Peruvian Guano. 
195 
A sample of good Peruvian guano, which furnished a quantity 
of nitrogen corresponding to 17 24 per cent, of ammonia, and 
contained 12 - 82 per cent, of moisture, was dried in a current of 
hot air for three hours at a temperature of 212 J Fahr. The am- 
monia driven off with the watery vapours was carefully collected 
in a bulb-apparatus containing hydrochloric acid, and the amount 
determined in the usual way with bi-chloride of platinum. At 
the end of 3 hours it was found to have lost *75 per cent, of am- 
monia. 
A second sample of the same guano was mixed with an equal 
weight of common salt, and submitted to the same process. The 
mixture contained 11 '20 of moisture, and furnished on com- 
bustion with soda-lime 8*73 per cent, of ammonia, or as nearly as 
possible half the quantity which was found in the pure guano. 
At the end of 3 hours' drying in a current of air at 2l2 J , the loss 
in ammonia was determined and found to amount to *40 per 
cent. 
The pure guano, it will be seen, lost no more ammonia than 
the sample mixed with 50 per cent, of salt. 
> Dried at 212° Fahr., the pure guano furnished altogether 19 - 77 
per cent, of ammonia, and the mixed sample 9'83 per cent. 
Equal weights of the pure and mixed guano were now exposed 
to the open air, in plates, during one month. At the end of that 
time the percentage of moisture, free ammonia, and total amount 
©f nitrogen, calculated as ammonia, were determined in precisely 
the same way as before. The pure guano then contained 17*65 
per cent, of moisture, '69 of free ammonia, and on combustion 
with soda-lime furnished altogether 16*30 of ammonia. The 
mixture of equal parts of salt and guano after a month's exposure 
to air contained 19*69 per cent, of moisture, '31 of free ammonia, 
and yielded altogether 7*94 percent, of ammonia. Calculated in 
a perfectly dry state, the pure guano produced 19*73 of ammonia, 
and the mixed sample 9*88, or almost exactly the same quantities 
which both samples yielded before exposure to the air. 
Notwithstanding the absorption of moisture during a month, 
neither the pure nor the mixed guano lost any ammonia. The 
absorption of moisture by the pure guano, it will be remarked, 
amounted to nearly 5 per cent, and that by the mixed sample to 
7 per cent. 
These results, arranged for the sake of greater perspicuity in 
the following tabular form, show at a glance that genuine Peru- 
vian guano loses but an insignificant proportion (f per cent.) of 
ammonia by long exposure to air at the ordinary temperature, or 
by drying in a current of air of the temperature of boiling water, 
and that therefore salt did not in these experiments exercise any 
chemical action. 
VOL. XXV. P 
