276 



NEW ENGLAND FARMER. 



March 21, 18-28. 



SCIENTIFIC AGRICULTURE. 



An Address delivered before the Hampsiiire. Franklin, and 

 Hampden Agricultural Socielj ; at Northaiinpton, Oct. 24. 

 1827. By Edward Hitchcock, Professor of Chemistiy and 

 Natural History in Amherst College. 



[Continued from pag^ 267.] 



Concerning the state of agriculture in Great 

 Britain, previous to the fifteenth century, we l<now 

 but little. We may conclude, however, that when 

 men begin to write books on any subject, an in- 

 terest in it is excited in the comimiiiity ; and as 

 early as 1534, Anthony F'itzherbert produced a 

 philosophical and ingenious treatise upon agricul- 

 ture. But in the succeeding hiindre ! years, noth- 

 ing appeared on the subject, worthy of notice. — 

 Indeed, though rural economy, sometimes wa.xing 

 and sotnelimes waning, was upon the whole slow- 

 ly progressing, yet no remarkable 3poch in its 

 history occurrnd till near tlie close ■ f the seven- 

 teenth century. In the early ages of Modern Eu- 

 rope, the Feudal system exerted a most tinpro- 

 pitious influence upon agriculture. C'o military 

 was the spirit of that system, such a servile de- 

 pendence did it produce on the one ham, and such 

 a haughty aristocracy on the other, that both sci- 

 ence and art were withered by its touch : and tho' 

 the system itself has long since been ncminally 

 extinct, yet its influence remained for cen- 

 turies. 



But a still more powerful obstruction to the 

 progress of agriculture, was an almost entire ig- 

 norance of tlie scientific principles on whicM it is 

 founded. Till near the close of the last ce; tury, 

 the very sciences from which those principlt ■; are 

 derived, can hardly be said to have had an c ust- 

 ence. Previous to that perioil, therefore, tre-iiises 

 upon agriculture were merely a collection of om- 

 naon place maxims, partly true, and partly fa'se, 

 mixed with most extravagant hypotheses and wild 

 and hurtful superstitions. And it is only justice 

 to say, that the Agricultural Chemistry ( f Sir 

 Humphrey Davy, contains more new and valuable 

 principles to guide the agriculturist in making 

 improvements in husbandry, than all which the ex- 

 perience and science of preceding centuries had 

 developed. And it is to be imputed mainly to the 

 application of these principles, by intelligent men, 

 chat agriculture, within the last half centu'y, in 

 Europe, and particularly in Great Britain, has 

 made such rapid progress. 



I know, indeed, that there is a prejudice exist- 

 ing in some minds, against the application of sci- 

 entific principles as guides in agricultural experi- 

 ments. It is thought that they serve rather to 

 bewilder, than direct. But if the agriculturist be 

 not guided by scientific principles, what shall he 

 follow.' True, his own experience alone may do 

 much to assist him ; and it hasaccompliahed won- 

 ders in times past. But will not a C')rrpct knowl- 

 edge of the compoution of soils, of the food of 

 plants, and of the mode in which that food is con- 

 verted into nourishment, will not this knowledge 

 prove an important auxiliary to e.xparience? The 

 experience of one man teaches him it is impor- 

 tant he shotild observe the position of the moon, 

 or whether the day of the week he lucky, or un- 

 lucky, when he sows and when he reaps. But sci- 

 ence tolls him, that these, and a hundred other 

 similar observances, are not only ufclcss, but of- 

 ten defeat his experiments. In every other art wt; 

 regard tho most scientific artisan, as most likely, 

 other things being equal, to make improvements. 

 Why (should it be diflTerent — it is not different — 



in agriculture ? In short, physical science is noth- 

 ing but the result of the most accurate and en- 

 lightened experience. 



If I mistake not, it is one important object ef 

 agricultural societies to give a right direction to 

 the efforts of the experimenter, by furnishing him 

 with correct scientific principles. Permit me, 

 therefore, gentlemen, to spend a few moments in 

 the exhibition of those principles that lie .nt the 

 foundation of agriculture ; and in their application 

 to practical husbandry. In doing this, I shall a- 

 void as much as possible the use of technical 

 phraseology. 



There are three sciences. Chemistry, Botany, 

 and Geology, with which the theory of agricul- 

 ture is most intimately connected. Chemistry 

 teaches us what is the composition of plants, of 

 the soil in which they grow, and of the atmos- 

 phere that surrounds them ; and of consequence, 

 shows us what is their proper food, and the best 

 manner of applying it. Botany dissects the veg- 

 etable kingdom, and discloses those curious ves- 

 sels by which the food of plants is taken up and 

 converted into the numerous distinct principles 

 and parts which they contain. Geology instructs 

 us in the general nature of the soils in which veg- 

 etables flourish, and enables us to predict what 

 varieties of soil will be most favourable to particu- 

 lar plants. 



The first point that should engage the atten 

 tion of the enlightened agriculturist, is to ascer 

 tain the nature and situation of those minute ves 

 sels by which plants absorb water from the soil 

 and the atmospliere, and by which these princi- 

 ples are modified and circulated to every part of 

 the vegetable, and are converted into the plant it- 

 self. So minute are these vessels, that even mi 

 croscopic observation has not been able to detect 

 all their intricacies. But their general structure 

 and arrangement have been ascertained. And it 

 is found that they bear a most striking analogy 

 to those vessels of animals by which nutriment is 

 conveyed, in ceaseless circulation, to every par: of 

 the system. In every plant we find one set of 

 small vessels, running from the roots to the ex- 

 tremities, through which the sap ascends, vhile 

 in its progress it is undergoing those changes that 

 will fit it for becoming a part of the vegetable. — 

 These vessels resemble the arteries in the ani- 

 mal system. When the sap is thus conveyed to 

 the leaves and other extremities of the plait, it 

 there comes in contact with the atmosphere, g.ves 

 oflf its redundancies, and absorbs water, and per- 

 haps other principles, essential to the health of 

 the plant. Tho leaves of plants, therefore, per- 

 form nearly the same functions as the lungs of 

 animals. A second set of vessels, exterior to the 

 first and mostly confined to the bark, now conveys 

 the food of the plant, thus prepared, to every part 

 that needs nourishment ; even to the very roots 

 frotn which it proceeded. These vessels corres- 

 pond to the veins. Other vessels are found in 

 plants, corresponding, probably, to those similarly 

 situated in the animal system ; yet too complica- 

 ted for explanation on this occasion. Sutfice it 

 to mention, that in the vegetable, as well as ani- 

 mal economy, we find the principle of life — itself 

 inscrutable — modifying and controlling every op- 

 oration and keeping the wonderful machinery in 

 ceaseless play. 



So much for the botany, or rather anatomy, of 

 the vegetable kingdom. Wo next enquire what 

 arc the simple substances that enter into the com- 



position of plants; for until the agriculturist 

 knows this, how shall he ascertain what materials 

 are best adapted to their nourishment .= And 



Chemistry stands ready to answer the enquiry. 



Out of the fifty simple substances or elements, 

 known to exist, we find vegetables iilmo.-it entire- 

 j ly composed of three, viz. charcoal and two gases. 

 I A few others are occasionally present, and in 

 ; gome cases seem essential to the constitution of 

 \ the plant ; such as silex, lime, iron, manganese, 

 &c. It is by variously combining these few ele- 

 ments that the numerous proximate principles of 

 vegetables, such as sugar, gum, starch, and the 

 like, are produced; and also the unnumbered 

 forms and properties of the stalk, the bark, the 

 wood, the leaves, the roots, the flowers, and the 

 fruit. A beautiful example of the simplicity of 

 nature ! 



The next point on which chemistry afibrds light 

 to th? agriculturist, is the composition of the soil 

 and itmosphere in which plants are placed. That 

 they derive their nourishment fiom the first, if 

 not the second of these sources, is certain. It is 

 tecessary, therefore, that in these, should be found 

 ill those simple substances that are essential to 

 : che constitution of vegetables; and the whole 

 subject of manures consists of little else than an 

 jjccoiintof the modes in w' ich these principles 

 are supplied. The analysis of the soil will show 

 which, if any, is deficient ; and thus point to the 

 j^est mode of supplying tliosa that are wanting. 



In regard to those changes that the sap of 

 plants undergoes before it is converted into the 

 vegetable itself, and its various peculiar princi- 

 ples, upon these changes, although entirely chem- 

 ical, chemistry sheds but a feeble light. We know 

 that every plant must be a perfect laboratory ; for 

 ve see the sap, which is nothing more than water, 

 holding a few things in solition, entering the ves- 

 sels of the vegetable, and having passed through 

 them, we find a most wonderful conversion of this 

 sap into pith, wood, bark, l-a\'es, flowers, fruit, 

 and numerous peculiar and couipound products i 

 such as gum, sugar, acid, and the like. Here is 

 proof that the most complicated and delicate 

 chemical processes are continually going on in all 

 living plants ; processes that infinitely exceed 

 tho skill of the most accomplished chemist ; and 

 vet, they are hid, from even microscopic observa- 

 tion, by the minuteness of the vessels and agents 

 concerned. We know only that a certain degree- 

 of heat and moisture are requisite, and sometimes 

 light also, to carry forward the operation. In 

 these wonderful transformations, however, there 

 is surely one thing the chemist can learn ; and 

 that is, a lesson of htimility. While he is able, 

 by putting in requisition all the resources of his 

 art, to produce scarcely one of the simplest vege- 

 table principles, twenty or thirty of these are an- 

 nually formed in every plant. 



By the science of geology we are maiie ac- 

 quainted with the nature of the rocks that consti- 

 tute the grent mass of our globe. iSow it is a well 

 established fact, that soils are nothing more than 

 rocks worn down or decomposed, and mixed with 

 animal and vegetable matter. Hence, in most ca- 

 ses, the nature of a soil is determined by the na- 

 ture of the rock beneath it. For instance, the soil 

 along the Connecticut is in many plates, of a red- 

 dish hue ; because that is the colour of the rock 

 bo.ieath it. Not unfrequenlly, however, the ma- 

 terials that are worn away from one rock, are 

 transported a considerable distance, and mingled 



