220 
On the Tlieoretical and Practical Value of 
\d. per lb. for phosphate of lime, rates which fairly represent 
the present market-value of these fertilising constituents, the 
value of the manure obtained by the consumption of different 
articles of food may thus be estimated with sufficient accuracy 
to be of considerable service in a practical point of view. 
Proceeding on this basis, Mr. Lawes constructed a table in which 
the estimated money-value of the manure from one ton of most 
ordinary articles of food is given. This table will be found on 
page 11 in Mr. Lawes's paper on the " Valuation of Unexhausted 
Manures," published in Vol. XL, Part 1 (No. XXI.), of this 
Journal. 
In illustration of the mode in which the manurial- and money- 
value of the various feeding-stuffs mentioned in Mr. Lawes's 
tables has been estimated, I wish to direct attention to the 
subjoined tabular statement, which gives the average compo- 
sition of good linseed-cake, decorticated and undecorticated 
cotton-cake, rape-cake, barley-meal, and barley-straw. 
Table II. — Shoicing the Average Composition of certain Foods. 
Linseed- 
cake. 
Decorti- 
cated 
Cotton- 
cake. 
Undecor- 
ticated 
Cotton- 
cake. 
Rape- 
cake. 
Barley- 
meal. 
Barley- 
straw. 
12-00 
10 
00 
11-00 
11 
00 
16 
00 
15 
00 
Oil 
11-50 
14 
00 
6-00 
10 
00 
2 
50 
1 
50 
*Albutninous compounds 
29-70 
40 
60 
22-50 
31 
25 
10 
50 
3 
00 
Mucilage, starch, and diges-'> 
27-80 
20 
90 
33-50 
28 
75 
61 
80 
34 
00 
12 00 
6 
50 
21-00 
11 
00 
7 
00 
42 
00 
tMineral matter (asli) . . 
700 
8 
00 
600 
00 
2 
20 
4 
50 
100 00 
100 
00 
100-00 
100 
00 
100 
00 
100 
00 
*Containing nitrogen 
4-75 
6 
50 
3-60 
I 
-00 
1 
65 
50 
Equal to ammonia . . 
5-75 
7 
90 
4-37 
-07 
2 
00 
60 
fContaiiiing potasli .. 
1-65 
3 
12 
2-00 
•76 
55 
63 
and phosj)lioric acid equall 
to phosphate of lime . . / 
4-92 
7 
•00 
4-50 
-75 
1 
33 
37 
Assuming the loss of nitrogen in the consumption of the 
cakes to amount to one-tenth of what they contain, and to 
15 per cent, in the case of barley-meal and barley-straw, and 
making slight allowance for the loss in potash and phosphate of 
lime, Mr. Lawes has calculated the amount of ammonia, potash, 
and phosphate which will pass into the manure resulting from 
the consumption of the several kinds of food. 
