260 
Annual Report of the Consulting Chemist. 
guano contains about 22 per cent of moisture, 30 per cent, of 
phosphates, and yields 12 per cent, of ammonia. In several 
samples of cargoes recently imported into England from the 
Guanape Islands, 1 find from 12 to 14, and in a few cases the 
guano yielded 15 per cent.; but, taking into account the average 
composition of Guanape guano, I do not think the buyer can 
count upon guano which yields more than 12 per cent, of 
ammonia, nor can he always depend upon being supplied with 
an article that is sufficiently dry and powdery to be economically 
applied to the land without having been previously mixed with 
some dry material and been reduced to a fine powder. 
This operation is both troublesome and entails expense, and 
if the guano is very wet and lumpy, it is scarcely possible for the 
farmer, with the means at his command, to reduce such guano 
into a fine powdery condition. 
- Guanape guano, moreover, I find contains a good deal of free, 
or, more strictly speaking, volatile carbonate of ammonia, and in 
consequence loses in quality on keeping. 
It is this volatile carbonate of ammonia which gives the pun- 
gent smell to Guanape guano, and which renders it liable to 
burn up the crop to which it is applied as a top-dressing, in case 
continued dry weather should set in directly after the top-dressing 
has been applied to the wheat or barley crop. 
In order to meet the inconveniences which arise from the wet 
lumpy condition in which Guanape guano frequently reaches 
the continent of Europe, and to neutralise the pungent and 
injurious properties of the carbonate of ammonia, it is desirable 
to treat the raw guano with about 20 per cent, of oil of vitriol, 
and after this treatment to keep it in a heap for several months, 
and finally to reduce the sulphated guano by suitable means into 
a fine and dry powder. 
By these means a very superior fertiliser is obtained, which 
possesses many advantages over wet raw Peruvian guano. It 
is, however, difficult on a small scale to treat Peruvian guano 
with sulphuric acid, and to convert it into a dry and soluble 
fertiliser. 
Soluble and ammonia-fixed Peruvian guano is highly spoken 
of both in this country and on the Continent, particularly in 
Germany, by farmers who have tried its effects in the field, in 
comparison with the raw Peruvian guano. In order to meet the 
increasing demand for soluble guano, extensive works were 
established a few years ago at Hamburg, for the manufacture of 
sulphuric acid, and the preparation of soluble Peruvian guano. 
In these works the Peruvian guano is dried if necessary, sifted, 
and then treated with just sufficient sulphuric acid to convert the 
volatile carbonate of ammonia of the raw guano into non- volatile 
