852 = 586 Influence of Chemical Discoveries on 
Feeding ex- 
periments. 
Plot 9. — 200 lbs. sulphate potass, 100 lbs. sulphate soda, 100 lbs. sulpha 
magnesia, 3s cvvt. superphosphate; and 550 lbs. nitrate sod 
containiug nitrogen =100 lbs. ammonia, il 
„ 10. — Farmyard manure, estimated to contain nitrogen = 100 lbs. ammoni 
„ 11. — Fannyard manure, estimated to contain nitrogen = 200 lbs. ammoni 
The notation Experiments. — Mr. Randell's original propositio 
was to compare, experimentally, the manure value of four differei 
descriptions of cake, namely — . 
Decorticated cotton-cake, Imsti 
Common cotton-cake, ^1 
Linseed-cake, '^^^ 
Rape-cake. 
Calculation showed, however, that taking into consideration th :s 
comparatively small proportion in the total dung of the cor n 
stituents yielded by the purchased food consumed, there woul se 
not be sufficient difference in the manure value of dung mad -It 
by the use of equal quantities in each case of these four feeding a; 
stuffs to lead to the expectation that separate feeding experiment fit 
with them, followed by separate field, experiments made with th n 
dungs produced, would give results sufficiently distinctive to fori m 
any reliable basis of estimates of their actual and comparativ m 
manure value. j 
It was decided, therefore, to limit the inquiry to comparativ -in 
experiments between decorticated cotton-cake, which, amon iji 
purchased feeding-stuffs, has a very high manure value, ani >i 
maize-meal, which has a very low manure value ; and to coin rjp 
pare the effects of the manures obtained by the consumption c k 
these foods with those of artificial manures supplying, in on «)i 
case, the same amount of nitrogen, potass, phosphoric acid, &c ija 
as is estimated to be contained in the manure from the cotton ^ 
cake consumed, and in another the same as in that from th j 
maize-meal consumed. 
Accordingly, four feeding experiments have been conductet 
in each of which the same amount of litter has been used, ani 
the same amount of roots and the same amount of wheat-strai 
chaff consumed. In Experiment 1, 1000 lbs. decorticated cotton u\ 
cake were given in addition ; and in Experiment 2, 1000 lbs _ 
maize-meal. In Experiments 3 and 4, no purch;\sed food wa 
given ; but in Experiment 3 artificial manures estimated to con t 
tain the same amount of the chief constituents as the manur 
from 1000 lbs. of cotton-cake, and in Experiment 4 the same a 
from 1000 lbs. maize-meal, will be applied to the land, in additioi 
to the root and chaff manure. 
It may be explained that the amount of nitrogen, &c., in th 
manure from the purchased foods is calculated according to th. 
same rule as that adopted in the construction of Mr. Lawes 
table of the estimated value of the manure obtained by the con 
