44 



THE GE^CKSEE FAEMEE, 



into the aubsoil, forming so many minor drains or 

 feeders, all leading to the conduit. These main 

 fissures have numerous s^mall ones diverging from 

 them, so that the whole mass of earth is divided 

 and subdivided into the most minute portions. The 

 main fissures are at first small, but gradually en- 

 lai'ge as the dryness increases^ and at the same time 

 lengthen out ; so that when a very dry season hap- 

 pens, they may be traced the whole way between 

 the drains. The following cut (fig. 16) will give 

 some idea of this cracking action. 



Tig. 16. 



"WTien the fissures are once formed, the falling of 

 loose earth into them, and the grooviBg action of 

 the water which passes through them, prevents 

 them from ever closing so perfectly as to hinder 

 the passage of water; whUe each successive sum- 

 mer produces new fissures, till the whole body of 

 the subsoil is pervaded by a perfect network of 

 them, which gradually alters the very nature of 

 both soil and subsoU ; and in connection with judi- 

 cious and liberal manuring, has tlie efiect of con- 

 verting poor cold clays into something not very 

 different from a good clay loam. 



We had intended offering some practical remarks 

 on draining springy lands, &c., but the length of 

 this article compels us to postpone them to some 

 future number. 



Dkaught of Plowing at Diffeeest Depths. — 

 It has been laid down in the books, that the draught 

 of a plow increasos rapidly when the furrow is 

 deepened, or, in mathematical terms, according to 

 the squares of the depth; that is to say, that if the 

 draught at four inches deep be 252 lbs., at seven 

 inches it will be as 49 to 16, or 756 lbs. But the 

 experiments of Pusey have proved that this is 

 erroneous. He found that in plowing a furrow 

 nine inches wide and Jive inches deep, the draught 

 was 32'2 lbs. ; at the same width and ia the same 

 soil, six inches deep, it was 308 lbs. ; at seten inches, 

 350 lbs.; at eight, 420 lbs.; at nine, 434 lbs. It 

 will be seen tliat the rate of iucrease is much less 

 than has been generally supposed; and the facts 

 above indicated furnish an additional argument in 

 favor of deep plowing, and one seldom alluded to 

 by agricultural writers. 



TKE AKALYSIS OF SOIL ANALYSES. 



Friexd IIaehis: — It is pretty e-videiit, fi-om your 

 reply to my last letter, that you desu-e a thorough 

 analysis of the practical value of soil-analyses from' 

 me, or you would not have asked me ''to define my 

 position more definitely," and quoted an analysis 

 made by me some twelve years ago to prove "a 

 change of views on this subject." So tar as a pres- 

 sure of other duties will ]iermit, I am wUlhig tO' 

 discuss this, or any other branch of rural science^ 

 with you, so long as there is either interest or profit 

 in the investigation for your readers. They will be,st 

 understand the merits of the question by having 

 placed before them a brief historical review of the 

 api)lication of chemistry to the study of soils, and 

 thereby learn what other men in other countries 

 think of the value of these chemical researches (a). 



In 1805, the Board of Agi-icnltnre in England 

 engaged Sir HuMritKET Davy to deliver an annual 

 course of lectures before them on Agricultural 

 Chemistry, wliich were continued eight years, and 

 then published in 1813. Davy Avas eminent as a 

 philosopher, and the discoverer of the metallic bases 

 of potash, soda, lime, and magnesia; and gi'catly 

 advanced, by his successful labors, the science to 

 wliich his life and genius were devoted. He not 

 only analyzed soils to the entire satisfaction of his 

 employers and tlie public, bnt probably did more 

 than any other man to introduce the practice on 

 the continent of Europe, and, ultimately, into this 

 country. Ilis knowledge of analytical chemistry 

 applied to the study of soils, enabled him to ascer- 

 tain and pubhsh to the world tJie important fact 

 that they are maiidy composed of three earths, viz : 

 sOiceons sand, clay, and carbonate of lime. lie 

 leai'ned, by repeated analyses, that land in which 

 there was little beside pure sand, or pure pipe clay, 

 or chalk, was nniformlr barren. Actifig on his 

 equally wise and scientific suggestions, enter])rising 

 farmers soon found by actnal expe'unent that to mix 

 these earths — that L^, sand with clay, clay with sand, 

 and lime with both, w^here analysis revealed that 

 either was deficient in quantity (h) — resulted in an 

 increase of fertility. ISov was an analysis necessary 

 to reduce to practice the principles thns established, 

 except in cases of doubt as to the deficiency of lime^ 

 or it might be as to an excess of iron in clay or 

 sand. Ilad practice in the field failed to confirm 

 the truthfulness and value of the teachings of the 

 chemist, it is obvious that his labors in that behalf 

 would soon have fallen into disrepnte with all who 

 had tried to benefit themselves by seeking the assist- 

 ance of the laboratory. Against every prejudice, 

 and all odds, soil-analyses maintained their gi-ound, 

 and rapidly extended into aU civilized and pro- 

 gi'essive nations. 



Ten years after Su- Htt^mpitrey had published his 

 Lectures on Agricultural Chemistry, Count Chap- 

 TAL, a peer of France, a member of the Institute, 

 and a large land-holder, published his Agricultriral 

 Chemistry, in which the analysis of soils forms a 

 pronunent feature. Eminent alUve in science, for- 

 tune, political and social position, he had no possible 

 inducement to speak more favorably of the value 

 of soil-analyses than justice and truth demanded. 

 He gives full and carefully-prepared directions for 

 the analysis of soils by farmers; and his first sen- 

 tence on the subject is m these words: "Though 

 experience and long observation may enable an 



