174 



QUARTERLY JOURNAL 



as in a tlung-j'ard — a similar action to burning, though of slower operation, takes 

 place; which indeed may be called a tardy combustion, in which the elements of the 

 water present take an active part. The greater portion of the carbon, hydrogen, and 

 oxygen, with nitrogen, are thus dissipated; the sulphates and phosphates are decom- 

 posed, producing stinking gases; and if in the mean time water be allowed to soak 

 through the mass and drain away, it carries with it the soluble salts, ultimately leaving 

 a black mass, consisting chiefly of carbon, with asmallquantity of hydrogen and oxy- 

 gen, and some insoluble earthy salts. If, therefore, decaj^ be allowed to proceed to 

 its greatest extent, it produces a much worse effect than absolute fire; inasmuch asal- 

 most all the soluble salts are lost. Vegetable matter reduced to this state is humus, or 

 that black vegetable matter contained in all rich soils, and those of old pasture land. 

 The only difference is in the mode of their production, the one having been produced 

 by the decay of plants on the surface, and the other from the decay of the roots and 

 leaves of, plants both above and beneath the soil. They operate in the same way in 

 the nourishment they yield to plants, namely, by the salts they yet retain, by attract- 

 ing moisture and ammonia from the atmosphere, and by slowly yielding carbonic acid 

 gas to the roots of the growing crop. 



If the quantity of water which mixes with the heap be limited, it is often evapora- 

 ted by the heat produced by the fermentation ; the chemical action in a great measure 

 ceases; 'and the heap, when opened, exhibits that appearance which is commonly 

 called "fire-fanged." When in that state, it will be found to have lost more than one- 

 half of its value ; but, if due care be taken to regularly mix the layers of dung, without 

 too much intermixture of horse-litter, there will be no danger of the dung made by 

 the cattle in the j^ards being overheated by fermentation, even in the warmest wea- 

 ther. Should that danger, however, be apprehended, an addition of road- scrapings, 

 or earth of any kind, will prevent it; and, in the winter, the cleanings of the cow- 

 house, as being of a cold nature, will answer the purpose. 



When plants and their seeds are consumed by animals, nearly half their weight in 

 a dry state is given out from the lungs and by perspiration from the skin in a gaseous 

 form, chiefly as carbonic acid gas and water, with some nmmonia; the remainder of 

 their substance, together with the effete, or dead matter of the animal organs, are re- 

 jected, as dung and urine, except that portion retained as nourishment by growing and 

 fatting animals. The solid excrement contains the woody fibre, the insoluble animal 

 matter and salts, and the urine, the more soluble sails and substances rich in nitrogen. 

 If no care be taken of the urine, and it be allowed to run about the 5'ard, it soon pu- 

 trefies — its nitrogen flies off in the shape of ammonia; its salts are carried away by 

 every shower of rain; and, although a portion of it may be saved bj^ its mixture 

 with the dung of the cattle, yet the greater part of its valuable contents are evaporated 

 by the action of the atmosphere. If it be allowed to drain into a tank or other recep- 

 tacle, it there also rapidly undergoes putrefaction; and, if this be not checked, a con- 

 siderable part of the ammonia produced will escape with the sulphur and phosphorus, 

 resulting from the decomposition of the salts containing those substances: occasioning 

 the intolerable stench observed in such cases. Now the ammonia, and the alkaline 

 and earthy salts, arc by much the most valuable part of farm-yard or stable dung, and 

 the former is always more abundant when cattle are fed with corn, oil-cake, and other 

 rich food. Without ammonia no seed could be produced; and without alkaline and 

 earthy salts, neither seed nor plants could exist. 



It is the deficiency of some of these substances, where moisture is not wanting, 

 which is the cause of the land producing poor crops ; and it is the almost total absence 

 of some, or all of them, which is the cause of complete sterility. Instances may al- 

 most every where be found of land which, though abounding in humus— such as hea- 

 thy and peaty soils— are, notwithstanding, incapable of bearing grain. If the valuable 

 substances above mentioned be wasted in the manner described— which is too often 

 the case, to an enormous extent— the crops will be very deficient; and if to this waste 



