60 CALCAREOUS MANURES-THEORY. 



Calcareous earth has power to preserve those animal matters which are 

 most liable to waste, and which give to the sense of smell full evidence 

 when they are escaping. Of this, a striking example is furnished by an 

 experiment which was made with care and attention. The carcass of a 

 cow, that was killed by accident in May, was laid on the surface of the 

 earth, and covered with about seventy bushels of finely divided fossil shells 

 and earth, (mostly silicious,) their proportions being as thirty-six of calca- 

 reous, to sixty-four of silicious earth. After the rains had settled the heap, 

 it was only six inches thick over the highest part of the carcass. The pro- 

 cess of putrefaction was so slow, that several weeks passed before it was 

 over ; nor was it ever so violent as to throw off any effluvia that the calca- 

 reous earth did not intercept in its escape, so that no offensive smell was 

 ever perceived. In October, the whole heap was carried out and applied 

 to one-sixth of an acre of wheat — and the effect produced far exceeded 

 that of the calcareous manure alone, which was applied at the same rate 

 on the surrounding land. No such power as this experiment indicated (and 

 which I have since repeated in various modes, and always with like results) 

 will be obtained, or expected from clay. 



Q,uick-]ime is used to prevent the escape of offensive effluvia from animal 

 -matter ; but its operation is entirely different from that of calcareous earth. 

 The former effects its object by " eating" or decomposing the animal sub- 

 stance, (and nearly destroying it as manure,) before putrefaction begins. 

 The operation of calcareous earth is to moderate and retard, but not to 

 prevent putrefaction ; not to destroy the animal matter, but to preserve it 

 effectually, by forming new combinations with the products of putrefaction. 

 This important operation will be treated of more fully in a subsequent 

 chapter. 



The power of calcareous earth to combine with and retain putrescent 

 manure, implies the power of fixing them in any soil to which both are ap- 

 plied. The same power will be equally exerted if the putrescent manure 

 is applied to a soil which had previously been made calcareous, whether by 

 nature, or by art. When a chemical combination is formed between the 

 ■two kinds of manure, the one is necessarily as much fixed in the soil as the 

 other. Neither air, sun or rain, can then waste the putrescent manure, be- 

 cause neither can take it from the calcareous earth, with which it is chemi- 

 cally combined. Nothing can effect the separation of the parts of this 

 compound manure, except the attractive power of growing plants — which, 

 as all experience shows, will draw their food from this combination as fast 

 as they require it, and as easily as from sand. The means then by which 

 calcareous earth acts as an improving manure are, completely preserving 

 putrescent manures from vjaste, and yielding them freely for use. These 

 particular benefits, however great they may be, cannot be seen very quickly 

 after a soil is made calcareous, but will increase with time, and, with the 

 means for obtaining vegetable matters, until their accumulation is equal to 

 the soil's power of retention. The kind, or the source, of enriching ma- 

 nure, does not alter the process described. The natural growth of the soil, 

 left to die and rot, or other putrescent manures collected and applied, would 

 alike be seized by the calcareous earth, and fixed in the soil. 



This, the most important and valuable operation of calcareous earth, 

 then gives nothing to the soil ; but only secures other manures, and gives 

 thein wholly to the soil. In this respect, the action of calcareous earth in 

 fixing manures in soils, is precisely like that of mordants in " setting" or 

 fixing colors on cloth. When alum, for example, is used by the dyer for 

 this purpose, it adds not the slightest tinge of itself—but it holds to the 

 cloth, and also to the otherwise fleeting dye, and thus fixes them per- 



