We have already referred to the guanos in the chapter on Guano.
The normal phosphate, Mg3P2O8, is found in some guanos, and as the mineral wagnerite.
The quantity of guanos of all kinds imported into this country and retained for home consumption now exceeds 240,000 tons a year.
According to Boussingault, some guanos contain small quantities of nitrates.
In the old rich Peruvian ...