UIHistories Project: A History of the University of Illinois by Kalev Leetaru
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Repository: UIHistories Project: Board of Trustees Minutes - 1871 [PAGE 204]

Caption: Board of Trustees Minutes - 1871
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106 that many kinds of rock are insoluble. At least they are often spoken of as such. The truth is, there is scarcely a rock but yields more or less to the action of water, and the more in proportion to the amount of its surface exposed. The experiments of the Messrs. Rogers are very instructive on this point. They pulverized a large variety of minerals, usually considered insoluble, and treated them with pure water and with carbonated water, carrying on the two sets of experiments side by side, and observing all the necessary precautions. "When the mineral was very finely pulverized and treated with pure water a considerable time, and then filtered, the first drops of the filtrate gave an alkaline reaction, while with carbonated water the effect was recognizable in less than ten minutes. With pure water the effect was much weaker than with carbonated water, still it was perfectly decisive in almost all the minerals tried. By digesting finely powdered feldspar, hornblende, grammatite, epidote, mesotype, chlorite, serpentine, and some twenty others, in pure water a week, and in carbonated water 48 hours only, they found that silica, alkalies, lime, magnesia, iron and alumina, had been dissolved to an extent equal to from A to 1 per cent, of the minerals taken. The solvent power of water was, doubtless, increased by digestion, but it can scarcely be doubted that the same effect would have been produced by cold water in a long time. The application to soils of the truth taught by these experiments, is plain. The soils of the prairie contain, without doubt, more or less of all these minerals ; and it is evident the more finely pulverized they are, the more readily they will be dissolved by water, and the more mineral food will they furnish for the crop. In this way, a very finely comminuted soil, like that of Union county, or of some river bottoms, seems to have an inexhaustible fertility, because the decomposition of mineral matter keeps pace with^the demands of vegetation. Were the particles of soil coarser, or less exposed to the combined influences of water, carbonic acid and oxygen, the supply of mineral food might fall below the demand ; that is, there would be, to that extent, exhaustion, to be remedied by manure or fallow. It is very probable that this is not the only principle involved in the explanation of the apparently permanent fertility of soils; but that it finds a place in it, seems to be plainly taught by experiment; and we will only add that these chemical changes taking place in a soil with greater or less activity, according to its more or less favorable conditions, sustain an intimate relation to an intelligent system of agriculture, and commend themselves to the careful attention and study of farmers.