832 
The Conservation of Farm-yard Manure. 
less than 7 d. per lb. ; that its phosphoric acid is worth 0'40/l per 
kilog., or nearly 2d. per lb. ; and its potash, 030/1 per kilog., or 
rather less than \\d. per lb. Seeing that in the most concentrated 
and available forms nitrogen may now be bought at less than 6 d. 
per lb., and phosphoric acid for 2 \d., and that in less rapidly 
efficacious forms they may be obtained at even much lower 
rates, it seems that M. Grandeau’s valuation is a somewhat ex- 
travagant one. The fact is, however, that the valuation of dung — 
which, except within easy reach of the stables of large towns, is not 
a purchasable commodity — is always an exceedingly difficult problem. 
Its value does not depend merely on its richness in what are some- 
times spoken of as the “elements of fertility,” but also, and this 
very largely, upon its general physical effects on the soil. 
The practical value of the properties which cause dung to pro- 
duce these effects must vary with the soil to which it is to be applied, 
and it might perhaps be said with reason, that a ton of dung on one 
farm is worth twice as much as a precisely similar ton of dung upon 
another farm, differently cultivated, differently constituted, or 
differently circumstanced. But if its chemical composition be taken 
as the basis of valuation, it appears to be an error to put it at such 
high figures as M. Grandeau adopts, though the error does not 
affect the principle, or the importance, of the lessons which he places 
before us. Taking his own valuations, however, and regarding only 
the nitrogen, phosphates, and potash, the manure yielded yearly 
by the live stock of France works out at nearly 1,650, 000, 000/1, or 
66,000,000?. sterling. What proportion of this value, he asks, is 
lost ? And how might its loss be prevented ? 
To answer these questions the experiments and observations of 
various chemists, from the early work of A r oelcker down to the 
recent work of Holdefleiss, are quoted and reviewed. 
As a general deduction, M. Grandeau calculates that if the 
whole of the manure were kept, as is too often the case, without 
any precautions for saving and utilising the drainage that flows 
from it during its making and storage, French agriculture would 
suffer in an annual loss of 193,000 tons of nitrogen. Even supposing 
that every dung-heap were placed above a liquid-manure tank, and 
watered diligently with the drainings that escape from it, there 
would still be a loss of over 112,000 tons of nitrogen. Without 
taking into account any other loss, we have here (at a trifle under 
7 d. per lb. for nitrogen) a loss of from 168,000,000 to 289,000,000/1, 
i.e. from 6,700,000?. to 11,500,000?. sterling. How is this loss to 
be diminished, even if it cannot be avoided ? Several approved 
methods are enumerated and examined. 
In the first place, M. Grandeau commends the production of the 
dung in deep stalls or feeding-boxes. 
The use of deep feeding-boxes in which the manure can accu- 
mulate and become consolidated under the feet of the animals 
producing it, is one in the economy and advantage of which most 
farmers who have experience of the method will agree. M. Grand- 
eau prefers loose boxes, in which animals can wander at liberty, to 
