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'trade, between Salem and eastern ports, and have instructed him how to steer that old schooner to Baltimore with safety to himself and his freighters? No. But a school-boy, who had never been aboard a ship, but who had studied well the science of navigation, could instruct that old seaman how he might find his way not only to Baltimore, but to the remotest island in the China seas, or any other spot in the known world.
So it is in agriculture. There are many old farmers, who, from long experience have acquired a valuable store of knowledge concerning the management of their own farms, which must die with them, for they cannot communicate this knowledge to others, so as to qualify those others to manage equally well other soils which may be differently constituted from their own. But whenever agriculture shall become a science, then the school-boy, who bas understandingly studied it, will be able to teach the practical cultivator how he must manage his lands to insure the largest crops. Until agriculture be made a science, all experiments, those for which premiums are offered and paid by our agricultural societies among the rest, must be of uncertain value. Others attempting to imitate those processes of tillage which have proved most valuable in other hands, fail to realize the same results, they know not why. The language used in stating these experiments is not definite. Take for example, one statement of the management, &c. of a crop of barley, in the Essex Agricultural Society's Transactions, selected at random, it being the first on which I cast my eye, on taking up the book to find something to illustrate the position stated above.
“ The land on which it grew is a clayey loam.”
What are its constituents? does it contain the salts of lime, potash, soda, magnesia?
The year previous “the land was planted with corn and potatoes, a shovel full of manure was put in the hill.”
Of what elements did this manure consist?
“ Last spring I spread two loads of compost manure on the lot.'
What were the constituents of this compost? I need not go through the statement. This must be sufficient to show that no other man can extract from it any information of the best method of cultivating barley on his own farm, whose clayey loam, his manure and compost manure may be altogether different articles from those mentioned by the same names in the statement from which I quote. Other statements in the same annual publication, my own not excepted, are liable to the same objections. And the principal reason why farmers derive so little benefit from books, and consequently often decry “book farming,” is that farming books are deficient in some of the most essential particulars—full of imperfect certificates and rules, owing to the fact that no analysis has been made of the soils and manures in question. “Hence,” says Dr. Jackson, "we account for the uncertainty of the results obtained by those who make trial of new methods of farming. If, however, all the conditions of the problem were understood by both parties, farmers would readily join hands with their scientific co-laborers, and the art of agriculture would soon become as certain as any other art, while, by the application of scientific principles, the business would become of a more exalted character, and assume its true rank in the consideration of all men.'
Towards reducing agriculture to a science, however, but little progress has, as yet, been made. And even that little often stated in terms not generally understood, and recorded in books to which but few have access, has hitherto been of little or no benefit to practical farmers. Any attempt therefore, however imperfect, to state some of the elementary principles of the science of agriculture in plain language, so that any one may, by giving to it that study and attention which is requisite to attain any other branch of human knowledge, understand and
apply it, will, we trust, be favorably received by the readers of these Transactions. Without study, no man has attained so much knowledge of arithmetic, as the every-day business of life requires. By as much study as is required to gain so much knowledge of arithmetic, a like competent knowledge of what is known of the science of agriculture may be attained. The elements of the science of agriculture are to be sought in treatises on Geology, Mineralogy, Chemistry, Vegetable Physiology, and Galvanic Electricity.
Many, for whose information I write, are presumed to know nothing of these sciences. Hence it becomes necessary to dwell a little on elementary principles, and endeavor to explain everything as we proceed.
MATTER. Matter exists in three forms, viz: as solids, fluids, and gases, or airs.
The particles of matter are supposed to be minute solid balls, that attract each other, although. surrounded by what chemists call caloric, or the cause of heat, which keeps them at a greater or less distance from each other, without adding to or diminishing their weight. In solids these particles are surrounded by so little caloric that power of attraction is so great as to prevent their being easily moved over each other; hence their fixed solid form. Add to this quantity of caloric by heating these solids until the particles are thereby farther separated from each other, and their attraction for each other lessened in the same proportion, until they assume the form of fluids, and roll freely over one another. Increase the caloric still more and they become gases, or airs perfectly transparent and of course invisible, as the particles of matter are too small to be seen by any aids to vision which we possess, and they are now so far separated from each other that light freely passes between them. But these particles remain unchanged, and by reducing the caloric, return to the same form and assume the same qualities as be
fore. The melting of metals and the conversion of liquids into steam are familiar illustrations of this theory. In the temperature of our atmosphere, different bodies exist naturally in the three forms. But the solid particles which surrounded by caloric compose, for example, the atmospheric air, may be individually as heavy as the particles of lead, and capable of uniting with the particles of lead, and by this union produce a substance very unlike either air or metalic lead—the well-known pigment red lead.
By such changes and combinations of the particles of matter, although only forty nine different kinds of matter are known, all the endless varieties of substances which exist around us are formed, and the particles of gases or fluids as readily unite with solids as the particles of solids with each other. Hence, in speaking of the constituents of soils, manures, and vegetables, we shall have frequently to describe such combinations. Component parts of fluids and gases become solids, and component parts of solids again become fluids and gases, both in the formation and decay, or decomposition of vegetables. These preliminary explanations, if carefully studied, will, it is hoped, be sufficient to enable those who have read nothing on Chemistry, to understand what we are about to say on the subject of soils, manures, and vegetables.
All geologists and chemists agree in considering soils the result of the pulverized and decomposed portions of rocks, with the addition of salts and vegetable and animal substances. Nearly all the rocks which exist in large quantities, are composed chiefly of silica or flint, alumina, pure clay, lime and iron. Magnesia exists in small quantities in many rocks and in the serpentine and soapstone in large portions. Manganese, another metal, in small quantities in the rocks, and consequently in the soils of New England. Potash and soda exist also in most of our rocks.
Most of the rocks in New England contain, on an average, 66 per cent. of silica; 16 per cent. of alumina; 6 or 7 per cent. of potash, and 5 per cent. of iron; lime and magnesia in much less quantity. And the composition of our soils will be found to correspond very nearly with these numbers; excepting potash and lime in their free state, which are soon so far exhausted by vegetation as not to be detected by the ordinary methods of analysing soils. By potash in a free state, I mean to distinguish it from its state or condition when combined with silica, alumina, &c. in rocks, pebbles, and grains of sand, consisting of broken pulverized but not decomposed compound minerals. The terms decompose, and decomposition must be understood to mean to divorce, or to separate, or the separation of the elements of a compound substance. Felspar, a large component part of granite, greenstone, and other of our most common rocks is, for example, composed of silica 63, alumina 17, potash 13, lime 3, oxyd of iron 1 in 100 parts; broken or pulverized, each particle is composed of these elements in their natural state chemically combined. Decompose felspar and we have the silica, alumina, potash, &c. still mixed perhaps, but divorced or separated so far as these terms express, the breaking of the bonds of adhesion which exist in their combined state.
In their combined, confederated, compact state, they aid each other in resisting the action of the hungry roots of vegetables upon them; decomposed, they readily become the prey of their vegetable devourers. Hence the potash, for example, of the decomposed felspar does not long remain in the soil, but will be found in the plants and trees growing thereon.
Among the elements which compose our cultivated vegetables, are found silica, lime, magnesia, oxyd of iron, potash, soda, sulphuric, and phosphoric acids. Hence these will be found constituents of all soils capable of producing them.