1.59 4.7 5.80
Water 9.14 }
} 32.3 23.42
Undetermined humus-like organic} 10.00 }
matters } }
------ ----- ------
100.48 100.0 100.00

These analyses illustrate two points--_first_, that in some samples the
decomposition has advanced to a greater extent than in others; for we
observe that the quantity of uric acid, or rather of urate of ammonia,
is greatly less in the last analysis than in the other two, and much
smaller than in the fresh dung, which contains from 50 to 70 per cent of
uric acid; and _secondly_, that guano is rich in all the constituents of
the plant, but especially in ammonia, the best form in which nitrogen
can be supplied, in uric acid which by decomposition yields ammonia, and
in phosphoric acid. But such analyses are too elaborate for ordinary
purposes, and much less convenient for comparison and for estimating the
value of the guano than the shorter analysis commonly in use, which
gives the water, the loss by ignition (that is, the sum of the organic
matters and ammoniacal salts), the phosphates, the alkaline salts, and
the quantity of phosphoric acid contained in them, and existing there in
a state similar to that in which it is found in the soluble phosphates
of a superphosphate. In addition to these, the quantities of sand and
other less valuable ingredients are also stated.

In the subjoined tables the composition of a great variety of different
kinds of guano is given. Most of these are averages deduced from a
considerable number of analyses of good samples. Those of some kinds of
guano, such as Peruvian, which present a considerable amount of
uniformity, afford a sufficiently accurate idea of the general
composition of the variety, but in other cases they are of less value,
because the imports of different seasons, and even of different cargoes,
differ so greatly in composition that no proper average can be made.
Several of these varieties are already exhausted, the importation of
others has ceased, and new varieties are constantly being introduced.

_Table showing the Average Composition of different varieties of Guano._

-------------------+--------+-------+-------------+---------------------------+
|Angamos.|Peru- | ICHABOE. |Bolivian or Upper |