Urate of ammonium 12.74 Oxalate of ammonium 13.60 Nitrogenous and sulphurous organic substances 3.61 Ammonium-magnesium phosphate 4.00 Ammonium phosphate .90 Ammonium sulphate 1.82 Ammonium chloride 1.55 Potassium sulphate 3.30 Sodium chloride 2.44 ----- 43.96 ----- 2. _Difficultly soluble in Water, soluble in Acids, Alcohol, and Ether._ Uric acid 21.14 Resin 1.11 Fatty acids 1.60 Nitrogenous and sulphurous organic substances 2.29 Calcium phosphate 18.22 Phosphate of iron 1.04 Silica .64 ----- 46.04 ----- In the above analysis it will be noticed that none of the ammonia is present as carbonate. In most samples, however, of Peruvian guano, the ammonia in this form amounted to from 1 to 2 per cent. In the inferior qualities, chiefly those which had been subjected to the action of water, and consequently of fermentation, to a certain extent, this form of ammonia was found to be most abundant. Such guanos were most liable to loss of nitrogen by volatilisation. The older Peruvian guano contained as high as 14 per cent of nitrogen (equal to 17 per cent of ammonia), and of phosphoric acid 12 to 14 per cent (equal to 26 to 28 per cent of phosphate of lime). It, however, gradually deteriorated in quality as the deposits became worked out, the percentage of nitrogen becoming year by year less, until latterly Peruvian guano, as imported, contains only from 3 to 4 per cent of nitrogen (equal to 4 to 5 per cent of ammonia). This guano is, however, richer in phosphates, containing often 50 to 60 per cent of phosphate of lime, and 3 to 4 per cent of potash.[192] (_b_) OTHER NITROGENOUS GUANOS.