NEUTRALIZING ACID* IN SOILS. 97 



the like proof, even without the other course of reasoning. There 

 is still another proof of this combination being formed, which is ob- 

 tained by a chemical process, but which is so simple that no chemi- 

 cal 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 sili- 

 cious 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 finest 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 combination 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 dif- 

 ference between good and bad soils (whether light or stiff), or those 

 naturally rich and those naturally poor, cannot escape the observa- 

 tion 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. 1842.] 



The next most valuable property of calcareous manures for the 

 improvement of soil is their poicer of neutralizing acids, which 

 has already been incidentally brought forward in the preceding 

 chapter. According to the views already presented, even 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 woodland, that 

 before 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 re- 

 ceives strong support from the facts established with regard to peat 

 soils, in which vegetable acids have been discovered by chemical 

 analysis } and though the peat or moss soils of Britain differ 

 entirely from any soils in eastern Virginia (except that of the 

 great Dismal Swamp, the only extensive peat bog known), still some 

 facts relating to the former class may throw light on the properties 

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