202 
Peruvian Guano. 
soluble. Insoluble phosphate of lime is more soluble in a liquid 
containing sulphate of ammonia than in pure water. When 
guano, therefore, is moistened with water, some of the insoluble 
phosphate, through the intervention of the sulphate of ammonia, 
becomes soluble, but as oxalate of ammonia is also present in 
solution, the oxalic acid forms with lime an insoluble salt, the 
phosphate of lime thus rendered soluble becomes changed into 
oxalate of lime, and phosphoric acid passes into solution. This 
action is slow, and its effects are therefore more marked when 
guano is kept for a considerable length of time thoroughly soaked 
with water. 
With a view of ascertaining whether or not the insoluble phos- 
phates in guano really become more soluble under the influence 
of sulphate and oxalate of ammonia, the following experiments 
were made. A weighed quantity of good Peruvian guano was 
exhausted at once with a large quantity of distilled water, and 
the matter insoluble in water collected on a filter and washed 
for a long time until very nearly all soluble matters were re- 
moved. 
The guano furnished — 
Matters soluble in water 74 - 25 per cent. 
Matters insoluble in water 25'75 „ 
It contained — 
Water.. 16-57 „ 
and yielded on combustion with soda-lime — 
Nitrogen 15*71 „ 
Equal to ammonia 19 - 00 „ 
In the portion soluble in water I found — 
Phosphoric acid • 313 
Equal to tribasic phosphate of lime (bone-earth) . . .. 6"78 
In the insoluble part there was — 
Tribasic phosphate of lime 18'27 
Oxalate of lime '85 
A second weighed quantity of the same guano was mixed with 
a little water and left for two days in a glass, after which time 
it was completely exhausted with distilled water like the first 
quantity. It produced— 
Substances soluble in water 74 - 44 per cent. 
Substances insoluble in water 25'56 ',, 
In the soluble portion I found — 
Phosphoric acid S'G6 ,, 
Equal to tribasic phosphate of lime .. .. 7"94 „ 
The insoluble portion contained — 
Tribasic phosphate of lime 17\>8 
