4 On the Valuation of Unexhausted Manures. 
1. Manure produced from purchased (or saleable) feeding- 
stuffs. 
2. Farmyard, or town-stable, manure. 
3. Rapecake (or other cake) used as manure. 
4. Bones. 
5. Nitrate of soda. 
6. Sulphate of ammonia. 
7. Superphosphate of lime, made from mineral phosphates. 
8. Guano, in its natural state, or manufactured. 
9. Other manures of more or less unknown composition.* 
10. Liming, chalking, marling, <Scc. 
The difference in the price at which the different items of 
purchased manure in this list can be brought upon the farm is 
very wide indeed. 
By way of illustration, it may be assumed that town-made 
dung will, in the majority of cases in which it is largely used, 
cost the farmer about 7s. ^d. per ton delivered on his farm. 
Nitrate of soda will, however, cost him, say 15s. per cwt., some- 
times more and sometimes less. Thus, he finds it worth his 
while to give about as much for 1 cwt. of nitrate of soda, 
as for 2 tons of stable-dung ; or, in other words, about 40 
times as much for an equal weight of the one manure as of the 
other. 
Sulphate of ammonia is dearer than nitrate of soda ; and 
although it is not purchased to any great extent by the 
farmer, it is much used in the manufacture of mixed artificial 
manures. 
Again, Peruvian guano contains, when of good quality, a 
considerable quantity of ammonia, as well as phosphates, and 
it costs about 13Z. per ton ; whilst inferior guano, poor in am- 
monia but rich in phosphate of lime, and superphosphate of 
lime containing no ammonia at all, sell for only from one-third 
to one-half as much. 
Nitrate of soda contains nitrogen as nitric acid ; sulphate of 
ammonia contains it as ammonia ; and Peruvian guano also 
contains, or by decomposition yields, it as ammonia. In fact, 
the money-value as manure, of nitrate of soda, or of sulphate of 
ammonia, is exclusively, and that of Peruvian guano chiefly, 
due to the nitrogen they contain. 
Thus it will be seen that the highest-priced manures arc 
those which are rich in nitrogen. A few illustrations may here 
be given of the effects of nitrogenous manures upon the growth 
of crops. 
* Of such manures, tlie Schedules of the Committee on Unexhausted Improve- 
ments include particulars relating to Kainit, ashes, night-soil, and town manure, 
soot, eea-weed, fish, and " other fertilisers uncnumcrated." 
