Oti the Analysts of Guano. 
293 
15 to 20 of earthy phosphates ; leaving no more than 50 or 55 per cent, 
of soluble matter, exclusive of moisture ; whereas decayed guano yields 
often 60 or 70 per cent, of its weight to water, in consequence of the 
uric acid and animal matter being wasted away, and the large portion of 
moisture in it, the latter amounting very often to from 25 to 35 per 
cent. The good Peruvian guano does not lose more than from 7 to 9 
per cent, by drying, even at a heat of 212° F. ; and this loss necessarily 
includes a little ammonia. Each analysis of guano executed for the 
information of the farmer should exhibit definitely and accurately to at 
least 1 per cent. : — 
1. The proportion of actual ammonia. 
2. The proportion of ammonia producible also from the uric acid and 
azotized animal matter present; and which may be called the potential 
ammonia. This is a most valuable product, which is, however, to be 
obtained only from well-preserved dry guano. 
3. The proportion of uric acid, to which, if 1-llth of the weight be 
added, the quantity of urate of ammonia is given. 
4. The proportion of the phosphates of lime and magnesia. 
5. The proportion of fixed alkaline salts, distinguishing the potash 
from the soda salts ; the former being more valuable, and less readily 
obtainable: the latter can be obtained by the use of common salt. 
Wheat, peas, rye, and potatoes require for their successful cultivation a 
soil containing alkaline salts, especially *hose of potash. 
6. The proportion of sandy or other earthy matter, which in genuine 
guano, carefully collected, never exceeds 2 per cent., and that is silica. 
7. The proportion of water, separable by the heat of 212° F. 
The farmer should never purchase guano, except its composition in 
the preceding particulars be warranted by the analysis of a competent 
chemist. He should cork up in a bottle a half-pound sample of each 
kind of guano that he buys ; and, if his crop should disappoint reason- 
able expectation, he should cause the samples to be analyzed ; and should 
the result not correspond to the analysis exhibited at the sale, he is 
fairly entitled to damages for the loss of his labour, rent, crop, &c. The 
necessity of following this advice will appear on considering the delu- 
sive, if not utterly false, analyses under which cargoes of guano have 
been too often sold. In a recent case, which came under my cognizance 
in consequence of having been employed professionally to analyze the 
identical cargo, I found the guano to be nearly rotten and effete; con- 
taining altogether only 2^ per cent, of ammonia, ^ per cent, of urate of 
ammonia, nearly 9 of sea-salt, 24 of water, and 45j of earthy phos- 
phates. Now, this large cargo, of many hundred tons, fetched a high 
price at a public sale, under the exhibition of the following analysis: — 
Urate of ammonia, ammoniacal salts, and decayed 
animal matter . . . . .17*4 
Phosphate of lime, phosphate of magnesia, and 
oxalate of lime . . . . , 48*1 
Fixed alkaline salts . . . . . 10*8 
Earthy and stony matter . . . . 1'4 
Moisture . . . . . , .22*3 
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