the second place, because it is more clear of weeds and other foreign plants. The first mowing clears the soil of everything, and the second growth of clover springs up with great rapidity, and is matured before almost every other plant found asso- ciated with it. The crop is thus cleaner, and being less thickly set u}X)n the ground, it has a more favorable oppor- tunity of bringing its seed to maturity, than the first crop had. 490. If there is no grass in the field which will eradicate the clover, it may be made to produce crops of hay for seve- ral years in succession. This is done by running a sharp coulter, or a sub-soil plow, through the clover very early in the Spring, so as to loosen all the soil, and give the seed left upon the land the preceding Fall, an opportunity to germi- nate and take root. The new plants thus produced will take HAY CROPS. 297 the places of the old ones as they die out. If the soil is a loose loam, harrowing and rolling will answer the purpose better than coultering. 491. Grasses. — We have not room for specific directions for the cultivation of all the grasses used in hay-making. Some general remarks on two or three of them must serve our present purpose. Timothy {Phkum pratcnse). — This is sometimes called " cat's-tail," and in some of our Northern States, " Herd's grass." It is a perennial, and makes hay of fine quality, when cut at the proper season ; and where the soil suits it, the crop is generally abundant. The Soil best adapted to timothy is a rich clay loam, moist, but not swampy. Alluvial meadow lands, free from stagnant water, and drained swamps, well subdued by the cultivation of a few grain crops, generally produce fine yields of this grass. Uplands, too, and more especially northern slopes of good clay loam, yield fine timothy, unless visited by severe drought in the early part of Summer. Solving. — Timothy may be sown either in early Autumn or in the Spring. One of the surest methods of getting a good stand of this grass, is to sow it with rye in the latter part of August. It then has time to get a tolerably strong root before Winter sets in, and it is, moreover, sheltered by the rye against the severity of frosts. If sown in the Spring, it may be put in with wheat, or with the oat crop. About a half-bushel of seed should be put upon an acre, to insure a sufficiently thick stand. The seed may be mixed with ashes and plaster, as before recommended for clover, and should be but slightly covered. As an ordinary harrow would cover many of them too deep to germinate, a very light brush-harrowing is quite sufficient; or, the method recom- mended for clover will also do well for this grass. A gallon of clover-seed per acre, added to the timothy, will make the 208 HAY CROPS. first and second crops mucli heavier than the grass alone ■will produce. Then the clover, being a biennial plant, and the timothy perennial, the former will disappear gradually from the spaces it has filled, while the latter will spread out, and soon cover the whole ground. 492. JIarvesfing. — Timothy has its highest nutritive value when the first heads begin to turn brown. A large part of the crop is at this time in bloom. The stalks are then suc- culent, and contain their largest quantity of starch, sugar, gum, and albumen. The hay should be cured as rapidly as possible, and without rain. By having the weaker hands engaged in tedding immediately behind the mowers, and then in turning, as soon as the top becomes tolerably well cured, it may be prepared in a few hours to be put up in small hay-cocks, where it will soon become sufficiently cured for the stack or the mow. It should be sprinkled with salt (5 or (3 quarts to the ton) when packed away. The after-crop of timothy makes a pasture of very supe- rior quality, for cattle, sheep, or horses. This grass also adds to the fertility of the land, partly by the decay of its abun- dant crop of blades about the root, and partly by the gradual decay and reproduction of its bulbous roots. 493. Orchard Grass. — This grass will grow upon almost any soil which is not swampy. It may be sown in the Spring with clover, which it eradicates after one or two seasons. It has a very strong root, and is not easily overcome by other grasses : it is, hence, very suitable for lots designed to be kept in grass for a long time. It starts early in Spring, and con- tinues green quite late in Autumn ; and is, therefore, valu- able for early and late pasture. As a hay crop, it holds no very high place generally. When harvested for hay, it (should be cut in full bloom ; because the hay has then its highest value, and the maturing of the seed, which is ex- hausting to the soil, is prevented. HAY CHOPS. 299 The sub-soil plow, when run beneath the sod of this grass once in two or three years, is of service, especially if the process is followed up by a top-dressing of stable or yard manures. Ashes and 2)l((sfcr should be used freely and fre- quently on all grass lands. The grasses demand an abun- dant supply of lime and potassa (see Table III). 494. Pasture. — For permanent pastures, limestone soils are most suitable ; and where they are level, and at all swampy, draining is wanted, to make them yield a crop which is good in either quantity or quality. The most durable* and nutri- tious grasses for pasture are what are called " Blue-grasses." The Kentucky Blue-grass should, most probably, stand first on the list, and should be introduced into every limestone region. The common " Spear-grass," or greensward, is an- other species of the same genus, and forms fine pasture. The proper care of pasture lands is too much overlooked by many of our farmers. Worthless briars and weeds are too often seen to occupy much of the best soil, where a little timely attention and labor would have secured a rich green sod of sweet and nutritious grass. Top-dressing with mine- ral and other fertilizers, will often be found as profitable on pastures, as upon cultivated crops. In those sections of country where the perennial grasses will not thrive, more attention should be given to the intro- duction of the annuals and hienm'als, to be cut for hay. The annual meadow-grass and biennial rye-grass, with other va- rieties, have been cultivated where those of more permanent character will not readily take root. The different varieties of millet, oats cut in full bloom, and corn sown broad-cast, or thickly drilled, all make good substitutes for hay, on lands where the best hay grasses and clover are not easily or abun- dantly produced. Experiments. — Every farmer should make repeated ex- periments on his own lands, with various kinds of grass, that coo QUESTIONS. he iiuiy dcteruiinc which are best adapted to his soil. Then it sliould be an established rule : (1) jVcocr to allow a field to he out of clorcr, or some Mnd of grass, when it is not oc- cupied hy other crops; (2) Never to miss an opportunitt/ of fallowing with clover or grass sod. It is the cheapest way of enriching a soil. QUESTIONS ON CHAPTER XX. 481. Why is Clover called Trifolium? Best variety for our cli- mate ? What is a biennial plant ? Its growth the first season ? The second ? When does it produce its heaviest crop ? 482, 483. What do some believe in regard to the change of red into white clover? How explained? Best soil for clover? How ma}' any soil be made to produce it ? Why is deep plowing important? 484,485,486. Best season for sowi'/jy clover ? On what crops may it be sown? How treated when sown on wheat? How is the sow- ing rendered uniform ? If clover is sown on oats, should it be har- rowed ? Why not ? 487, 488. When should clover be c«i! /or Aery.? Why? Which crop is most valuable ? Why do the leaves of clover require especial care? Does it be.ar tossing? How may straw and salt be used for hay? 489,490. Best crop for «eerf .? Why? Why clear of weeds? How may clover be made to produce good crops for several years in suc- cession ? How to be treated if the soil is loose ? 491, 492. What is Timothy sometimes called? Why called a pe- rennial ? What soj'Zi best adapted to it? Seasons for som-'w^.^ With what crops may it be sown ? How much seed per acre ? How pre- pared ? AYhat of mixing clover-seed with it? AVhen should timothy hi: cut? Why? How cured? For what is the after-crop valuable? How does it enrich the soil? 493, 494. Soils adapted to orchard grass ? When sown ? For what lots is it suitable ? Its value for pasture ? As a hay crop ? When cut? Why? How should it be treated occasionally? Lands best suited for pasture? How treated if they are level and swampy? Best grasses for pasture? Examples? How should pasture lands generally be treated ? What may be substituted for perennial grasses ? How should every farmer test his own lauds ? What established rules should be observed everywhere? BEANS AND PEAS. 301 CHAPTER XXI. BEANS AND PEAS. 495. Value. — There is a large class of plants which have their seeds enclosed in a sort of bivalve pericarp, usually called a ''pod." These are called "leguminous" plants. The different kinds of hean and pea are examples of this class. The varieties of clover are also leguminous, having their seeds enclosed in pods. Red clover has usually one seed in every pod, but some kinds of white clover have seve- ral together in the same pod. 496. This whole class of plants is remarkable for the quantity of nitrogen they contain. The nitrogen is chiefly found a.s one of the constituent elements of a proteine body, which we have called "legumen" (§ 157). All the proteine compounds have been spoken of as possessing a high nutri- tive value, and as forming a most important ingredient of animal food. They bear a relation to animal nutrition some- what similar to the relation of ammonia to plant nutrition. The legumen of beans and peas is so abundant as to place them above both wheat and corn in nutritive value. On this point more will be said hereafter. The stalks of these plants also abound in proteine matter, and in that respect resemble clover hay in composition and value, and hence make excel- lent rough forage for stock. 497. We have learned that, when proteine substances un- dergo decay (§ 159), ammonia is always one of the products. This has also been mentioned as the most valuable ingredient in organic fertilizers. If, then, bean and pea crops are plowed into the soil at the proper period of growth — that is, at the 26 302 BEANS AND P K A S . period when tliey contain the greatest amount of protcine matter — considerable quantities of that most important fer- tilizer, ammonia, are generated in the soil. Clover was once regarded as almost the only suitable crop to be employed as green manure, but experience has shown that other legumi- nous plants have a similar value ; and, in some climates and soils, certain varieties of beans and peas seem to be even superior to clover for the purpose of fallowing. 498. Varieties. — DiiFerent latitudes require different varieties. Those only which have a comparatively short period of growth, are adapted to the Northern States. Such are the China Bean, Horse Bean, and the different varieties of Field Pea. Those which require a longer season and more hot sun, are confined chiefly to the Southern States. There is a species of hean cultivated extensively in some of the older Southern States, of which there are a good many varieties. All the varieties are embraced under the general names of ''Cornfield Pea" and " Southern Pea." Mr. Ed- mund Ruffin, Sr., in his valuable Essay on this crop (for which a premium was awarded by the Virginia Agricultural Society, 1854), enumerates nine varieties. (1) "The buff- colored pea, usually called either the cow or day pea.^' (2) '' The Bass (red) pea, used extensively on the Lower Roan- oke, in N. C." (3) " The hiack-ryc pea, of several varie- ties, was formerly most generally known, and indeed was almost the only kind cultivated." (4) " The early black pea has perfectly black and large seeds." (5) " The mottled or shinney pea, which has been so much celebrated in latter years, differs in some respects from all others. The seed are of a light brownish color, thickly streaked or mottled with deeper brown." (6) "Large black or Tory (late) pea." (7) " Small black and late pea." (8) " Green-eye white pea." (9) " The small green or bush pea " — sometimes called " Chickasaw" and " Oregon Pea." But these are by no BEANS AND TEAS. 303 means all the names applied to the varieties of " Southern Pea; for the same variety passes under different names in different sections of the same State. '' This kind only, of all enumerated and described here, seems to be a true pea ; and, therefore, is not of the same species with all the other kinds here termed varieties of the Southern Pea." 499. Climate. — The different species of bean have the quality of gradually adapting themselves to different lati- tudes, at least to some extent. If the pods which first come to maturity are always selected for seed, the time of ripen- ing may be made to occur several weeks earlier, after a few years' culture. At present, the Southern Pea is not much cultivated north of 37° 45', nor will many varieties come to maturity so far north as this, in an ordinary season. But with proper attention several of them might, most probably, be adapted gradually to still higher latitudes. Their great value, for both forage and manure, would certainly justify a fair experiment on this point. 600. Some of the earlier kinds, such as the ''Early Black" [(4), above] and the "Shinney" (5), are thought to be best adapted to the climate of Virginia ; taking into con- sideration the time of maturing, and their productive value for feeding and fallowing. For table use some of the lighter colors are generally preferred, such as the "Black-eye" and " Green-eye White Pea." In more southern latitudes, the " Shinney," " Clay," and "Bass," are among the varieties preferred, and most extensively cultivated. 501. Soil. — Crops of this class will grow well on almost any kind of land not deficient in lime. The best soil for beans is a warm, sandy loam, of medium fertility. A very rich soil produces a most luxuriant growth of vines, espe- cially in the "Southern Pea;" but the quantity of seed is then but small. On medium quality of soil the crop of vines is not so heavy, but the grain crop very abundant, provided 304 BEANS AND TEAS. the culture and season have been favorable. The very 'poor soil will generally produce a crop sufficient, when turned under, to add considerably to its fertility. This is proverb- ially true in the culture of the Southern Pea. Land in lower Virginia, which "will not produce Black-eye Peas," is re- garded as in rather a hopeless condition. South of 37°, almost an}' soil may be restored to fertility from the most exhausted condition, by cultivating the pea, with the appli- cation of some form of lime ; either marl, caustic lime, gyf- stim, or ashes, attended with proper rotation, and as frequent fallowing as possible. 502. Plowing, for bean and pea crop, should be deep and thorough. The roots penetrate a well-broken soil to a great depth ; and as the plant gathers mineral substances largely through its roots, especially lime and potassa, with sulphuric and phosphoric acids, these will be transferred from the lower to the higher parts of the soil, and be left by the decaying crop in a good condition to form the food of succeeding crops of grain, tobacco, cotton, etc. 503. Planting. — The methods adopted for planting may vary with the object to be attained. If the crop is cultivated for its grain and forage, the largest yield can be obtained by cultivating in rows, varying in distance according to the kind of bean or pea to be planted. The varieties which grow erect (bush-beans) may be planted in rows two or three feet apart. Those which spread their vines, like the Southern Pea, should be in rows from three to four and a half feet. The seed may be drilled in the rows, or planted in separate hills. If the object is to prepare a crop for fallow, the land should be well prepared, and the crop sown broadcast, and covered with the harrow or cultivator. 504. The Southern Pea has been cultivated in the Southern Atlantic States from time immemorial. Some of the methods BEANS AND PEAS. 305 pursued in Virginia, and the States farther south, arc the following : 1st. " The oldest and still most extended culture [in Vir- ginia], is to plant the peas after and among corn. When the corn is mostly about 8 or 10 inches high, and has been just plowed and hoed, peas are planted, either in the nar- row intervals between the stations of corn, if in drills; or otherwise, in a plowed furrow, the last made by the plow in the middle of the wide intervals between the corn rows. In either case, usually 10 or 15 peas are dropped together, and come up and grow in a cluster. So many seeds are put to- gether, for the 3'oung plants to better force their passage through the earth. But some experienced cultivators of North Carolina think that 5 or 6 plants together, produce better than a greater number. One more plowing is all that is afterwards given to the corn — which, at very little more trouble, is all the culture required for the peas. " 2d. The next most extensive, though, in Virginia, a very recent mode of pea-culture, is also as a secondary crop amongst corn, but made by sowing broadcast, when giving the last horse-tillage, and covering the seeds more or less perfectly by that tillage process. This costs but the seed and the labor of sowing. The crop all goes for manure, and is seldom ripe enough (in Virginia) for good manure. " 3d. The third mode, and, as I think, the cheapest and best, to raise the pea-crop for manuring, is to sow tho seed broadcast, on a separate field, or without corn." — Edmund Hvffin's Essay, Ya. IS. Ag. Soc. " In sowing peas broadcast as a fallow crop, in preparation for wheat or other crops, the land should be broken up in the Winter deeply, and about the first week in June (in our latitude), the peas sowed at the rate of one bushel or five pecks to the acre, and either harrowed in with a heavy har- 26* 300 BEANS AND PEAS. row, or plowed in with single plows, according to the state of the land." — P. M. Eclmomhtoii, of North Carolina. 4th. " In planting as a separate crop, break up the land, if possible, in Winter; and at the time of planting (which in this latitude is best during the first fifteen days of June), run oiF the land in rows 4, 42, or 5 feet distant, either by running one furrow, or listing with three furrows, according to the condition of the land. If it is grassy, it should be listed — drop the peas from two to three feet distant in the row, from ten to fifteen peas in a hill, and cover with the hoe, harrow, plow, or cultivator with the front hoe removed. After the peas have made two or three of the second leaves, run the bar of the plow as near as possible, throwing the earth from them, as in the first working of corn, and, if necessary, throw out the middle and run over them with the hoe, cutting out the grass and weeds, and a little after the vines have commenced to run, plow again, throwing the earth to them. This is all the cultivation necessary; and on fertile land, with favorable seasons, it will give a good return for the labor spent — say an average of sixteen or twenty bushels to the acre, which, at seventy-five cents per bushel, will equal twelve or fifteen bushels of wheat, at one dollar per bushel. This method of planting will take about one peck and a half, or three half-pecks, to the acre." — Llem. This last method is best when the peas are to be gathered, not only because the mode of culture brings a better crop, but because of the greater convenience of gathering. It has the further advantage of leaving the land in a condition free of grass and weeds, and hence in a better state of preparation for the succeeding crop. Some farmers prefer it even for fallows, because of the greater certainty of getting a good stand of peas when planted in this way. When peas are planted with corn, they do not seem to in- terfere, to any great extent, with the growth of the corn BEANS AND PEAS. 307 crop ; because the latter is well matured before the peas reach their stage of most rapid growth, provided they are not planted before the corn approaches the time of tasselling. 505. Gathering. — "When the pods are ripe, or enough of them to provide as much seed as is wanted, they are picked off by hand; and when sufficiently dry, are threshed out with flails or sticks, or are run through a threshing ma- chine. If the greater part of the crop is intended for ma- nure, it should be plowed down as soon as the gathering is finished. The seeds are believed to have a higher fertilizing value than the vines, if they come to maturity; but by this time the vines have lost part of their value. The question as to the proper time for plowing down resolves itself into this form: "When will the seeds and vines together, gene- rate the greatest amount of ammonia in the soil?" Chemistry would reply, — "When nearly all the seeds have become Jinn in the pods, but not dry." At this time the most forward pods will be dry, but the vines will still retain much of their greenness. Consequently, the seed portion of the crop will now contain nearly its maximum quantity^ of ammoniferous matter, while the vine j^ort ion will not yet have lost much of what belonged to it. This is the theory which science would present to the inquirer, inde- pendent of experiment, and based only upon the well-known character and composition of bean and pea crops generally, at the different stages of their growth. The experiments of the most successful pea-growers of the South confirm these simple deductions of science. 506. If the vines are to be used as forage, they may be cut off close to the ground with sharp hoes, or still better with short stout scythes, and cured like clover hay. The curing is a somewhat difficult process. IMr. Ruffin remarks, that " at maturity of growth they should be pulled up, if planted in clusters (or perhaps cut by the scythe, if broad- 308 B K A N S AND PEAS. cast ?), and put up in tall and slender shocks, supported by a small stake set in the ground, to remain till cured enough to stack, or to be put away in a house." Clover may be cured in the same way. 507. Mr. Edmondston, of North Carolina, says: "As an article of forage or fodder, there is none superior to the pea- vine. Horses and cattle will eat it with avidity, and in pre- ference to any other kind of fodder. The difficulty of saving these vines has constituted the chief objection to their use. The writer believes that they can easily be saved, by cutting them oflF close to the ground with sharp hoes, in the month of September ; and then, having first provided forks and poles, plant the former in the ground in a straight line, and so place the poles upon the forks, that a common-sized man can clasp his hands over the poles [?'. e., they must be about 6 feet above the ground]. Place rails, with one end resting upon the ground, the other upon the pole, about 6 or 8 inches apart, after the manner of a top-stack or fodder- house, as it is called, leaving both ends open, and upon these rails throw the vines, until they are about one foot deep ; throw over all some straw or grass, and a good supply of the best fodder for milch cows, or any other kind of stock, will be obtained." 508. The Black-eye, and other early varieties of this pea, grow well in the valley counties of Virginia south of Au- gusta, at least well enough to give a good fallow ; and it is probable that they could soon be acclimated still flirther north, at least until a sufficient growth could be attained to make them well worthy of attention as a fallow crop. They grow well on both the clay and sandy soils of the south-west- ern part of the valley ; and in cases where soils are too poor to produce clover, the pea may be cultivated and turned down, until the soil is rendered sufficiently fertile for the improvement to be continued with clover. Another valuable QUESTIONS. 3C9 purpose might be served by attention to this crop. There are cases in which farmers fail to get a stand of clover ; sometimes this occurs repeatedly for several years, until the land suffers seriously for want of a fallow crop. When such failures occur (and they are not unfrequent), a pea crop might be sown, and the land fallowed the next season. The Southei'u Pea could thus be made a valuable auxiliary to clover in enriching our lighter soils, and in rendering our stiff clays more mellow, as well as more fertile. 509. The wheat drill may be used in planting peas. The quantity of seed can thus be regulated with accuracy; and in cases where the drills are thought to be too close, every alter- nate tube may be closed up, and the drills will then be double the width of those of wheat. QUESTIONS ON CHAPTER XXI. ^§ 495, 496, 497. What are leguminous plants ? Examples? What valuable element do they contain in large quantities? What prote- ine body is found in them? What of the stalks? Product of the decay of proteine bodies? What if bean and pea crops are plowed down at the proper season ? What was once regarded as almost the only crop suitable for falloicing? 498. Varieties for different latitudes? What suited to the Northern States? What extensively cultivated in the Southern States? Va- rieties of the Soulhern Pea?" 499, 500. What is said of adapting themselves to climate? IIow may they be rendered earlier? Present limit of the Southern Pea? AVhich varieties are best adapted to the climate of Virginia? Which variety best adapted to table use ? Which to culture in the States farther south ? 501, 502. What soiV best adapted to beans and peas? Influence of a very rich soil? What of the crop on poor soils? Where may the Southern Pea be especially available in restoring poor soils? What mineral manures does the crop require? What kind of plow- ing does this crop demand ? Why ? How does the crop fertilize the eoil? 310 QUESTIONS. 503, 504. Modes of Plantmg. — If cultivated for grain and forage, what should bo the mode of planting ? If the crop is to be plowed down for fallow, how may it be cultivated? First method given as practised in the Southern States? Second method? Method prac- tised in North Carolina for fallow crop ? Describe the fourth method. Why is this last method best where the peas are to be gathered? Why do they interfere so little with the corn among which they are planted ? 505 — 509. 3Iodc of Gathering. — If the crop is intended chiefly for manure, when should it be plowed down? Value of the seeds as a fertilizer ? What question decides the time for plowing down ? How does chemistry settle this question? How does experiment settle it? How are the vines collected for forage ? How cured? Their value as forage ? Chief objection to their use ? Method of curing given by Mr, Edmondston, of North Carolina ? What varieties grow in the valley of Virginia? Of what crop may they prove an auxi- liary ? What instrument may be used in planting peas ? TOBACCO. 311 CHAPTEE XXII. TOBACCO. 510. This important Southern crop is becoming more and more widely cultivated, and the prospect of continued high prices is inducing many of our farmers to turn their atten- tion to its culture, in portions of Virginia and other States, both north and south of us, where, in former times, people have grown up to manhood without ever having seen a growing crop of tobacco. While so many new hands are thus engaging in its culture, it becomes important to have the leading points and principles involved in its management collected and set forth in a concise, systematic, and accessible form. The following discussion of this subject is the result, first, of the writer's personal observations of the methods pursued by some of the. most successful planters in Virginia and Kentucky; secondly, of information gathered from those familiar with the business; and thirdly, of gleanings from books and agricultural journals — especially the "Southern Planter." 511. Climate. — Tobacco requires a long summer season to bring it to maturity. Hence, so far as our own country is concerned, the best tobacco can be cultivated only in the Southern States. Elevation has an influence somewhat similar to increase of latitude, not in the varying length of days, but in the lateness of Spring, and the early appearance of the cool nights and frosts of Autumn. This makes the culture of tobacco uncertain in the high and mountainous parts of Western Virginia, while a like risk is not felt in 312 Ton A ceo. tlio same latitude further east, where the elevation is not so great. A variety, called the " Connecticut Seed-leaf," is begin- ning to be cultivated in considerable quantities in New England, and at present commands a good price. It requires a shorter season than the kinds cultivated farther south. 512. Soil. — Tobacco will grow upon almost any good soil, when well prepared by thorough tillage, but that best adapted to its culture is a rich, dry loam, newly cleared and brought under cultivation. Although the light clay and sand loams, well manured, are the most reliable for making the finest qualities of tobacco, yet the clay soils — even the stiff clays of the limestone formation of the Valley of Virginia — produce excellent crops, but they require free applications of rich organic manures to render them suffi- ciently porous. The sandy loam, which has been drifted down from the mountain-gorges, along the northwest side of the valley, is well adapted to the growth of tobacco. 513. Varieties. — " Owing to the great diversity of cli- mate and soil in Virginia, a corresponding change is pro- duced in the grades of tobacco raised throughout the State, yet she produces more valuable tobacco than any other State in the Union. The Orinoko and the Prior for manufac- turing, and the White Stem and Big Frederick for shipping, both in strips and stems, are the most profitable to the planter of all the various kinds rai.sed. Having had twenty years' experience in cultivating and manufacturing, and the la-it five years in selling the article, I am clearly of the o; inion that, on all lands suitable, the Orinoko is decidedly preferable for manufacturing, from the fact that it is the only kind that is sweet by nature, if ripe. It should be sun-cured, or as much so as the season and circumstances will admit. If thoroughly ripe it is much easier to be cured of the right color (I know of no object in nature that is TOBACCO. 313 nearer that color than the land-terrapin, which, doubtless, is familiar to every planter), and it stands manufacturing better. If cut before being ripe, it chews bitter, its color is forced, and it will not hold it. The Prior is a good kind to culti- vate on all mountainous lands, as it stands the wind better than any other kind, being tough. For shipping purposes, I give the preference to the White Stem. It can be grown large and rich, is smooth and tough when cured, and loses less weight in the curing than any other kind." — W. H. Brown, ^'Southern Planter," Jan., 1854. 514. Plant-beds. — The climate, the soil, and the variety to be cultivated, being all favorably determined, the first and one of the most important ends to be attained, in order to insure success, is to secure an abundance of (/ood plants. To do this, the planter must look well to the preparation of his plant-beds. Of these he should have several, sown at dif- ferent periods, or one very large one, divided into several parts, to be sown at different times. He will thus secure a succession of plants, and can then avail himself of the most favorable season for " planting out." The condition of weather for the germination and growth may be very unfa- vorable after the planting of one bed, but more favorable for one planted earlier or later. To meet all the contingencies that may arise, and still secure an abundance of plants, enough of ground should be sown to produce (if all portions do well,) a large excess over what the crop to be raised will require. 515. Preparation of beds. — The general practice is to burn the surface of the beds before planting. A warm and dry locality, exposed to the sun, and well protected against cold winds, is most suitable. A southern or south-eastern exposure should be selected, if possible, having a loose, rich soil. It should be well cleared of roots, stones, and every thing that might interfere with a proper tillage of the sur- 27 314 TOBACCO. face, or with the subsequent growth of the young plants. The burning process is then conducted by covering the bed entirely, or in part, with brush or logs previously collected, and igniting them at a time when they are dry enough to burn freely. The fuel should not be allowed to lie flat upon the ground while burning, but should be sustained upon cross logs placed beneath it. The whole bed need not be covered with fuel at one time ; because, when one portion has been subjected to the fire for an hour or two, the burning fuel may be removed to another portion, and thus the several parts be burnt in succession. Some important effects are produced by this roasting process. In the first place, any seeds of grass, weeds, &c., which may be in the soil, ready to spring up with the plants, are entirely or partially de- stroyed; and secondly, the condition of the soil is improved by burning (§ 424), and by the quantity of ashes left upon it. Beds should generally be burnt just before they are sown ; though, in some soils, it is better to burn and expose to frost a few weeks before planting. As soon as the surface is cool, guano, or some finely-pulverized manure rich in am- monia, and clear of seeds of every hind, should be freely applied, and the surface then be finely chopped up with the hoe, and smoothly raked. It will then be ready for the seed. "About two table-spoonsful of seed for every 100 square yards will be sufficient, and not too much. The seed are mixed with old ashes, and, to sow them regularly, it is best to sow one half over the bed, and the other half across the first sowing. It is then trodden, and thickly covered with brush." * The object of the covering with brush is to pro- tect the young and tender plants against frost and sudden changes of weather, and at the same time to admit the air, and the light and heat of the sun. The covering is removed * Wm. H. Jones, "Southern Planter" for November, 1854. T^OBACCO. 315 when there is no longer danger of frost. One bed, at least, should be sown during the Winter, and others betimes in the Spring, so as to multiply the chances for an early supply of plants. Then, for later plants, another sowing should be made at a more advanced period in the Spring. Plants have been successfully grown by the application of guano abundantly, without the labor and expense of burning. . — (*S^ee '^Journal V. S. Agricultural Society," Vol. II., pp. .69, 70.) 516. The fly is the great enemy of plant-beds. Various remedies have been tried for this evil, but none, perhaps, have succeeded better than the sprinkling of dry, fresh ashes, or newly-slacked lime, over the leaves of the young plants, by means of a sieve, or with the hand, as soon as the fly begins its depredations. An occasional application of guano and plaster, during the growth of the young plants, has the efi'ect generally of push- ing them forward, so that they spring up rapidly in spite of the fly. All weeds and grass should be pulled out of plant-beds as soon as they begin to make their appearance. To render the process of weeding convenient, and also to facilitate the drawing of plants, the beds are-frequently divided into smaller secondary beds, four or five feet wide, with narrow walks between them. 517. Preparation of Soil. — This is a point of the very first importance in making a crop of tobacco. The soil must be both rich and mdlow. If the land is neidi/ cleared, all the undergi'owth must be well grubbed out, and everything be burnt upon the land, or removed fi-om the surface, which would impede the culture of the crop. This should be fol- lowed by two or three thorough coulterings, with strong teams, so as to break up as completely as possible all roots left in the soil. Hands should follow the coulter to cut out 316 TOBACCO. and remove all the broken and exposed roots. The soil should be thoroughly plowed, and then listed and hilled in the best way, which the number of stumps present, and the general character of the surface will permit. Sometimes the hilling has to be done altogether with hoes, on account of the steepness or roughness of the ground. Such is often the case on the steep lands of those counties lying along the base of the Blue Ridge, and in many other places. At other times the soil may be first thrown up into beds or lists, and these be divided into hills with the hoes. New land is generally the best for tobacco. But in the best tobacco-growing sections, the land is nearly all cleared, except so much as is required to be kept in timber for fencing and fuel. The preparation of old land is here the matter of most importance. The point to be attained is to get a rich soil, deep and well pulverized. Tobacco requires an abundant supply of ammonia, as well as mineral matter, especially lime and potassa, with phosphoric and sulphuric acids. Hence, guano and rich stable or hog-pen manures, lime, ashes, plaster, and the phosphates, are all valuable fer- tilizers for this crop, unless they are already present abun- dantly in the soil. It has been shown that ammonia is not generally abundant in soils that have been frequently culti- vated without manure ; hence, old land usually requires an application of some form of ammoniferous manure, to secure a full crop of tobacco. A good clover or pea fallow may be plowed down in the Fall, and manured well and re-plowed in the Spring, with sub-soiling, where the land requires it; then, if necessary, in order to get it fully pulverized, let it be stirred with shovel-plows, and well harrowed. This will mingle the manure thoroughly with the soil, as well as reduce the soil itself to the desired condition. If manure is not abundant^ some guano should be mixed with it, and a smaller TOBACCO. 317 quantity will then answer tlie purpose. All wet lands must be ^vcU drained for tobacco. 518. Listing * and Hilling. — Listing here consists in throwing up small parallel ridges with the mould-board plow, at proper distances for the rows of tobacco. These ridges are often called " lists." The distance between the tops of these — or, in other words, the distance between the rows of tobacco — should be from 3 J to 4^ feet, varying with the soil and variety cultivated. The width should always be suflScient to allow the hands to pass between the rows, when the crop is fully grown, without danger of breaking the leaves. To secure uniformity of distance be- tween the lists, it is best to lay off the ground first with single furrows, at the required distance, and upon each one of these, as a central line, throw up the soil equally from both sides, with the mould-board plow, until all the soil has been thrown out from the middle of the intervening spaces. The lists may then be divided into sections, out of which the hills are to be formed. The hills should be about 3 feet apart in the rows. This distance can be regulated, with con- siderable uniformity, by running a shovel-plow across the lists at right angles, making cross-furrows three feet apart. The sections into which the lists, or ridges, are thus divided, are then heaped up in the form of sharply-peaked, conical hills, thus to remain until they are to receive the plants. 519. The hilling serves several important purposes : (1) It elevates the plant, so as to prevent the points of its low- est leaves from reaching the ground so readily, and becoming soiled. (2) On soils which retain much water in wet sea- *• "Listing," in Soutliern agriculture, denotes: (1) The dividing of land into narrow strips by furrows, as in preparing it for plant- ing corn. (2) The same term is used to indicate the process of throwing the surface soil up into small parallel ridges, out of which the tobacco hills are afterwards formed. 27* 318 TOBACCO. sons, the plants are kept with a large portion of their roots above the water which settles along the furrows. But if wet seasons continue long, the crop is always injured, not- withstanding the elevation of the hills. (3) The air has more free circulation beneath the leaves when they become large, if the plants are thus elevated. 520. Planting. — The season best suited for field plant- ing, in Vii'ginia, is from about the middle of May till about the middle of June, or later, in the southern part of the State. The process of planting can be carried on only when there is a considerable quantity of moisture in the hills, else just before there is a certain prospect of immediate rain; that is, just before or just after a rain. The hills are pre- pared to receive the plants, by having their conical tops cut ofi" with the hoe, and the flat surface thus formed, pressed down or struck with the lower face of the same instrument, so as to form a compact soil to receive the roots of the plant. While this operation is performed by one set of hands, others should be engaged in setting the plants. A careful man should draw the plants from the bed, which can be done with the hand alone, if the soil of the bed is loose and moist 3 but if the bed has become somewhat hard, as often happens where there is much clay in the soil, the aid of a sharp flat instrument to pass under the roots may be necessary, as it is important to guard against bruising either the top or root of the young and tender plant. Some of the weaker hands take the plants in baskets, and, following those engaged in flattening the hills, drop a plant at each hill; while others follow with sharpened sticks or pegs, with which they make holes in the centres of the hills, to receive the roots. Care should be taken to have the root extend straight downward in the hole, and not doubled back upon itself: it is then more certain to grow, and to grow well. The plant should be inserted low enough to have TOBACCO. 319 all the root completely covered, but not so low as to let the bud be below the surface. After the root has been inserted in the hill, the soil is firmly pressed around it. If the ground is not very moist, or if the sun is very hot, at the time of planting, a leaf of some kind, or a little handful of broken straw or chaff, should be laid over each plant till it has taken root. 521. The same ground should be passed over at every good planting season, for the purpose of replanting. Some plants of the first setting will have died, while others will have been destroyed by cut-worms. To secure a plant to every hill, then, the replanting may have to be repeated several times. 522. Another method of planting, differing a little from that just described, is said to be pursued by a very intelli- gent and successful planter in Buckingham county. His land is prepared and listed in the method just given; but instead of making hills, he lets the ridges (lists) stand as they are thrown up by the plow, until he is ready to plant. The tops of the lists are then flattened, and at the same time compressed, by running a one-horse roller along them from end to end. The roller is made sufficiently long to rest upon two lists at the same time, while the horse that draws it walks between. There is, moreover, an attachment to the roller for marking off the stations for the plants, at a uniform dis- tance. This consists of pegs projecting from the surface of the roller, and so situated that each one will make a hole for a plant at every revolution ; while those at the same end are just as far apart on the surface of the roller, as the plants are to be distant in the rows. If the diameter of the roller is near two feet, the circumference will be about six. Now ,two pegs, placed on opposite sides of a roller of that size, would, during its revolutions, mark off spaces of three feet each ; that is, two spaces for every revolution. Each end o20 T O 15 A C C O. of the machine may thus be made to flatten the top of a list, and at the same time leave holes prepared to receive the plant. The difficulty of making a single peg always strike the centre of the list as it comes around, may be obviated by having several pegs near together, in a line running lengthwise. Some one of these will be certain to leave a hole near enough the middle of the list for the plant. , The plants are next dropped and set by hands following the roller. 523. This method has the advantage of substituting cheap horse-labor for more expensive hand-labor ; but it may have more than compensating disadvantages. In rough or stumpy land, it would be impracticable. It omits the neat hoe- dressing applied in hilling. The plants are in rows in only one direction, and, consequently, cross-plowing cannot be done. Still, the plan is worthy of a fair trial, and on many fields may greatly economize labor. The substitution of horses or mules for men, is a point at which all farmers should aim, wherever such substitutions can be made. The hire of a first-class hand for one year, would buy a good mule ; while the expense of keeping the hand one year would feed the mule for two years. Then in many opera- tions the mule, with a little management, can be made to do the work of two or three good hands. 524. Culture. — The two leading objects to be kept in view in the culture of tobacco, are the same as those men- tioned in connection with the culture of corn : (1) All weeds and grass must be kept down ; and (2) the ground must be kept mellow and well aired. The culture should be com- menced as soon after planting as possible, and kept up con- stantly until the plants are too large for its continuance. Within a week or two after planting, the soil on the surface of the hills may become crusted, especially in clay soils; also, grass and weeds may begin to make their first appear- TOBACCO. oJiL ance. In either case the hoe should be applied, to scrape down the surfaces of the hills. A clean, loose surface will thus be formed around the plants. This should be followed by a deep plowing, which should be made so close to the rows as to cut down a considerable portion of the hills, the mould being thrown out into the spaces between the rows. Guano, or a mixture of guano and salt, should then be ap- plied. By a subsequent plowing within a week or two, the soil should be thrown up again to the rows, and the hills again dressed up with the hoes. The kind of plow used must be determined by the character and condition of the soil. To a firm soil, the coulter should be first applied to as great a depth as possible ; then the shovel, or small mould- board, for throwing the earth to and from the hills. In short, the best means should be adopted for accomplishing the two objects above mentioned. 525. Priming and Topping. — When the plant has grown to the height of two or three feet, a round bud will make its appearance in the centre of the plant. This is the fiower-hud, and is called the " button" in some parts of Vir- ginia. At this period of growth, some of the lower leaves should be pulled oif, so as to leave the stalk naked for five or six inches above the ground. The stripping of these lower leaves is called '' priming." At the same time that the prim- ing is done, the flower-bud is broken or nipped off with the thumb and finger. If the plant is sufficiently large, it may be topped before the flower-bud appears, by nipping out the central leaf-bud. '' There is great difierence of opinion aa to the proper height of topping. From 8 to 20 leaves are recommended — the latter for manufacturing. If the tobacco is pretty forward and the land rich, at first, prime off just enough of leaves to hill up the tobacco weir, and top to 12 or 14 leaves. Continue to top to 12 leaves until 1st of Au- gust, then top to 10 until middle of August, and from that 322 TOBACCO. time until 1st of September top to 8, afterwards to 6." * If the topping were omitted, the flower-bud would soon be de- veloped into a branching top, full of clusters of flowers, from which the seeds are afterwards produced. 526. SucKERiNG. — Soon after the topping is done, the axillary buds at the bases of the leaves begin to grow rapidly, and, if let alone, form branches of the main stalk. They are called " suckers," and must be broken out as soon as they are large enough to be caught with the thumb and finger. This process has to be repeated from time to time, as new suckers make their appearance. Meantime the green worm will have commenced its ravages, and must be care- fully picked off" and destroyed ; otherwise, it will soon dis- figure and greatly injure the crop. 527. The p^iilosophy of priming, topping, and suckering is easily understood when we refer back to what has already been said (Chap. XI) on the physiology of plants. All parts of the plant are designed to aid in its mature growth, and ultimate production of seeds. As the period approaches for maturing the seeds, nearly all the vital energy of the various organs seems to be directed towards, and expended upon them. If the first flower-bud is removed, the natural vigor of the plant is not destroyed, but only diverted towards the leaves and axillary buds, strengthening the former, and caus- ing the latter to spring up as suckers. But when the suckers are removed, the whole vigor of the plant is concentrated in the remaining leaves. A choice of the most perfect leaves is made by " priming off"" those nearest the earth, and which not only would not themselves attain a vigorous growth, but would exclude the air and light too much from the middle leaves of the plants, which are always the most vigorous. The number of leaves left in topping is determined in part * Southern Planter, Nov. 1854. TOBACCO. • 323 by the apparent strengtli of the plant, and in part by the length of time it has for maturing its leaves. The more for- ward plants have a longer season of growth after topping, and can hence bear a greater number of leaves j while the later ones must be topped lower. 528. Cutting. — The maturity of the plant, and conse- quent fitness for cutting, is indicated by the points and edges of the leaves curling downward, the leaf becoming thick and brittle, and its surface assuming a yellowish spotted (piebald) appearance in some varieties, and on some soils, especially new land; and a fine glossy appearance in others. At this stage, the plant contains more of those ingredients which subsequently give value to it, than at any period either earlier or later. It should then be cut, and not till then, unless it is becoming fired,* or is in immediate danger from frost. The cutting consists in splitting the stalk with a sharp, thin-bladed knife, down nearly to the lowest leaf, and then cutting it off just below this leaf. As the plants are cut, they are inverted between the hills, and allowed to re- main in that position a few hours, until they are sufficiently wilted to be handled without being broken. They are then collected and placed (8 or 10 together) upon sticks, and hung upon scaffolds in the open air, or in the tobacco barn. 529. Curing. — The process of curing is a matter of the highest importance. On it depends, to a very great extent, the market value of the crop. It should, therefore, be at- tended to with great care. The modes adopted vary some- what with the end for which the crop is designed, " To- bacco for manufacturing purposes should be exposed to the air on scaffolds; and if ripe and sun-cured, it will have that * The "Black Fire" is a disease which is often very destructive to Ihe tobacco crop. It produces decayed spots over the leaves. A mixture of common salt with guano is recommended as a preventive. —Southern Planter, May, 1 858. 324 • T O R A c c o . sweet, aromatic flavor so peculiar to good tobacco. * * * After cutting, it should be carried to the scaffolds and hung, about 8 plants to the stick, and closed on the scaffolds for the purpose of sweating, by which process the green color is expelled, and the tobacco becomes yellow, which is far pre- ferable." * It should then be removed to the barn, to be fully cured by firing. " If time will allow, and the weather is not threatening, I prefer housing the tobacco without scaf- folding. It will yellow as well, crowded in the barn, as on the scaffold ; and all danger of injury from rain is avoided., as well as the loss of some from the effects of the sun. * * * It is carried from the field, crowded as closely as possible on the tiers, and permitted to remain from 6 to 8 days, or longer, until it is yellowed sufficiently ; then it should be opened, and the sticks arranged in the barn for firing. The sticks should be placed from G to 8 inches apart, and may be placed a little closer in the roof than in the body of the barn.""!" 530. Chemistry. — During the process of curing, tobacco undergoes important chemical changes. Its peculiar pro- perties are owing to the presence of several remarkable com- pounds, of which one called " nicotine," and another called " nicotianine," are most important. Nicotine is an alkaline substance, and has the form of an oily liquid when separated from other compounds. In its concentrated form, it is a most deadly poison ; but when taken in the dilute condition in which it reaches the stomach in chewing, or the lungs in smoking "the weed," its effects are greatly modified. The quantity of nicotine varies in the different qualities of to- bacco cultivated in the same region, and still more does it vary in that cultivated in different countries. The Havana has about 2 per cent of nicotine, hence its mildness. Vir- ginia (best manufacturing) tobacco has 5 or 6 per cent, * T. D. Edmunds. f Wm. H. Jones, of Mecklenburg. TOBACCO. 325 while the stronger varieties have about 7 per cent. The French tobacco has from 3 to 8 per cent of nicotine, accord- ing to the region in which it grows. Nicotlanine is a more volatile substance than nicotine, and is more odoriferous. The pleasant odor of good tobacco is due to this compound chiefly. 531. The nicotine and nicotianine do not exist in the green leaf, but are formed during the curing of the tobacco, from substances already in the plant in variable quantities. If the leaves are dried very rapidly, these compounds are not fully formed ; and if the heat is raised too high in firing, they may both disappear to some extent, by being either volatilized or decomposed. They both contain nitrogen, and, like all other compounds containing that element, are readily decomposed. Hence the firing should be commenced at a low temperature, which should be gradually increased, and may be advantageously suspended at night. The tempera- ture should never rise above 120°. 532. Tobacco-barns should be closely planked, or in some way made close, having windows for ventilation, which may be opened or closed at pleasure. Smaller, and hence safer fires, will be sufficient in such houses. Curing yellow to- bacco with cliarcoal at a high temperature, kept up day and night, is recommended.* " It is best to fire all grades of shi]/2)ing tobacco, and cure it a dark nutmeg color. * * From 24 to 36 hours after cut- ting, if the tobacco is ripe — if not, from 36 to 48 hours, according to the weather — seems to be about the right time to commence firing. Begin with small fires, and bring the tobacco to a proper state, and then increase the fires." f 533. Stripping, &c. — After the tobacco has been fully * See Southern Planter, Oct. 1858. f Wm. H. Brown, Richmond. 28 32G TOBACCO. cured, the nest step is to strip the leaves from the stalks, and tie them up in little bundles ('' hands,") to be pressed (" prized,") into hogsheads for market. The two points requiring most attention in stripping are, first, to have the tobacco in proper ''order;" and, secondly, to assort carefully, so as to separate the different qualities. 534. The tobacco is in " order" when the leaf, or rather the blade of the leaf, is sufficiently moist to be pliant, and yet the stems dry enough to break off readily from the stalk. This condition can be secured only in the beginning of a spell of damp weather. After the weather has continued damp for some little time, the moisture penetrates the stems, as well as the thinner parts of the leaves, making them too tough to be easily broken from the stalks, and rendering them liable to mould when wrapped together, or when the tobacco is laid down " in bulk." If the stems have thus become pliant, the tobacco is in " too high order," and must be thoroughly dried, and allowed to come in order again before the stripping can be done. 535. A large quantity may be kept in order for stripping, by packing it down when in the proper condition, upon an elevated platform extended along one side of the barn. This is called '' bulking." The tops of the plants must be lapped over each other in the middle of the pile, the lower end of the stalks being turned outward. The whole mass must then be covered up with straw, or something else, which will preserve it in order until it can be conveniently stripped, which is generally at times when the weather is unfavorable for out-door work. 53G. The business of assoiiinr/ requires both care and judgment. It should, therefore, be the business of the most experienced and trustworthy hands. It is accomplished chiefly during the process of stripping, but may be made more complete by the hands engaged in tying, attending QUESTIONS. 327 properly to the sorting out of such leaves as do not properly belong to the quality upon which they are engaged. The number of grades or qualities must be determined by the purpose for which the crop is designed. Where the only object is to make the dark shipping tobacco, the best leaves are assorted, according to size and quality, into first and second quality of " leaf;" while the lower leaves of the stalks, together with any othei-s that may be injured or ragged, form first and second qualities of '' lugs." If the crop is designed for the manufacturer, the color, as well as other qualities, must be taken into account. The dark and yellow colors must be first separated into two general classes, and then each of these again assorted according to their several 'Equalities." 537. When the assorting and tying have been completed, the bundles should be " bulked down," unless the stems are found to contain so much moisture as to be in danger of moulding. It should then be hung up on the sticks, and dried. It is always thoroughly dried before prizing. Then, at the first favorable time before prizing, it should be again packed down in bulk. The bundles should be carefully straightened in packing down ; and, when it is aftei-wards transferred to the hogsheads, the same, or still greater care, should be taken to have every leaf straight, and in its proper place. The hogsheads usually contain about 1300 or 1400 pounds. The price of tobacco depends very much upon the skill icith which it has been cured, and tlie care bestowed upon the assorting, tying, and subsequent handling. QUESTIONS ON CHAPTER XXII. §•510, 511. What is said of tlie extension of the culture of To- bacco? What citma^fi is best suited to this crop? Wliy? Influence of elevation? 328 QUESTIONS. 512. Soil best adapted to tobacco ? What of the clay soils ? What of the drift deposits in the valley? 513. What gives rise to variety o^ grades in tobacco? Variety best for manufacturing? For shipping? To what lands is the Prior adapted ? 514-51 G. Why do Plant-beds require special attention? How is a succession of plants to be secured ? Why important ? The general practice in the preparation of beds ? Locality selected ? Preparation of the ground ? How is the burning conducted ? Effects of burning? When should beds be burned? What is said of the application of guano? How are the seed prepared? How planted? Time of planting? Growing of plants without burning? Great enemy of plant-beds? lleniedy? AVhat application should be made during the growth of the plants? Attention to weeding? 617, 518. What is especially required in Xhe preparation of the soil? How is new ground to be managed ? How is the hilling performed ? Preparation of old land ? What fertilizers are especially required by tobacco ? What fallow-crops make a good preparation for tobacco ? How must wet lands be treated ? V/hat is meant by listing tobacco land ? Proper distance between the rows ? How is uniformity of distance secured ? Dist,ance between the hills ? 519. nUling? Fii'st purpose served by hills ? Second? Third? 520. Planting season? How are the hills prepared to receive the plants? Describe the process of planting. 521. 522. What of replanting ? What method of planting without hilling is described ? Detail the process. Advantage of this method ? 524. Leading objects to be observed in culture of tobacco ? When commenced? How conducted? 525-527. When are priming and topping commenced ? What is priming? What is topping? What determines the number of leaves to be left ? What renders suchering necessary ? How performed ? Jixplain the philosophy of pruning, topping, and suckering. 528, 529. When is the plant fit for cutting? How indicated ? Why is it then most valuable? How is the cutting performed ? What is next to be done ? Why is the process of curing a matter of great importance? How is manufacturing-tobacco cured? 630-532. What chemical changes take place in the curing of to- bacco ? What substances are formed in the tobacco? The proper- ties of these ? Quantity of Nicotine in difiFerent varieties ? Influence QUESTIONS. 329 of drying the leaves very rapidly? Effects of too high temperature? Advantage of closely-planked barns? Curing with charcoal? How should shipping tobacco be fired ? 533-537. In what does the stripping of tobacco consist? Two points to be observed? When is tobacco "in order"? When should it be laid down in bulk ? How may a large quantity be kept in order? What does the business of assorting require? AVhat points decide the quality of tobacco? What process follows stripping and tying ? On what does the price of tobacco very much depend ? 28^ oO COTTON, CHAPTEK XXIIl. COTTON. 538. The following remarks on the planting and culture of cotton are compiled chiefly from the " Cotton Planter's Manual" (J.A.Turner). All the leading points to be observed in the management of this great Southern crop are believed to be here presented. Modifications, of course, must be made to suit differences in soil, climate, &c. Those who wish to investigate the subject fully are referred to the valuable "Manual" above mentioned, and to Southern Agri- cultural Journals. 539. Kind or Soil. — "The first inquiry which presents itself is, to know what are the peculiarities of those soils which suit the growth and maturity of cotton. Experience is, perhaps, the safest and most reliable test, in the settle- ment of this question — and it is now pretty universally con- ceded, that- our best cotton lands are those which are of deep and soft mold, a sort of medium between the sandy and spongy, and those soils which are hard and close — those which are penetrated by the warming rays of the sun, im- bibing readily the stimulating gases of the atmosphere, and which allow the excess of rain-water to settle so deep into the earth, as to lie at a harmless distance below the roots of the young plant. These are the properties of soil needful to the vigorous growth and early maturity of the cotton plnnt; and the knowledge of this fact is of great, and perhaps I might add, indispensable importance, to its successful culti- vation. For though we may not find, and indeed it is very improbable that we should often find, all these essentials in COTTON. 331 the selection of a farm, yet by the aid of the plow, the hoe, and the spade, and the incorporation of foreign substances, we may remedy many defects, and supply many of the pecu- liar demands of this plant. 540. Preparation of Soil. — ''The best and most im- portant part of the work in cotton making, consists in a judicious and proper preparation of the soil for planting. It is difficult to say, in all cases, and in the varied condition in which lands are found, and the diversity of soils, what the process of preparation should be ; but we lay down gene- ral principles for our government, and results to be obtained, and leave the planters to the selection of the best means at command for their accomplishment. All lands for cotton ought, before the crop is planted, to be broken deep, close, and soft ; and this to be done long enough before planting to allow the rains gently to settle them. It is the most common and perhaps the best plan, to prepare all lands in- tended for cotton, in beds made by the turning-plow; and in flat and wet lands, sometimes an additional elevation ought to be given, by drawing up the beds with the hoe. I think, in this work, we have often followed too much the example of our neighbor, and have looked too little to reason, in the indiscriminate bedding and high elevation of all lands. I am the advocate of deep, soft beds, made by very thorough and close plowing, but cannot consent to the necessity or benefit of elevating much lands which are warm and dry, and which are not subject to inundations from excessive rains. For the convenience of culture, I would have the young cotton stand on a slight elevation ; but when the con- dition of the land did not require it, I would not give it more." — Col. Chambers's Essay, pp. 11—13.) 541. Manures. — "Every kind of compost, green crops turned in, cotton-seed, and even naked leaves listed and left to rot, improve this crop. When planted on cotton-seed, 332 COTTON. and sometimes on strong stable manure, it is more difficult to retain a stand, owing, probably, to the over-stimulus of these strong manures. So, on leaves, unless well-rotted, the cotton will long continue to die, in consequence of the leaves decaying away, and exposing the root too much to sun and rain. These difficulties maybe avoided by a little pains; and by no means justify the opinion entertained by some, that cotton should never be planted on freshly-manured land. The only question is the cost of the manure. A great deal may be made on every plantation, without much trouble or expense, by keeping the stables and stable-yard, hog and cow-pens, well supplied with leaves and straw; and also from pens of corn-cobs, sweepings from negro and fowl-house yards, and rank weeds that spring up about them, collected together, and left to rot. Whenever the business is carried further, and a regular force is detached to make manure at all seasons, and entirely left out from the crop, it becomes the owner to enter into a close calculation of the cost and profits. In many agricultural operations, such a course the experience of all countries has proved to be profitable; but these operations partake more of the farming and gardening, than planting character ; and whether the same method will do for the extensive planting of short-staple cotton, remains, in the opinion of your Committee, yet to be tested. If any- thing like an average of past prices can be maintained, it is certain that more can be made by planting largely than by making manure as a crop. If, however, prices continue to fall, and the growing of cotton be confined to a few rich spots — those susceptible of high manuring — then our whole system must be changed, our crops must be curtailed, and, staple-labor losing its past value, the comparative value of a cotton and manure crop will preponderate in favor of the latter. As a substitute for manuring on a large scale, rest- ing and rotation of crops is resorted to. In our right level COTTON. 333 land, the practice of resting cannot be too highly recom- mended ; and, by a judicious course, such as resting two, and planting two, or at most three years, our lands may not only be kept up forever, but absolutely improved. From rotation of crops, but little is done for cotton. After small grain — whether from the exhausting nature of that crop, on light lands, or because the stubble keeps the ground rough and porous — cotton will not do well. After corn it is difficult to tend, as, from our usual manner of cultivating corn, grass is always left in full possession of the field. It does best after cotton, or after a year's rest. Rest is the grand re- storer, and the rotation chiefly required in the cultivation of cotton." — Gov. Hammond's Report, p. 27. 542. Application or Manures. — Dr. Cloud, after va- rious experiments, says : " I determined upon a new mode of application entirely, which consisted in spreading all the manure used broadcast. This was done by hauling the ma- nure out on the land, and depositing it in heap rows, say thirty feet apart, and the heaps thirty feet apart in the rows, with ten bushels of manure in each heap. The cotton-rows being first laid, the manure was spread broadcast, and the land bedded out. On or about the 10th of April, the cotton- seeds were planted after a spacer, by which the hills are regulated precisely as desired. The result was a perfect stand, with the cotton healthy, and all of the same age. There is no difficulty in understanding the difference here in favor of broadcasting the manure, and in bedding out the rows. It is not deposited a half-gallon in a place, but is in- corporated evenly throughout all the soil. The consequence is, that however rich the manure may be in alkaline matter, its thorough incorporation with the soil, so quickly and effectually dilutes it, as to render it entirely innoxious to young cotton. There was no part of the experiment that gave me so much satisfaction as this. Every planter knows 334: COTTON. the value of a first uniform and perfect stand. I use tlie term perfect, because, by the use of the spacer, I approxi- mate nearer a perfect stand than it is possible to accomplisli by any other process." — Dr. CloutVs Exjicrimcnts, p. 72. 54:0. Planting. — '' The distance to be given is the next inquiry to be considered. This is a very important object, and one upon which we are very dependent for success ; and yet it must be varied very much by circumstances, some of which are beyond our knowledge or control. The general principle may be stated, and then our best judgment must guide us in its ajiplication. " When the crop is at maturity, the branches of the stalks ought slightly to interlock every way. We cannot, there- fore, do better in planting, than make an estimate of the probable average to which the weed will grow, dependent, of course, upon the vicissitudes of the seasons. It would, therefore, be vain to attempt to be more specific in direc- tions, which must be varied always to suit the varied cha- racter of the soil. This whole question, then, is to be set- tled upon the principle already stated. The planting should be in drills, chiefly because of the difficulty of obtaining good stands in hills ; and I would add, for the information of those who may be without experience, that in the com- mon medium lands of the country, these rows ought ordina- rily to be about five feet apart, and the stalks in the drill should be thinned, so as to stand from fifteen to twenty inches from each other. The width of the rows, and the distance in the drill, may be increased upon better lands; and in some cases of very thin lands, it may fall a little below the distances designated. I do not regard it as a matter of indispensable importrnce, but should decidedly prefer that the rows should run in such direction as to give the plant the largest benefit of the sun, from early morn to its setting. The cotton is decidedly a sun plant. COTTON. 3^5 544. The Mode of Planting. — " Here -we have many plans, all setting up claims to some peculiar merit. With the preparation which I have indicated, it would hardly be necessary to stop to discuss the relative merits of these modes, or seek to do more for the accomplishment of our purpose than to select some one, which we know to answer well. I therefore advise the use of some small and very narrow plow for the opening furrow. This should be run in the centre of the bed, opening a straight furrow of uniform size and depth. In this the seed should be strewed by some careful hand, scattering them uniformly along the furrow, just thick enough to secure a good stand the whole length of the row. These I would cover with a board, made of some hard wood, an inch or an inch and a half thick, about eight inches broad, and thirty inches long, beveled on the lower edge so as to make it sharp, slightly notched in the middle so as to straddle the row, with a hole bored in the centre one inch from the upper edge, and screwed on the foot of a common shovel or scooter-plow stock. This wooden scraper and coverer, when drawn over the row, covers the seed nicely, leaving a slight elevation to prevent the settling of water, and dresses the whole surface of the bed neatly for the space of fifteen inches on each side of the drill. Thus all clods or obstructions arc removed, and a clean space is left wide enough for the passage of the plow in the first working between the young cotton and the rough land. This is an advantage of much importance with a crop so tender and small as cotton at this stage. 545. Culture. — "As soon as the young cotton is up to a good stand, and the third and fourth leaves begin to appear, the operation may commence. In lands which are smooth and soft, I incline to the opinion, that the hoes should pre- cede the plows, chopping into bunches, passing very rapidly on, and let a careful plow-man follow on each side of the 33G COTTON. dilil, throwing a little liylit dirt into the spaces made by the hoe, and a little also about the roots of the cotton, covering, and leaving covered, all small grass which may have sprung up. This is, indeed, the merit claimed for the operation that, after the hoes have passed, the plows come on and effectually cover and destroy the coat of young grass then up. This is known to practical planters to be the crop of grass which escapes the hoe, and does mischief to the cotton. But when the land is so rough as to endanger the covering of the cotton with the plow, the operation must be reversed, and the hoes follow the plows. All that is now proposed to be done is a very rapid superficial working, reducing the crop to bunches, soon to pass over and return again, for a more cai'eful operation. This should be done as soon as possible, as will be indicated by the necessities of the case. The grass and the weeds must be kept down, and the stand of cotton reduced. At this first working, unless in lands already very soft, I should advise the siding to be close, and to be done with some plow which would break and loosen the earth deep about the roots of the young plant. Others may theorize as they choose, but with a plant sending out a tap-root, upon which it so much relies, and striking so deep into the earth, as that of cotton, I shall insist upon its accommodation, by providing a soft, dee]), mellow bed, into which these roots may penetrate. 546. " In the second working, the plows should in all curies go before the hoes, and in all lands at all tenacious or hard, let the work be deep and close again, and the middle of the rows also be well broken up at this time. Now the hoes have an important and delicate duty to perform. The cotton is to be reduced nearly to a stand, though it is now rather early to be fully reduced. It is, perhaps, best to leave two stalks where one is intended to grow. The young stalk is very tender, and easily injured by bruises and skins COTTON. 337 from rough and careless work, and it is much better to aid a little sometimes with the hand in thinning, than to spoil a good stand by bruises from the hoe. The cut-worm and the louse are charged with many sins, which ought to be put down to careless working at this critical stage of the crop. The distance to be given I have before stated, and, in the first operation of bunching, this ought to be looked to, and the spaces regulated accordingly. At this second passing over, the hoes must return a little soft dirt to the foot of the stalk, leaving it clean and supported. If this work is well done, the weed will grow on, without any necessity for fur- ther attention for some twenty days or three veeks, when the plow should return again. At this time, some plow should be used next the cotton, which will tumble the soft earth about the root, covering the small young grass which may have sprung up since the last working, but the plowing should be less close, and shallower than the former working. 547. " The hoes have much to do in the culture of this crop, and must be prepared to devote pretty much all their time to it, constantly passing over, and perfecting that which cannot be done with the plows, by thinning out surplus stalks, cleaning away remaining bunches of grass, stirring about the roots of the plant, and, if need be, adding a little earth to them. It is difficult, in a treatise of this sort, to say how often, and in what manner, this crop should always be worked, when the character of the seasons, and the dif- ference in the land, must have necessarily so much to do in settling this question. The general rule must be, to keep the earth loose and well stirred ; the early workings to be deep and close; and as the crop comes on, and the fruit begins to appear, let these workings be less close, and shal- lower, keeping the soil soft and clean. It is of great import- ance to work this crop late, and it should not cease until the branches lock, or the cotton begins to open. I do not con- 29 338 COTTON. sider tliat it is necessary to pile the eartli in large quantities about the roots of the cotton, but think the tendency of all the workings should be to increase the quantity. 548. Selection of Seed. — " The selection of seed is an interest not to be disregarded. We have been humbugged a great deal by dealers and speculators in this article, yet we would greatly err to conclude that no improvement could be made. We should, however, save ourselves from this sort of imposition, and improve our own seed, by going into the field, and picking each year from some of the best-formed and best-bearing stalks, and thus keep up the improvemfent. Great benefits may often be derived by changes of seed in the same neighborhood, from difi"erences of soil, and occa- sional changes from a distant and different climate, may be made to great advantage. 549. Picking. — " The picking of cotton should commence just as soon as the hands can be at all profitably employed — r say as soon as forty or fifty pounds to the hand can be gath- ered. It is of great importance, not only to the success of the work, but to the complexion and character of the staple, to keep well up with this work, so that, as far as possible, it may be saved without exposure to rain. The embarrass- ments to picking when once behind, and a storm or heavy rain shall intervene, mingling it with the leaf, and tangling in the burr, are just as great as to get behind in the cultiva- tion of the crop, when much additional labor will be required to accomplish the same object. " In the early pickings, when the seeds are green, some sunning is indispensably necessary; but, after some maturity and dryness, very little will be required. This must be de- termined very much by circumstances; but dew or rain-water should always be removed by drying upon the scaffold, before the cotton is bulked in the house. AVith proper care and attention, great improvement may be given to the complexion COTTON. 339 of the staple by a little heating in the bulk, extracting the oil from the seed, and imparting a slight cream to the color. This process, however, must be conducted with great caution and care, lest the heating proceed too far, and injury be done. It is easily checked by stirring and exposure to the air. It is an advantage to all cotton to lie in the bulk before ginning, and we doubtless often lose much of this benefit for want of sufficient house-room. Indeed, I think it a very common error in our plantation arrangements, not to build houses for this special object. The cotton, when ginned, ought to be so dry that the seed will crack when pressed between the teeth. It is often ginned wetter, but just as often the cotton samples blue. A gin should be used which will neither cut nor nap the cotton, but send out the fibre straight and smooth, so that when the samples are drawn, they will have the appearance of having been carded. This is greatly promoted by the largely increased number of brushes now added by the best manufacturers. 550. Packing. — " The packing should be in square bales; and, without reference to freight, or any of these mere inci- dental influences, I think the weight of the bale should be fixed at about four hundred or four hundred and twenty-five pounds — to be in two breadths of wide bagging, pressed until the side-scams are well closed, or a little lapped, and then secured with six good ropes, the heads neatly sewed in ; so that, when complete, and turned out of the press, no cotton should be seen exposed. These packages should be nearly square, for the greater beauty of the bales, but, still more, for the greater convenience with which they may be handled and shipped, saving the necessity for tearing the bags, and giving a better guarantee that they will reach a distant market in good order." — Col. Chambers's Essay, pp. 16-20. 340 QUESTIONS. 551. Remarh. — I do not pretend to endorse every position taken, and opinion expressed, in the above comj)ilation. The writers are intelligent and responsible men, and have had personal experience in the matters about which they write. I have never lived in a cotton-growing region ; and, there- fore, have had but little opportunity of personal observation in the culture of this important crop. But, in addition, to what has been given, I will venture a suggestion, based upon my general knowledge of the cultivation of the soil. One of the writers quoted speaks of rest, as '' the grand restorer, and the rotation chiefly required in the cultivation of cot- ton." Now I venture to suggest a ^^ea fallow, with gypsum and ashes, as probably much superior to "rest" for any soil. "Rest" can never restore to land what the crops are every year carrying away; and unless the rest is emploijcd in the production of something which will collect organic fertility from the air, and improve the chemical condition of the mineral matter, which needs elaboration, it can certainly do but little for the ultimate improvement of the land. QUESTIONS ON CHAPTER XXIII. § 538, 539. Is the proper culture of Cotton the same for all locali- ties ? Soil best adapted to this crop ? Why ? 540 — 542. What of preparation of soil ? How should the soil be broken up? Why should cotton be planted on beds? Kind of ma- nures suited to cotton? How is the cost of manure to be attended to ? Modes of applying manure ? 543, 544. How is the distance of planting determined ? How should the planting be conducted ? AVidth of the rows and distance in the drill ? Mode of planting given ? 545 — 548. First step in the c!/Z> K 41 14 13 3 15 12 2 100 "a O 30 5 11 5 33* 13 3 100 ■*-j 03 .a 3 n 45 5 10 1 26* 11 2 100 S, 40 6 25 3 10 14 3 100 i 4 6 1 4 12 1 100 d 1 O o >-. 3 12 7 3 50 15 9 100 o 5 3 IS 9 4 45 16 10 10.) is 1 7 2 2 70 12 6 100 i 4 10 12 2 52 15 100 Starch Gum and Sugar. Proteine Matter. Oily Matter Vei^etablo Fibre.. Water Minerals in I Ashes J ■■ 15 .*< 74 1 100 2 3 3 2^ 88 1>^ 100 * The chaffy husk of oats, and the, black husk of buckwheat, are both composed chiefly of fibre. 358 VALUE OF c 11 r s as food. In the foregoing Table, equal quantities (by weight) of the sevei'al crops are compared, and we are thus enabled to estimate the quantity of each of the proximate elements consumed with a given weight (say 100 lbs.) of each kind of food. If, for example, a horse consumes 100 lbs. of corn, he consumes of starch 45 lbs. ; of gum and sugar, 8 ; of proteine mattei*, 18 ; of oil, 9. But in 100 lbs. of clover hay he eats only about 3 of starch ; of gum and sugar, 13 ; of proteine matter, 9; of oil, 4. If 100 lbs. of potatoes were consumed, the corresponding quantity of starch would be five times as great as in the hay, but the quantity of other nutritive substances would be greatly less. The water, which constitutes the greater part of the weight of potatoes, has no money value, because it is easily obtained from other sources. So, we place a low estimate upon woody fibre, because of its abundance, though it is important in forage. 576. Of the substances which give to articles of food their chief value, we place the proteine compounds first ; because they do most towards building up the animal system — they are most nutritious. In fact, they are often spoken of as constituting the nufritious part of food. They are certainly more largely appropriated in the nourishment and growth of animals, than are any other forms of food ; but the oily por- tions, which may be regarded as next in importance in feed- ing, certainly deserve to be regarded as nutritious; for on these, to a great extent, the fattening of animals is depend- ent. Starch, gum, and siigar may be classed together, since they serve a like purpose in sustaining animal life. After undergoing digestion, they are all thrown into the veins, where they become a constituent part of the blood, to be consumed during respiration (§ 611). These are sometimes called "respiratory food," because tl icy are chiefly consumed by the oxygen conveyed to the blood in breathing. 'Jliey are not less essential to animal life than other forms of diet; VALUE OF CROPS AS FOOD. .o59 yet, from their abundance in vegetable products, tliey are not estimated at so high a value as the proteine and oily parts of plants. 577. To estimate the value of the crop grown upon a given piece of ground, we must not simply take into account the relative quantities of these three kinds of food (the nutri- tive, the fattening, and the respiratory) contained in a given weight of the crop, but the quantities contained in the whole product of the land. A hundred pounds of potatoes contain only about one-eighth as much proteine matter as the same weight of corn, one-ninth as much oily substance, and one- third as much starch. This shows that a given weight of potatoes is far inferior in A^alue to the same weight of corn. But when we come to compare the products of an acre of land cultivated in corn, with the products of an acre culti- vated in potatoes, the case stands very differently. In order to institute such a comparison, we may suppose that an acre which would yield 60 bushels, or about 3500 lbs. of corn, would, if properly cultivated, yield 400 bushels, or 20,000 lbs. of potatoes. Now, 3500 lbs. of corn contain, according to the preceding table (Table VIII), 630 lbs. of proteine, 815 lbs. of oil, and 1855 lbs. of starch, sugar, and gum; while 20,000 lbs. of potatoes contain 400 lbs. of proteine substance, 100 lbs. of oil, and 3300 lbs. of starch, sugar, and gum. If, then, we estimate the feeding value of these crops by the quantities of their proteine and oily substances alone, the corn has greatly the advantage, but if we bring the starch, etc. into the account, the potatoes again surpass the corn. 578. Let us now assume some relative value per pound, which may be attached to each of these three kinds of food. Suppose the starch, etc. in corn or potatoes to be worth one cent per pound for feeding stock, while the proteine and oily substances are worth three cents per pound. Then the acre 3G0 VALUE OF CROPS AS FOOD. of eora will give starch, sugar, and gum, worth $18.56; pruteiuc and oily matter, worth $28.35 ; total, 34G.90, ex- clusive of the value of the fodder. The acre of potatoes will give starch, etc., worth $33.00 ; proteine and oily mat- ter, worth $15.00 ; total, $48.00. Under the suppositions here made, the products are nearly equal ; but the labor re- quired by the potato crop is greater than that required by the corn, and for this due allowance must be made. 579. In order to compare at a glance the forage value of the prohaUc products of an acre of several common crops, with, reference to the three classes of food we have been considering, let us arrange them in tabular form. In the first column we place the probable average products in bushels and pounds; in the second, third, and fourth, the quantities of the three classes of food in each crop; and, lastly, the money value under the suppositions just made. Wlieat is not included, because it is especially appropriated to man, and hence has a higher value than could be assigned it as forage. This Table must not be regarded as giving accu- rate estimates, but simply as indicating the proper method of comparing crops, so as to determine their relative value in feeding. TABLE IX. FORAGE VALUE OF SOME CROPS. One Acre, producing Starch, Sujiar, & Gum. Prote'c! Mat- ter. Oil. Money value (?). Corn, 30 bus. =r 1,750 lbs. 927 315 158 $23.46 Oats, 40 " = 1,300 " 455 143 G5 10.79 Peas, 20 " = 1,200 " 540 300 36 15.48 Potatoes, 200 " =10,000 " ICoO 200 50 24.00 Cabbage, 10 tons. = 20,000 " 1000 GOO 100 31.00 Clover Hay, U " = 3,000 " 480 270 120 16.50 Pea Hay, IJ " = 3,000 " 420 360 60 16.80 If the ])eas and the pea hay above given are both the product of the same acre of ground, as may be the case, the QUKSTIONS. 361 sum of their values is $32.28. When the fodder of corn and the straw of oats are preserved, these must be added to the grain crops. In order to understand clearly the relation of the animal kingdom to the vegetable, and to comprehend the principles which should regulate the application of crops to feeding, and which should guide us in the general management of animals, we must direct our attention for a little while to some of the leading points of " Animal Physiology." QUESTIONS ON CHAPTER XXV. § 565. What is the leading object of the cultivation of the soil? How is the value of a crop determined ? What is meant by the "proximate composition of plants" (133)? Whence do animals generally get nourishment? 5G6. What ingredients of plants are valuable for food ? 567. Which is the most abundant proximate element in the grain crops? Of what is starch composed? Is the proportion of starch constant in the same grain? What per cent, is found in wheat? In corn, rye, oats, &c. ? In rice? In potatoes? In hay? 508. To what are gum and sugar similar in composition? Are they abundant? 569. What are proteine compounds (154).? Why are they import- ant in the nutrition of animals? 570. What is here said of beans and peas? What is "legumen" (157)? How much of it in beans and peas? AVhat is "gluten" (155)? Where found? Why is cabbage nutritious? 571. Is oil widely diffused? How does it become valuable in feeding ? Do any gi-ains contain too much oil to be fed alone ? What per cent, of oil in the several grains? 572. Is woody fibre digestible ? Why then has it any value ? What crops are composed largely of this substance? 573. What is said of water in articles of food, and of its value? 574. Why are the mineral constituents of food not to be disre- garded ? What do you learn on this subject from Table III. ? 575. What is given in Table VIII. ? How are the several crops here compared? If equal Avcights of different articles have been 31 362 QUESTIONS. given to an animal, do they always afford equal amounts of nutritious matter ? How is this illustrated ? 576. What compounds stand first, in estimating the value of arti- cles of food? Why are these placed first? AVhat stands next in value? Why? Why are starch, gum, and sugar, classed together? What part do they perform? Why are they not as highly valued as profeine and oily compounds? 577. How can we fairly estimate the value of the products of a given quantity of land? What examples are given? 578. How may the value in money of different crops be deter- mined ? Illustrate. 579. What is the object of Table IX. ? Why is wheat not included ? For Tvhat reason should we now give some attention to "Animal Physiology " ANIMAL niYSIOLOGY. 363 CHAPTER XXVI. ANIMAL PHYSIOLOGY. 580. Animal Physiology treats of the functions per- formed by the various organs of animals. But in order to get a clear view of the offices fulfilled by these organs, we must examine their structure to some extent. Wc here have a very wide field, of which we can look only into a very limited portion. As every man should have some knowledge of the structure and functions of the organs of his own body, that he may know how to preserve them and promote their healthful action, so the farmer should have not only this knowledge with regard to himself and the members of his household, but also with regard to the different kinds of ani- mals which stock his farm. There is a close analogy between the organs of man and those of the lower animals. We shall frequently refer to this resemblance, and shall make use of the organs of man's body as ti/jjcs of the most perfect structure. 581. The Skin. — All the animals of which we shall speak have their bodies enveloped in a tough, elastic, external covering, which consists of two distinct layers. That which forms the outer surface is called the " cuticle ;" * and that which lies next to the flesh is called the " true skin " (cutis vera). 582. The cuticle is generally very thin, and almost trans- parent. It has no blood-vessels or nerves, and may be removed from the surface without pain. On the palms of * Also called "Epidermis." 3G4 ANIMAL PHYSIOLOGY. the hands and soles of the feet it is made thick and strong, so as to protect these parts of the body, which are exposed to most constant friction and pressure. With a sharp knife or razor, thin shavings of cuticle may be cut from the front part of the hand, without exposing either nerves or veins. But if the whole thickness of the cuticle is removed, so as to expose the outer surface of the cutis vera, a smarting pain is felt, from the contact of the air with the nerves which are then laid bare. (See Fig. 49.) The cuticle has various openings in it called <' pores," through which the perspiration from the true skin passes out to the surftice. There are other openings also, through which oily secretions are thrown off. The number of pores in the cuticle is immensely great. Wilson says, " 2800 might be taken as a fair average of the number of pores in the square inch" of the human body. The lower surface of the cuticle consists of a colored layer. The coloring matter is secreted under the influence of the light and heat of the sun. In this respect there is an analogy between the animal and vegetable kingdom. It has been shown (§ 179,) that the leaves of plants require the light of the sun to develop their coloring principle ; so we find the human skin varying in color, in the same individual, very much in proportion to its exposure to the sun-light. The activity of the skin's secretions is promoted by light. If the light is too much excluded, the health of the animal body, like that of the plant, is impaired. The dark races of men doubtless derive their peculiarities of color, {71 part, from long-continued exposure to the sun, for generation after generation, until color, like other peculiarities, becomes hereditary. The cuticle is continually (jruicing, and, as new layers are formed beneath, the outer surface becomes dry and scaly, and gradually disappears. Where the skin is naked, the ANIMAL PHYSIOLOGY. 3G5 scaly portions are I'emoved by ordinary friction as fast as they are formed ; but where the svirfuce is covered with hair, they accumulate and form scurf. The healthy action of the skin of all animals is promoted by the frequent removal of this accumulation. Washing with soap softens and removes the surplus dead cuticle from the pkin, and with it particles of dirt which have become imbedded in it. 583. The ntlis vera (true skin) is composed of two layers; the outer one consisting of very minute bundles of fibres, so closely interwoven as to give it quite a compact structure. It is pervaded by a great number of veins and arteries which circulate the blood through it, and convey the necessary nourishment both for it and the cuticle. These veins and arteries arc also accompanied by nerves, which make this layer of the skin very sensitive. Where the veins and arte- ries meet, they form little projections or elevations, called ** papilla)," which make the surface of the skin uneven. The papilla) may be distinctly seen as little, red, conical ele- vations on the surface of the tongue. This layer is called the "sensitive, or papillary tissue" (Fig. 49). The inner layer of the true skin is much thicker, and more coarsely fibrous in its structure. Its veins, arteries, and nerves, are numerous, but fewer in number, though larger, than those of the sensitive layer. In this, the oil-glands of the skin are imbedded, and ai'e connected with the surface by tubes passing up through the cuticle. These oil tubes usually open in pairs into the sheaths of the hair, and thus provide the natural oil which gives the hair its beautiful glossy appearance. The persjyiratory glands are also situated in this part of the cutis vera. They separate impurities from the blood, and throw them out with the perspiration through the cuticle at the pores. 584. There are cells in the lower part of the true skin filled with fat. Such cells form what is called " adipose tis- 31* 366 ANIMAL P H Y S I L O O Y. sue." The following figure, from Cutter's Anatomy and Physiology, will aid the student in getting a clear idea of ihn •• ■'itive situation of the parts of the skin, as described It represents a vertical section of the skin, through thickness, but greatly magnified. Fig. 49. Fig. 49. — 1, 1, The lines, or ridges of the cuticle, cut perpendicularly. 2, 2, 2, 2, 2, The furrows, or wrinkles of the same. 3, The cuticle. 4, 4, 4, The colored layer of the cuticle. 5, 5, The cutis vera. 6, 6, 6, 6, 6, The papillae. 7, 7, Small furrows between the papillae. 8, 8, 8, 8, The deeper furrows between each couple of the papilla?. 9, 9, Cells filled with fat. 10, 10, 10, The adipose layer, with numerous fat vesicles. 11, 11, 11, Cellular fibres of the adipose tissue. 12, Two hairs. 13, A perspiratory gland, with its spiral duct. 14, Another perspiratory gland, with a duct less spiral. 15, 15, Oil-glands with ducts opening into the sheath of the hair (12). 585. Functions of the Skin. — The leading ofiice of the skin 4s to protect the surface of the body. For this purpose, it is most admii'ably adapted by our beneficent Creator, being made both tough and elastic — resisting all ordinary forces in the form of blows and friction, yet yielding to slight pres- sure, and to the bending of every joint. The cuticle is made ANIMAL P II y S I O L O G y. 3G7 without nerves, that it may cover the more sensitive layer beneath ; and yet it lies so closely in contact with the web- work of nerves on which it rests, that almost the slightest touch, even a breath of air, makes known its presence through these little nervous channels j the sensation, how- ever, is made pleasant by the intervening of the cuticle, while it would be extremely painful if this layer were re- moved. When injured or broken, the cuticle is renewed very rapidly, while the bruised surface beneath throws out, in the mean time, liquid matter which, drying, leaves a scab over the surface as a temporary protection. The cuticle is constantly worn away by friction, but it as constantly grows again ; and when the amount of friction or pressure becomes greater than usual, and is rapidly applied, it is sometimes worn off, so as to expose the sensitive layer below, and sometimes only loosened from its contact with this layer, causing the secretion of fluid matter beneath, giving rise to blisters. Such effects are seen upon the hands of one who undertakes more severe manual labor than he has been accustomed to perform, and upon the shoulders of young horses when first put into harness. But if care is taken to apply the increased pressure and friction gradually, no great inconvenience is felt, because the cuticle has the property of increasing in thickness, whenever the protection of the other layers requires it; provided time enough is allowed for the necessary change to take place. 586. The sensitive layer, by its abundant supply of nerves, acts an important part in giving warning whenever an ex- ternal body comes in contact with any part of the system. If the mind were not thus made conscious of the presence and action of outward forces, the body might be seriously injured, before the necessary means could be adopted for its protection. 587. T\\Q pores serve as outlets for the perspiration, which 8G8 ANIMAL r II Y S I L O G Y. is constantly secreted from the blood, and carries out in solu- tion, surplus matter, both mineral and organic. This process is constantly going on. If the temperature of the body is much increased by exercise or warm clothing, the perspira- tion collects more rapidly than it is evaporated, and forms drops upon the surface if naked, or moistens the hair or other covering of the skin. At ordinary temperatures, the perspi- ration is not thrown out more rapidly than it is evaporated from the surface ; but still it goes on. It is then called " insensible perspiration." Experiment.' — Insert your hand into a dry, clean jar of clear glass, having wrapped your handkerchief, or something of the kind, around your wrist, so as to close the mouth of the jar. In a short time, the inner surface of the glass will be covered with a film of moisture. This is the insensible perspiration made sensible, by being collected as fast as it escapes from the pores of the skin. Perspiration is necessary to health in both man and beast, hence anything tending to check it, is apt to result in injury. The impurities, instead of being thrown out, are retained by the blood, and inflammatory diseases are the consequence. Sudden chilling of the body, after free exercise, is always dangerous. Any one who remains at rest in the cold air, after taking violent exercise, should at once increase his quantity of clothing. The practice of leaving a horse ex- posed to a cold wind after brisk exercise, is very pernicious; but to ride him into a deep pond to cool him oft', while he is sweating freely, is still worse. The pores of the skin are suddenly closed, and inflammation, and frequently conges- tion in some part of the body, is a very common result. The safest plan for both man and horse, is to rub the skin briskly as it cools oft", protecting it at the same time from cool currents of air. Or if this cannot be conveniently done, ANIMAL PHYSIOLOGY. 3G9 the man sliould throw a cloak over "himself, and a blanket over his horse. 588. The oily secretions from the skin protect it against sudden changes, to some extent, by forming a non-conduct- ing film over the surface. They also diminish friction be- tween the cuticle, and the bodies with which it comes in contact, and thus prevent it from being abraded so often as it would be, if the surface were more dry and harsh. Cleanliness promotes the healthy action of the skin. Children and servants should be required to bathe fre- quently, and rub briskly afterwards. A foul skin and foul clothing are fruitful sources of disease. Horses, cows, and even hogs, should have clean, dry beds ; otherwise, they will be liable to cutaneous diseases. 589. The peculiar structure of the skins of animals, gives them their value in the manufacture of leather. The cuticle forms the grain of the leather, while the true skin forms the main body, and the stronger part of the material. Its pecu- liar net-work of fibres gives it both toughness and elasticity. For the chemistry of tanning leather, see § 196. 590. Appendages of the Skin. — Hairs, feathers, nails, claws, hoofs, and horns, may be regarded as appendages to the skin (§ 201). Hairs have their origin in the true skin, and spring from a bulb-like root (Fig. 49). They have neither veins nor nerves, and hence have no vitality in themselves. They grow at the root only ; and the upper part is thrust out by the increase of length at the lower extremity. A hair con- sists of three parts: 1. The cuticle, or external scaly cover- ing; 2. A horny, cylindrical tube, having a fibrous struc- ture; 3. A ^5?'