330 



^n Essay on Agriculture. 



III. 



thincT except the fust'ian of tournament?, and 

 the " pomp and circumstance" of the w ar?, 

 excited mainly by the blind zeal or wily arti- 

 fice of the monastic orders. The only glini- 

 merings of science that were then elicited, 

 were the result of the labors of visionary al- 

 chymifts; and durins-alon? period of Cimme- 

 rian darkness, norriculture was attended to by 

 the base and ignorant vassals of the preat alone^ 

 But as learning revived and true science had 

 ao-ain her votaries, it soon became respectable 

 as an art, and may now be justly dignified as 

 a science ; and that too, of primary importance. 

 The author of Lacon has well said that "Ag- 

 riculture is the most certain source of health 

 and strength and independence. Commerce 

 flourishes by circumstances, precarious, con- 

 tingent, transitory— almost as liable to change 

 as the winds and waves that waft it to our 

 shores. She may well be termed the younger 

 sister, for, in all emergencies, she looks to 

 agricMlture both for defence and supply." 



In Europe, men of the highest attainments 

 have turned the lights of science upon this 

 subject, and the consequence is, that many 

 things which were considered as forever hid- 

 den among the arcana of nature, are now ea- 

 sily distintruished. The theories that have 

 been built upon the discoveries thus made, are 

 applied to practice in many of the best farm- 

 ing districts of Great Britain and the Euro- 

 pean continent, with very beneficial results. 



Felix qui potuit rerum cognascure causas. 



We have cause of gratulation that, in our 

 own country too, many di.«tinguished names 

 are enrolled among the cultivators of the soil, 

 whose W\fh theoretical knowledge and great 

 practicalWl and skill are deserving of much 

 commendation. There is still, however, a 

 great deal to be done, and the foundation of 

 every improvement not resulting from mere 

 accident, must rest upon a knowledge of the 

 causes of the effects that we see produced in 

 the vegetable kingdom, and a proper ac(iuaint- 

 ance with the physiology of plants. A wide 

 range is thus opened before us, to pursue 

 whi'ch, would lead to the discussion of many 

 botanical points, as well as to investigations 

 relating to geology, and to the nature and use 

 of marl, lime, sand, ashes, gypsum, dung, and 

 other matters; the judicious application of 

 which is generally admitted to fertilize the 

 soil. Remembering the proposition ofKerwan, 

 that, manures are applied In sitppJy (he de- 

 fective, ingredients of a soil, or iwprove its 

 texture, or correct its vices, we should be in- 

 duced moreover to inquire, particularly, what 

 are the proper agents to apply to such soils as 

 rest upon the primitive rocks of the eastern 

 section of our country, which arc generally of 

 but little fertility— to such also, as are of the 

 light alluvial character, which class embraces 



L»-)ng Island, and the whole seaboard as far as 

 the Giilfof Mexico— and again to such as are 

 embedded upon the strata of the transition 

 kinds, which soils are mostly susceptible of a 

 liigh degree of cultivation, and fill up the 

 space between the varieties just named and 

 the Alleghany mountains, at the western foot 

 of which, commences the vast fertile region 

 of the secondary formation, known as the 

 great valley or basin of the Mississippi. 



I have neither the ability, nor would the 

 time allotted to the session of the Cabinet, 

 permit the examination of these varied, in- 

 tricate, and hiehly interesting subjects. I 

 shall confine myself, therefore, to the consid- 

 eration of lime, dung, and plaster of pans, 

 which are chiefly depended upon as manures 

 I by the farmers of the district in which we re- 



l side. . 



I Lime, as most generally found in nature, is 

 I a carbonate, which, upon being exposed to a 

 strono- heat for some time, will lose its carbo- 

 I nic acid, and its water of crystallization. In 

 1 this state it has a caustic, alkaline taste, and 

 ' when exposed to the air, soon becom.es what 

 is usually called fallen lime, and is denomi- 

 nated bv Dalton, an hydrat of lime. It is now 

 very soluble, and may be readily taken up by 

 the absorbents of vegetables. The food ot 

 plants is universally admitted by the scienti- 

 fic world to be chiefly water, and carbonic 

 and calcareous matters. Were it not so, from 

 what source would all herbiverous as well as 

 all other animals derive the lime that enters 

 into their bony structure? By the experw 

 ments of Gay, Lussac and Thenard, it has 

 been proven also, that the woody fibre, or lig- 

 nem, consists of carbon, and of oxygen and 

 hydrogen in such proportions as are necessary 

 to the'^formation of water. 



It may not be irrelevant to state here, that 

 Ino-enhong and other experimentists have 

 shSwn, that plants give out pure oxygen gas 

 while acted upon by the sun's rays ; that they 

 have the power of decomposing water, and 

 appropriating its ingredients to supply their 

 own vvants; and that, with other matters they 

 absorb nitrogen and carbonic acid gas. 



The hydrogen taken up assists in the forma- 

 tion of oil and resin : a portion of the oxygen 

 a« shown by Cruikshanks, is necessary to the 

 conversion of mucilage into sugar, and the 

 sap of all useCul vepelables is of a saccharine 

 character. The remaining portion ot oxygen 

 is thrown ofi' in the manner alluded to above ; 

 and the carbon, as has been before observed, 

 enters largely into the composition of the 

 woody fibre. , . j u 



From these facts we may understand how 



1 wise a provision has been made for the pre- 



Iservation of the purity of the atmosphere, 



contaminated as it is by every respiration of 



I animals, and by a thousand other causes,— 



