On the Analysis of Guano. 
303 
of several samples of guano, which I made for Messrs. Gibhs of London, 
and Messrs. Myers of Liverpool, the co-agents of the Peravian and 
Bolivian governments : — 
" In these various analyses, performed with the greatest care, and with 
the aid of the most complete apparatus for both inorganic and organic 
analysis, my attention has been directed not only to the constituents of 
the guano which act as an immediate manure, but to those which are 
admitted by practical farmers to impart dural)le fertility to the grounds. 
The admirable researches of Professor L ebig have demonstrated that 
AZOTE, the indispensable element of the nourishment of plants, and es- 
pecially of wheat and others abounding in gluten (an azotized product), 
must be presented to them in the state of ammonia, yet not altogether 
ammonia in the pure or saline form, for, as such, it is too readily 
evaporateii or washed away ; but in the dormant, or as one may say, in 
the potential condition in contradistinction from tlie actual. Genuine 
Peruvian and Bolivian guanos, like those which I have minutely analyzed, 
surpass very far all other species of manure, whether natural or artificial, 
in the quantity of potential ammonia, and, therefore, in the permanency 
of their action upon the roots of plants, while, in consequence of the 
ample store of actual ammonia which they contain ready formed, they 
are quahfied to give immediate vigour to vegetation. Urate of ammonia 
constitutes a considerable portion of the azotized organic matter in well- 
preserved guano ; it is nearly insoluble in water, not at all volatile, and 
is capable of yielding to the soil, by its slow decomposition, nearly one- 
third of its weight of ammonia. No other manure can rival this animal 
saline compound. One of the said samples of guano aflFurded me no 
less than 17 per cent, of potential ammonia, besides 4^ per cent, of the 
actual or ready formed ; others from 7 to 8 per cent, of ammonia in each 
of these states respectively. The guanos which I have examined are the 
mere excrement ot birds, and are quite free from sanJ, earth, clay, and 
common salt, reported in the analyses of some guanos, and one of which 
(sand) to the amount of 30 per cent. I found myself in a sample of 
guano from Chile. 
"The Peruvian guano, moreover, contains from 10 to 25 per cent, of 
phosphate of lime, the same substance as bone-dust, but elaborated by 
the birds into a pulpy consistence, which, while it continues insoluble 
in water, has been thereby rendered more readily absorbable and di- 
gestible (so to speak) by the roots of plants. I have therefore no doubt, 
that by the judicious application of these genuine guanos, mixed with 
twice or thrice their weight of a marly or calcareous soil, to convert their 
phosphate of ammonia into phosphate of lime and carbonate of ammonia, 
as also to dilute all their ammoniacal compounds — such crops will be 
produced, even on inferior lands, as the farmer can scarcely raise upon 
more improved soils by ordinary manure. To the West India planter, 
guano will prove the greatest boon, since it condenses in a portable and 
inoffensive shape the means of restoring fertility to his exhausted cane- 
fields, a benefit it has long conferred on the poorest districts of Peru. 
" I respectfully observe, that no analysis of guano hitherto made public 
at all exhibits the value of the cargoes referred to above, while none gives 
the quantity of ammonia dormant in the azotized animal matter of the 
bird's dung, which, called into activity with the seeds in the soil, be- 
