of limited extent, and in loading it considerable
quantities of the subjacent soil are taken up, so that very great
differences may exist even in different parts of the same cargo. Nor
must it be forgotten that, except in the case of Peruvian, the name is
no guarantee for the quality of the guano, even if genuine. Peruvian
guano is all obtained from the same deposits, those of the Chincha
Islands, but the guanos which are brought into the market under the name
of Patagonian, Chilian, etc., are obtained from a great variety of
deposits scattered along the coasts of these countries, sometimes at a
distance of several hundred miles from each other, and which have been
accumulated under totally different circumstances. In illustration of
this, it is only necessary to refer to the subjoined analysis of
samples, all of which I believe to be genuine as imported, and which
were sold under the name of Upper Peruvian Guano.

I. II. III.
Water 7.80 6.65 8.85
Organic matter and ammoniacal salts 10.85 19.16 10.20
Phosphates 67.00 20.41 17.10
Carbonate of lime ... 21.15 ...
Alkaline salts 11.10 5.31 61.30
Sand 3.25 27.32 2.55
------ ------ ------
100.00 100.00 100.00

Ammonia 2.29 5.73 1.48
Phosphoric acid in the alkaline salts 2.24 ... 1.70
Equal to phosphate of lime 4.89 ... 3.70

With the exception of Peruvian, the supply of _good_ guanos of uniform
composition is by no means large, and phosphatic guanos of good quality
are now especially rare. The Saldanha Bay, and other similar deposits,
have been exhausted, and few guanos of equally good quality have been
lately discovered. There is no doubt, however, that such guanos are very
useful, and if obtained in large quantity, and of uniform composition,
would be used to a much larger extent than they at present are.

The value and use of guano are now so well understood, that it is
scarcely necessary to enlarge on the mode of its application. Peruvian
guano owes its chief value to its ammonia and phosphates, but it also
contains potash, soda, and all the other constituents of plants in small
quantity, although in a readily available conditi