GUANO 751 



animal matter. In a sample of Peruvian guano I obtained 5 per cent, of ammonia 

 from this source. 



17. The whole quantity of ammonia producible from guano is to be determined by 

 gently igniting 25 gr. of it well dried, and mixed with 10 times its weight of the 

 mixture of hydrate of soda and quicklime (2 parts of the latter to 1 of the former). 

 The ammonia disengaged is condensed and measured, as described above. 



18. The ready-formed ammonia is in all cases determined by distilling a mixture of 

 100 gr. of it with 50 gr. of slaked lime, condensing the disengaged ammonia, and 

 estimating it exactly by the meter. 



19. The relation of the combustible and volatile to the incombustible and fixed 

 constituents of guano, is determined by igniting 100 gr. of it in a poised platinum 

 capsule. The loss of weight denotes the amount of combustible and volatile matter, 

 including the moisture, which is known from previous experiments. 



20. The insoluble matter is digested in hot water, thrown upon a filter, dried, and 

 weighed. The loss of weight is due to the fixed alkaline salts, which, after concen- 

 trating their solutions, are investigated by appropriate tests : 1, nitrate of baryta, for 

 the sulphates ; 2, nitrate of silver, for the chlorides and sulphates ; and 3, bichloride 

 of platinum, for distinguishing the potash from the soda salts. 



21. The insoluble matter (of 20) is digested with heat in dilute nitric or hydro- 

 chloric acid, and the whole thrown upon a filter. The silica which remains on the 

 filter is washed, ignited, and weighed. The lime, magnesia, and phosphoric acid may 

 be determined as already pointed out. 



If, however, the remarks made in an earlier part of this article be correct, it is 

 altogether unnecessary, in order to ascertain the commercial value of a sample of 

 guano, to perform so elaborate a series of operations as that described above. 

 The following points are all that are required to be investigated : 

 The amount of water ; organic matter ; nitrogen ; proportion of ash ; analysis of 

 the ash as to phosphoric acid and alkalis potash and common salt; sand. 



1. Water. The most delicate and troublesome operation is perhaps the d*etermina- 

 tion of the amount of water. If the substance be dried in the water-oven, as is the 

 usual practice, at 212 F., a very large quantity of ammonia is expelled : so that it 

 becomes necessary to desiccate by protracted exposure under a bell-glass, over a vessel 

 of sulphuric acid. Even in this manner, the error is not entirely eliminated, and Mr. 

 Way suggests treating the specimen in a shallow platinum dish, with a few drops of 

 hydrochloric acid, which is allowed to soak through the whole : he states, that it may 

 then be dried at 212 F., without loss. 



2. Organic matter. The proportion of organic matter is determined in the usual 

 way, by burning it off in an open platinum crucible, until nothing is left but the white 

 or brownish white ash, which is then weighed. 



3. Determination of nitrogen. This is best performed by Will and Varrentrapp's 

 process. See Watts's ' Dictionary of Chemistry.' 



4. Phosphoric acid. The phosphoric acid in the ash of the guano is determined by 

 conversion into perphosphate of iron, and then separation as ammonia -magnesia 

 phosphate, in the usual way. Under the head of ASH OF ORGANIC BODIES, in Watts's 

 ' Dictionary of Chemistry,' will be found the general method for the complete analysis 

 of the ashes of organic bodies, which, if it be thought desirable, may be carried out, 

 in extcnso, in the case of the ash of guano. 



5. Mkalis. This is, however, scarcely necessary, so long as the alkalis are deter- 

 mined to ascertain the amount of the valuable alkali potash, and the extent of con- 

 tamination with common salt. 



6. Sand. The quantity of sand is determined by treating a portion of the dried 

 guano with hydrochloric acid and water, till nothing more is dissolved, then igniting, 

 and weighing the residue. 



Statistics of the guano trade at Peru. We extract the following from an article 

 published in the official journal at Lima : The exportation of guano began in 

 1841, under the contract with the house of Messrs. Quiros, Allier, and Co. Up to the 

 end of 1856, the exportation from the Cincha Islands has been 1,967,079 tons, of 

 which 1,626,405 tons were sold, and 23,885 were lost at sea. The stock in hand of 

 the company was 316,789 tons. The gross proceeds of all these sales came to 

 $100,263,518; the charges amounted to/ 61, 008,881, leavingnet proceeds,^" 39,254,647; 

 say at ll. per $ 5 7,850,927^. In the year 1857 the exportation amounted to 

 472,965 tons, which, added to 316,789 tons, left on hand in the previous year, gives 

 789,754 tons; of these 304,589 tons were sold, and 19,156 were lost at sea, leav- 

 ing 466,009 tons. The net profit that year was g 12,531,016, or at g 5 per 11. 

 2,507,70$. 



In addition to the importation of guano already given on p. 741, the Trade and 

 Navigation Eeturns for 1872 give the following statement under the head of 'Manures 



