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Show ! HOW THE SJ6L S.FORME0 i- A COMMONPLACE SUBJECT, BUT ONE EXTREMELY ffli - FULL OF INTEREST IF IT IS STUDIED. II i j ' . By Alfred Vlviitn, Ohio. I y i Ono could scarcely lmagino a moro I j uninteresting oubjoct for discussion, I I nor think of anything loss? likely to : ' prvo of Importanco to tho carolcss ' I j observer than that of tho soil. 1 j I Wo aro acauntomod to think of tho I coll as merely "dirt", a thing to bo j ' shunned as far oh poosiblo, and kopt I I hidden from night. & ' Perhaps you -will not think tho boII a I "worthy of interest and study, but did H you ever stop to think that without H j tho soil wo could not bo living: In this -world today? ij j Tho food which you eat could not M have boon produced if thoro wero no H soil, for tho plants which mako the Iff food for animals, in their turn dorivo gf all their nourishment from tho soil. Iflj Bo. you sco tho ocftl is, aftor all, very mS ' Important to mankind. . w9 I We aro eo familiar -with tho soil as E i It now exists that most of un do not ffi j stop to think that it was ovor any- f jB I thing: different, but It has really 9 taken a Ions' time for nature to form l what wo call tho soil, and in doing so If , I she has omployod tho most wonderful I I agencies. 1 Oxen Stm In TJso In Somo Parts of i ', tie United States, 1 1 , I ' I Somo ono has defined tho soil as 1 I i "that portion of tho earth at or near I the surfaco which consists largely of I j fine particles." f l) And again it has been described as Ji j jj that part of tho earth Into which the I t plants send their roots and from It J which they take much of their food. j Well, if tho soil Is tho portion of I ( ! the earth at the surface, what Is bell be-ll ) j i low tho soil ? Most of you know that I j j B If you dig down deep Into the soil you I 1,1 will come to solid rock. H ) li L Jy Sometimes rock is reached a few K VI f lnohes below tho surface, and again H IN you must dig many feet befora you I ; fn como to It, but sooner or later you II 1 aro suro to find a bed of stone. 1 1 II We learn therefrom this first in- H j l toresting fact that underneath all m mi j ' soils aro found solid rocks. If ' Now, If you wore to examine a I ramplo of soil with a strong magni- r fylng glass or a' microscope, you would j find that it Is largely mado up of vory I flne-partlcloB of rock. I i Mixed with theBe particles Is a much smaller quantlt" of black material ma-terial which is cullod organic matter, or sometimes humus. A Uttlo closer examination will sho-7 that tho organic or-ganic matter is simply tho remains of plants which huvo formerly grown upon tho land, and whioh. havo partially par-tially decayed or rotted in tho soil. T"ako a small quantity of a black soil, heat It In tho lid of a baking-powder-can, and hoo if tho odor that comes off Is not vory much like that you notlco on heating bits of leaves In tho same way. Wo find thon that tho boII is com-posod com-posod of small partlolos of rock mlxod with tho remains of formor plants, and that by far tho larger part con-slats con-slats of theso rock partlolos. This suggests tho thought that tho soil has been formed from tho Bolld I rock such as are found beneath it. and this, Indeed, 1b what the mon who havo studied the subject havo found to bo true. Geology teaches us that at ono tlmo all tho surfaco of tho earth was solid rock. At that time there was nothing llko what wj now know as tho soil. These rockn contained all tho constituents con-stituents noccssary to mako a soil and all tho substances which tho plants ubo aB food with tho exception of the element nitrogen. This plant food, however, was not In forms In which tho plants could ubo It. Suppose you had a sack ff wheat. You know that thoro Is plenty of food thero to nourish you for some time, but It Is not In a very good form to eat so long as It Is In the whole, wheat kernel. One of tho first things you would do would be to grind It to a flour. J. And that Is ono of the first things that ' nature docs In preparing tho food . for plants; sho grlndo tho rocks to flour. In other words the first process in thi formation of a soil Is tho pulverization pulver-ization of the rocks, Xaturc uses several method to bring about tho grinding or rulvri:.i-tlon rulvri:.i-tlon of the rocks. Tho first .,' those Is change of tomporature, or heal and cold. If you examine a piece of granite you will find that instead of being a simple rock it is composed of different dif-ferent minerals cemented togethor. Now theso minerals aro dlfTorently affected by heat and cold. You knon that most substances oxpand whon heated. Tho amount of expansion varies for the different minorals m tho granite and as a result the effect of chango In temporaturo Is to separate sepa-rate tho minerals, thus breaking the rock Into smallor pieces |