.23
" oxalate 9.14
Basic ammonium phosphate 12.09
Precipitated ammonium phosphate 4.78
Organic matter .94
Insoluble 1.90
Water 2.06
------
100.00
------

NOTE IV. (p. 306).

The following analyses, being the average of a large number of different
samples analysed from time to time in the chemical laboratory of the
Pommritz Agricultural Experimental Station, show the gradual
deterioration of Peruvian guano, as regards its percentage of nitrogen,
during the years 1867-81:--

Nitrogen. Nitrogen.
1867 13.16 | 1873 9.16
1868 11.98 | 1874 9.83
1869 13.66 | 1878 7.10
1870 12.37 | 1879 6.95
1871 10.04 | 1880 7.07
1872 10.72 | 1881 6.93

NOTE V. (p. 309).

COMPOSITION OF DIFFERENT GUANOS.

The following is a list of the more common nitrogenous and phosphatic
guanos which have been used in the past or are at present in use. Those
printed in italics are still being worked. As their value depends on
their nitrogen and phosphoric acid, these alone have been given. The
percentages must be taken as mere approximations, as the quality of
different cargoes from the same deposits varies very much. The table may
be found useful for reference.

_Nitrogenous Guanos._
Phosphoric } { Tricalcic
Nitrogen = Ammonia. acid } = { phosphate.
per cent. per cent. per cent. per cent.
Angamos 20 24 5 11
Chincha 14 17 13 28
Ballestas 12 15 12 26
Egyptian 11 13 19 41
Guanape 11 13 - -
Macabi 11 13 12 26
Corcovado 11 13 15 33
_Saldanha Bay_ 9 11 9 20
_Ichaboe_ 8 10 9 20
Independence Bay 7 9 12