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The widest prejudice against the application of science to the art of agri culture, has arisen from confounding science with the operations of men who have gone to the fields, book in hand, trusting to reach judicious culture by a prescribed formula. I deliver over all such sciolists and smatterers to the appropri ate awards of a poetical justice. If the "book farmer" has not succeeded, his failure was the result of one or more of three causes: First, the book did not con tain the requisite science or knowledge; second, if it did, the farmer did not find it out; or third, he had not the practical experience or industry to apply the knowledge the book contained. I join in no crusade against books. They have been, and are, and will be in all coming time, the repositories of science. They are the caskets which contain the jewels of the mind, wrought by genius in every age. Yet unlike other caskets, while they collect they distribute also.

But, gentlemen, that would be indeed a rare book—invaluable as rare— which contained all the science necessary to the farmer. The art of agriculture demands the aid, not of one only, but of many sciences. The aggregate fills the entire circle of the natural sciences. The elements of agriculture have rested on botany. The indications of vegetable physiology have been, and yet are, the chief guides of the practical farmer.

Mechanics and hydraulics, are as essential to his yearly operations, as the seed he sows. Geology only, can accurately teach him the origin of his soils, the cause of the diversities which they frequently exhibit, not only in the same farm but sometimes in the same field, the nature and differences of his subsoil and the advantages he may expect in bringing them to the surface.

Meteorology makes for him her tables, showing the highest, the mean and the lowest temperatures, and also the quantity of rain that falls during each day and each month of the year-knowledge eminently useful for the proper culture of the land. While chemistry discloses the composition of soils-the composition of the atmosphere the food upon which every plant must live-from whence obtained-whether from the earth or the air--the deficiencies of soils, to the growth of plants-and how the deficiency may be supplied, and when the adaptation of particular soils to the growth of particular plants-the causes of exhaustion of soils-the means of restoration-when nature will supply deficiencies -and when man must do it for her, and how-the principles upon which alone, a judicious rotation of crops can be applied to a given soil-in a word, the office of chemistry is to explain the processes of vegetable life, in every stage of its being, and to show forth the results of decay and death. To this science agriculture must ever look for its highest achievements; other sciences may be important auxiliaries in every step of her progress; but chemistry must conduct her to prosperity. However dissevered, as they have been; however strife and ill-feeling may have come between them; however jealousy and ignorance may have disturbed their union, agriculture and chemistry are inseparably united; and what God hath joined together let no man put asunder.

Look at the art of culture as it now obtains in our country, is it not essentially a chemical art? You put lime, or gypsum, or guano on your land-what are they but chemical agents? and why do you add them to the constituents of your soil? Is it not solely from the hope of chemical action? If you drain your meadows, or irrigate them, are you not seeking chemical action? If you subsoil-what are you in search of but chemical action? If you let your fields lie in fallowwhat are you waiting for, but chemical action? If instead of rest you practice rotation in crops on what principle can you explain your practice other than upon the laws of chemical action? Even your mechanical operation of plowing what is it, but a means of inducing or facilitating chemical action? And when you come to the composition of your manures, whether vegetable, or animal, or mineral, or all combined, you are engaged in that which demands a large knowledge of the laws of chemical action. Knowledge of the constituents of your soil-knowledge of its deficiency-knowledge of what will supply that defici ency—and knowledge how, and from what source that supply shall come.

It is thus manifest beyond the reach of cavil-that the agriculturist, whether he knows it or not, and in spite it may be of the profoundest ignorance of chemistry, is nevertheless practically a chemist.

Will a knowledge of chemistry help the experimenter to his desired result? Ought he to rely upon the ascertained and established truths of science, or trust to chance? That is the question-that is the question. The question of this hour -the question of this age, put by me, with a gravity due to its importance-to every agriculturist in the land-to all who are indirectly interested in the pro

ducts of the soil and to the public authorities. Upon a question so vital to the State-so big with results-so full of weal or woe to us in our day and generation, and especially to those who shall come after us. I would invoke the shades of our mighty departed for an answer. If it could be, Fort Hill and the Hermitage, Marshfield and Ashland, Monticello and Montpellier would each find a tongue, and rising high above them all, the solemn, benign and parental voice of Mount Vernon would give power and emphasis to the joint reply. Do you doubt what that reply would be? Differing widely as to the actual adjustment of powers in our Federative system, and sometimes apart upon the measures of policy-no dissension ever came between them as to the true position of agriculture. They loved the fields, and with a love that defied the intoxicating influences of power and the seductive spell of high station. Their graves are farmers' graves. the Capitol, amidst cities, on the summits of mountains, cenotaphs and mausoleums speak in enduring marble the nation's gratitude, but their bodies moulder in the soil they tilled. When was it in their lives that a sentiment escaped from either of them adverse to the healthful influence of science on culture?

At

In their day and generation, amidst the monopolizing cares of State, when did either of them lose an opportunity to avail himself of any achievement of the mind calculated to increase the fertility of the earth? Or when did they fail to give to Science, on her pathway of toil, a cheering word? They were philosophers as well as statesmen, and in the quietude and repose of their fields-in that "solitude" which is "the school of genius" in the contemplation of Nature working out in her mighty laboratory, the processes of vegetable and animal life their minds expanded to the measure of true greatness.

Some of them were surrounded by a philosophical apparatus, and worked in their home laboratories. Mr. JEFFERSON, while minister at the French court, found time amidst the engrossing cares of diplomacy, not only to watch the throes of a revolution, but to make himself master of every new discovery in science. The interest of agriculture engaged his special attention; every new implement of husbandry-every new mode of culture-every plant useful to man not grown in our land, became the object of his regard. His well known journey through the interior and south of France, and over the ranges of the lesser Alps, had for its motive the pursuit of scientific agriculture. If in that day an agricultural school or college could have been found in France or Switzerland, who can doubt that he would have been drawn to it by an irresistable attraction. Mr. Madison on his skillfully conducted farm, up to a late period of his life, kept pace with every advance of chemistry. His letters-the letters of Washington and Webster-form a beautiful and instructive portion of our agricultural lite

rature.

But I turn from these bright names to call you back to your own farms, and to your own operations in husbandry.

You put gypsum on your land. In one district of country its effects are lauded, in another its efficacy is doubted, while in a third it is decried. How is that? and why is it? Is it the freak or fickleness of the mineral? Is the result in each case a chance medley? or does it spring from cause? Just so sure as that the earth we inhabit moves in its orbit round the sun by law, so sure is it that the result in each case is the effect of principle, and that principle science can discover.

Again, you put upon your soil animal manure-you find its action powerful and its effect permanent. Other animal manures act only for a time, and their effect is speedily exhausted. Do you know the cause? Chemistry can answer.

"Does a mixture of animal and vegetable manures prepare your land best for certain kinds of grain? Do you employ common salt, or nitrate of soda, lime, the ash of wood, bone dust, or any other substance with, advantage? In all these cases you observe chemical results, which you would be able to control and modify did you possess the requisite chemical knowledge."

Some barren soils are capable of reclamation-others not profitably under the present state of science. Is it not a matter of importance to be able to distinguish between them? But what is more particularly applicable to us-some soils that to the eye seem good will not produce. Now, by what rule will the common farmer work to give fertility to such land? Has he any rule? Ignorant of the disease, how shall he apply the remedy? Shall he experiment in the dark and work on as the sanguine Micawber lived-"in the hope that something will shortly turn up?"

By a beautiful economy in nature, many of the inorganic elements necessary to the growth of plants exist in the soil in quantities so small as to become appreciable only by a refined analysis. How shall the practical farmer detect their absence by the best use of his powers of observation? I repeat the question— how shall he work? Blindly in the dark? or growing tired of unprofitable toil, shall be shift the responsibility by selling out? or shall he call upon science to tell him the exact chemical constitution of the earthy part of his soil? Perhaps the reply of the chemist may be "Your soil is excellent, and wants only a small portion of what is known to science as phosphoric acid, which you can supply at little more than nominal cost." Or perhaps he may suggest the presence in the soil of some one of the salts of iron, or other noxious principle easily and cheaply deprived of its hurtful influence by the application or well known chemical agents. In reference to such soils Sir HUMPHREY DAVY more than half a century ago, when agricultural chemistry was comparatively unknown, said "the application of chemical tests to such soil is obvious-it must contain some noxious principle," (or be deficient in some necessary element, adds JOHNSON thirty years later,) which may be easily discovered and probably easily destroyed. Are any of the salts of iron present? they may be decomposed by lime. Is there an excess of silicious sand? the system of improvement must depend on the application of clay and calcarious matter. Is there a defect of calcarious matter?-the remedy is obvious. Is there an excess of vegetable matter indicated ?-it may be removed by liming, paring and burning. Is there a deficiency of vegetable-matter?--it is to be supplied by manure." Since his day soils are better understood, and in many cases chemistry can now accurately determine what a soil must contain before it will produce a given crop.

In our own country the value of chemical tests applied to the soil is abundantly established. I cite a few examples out of many furnished me by your Secretary, my friend MINOR, to whose enterprise and zeal you and the State are largely indebted for your present organization.

In the Agricultural Transactions of the State of Massachusetts for the year 1851, (a book which I would commend to those engaged in diffusing agricultural literature among our people.) I find recorded some authentic facts which illustrate the matter in hand. Professor MAPES, a gentleman of large attainments in various departments of science, furnished the results of the analysis of the soils of more than one hundred farms in the State of New Jersey. Take two or three of them:

He analysed the soil of a field of J. J. SCOFIELD, of Morristown, on which the owner desired to raise ruta baga turnips. It was found deficient of the following constituents of that crop: phosphate of lime, potash, o ganic substances, including a slight quantity of animal matter. These being supplied, the result

was fourteen hundred bushels to the acre, as certified to the Legislature!

He also analysed the soil of a field of Dr. JNO. WOODHULL, which he had appropriated to the growth of wheat, and from which he had the preceding year obtained less than fifteen bushels to the acre. After supplying the deficient constituents, he obtained, the succeeding year, fifty-seven bushels to the acre.

Another instance I cite, to show the value of subsoiling, under scientific direction. The farm of RoвT. RENNIE was deficient in its surface soil. Its subsoil by analysis proved to be rich in substances not contained in the surface soil. He prescribed subsoiling and a thorough mixture of upper and lower soils. The preceding crops were fifteen bushels of corn and sixty bushels of potatoes to the acre, but the succeeding one hundred and fifty bushels of ears of corn and three hundred and fifty bushels of potatoes. Once more: a field of a gentleman in Maryland had become barren under culture. It was reduced to a yield of one bushel per acre. He applied to a distinguished chemist, who on analysis, detected the absence of but one element of fertility-phosphoric acid. That element was supplied and the product was twenty-nine bushels of wheat to the acre. It is needless to multiply examples-these establish the connection between science and agriculture-but the union must be more complete.

I value at a high rate the practical skill-obtained by a long course of ob servation, possessed by many of our farmers-common sense, sound judgment, have done much for the soil, aided by little exterior information; and the light of Science will never dispense with the use of such qualities; but we cannot shut our eyes to the fact that, under our present system of culture, the soil of our country is undergoing exhaustion. Its richness, in the Valley of the Mississippi, will postpone the ultimate period of barrenness, but it must be witnessed by

those who shall live upon the earth when we have passed away, unless the process of exhaustion be arrested. The law of supply and demand, explains both the evil and its cure. That law is the great, primary law of Nature. Why does this noble river, on whose banks we stand, roll in ceaseless and perpetual flow on to the ocean? Whence comes its eternal supply? Ask the sea and the sun and the cloud, and they will answer. In this invisible air around us, are four elements, without which there can be no living thing-neither vegetable nor animal. Without them there must be universal death. Every moment in our lives we must have them, and so must every plant, The vegetable and animal kingdoms are the active, ceaseless, eternal consumers of these commodities. Why are they not exhausted? Why is it that the atmosphere, everywhere, still furnishes a supply to this never-ending demand? Go to Pompeii-dig up from its ruins a vase which has been covered by the lava of Vesuvius for eigtheen centuries analyze the air it holds-and you will find in it the exact amount of oxygen contained in the same volume of atmosphere that plays around the highest peak of the Alps. Whence is this universal supply? The answer is: every animal that breathes, at every breath, absorbs oxygen and gives out carbon, while every plant in its respiration, takes in carbon and gives out oxygen. The inde structibility of matter, perpetuates this exchange of the two kingdoms through an eternal circle. This is the operation of organic life, but decay and death are pledged to the same office of restoration. Burn a plant in flame, and it disappears-all save its ashes. In life its substance was mainly composed of the four elements--oxygen, carbon, hydrogen and nitrogen-and these it drew from the air, while it contained also small portions of several substances which it did not get from the air. Now, in the process of combustion, death comes, and at the moment of dissolution, every element is set free, and what is beautiful, each element knows its place, and whither it must go. The elements of air have gone to their home, and what came from the earth is left upon it.

In regard to the laws regulating the supply of nitrogen-an element which in the form of ammonia-is so intimately connected with vegetable life, as to claim the special attention of the practical farmer-there is more uncertainty. Whether the atmosphere be its primary source, as most chemists conclude, or whether LIEBIG be right in his conclusion, that is it a part--a primary constituent of the globe itself"--all chemists are able to trace the various secondary sources of supply of this essential fertilizer, and all concur in showing, that upon man devolves a large portion of the work of restoration. It is the great office of science to distinguish between the cases in which nature does, and does not, need the aid of man. Her processes are of themselves sufficient for her purposes she can clothe the earth in verdure--and by decay and death she renders that verdure perpetual-but man tasks her powers, and by continual drafts on her fertility, he may reduce her to barrenness. To prevent this, what she demands of man, is, that after he has used what he has taken from the earth, he shall bring it back to her exhausted bosom, or if he will not do that, let him go to her magazines of supplies, wonderfully and bountifully provided, to meet the exigencies of his improvidence. The immense coal fields which lie imbedded in the earth, of vegetable origin, furnish a sample of her prudent forecast and care. The nitre beds of India and South America, are other instances-and in our own country, on the shores of Lake Champlain, in New Jersey and New York, beds of phosphorite have been discovered, more valuable than mines of gold. To supply what they furnish England expends a half million of pounds sterling every year. She sends her ships abroad, to other countries, and digs for bones on the field of Waterloo. And nearer to us the Mammoth Cave in Kentucky, constitutes an inexhaustible nitrate reservoir. I venture to predict, that one of the proudest achievements of science, will be to convert the yet undeveloped resources of the mineral kingdom into the richest and cheapest fertilizers of the soil. I venture also to affirm that science, will never reach her highest attainment for agriculture, until she has perfected a system of specific manuringthat is, a system of manuring, by which one or many chemical agents shall be classified and adapted to the supply of a given deficiency-or the correction of a vicious quality of the soil.

General and indiscriminate manuring must, as it seems to me, give way as science advances. The ordinary mode in which farmers supply nitrogen, is by the manure pile, collected from the stable, and the barn-yard; and animal ma nures are richest in this particular substance--but in them it takes the form ammonia, and ammonia has wings so nimble, that they need clipping. Science

only can perform that operation well. There is something very curious and interesting in nitrogen. It presents an anomaly in nature. If it had anything to do with the affairs of State, some politicians would affirm that it presented the beau-ideal of what is sometimes called a "masterly inactivity"--others might maintain that it was a happy illustration of the "manitest destiny" doctrine 3 while an ardent Whig would be sure to claim it as a "conservative and against intervention"-it would become a Taleyrand in politics, and could live, in favor, under every dynasty. In the air it is in the midst of very active, and combustible agents, that have a wide range of affinities, prompting them to unite with many substances-but nitrogen is characterised by its utter indifference to all other substances-it has an apparent reluctance to enter into combination with any of them.

Whenever by the force of circumstances it is compelled to unite with some thing else, it remains in union, only because of its tendency to remain in the same place--and the slightest cause will disunite it from its compounds-yet it is an invariable constituent of plants, and during their life, is subject to the control of their vital powers; but the moment the mysterious principle of life ceases to influence it, it disengages itself, and promotes decay by its escape. It forms much the largest portion of the atmosphere, and saves nature from total destruction, by the check which its indifference opposes to the activity and energy of oxygen. It is the great conservative power of nature-but its disposition to be released from all other substances, and the slight force necessary to its escape, demand the minutest care of the practical farmer, when he wishes to restore it to his soil. This gas and hydrogen form ammonia--and the votatility of the ammonia of animal manure must be fixed, or you can never cart it to your fields. The agency of man in the supply of nitrogen, is a clear necessity. It is doubtful whether the nitrogen of the atmosphere, either as gas or in solution in water, ever enters directly into the living plant. If at all, it does so in quantities too small for its supply. It comes to it in the shape of compounds, as ammonia, nitric acid, and other compounds, some of which are produced by the decay of animal matter.

The

The volcanoes of the globe furnish ammonia-the consumption by burning of coal fields contributes indirectly to the supply of nitrogen. The electricity of the atmosphere aids in its production-but the farmer cannot rely upon these operations of nature for supplying the continued demand for nitrogen created by continued cultivation. Animal life is a great consumer of this element. fields are exhausted of it by the demands of cities, crowded with population, and, unhappily, what is thus carried away never returns. Lastly, this element is much less abundant in nature outside of the atmosphere than any other of the organic elements.

The supply of the remaining element, hydrogen, is not, in any important respect, dependent upon the agency of man. Its main source is water, in its various forms, and the artificial application of this bountiful fluid, to the garden and the field, seems to be the limit of man's action in the premises.

I pass from the elements of air to those of earth. When a plant is submitted to flame, we have seen its organic elements are given back to the air, while an ash remains which fire does not destroy. This ash constitutes the inorganic portion of plants. It forms so small a part of the plant, that for a long time it was supposed this organic matter, derived from the soil, was accidentally present, and could be of no essential or vital consequence to the plant. Science has for ever expelled this error. Careful experiments have shown

1st. That on whatever soil a plant is grown, if it shoots up in a healthy manner and fairly ripens into seed, the QUANTITY and QUALITY of the ash is nearly the same; and

2d. That though grown on the same soil the quantity and quality of the ash left by no two species of plants is the same--and that the ash differs more widely in these respects the more the plants differ from which the ash is derived.

It is thus certain that these inorganic constituents contained in the ash are essential parts of the plants--that they cannot live a healthy life and come to perfection without them--and the practical consequence is that the farmer must supply these inorganic substances to every deficient soil. If anything was needed to make this conclusion absolute, it was supplied in the experiment which establishes that if you take a healthy young plant, and place it on a soil where it cannot obtain this inorganic matter found in the ash of the mature plant of its species, it droops and dies.

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