| I. | II. | III. |
| Urate of ammonia | 10·70 | 9·0 | 3·24 |
| Oxalate of ammonia | 12·38 | 10·6 | 13·35 |
| Oxalate of lime | 5·44 | 7·0 | 16·36 |
| Phosphate of ammonia | 19·25 | 6·0 | 6·45 |
| Phosphate of magnesia and ammonia | ... | 2·6 | 4·20 |
| Sulphate of potash | 4·50 | 5·5 | 4·23 |
| Sulphate of soda | 1·95 | 3·8 | 1·12 |
| Sulphate of ammonia | 3·36 | ... | ... |
| Muriate of ammonia | 4·81 | 4·2 | 6·50 |
| Phosphate of soda | ... | ... | 5·29 |
| Chloride of sodium | ... | ... | 0·10 |
| Phosphate of lime | 15·56 | 14·3 | 9·94 |
| Carbonate of lime | 1·80 | ... | ... |
| Sand and alumina | 1·59 | 4·7 | 5·80 |
| Water | 9·14 } |
| } | 32·3 | 23·42 |
| Undetermined humus-like organic matters | 10·00 } |
| ——— | —— | ——— |
| 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. | Peruvian. | ICHABOE. | Bolivian or Upper Peruvian. |
| | | | Old. | New. | Old. | Government. | Inferior |
| Water | 12·36 | 13·73 | 24·21 | 18·89 | 12·55 | 16·44 | 14·15 |
| Organic matter and ammoniacal salts | 59·92 | 53·16 | 39·30 | 32·49 | 35·89 | 12·28 | 26·14 |
| Phosphates | 17·01 | 23·48 | 30·00 | 19·63 | 27·63 | 56·09 | 23·13 |
| Sulphate of lime | ... | ... | ... | ... | ... | ... | 9·65 |
| Carbonate of lime | ... | ... | ... | ... | ... | ... | 12·87 |
| Alkaline salts | 7·20 | 7·97 | 4·19 | 8·82 | 15·29 | 11·33 | 5·97 |
| Sand | 3·51 | 1·66 | 2·30 | 6·72 | 8·64 | 2·81 | 8·09 |
| | 100·00 | 100·00 | 100·00 | 100·00 | 100·00 | 100·00 | 100·00 |
| Ammonia | 21·10 | 17·00 | 8·50 | 10·42 | 8·99 | 2·57 | 3·26 |
| Phosphoric acid in alkaline salts | 1·20 | 2·50 | ... | ... | ... | 3·11 | ... |
| | Pacquico Island. | Latham Bay. | Saldanha. | Australian. | Kooriamooria. |
| Water | 8·38 | 24·96 | 21·03 | 13·20 | 8·91 |
| Organic matter and ammoniacal salts | 23·10 | 10·96 | 14·93 | 13·77 | 7·72 |
| Phosphates | 32·36 | 54·47 | 56·40 | 44·47 | 44·15 |
| Sulphate of lime | 2·92 | 2·82 | ... | 4·55 | 3·19 |
| Carbonate of lime | ... | 2·20 | ... | 8·82 | 3·37 |
| Alkaline salts | 25·43 | 4·06 | 6·10 | 7·34 | 11·23 |
| Sand | 7·81 | 0·51 | 1·54 | 7·85 | 21·43 |
| | 100·00 | 100·00 | 100·00 | 100·00 | 100·00 |
| Ammonia | 6·58 | 1·26 | 1·62 | 1·01 | 0·42 |
| Phosphoric acid in alkaline salts | 3·50 | ... | ... | ... | ... |
| | Patagonian. | Chilian. | Mexican. |
| Water | 20·61 | 14·89 | 18·80 |
| Organic matter and ammoniacal salts | 19·72 | 16·81 | 12·88 |
| Phosphates | 30·66 | 36·90 | 18·38 |
| Sulphate of lime | 1·30 | ... | 27·79 |
| Carbonate of lime | 3·06 | 10·28 | ... |
| Alkaline salts | 7·01 | 6·84 | 16·95 |
| Sand | 17·04 | 14·26 | 5·20 |
| | 100·00 | 100·00 | 100·00 |
| Ammonia | 2·69 | 1·42 | 0·42 |
| Phosphoric acid in alkaline salts | 3·00 | ... | ... |
Table shewing the Composition of some of the less common varieties of Guano.
Note.—The numbers in this Table are mostly derived only from a single analysis and have no value as determining the average composition of these Guanos, but they serve to give a general idea of their value.