ON THE ACTION OF GYPSUM AS MANURE. 



Hig Lick, Botetourt, } 

 3Iay 22d., 1836. $ 



To the Editor of tlic Farmers' Register. 



An intelligent contributor to yonr first number ol 

 the present volume, deduces from his experience 

 in the cultivation of clover, with the aid of plaster, 

 that they are insufficient ibr the restoration or ini- 

 provement of worn out lands. From his experi- 

 ment, it appeared, that through the agency of clo- 

 ver and plaster, the productiveness of his land was 

 materially increased tor a lew years; but that atier 

 the second year, his crops began to deteriorate so 

 much as to induce]him to abandon the clover sys- 

 tem, and rely upon marsh mud and putrescent 

 manures. This statement of i'acts is so much at 

 war with the generally received opinion of the 

 effects of clover and gypsum, and so opposed to 

 what I had before considered the well-established 

 theory of plaster, that I felt some curiosity to see 

 how they could be reconciled. The m3'stery 

 which has heretolore veiled the character of this 

 mineral, when considered as a manure, has been 

 measurably drawn aside by ihescienlificresearches 

 and practical labors of Count Chaptal. Belbre his 

 genius and erudition andj sound judgment were 

 devoted to agriculture, and excited totlie most en- 

 ergetic action by a passionate love ibr the study, 

 the whole world, learned and unlearned, were en- 

 tirely ignorant of" its modus operandi. Some ur- 

 ging, what the experiment of yourcontributor would 

 seem to prove, that plaster was a powerful stimu- 

 lant, which excited the land to unnatural produc- 

 tion, and having wasted its fertility in a kw years, 

 would leave it altogether inert and barren. Others 

 laid great stress on its being an absorbent of mois- 

 ture, and confined its benefits to periods ol'drought: 

 whilst others, guided by the feeble lights which 

 science had shed upon the subject, embraced the 

 opinion, that, although its stimulating and absorb- 

 ent qualities were entitled to some consideration, 

 yet, that its great value consisted in its being so- 

 luble, and acting directly as a pabulum to the crop. 

 Among those who adopted this theory, and whose 

 reputation gave it the stamp of currency, was Sir 

 Humphry Davy, a philosopher upon whom nature 

 had scattered the rays of genius, and the inspira- 

 tion of mtellect, with a bountiful hand — one whose 

 eflbrts to improve the science of aoriculture, as 

 connected with chemistry, entities him to our high- 

 est admiration and lasting gratitude — and one 

 who, had he been so situated as to have brought 

 his theories to the touchstone of experience, would 

 have shed a flood of light upon the path of the 

 husbandman, which would have cheered him 

 through many a drear}- jungle of contradictions 

 and difficulties, which perplex and annoy him. 

 From an analysis of the soil in those districts of j 

 England, in which plaster is inoperative, he as- 

 certained that they contained a much larger pro- 

 portion of gypsum than the soil of those wiiere 

 it was beneficially employed. He, likewise, ascer- 



tained, from a series of the most carefully con- 

 ducted experiments, that those plants, upon which 

 the efi'ects of plaster were most striking, contained 

 it in the largest quantities. From which two facts, 

 taken in connection, he inferred that gypsum was 

 an essential constituent in the organization of 

 those vegetables upon which its influence is most 

 discernible; tliat it was a species of food which 

 was all important to them; that some soils were 

 surcharged with it, and others deficient; that of 

 course in the one case it would be waste to apply 

 it, and in the other, an indispensable auxiliary. 

 Such being the thooiy of this great man, the whole 

 world seemed to acquiesce in its correctness, until 

 Count Chaptal, profiting by the researches of Sir 

 Humphry, and possessing the incalculable advan- 

 tage of experience as a practical agriculturist, 

 gave to the world the fruits of a life time spent in 

 the ardent pursuit and patient investigation of" ag- 

 riculture, as a science. 



Looking upon his vocation, not only as the most 

 important, but as the most dignified and indepen- 

 dent and honorable of all others, and as requiring 

 the exercise of the highest f"aculties of the human 

 mind, he prosecuted it with a zeal and energy that 

 never wavered; and in the maturity of age and 

 experience, presented the public with a work en- 

 titled Chemistry applied to J/gricu!ture — a work in 

 which the perspicuity of his mind, and the solidi- 

 ty of his judgment are every where cons[)icuous — 

 a work in which he seems to thread the intricacies 

 of the science with intuitive sagacity, and to illu- 

 mine its paths with a torch, which renders them 

 plain and easily travelled by all. In that portion 

 of his book which treats of stimulating manures, 

 he bears testimony to the immeasurable utility and 

 extraordinary efficacy of plaster. He unites with 

 Davy in discarding the idea of its value consisting 

 in its attraction for moisture, for the very plain rea- 

 son that it solidifies what it absorbs, and of course 

 does not impart it to the plant. He also concurs 

 in the correctness of Davy's experiments, which 

 proved that it was not favorable to decomposition. 

 He attaches no importance to it as a pabulum, and 

 thinks that its great virtue resides in its stimulating 

 proj)erties. The fact that it requires 500 parts of 

 water to dissolve one of plaster, thus affording a 

 moderate, constant, and uniform stimulus to vege- 

 tation, he considers its most valuable feature. 

 These opinions he deduces from numerous well 

 established analofrics, and which, to those who 

 read his work, will seem to follow naturally and 

 inevitably. If, then, Chaptal be not mistaken, 

 your correspondent has certainly erred in inferring 

 i'rom his experiment, that plaster was a mere alter- 

 alive or stimulant, whose effects weakened the 

 productive powers of his soil after a few years. 

 If he means further to convey the idea that though 

 the land continued to produce clover luxuriantly 

 by the aid of plaster, that the soil was not im- 

 proved, and the wheat and corn crops deteiiorated 

 annual!}", I must insist that he has mistaken the 

 cause, though I am unable to suggest the true 

 one, without a more intimate knowledge of his 



