302 
On the Analysis of Guano. 
D. Chincha Guano, of a somewhat darker colour than the preceding, 
and alkaline reaction; specific gravity, 1 '62. Digested with water and 
strained, 56' 75 parts remained afeer drying it at 212° F. The solution, 
evaporated and dried also at 212°, afforded 31 '25 of saline matter. This 
saline mass being mixed with four-fifths of its weight of slaked lime, 
nine times its weight of water, and distilled, afforded of ammonia 14 "28 
per cent. Some chemists have prescribed potash histead of lime, for 
separating the ammonia in distillation ; but no person of intelligence 
who has made the experiment will choose to repeat it, because the potash 
forms with the organic matter of the guano a viscid compound, that 
froths up like a mass of soap-bubbles, and coming over with the vapours, 
obstructs and vitiates the result. 
2. When dried altogether by a steam heat, 100 parts lost 12 in mois- 
ture ; whereas by evaporating and drying the soluble matter by itself, 
the loss amounted to 16 "3, no doubt by the dissipation of some of the 
ammoniacal salts ; for 100 parts of the entire guano afford, by distillation 
with quicklime, 9 parts of ammonia, and by the transforming decom- 
position with hydrate of soda' and lime 16 '25, indicating 7 '25 of 
potential ammonia, in addition to the 9 of ready formed. The insoluble 
matter of 100 parts afforded to borax water a solution containing 16' 5 
of uric acid, corresponding to 18 of urate of ammonia. There re- 
mained on the filter, after drying it at 212° F., only 33'8 parts; so that 
about 5 parts of soluble organic matter had passed through the filter in 
the borax water. These 33' 8 consisted of subphosphate of lime 17, 
magnesian phosphate of ammonia 5 "5, silica 0"7, and combustible 
organic matter 10 '6. 
The ammonia in the soluble portion w as in the state chiefly of phos- 
phate; there was merely a famt trace of oxalate of ammonia. 
E. African Guano. — Among the many samples of African guano 
which I have had occasion to analyze for the importers, none has con- 
tained any appreciable quantity of uric acid, or of consequence of poten- 
tial ammonia. The best afforded me 10 per cent, of ready-formed 
ammonia, existing chiefly in the state of a phosphate, though they all 
contain carbonate of ammonia, and have of consequence an alkaline reac- 
tion. The said sample contained 21 '5 of moisture, separable by a heat 
of 212° F. Its specific gravity was so low as 1*57, in consequence of 
the large proportion of moisture in it. It contained 23 per cent, of 
subphosphate of lime, 3 of magnesian phosphate of ammonia, 1 of sdica, 
and 1*5 of alkaline sulphate and muriate. The remaining 50 parts 
consisted of decayed organic matter, with phosphate of ammonia, and a 
little carbonate, equivalent to half a grain of ammonia, which is the 
largest quantity in such guanos. Other African guanos have afforded 
from 2-1 to 36 of moisture ; no uric acid ; no potential ammonia ; but 
decayed organic matter; from 5 to 7 of ready formed ammonia in the 
state' of phosphate, with a little carbonate ; from 25 to 35 per cent, of 
subphosphate of lime ; 5 or 6 of the magnesian phosphate of ammonia ; 
more or less oxalates from the decomposition of the uric acid, and 3 to 
5 per cent, of fixed alkaline salts. 
F. The Chilian Guano gathered on the coast contains a remarkable 
proportion of common ealt, derived prol)ably from the sea spray. 
The following is the General Report of the chemical examination 
