596 
On the Valuation of Unexhausted Manures. 
But when we come to consider — of what the accumulation 
consists, what is its amount, and what its money-value, the real 
difficulties of the problem to be solved become apparent. 
Each individual food, when judiciously used in conjunction 
with others, contributes more or less to the increase of the 
animal consuming it ; and the increase will carry away a 
certain amount of the constituents of the food. The remainder, 
which constitute the manure, will in the first place increase the 
produce of the crops to which it is applied ; but it will also 
leave an unexhausted residue, the amount, and the monev-value 
of which to the succeeding tenant, we have to endeavour to 
determine. 
We must, then, in the first place, form an estimate of the 
amount of increase in live-weight of animals which a given 
quantity of each food will produce, and of the amount of 
manure-constituents which that increase will take from the food. 
INext, we must endeavour to estimate the increase in the crops, 
and the amount of constituents so removed. Lastly, the amount, 
and the value, of the manure-residue has to be estimated. This 
we have done in the case of a number of the foods, the com- 
position, the original manure-value, and the unexhausted 
manure-value of which, are given in the Tables which follow. 
We have then decided upon a scale of reduction of the un- 
exhausted manure-value from year to year, and in this way 
arrived at an estimate of the money-value of the residue 
accumulated over a period of eight years. Finally, having 
thus come to a conclusion as to the amount of what may 
be called the compensation-value of the accumulated residue, 
we have devised a simple method of calculation, starting from 
the total, or oricjinal manure-value of the various foods ; that 
is, from the value deducting the constituents in the increase 
in live-weight only. 
I. Average Composition of Cattle Foods. 
The first Table we have to call attention to shows the 
average composition, per cent, and per ton, of thirty-six dif- 
ferent foods, so far as this is necessary for the purpose of 
manure-value calculations ; that is, it gives the amount per cent. 
of dry matter, nitrogen, total mineral matter (ash), phosphoric 
acid, and potash, and the amounts per ton of the foods, of 
nitrogen, phosphoric acid, and potash. In some cases the 
figures are the same as in our original Table, published about 
twenty-five years ago, but in all cases more recent analyses 
have been had recourse to, and alterations have been made if it 
seemed desirable. 
