CALCAREOUS MANURES— THEORY. g| 



manently together. Without the mordant, the color might have been 

 equally vivid, but would be lost by the first wetting of the cloth. 



Thus, reasoning a jpWoW, from that chemical power possessed by calca- 

 reous earth which is wanting to both sandy and clayey earths, would 

 lead to the conclusion that calcareous earth serves to combine putrescent 

 matters with the soil in general ; and the known results of fertihty being 

 tlierein so fixed, might serve for the like proof, even witliout the other course 

 of reasoning. There is still another proof of this combination being formed, 

 which is obtained by a chemical process, but which is so simple that no 

 chemical science is requisite to make the trial. 



If a specimen of any naturally poor soil, after being dried and reduced 

 to powder, be agitated in a vessel of water, (as a common drinking glass,) 

 and then allowed to stand still, the coarser silicious sand will subside first, the 

 finer sand next, and last the clay. In this manner, and by pouring off the 

 lighter parts, before their subsidence, it is very easy to separate with 

 sufficient accuracy the sand from the clay. But if a specimen of a good 

 rich neutral soil be tried in that manner, it will be found that the fine 

 sand and the clay and putrescent matter hold together so closely that they 

 cannot be separated by mere agitation in water. Then take another 

 sample of the same soil, and pour to it a small quantity of diluted muriatic 

 acid ; and though no effervescence is produced, (the lime not being in the 

 form of carbonate,) the acid will take away the lime, or destroy its combi- 

 nation with the other earths, so that the sand and the clay may then be 

 separated by agitation in water, as perfectly and easily as in the case of 

 the poorest soils. This difference between good and bad soils, (whether 

 light or stiff,) or those naturally rich and those naturally poor, cannot 

 escape the observation of the young experimenter ; and the cause can be 

 no other than what I have supposed. This then serves as the third mode 

 of proof of the important position, that calcareous earth (or lime in some 

 other form) not only combines with vegetable and animal matters, but also 

 serves (as a connecting link) to combine these matters with the sand and 

 clay of the soil. 



The next most valuable property of calcareous manures for the improve- 

 ment of soil is their poiver of neutralizing acids, which has already been 

 incidentally brought forward in the preceding chapter. According to the 

 views already presented, our poorest cultivated soils contain more vegetable 

 matter than they can beneficially use; and when first cleared, they have it in 

 great excess. So antiseptic is the acid quality of poor wood-land, that be- 

 fore the crop of leaves of one year can entirely rot, two or three others 

 will have fallen ; and there are always enough, at any one time, to greatly 

 enrich the soil, if the leaves could be rotted and fixed in it at once. 



This alleged antiseptic effect of vegetable acid in our soils receives strong 

 support from the facts established with regard to ijeat soils, in which vege- 

 table acids have been discovered by chemical analysis ; and though the 

 peat or moss soils of Britain differ entirely from any soils in eastern Vir- 

 ginia, (except that of the gi'cat Dismal Swamp, almost the only peat bog 

 known,) still some facts relating to the former class may throw light on the 

 properties of our own soils, different as they may be. Not only does vege- 

 table matter remain without putrefaction in peat soils and bngs, and serve to 

 increase their depth by regular accretions from the successive annual growths, 

 but even the bodies of beasts and men have been found unchanged under 

 peat, many years after they had been covered.* it is well known that the 

 leaves of trees rot very quickly on tlu> rich lime-stone soils of the western 



* See Aiton's Essay on Moss Eartli, rcpiiblislicd in Farmers' Register, vol. v., p. 462. 



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