Annual Report of the Consulting Chemist. 
261 
neutral sulphate of ammonia, and at tlie same time to render tte 
jrreator part of the insoluble phosphate perfectly soluble in water. 
By these means a highly concentrated, dry, and finely powdered 
fertiliser is produced, which may be said to combine the qualities 
of a good superphosphate with those which are characteristic of 
Peruvian guano. 
Although the prepared guano is sold at about \Qs. more per 
ton than Peruvian guano in its natural condition, the sales of 
the soluble guano in Germany have steadily increased from year 
to year, and last year I am informed that they amounted to more 
than 60,000 tons. 
Two samples of soluble Peruvian guano, recently analysed by 
me, had the following composition : — 
Composition of two Samples of Soluble Perutiak Guano. 
Moisture 
VViitcr of combination and| 
*Organic matter / 
Biphosphate of lime (mono-basic phosphate of lime") 
Equal to bone-phosphate (tri-basic phosphate of\ 
lime) rendered soluble by acid / 
Insoluble phosphates 
Sulphate of lime 
Alkaline salts and magnesia 
Insoluble siliceous matter 
* Containing nitrogen 
Equal to ammonia 
Sept. 18^2. 
Dec. 1S72. 
14-65 
16-78 
42-57 
41-88 
13-86 
13-20 
(21-71) 
(20-68) 
5-09 
7-19 
lG-36 
13-39 
3-78 
4-39 
3-69 
3-17 
100-00 
100-00 
8-72 
8-9G 
10-59 
11-88 
It will be seen that the soluble guano which is prepared at 
Hamburg contains from 20^ to 21 1 per cent, of soluble phosphate, 
from 5 to 7 per cent, of insoluble guano phosphates, and nearly 
as much ammonia as Guanape guano in its natural wet 
condition. 
There can be no doubt that Peruvian guano, treated with acid 
and sold in a dry and fine condition, and with the guarantee of 
containing 21 per cent, of soluble phosphate and 11 per cent, of 
ammonia, will find a more ready sale than raw guano, which is 
still sold without any guarantee whatever as to quality. Guanape 
guano is frequently far too damp and sticky for application to 
the land in its natural condition, and it often contains no more 
ammonia than is supplied in the prepared guano, the quality of 
which is guaranteed by analysis. It is, therefore, manifestly to 
