604 On the Valuation of Unexhausted Manures. 
maturity, the increase comprises a larger proportion of growth 
than in mere fattening, the amount of the nitrogen of the food 
which will be lost to the manure will be between that given in 
the Table and twice as much. 
The third division of the Table relates to the phosphoric acid, 
and there are given for each food, as in the case of the nitrogen, 
the amounts of it per cent, and per ton, of the foods ; the amount 
estimated to be retained in the increase ; the amount remaining 
for manure, and the money-value of this at 3f/. per lb. 
It will be seen that there is only about two-thirds as much 
phosphoric acid as of nitrogen retained in a given weight of 
fattening increase ; but owing to the very generally less, and 
sometimes much less, amount of it in the foods, a greater pro- 
portion of that consumed is retained in the animal, and a less 
proportion remains for manure. It should be added that, in the 
case of store and still growing animals, the amount of phosphoric 
acid retained in a given weight of increase will be very much 
greater than in mere fattening ; indeed in mere store increase it 
may, as in the case of the nitrogen, be nearly twice as great as 
in mere fattening. 
Of potash, the Table shows that a given weight of fattening 
increase retains only about one-eighth as much as it does of 
phosphoric acid ; and the percentage of the whole in the food 
which is lost to the manure is generally very small. In its case, 
as in that of the nitrogen and phosphoric acid, the amount 
retained in mere store increase will be nearly twice as much as 
in mere fattening increase, but the total quantity retained is still 
very small. The potash remaining for manure is valued at 2JcZ. 
per lb. 
The last column of Table II. shows the total manure-value of a 
ton of each of the foods after consumption, reckoning the nitro- 
gen, the phosphoric acid, and the potash, at the prices cvbove 
named, which are those at which they can, at the present time, 
be purchased in artificial manures. In our formerly-published 
estimates we valued the nitrogen and phosphoric acid at the 
prices at which they could then be purchased in Peruvian 
guano. In those estimates ammonia was taken at d>d. per lb., 
but now it is reckoned at only Gc?. ; phosphoric acid was taken at 
about 2^f/., but now at 3^/. per lb. (as in " precipitated phos- 
phate ") ; and potash was then valued at 2d. per lb., but now 
at 2y. 
Notwithstanding the somewhat higher value now given to 
phosphoric acid and potash, and the less amount of the nitrogen 
of the food now reckoned to be lost by the feeding, the reduction 
in the price of ammonia by one-fourth, brings all the estimates 
of total manure-value lower now than formerly. Thus, the 
