130 Mr. Denham Smith on the Composition of 



contained only minute traces of soluble matter, the insoluble 

 portion was collected on a filter, dried at !212° and its weight 

 noted. The mixed solutions being gently evaporated to dryness, 

 the productwas weighed and treated with cold water, the weight 

 of the matter insoluble in the cold water was noted, and the 

 substance reserved ; the solution obtained by thus treating it, 

 being again evaporated to dryness, was weighed, ignited, and 

 the loss of weight noted, indicating the organic matter, with 

 traces of water and ammonia; the fused residue was treated 

 with water, the filtered solution precipitated with nitrate of 

 silver, and the weight of the phosphate of silver was ascer- 

 tained; this was assumed to be due to the presence of phosphate 

 of soda, but the quantity was always too small to ascertain 

 whether this alkali or potash was present; the portion insoluble 

 in water was then dissolved in a little hydrochloric acid and 

 treated in the manner before described, to estimate the pro- 

 portion of phosphate of lime and phosphate of magnesia. 



The reserved portion, which was insoluble in the cold water, 

 was then treated to ascertain the existence and proportion of 

 free uric acid. It was boiled in successive small portions 

 of water, four or five fluid ounces each time, until the solu- 

 tion ceased to become turbid on cooling; these solutions were 

 mixed together, boiled, and allowed to cool very gradually : 

 if free uric acid were present a few crystalline grains of this 

 substance would be deposited, which, when weighed, were 

 ascertained to be uric acid by means of potash and nitric 

 acid. The portion left undissolved by these small portions of 

 boiling water was then treated with a few drops of very dilute 

 potash, the absence of ammonia was proved by test-paper, and 

 the solution precipitated by sulphuric acid, which threw down 

 the uric acid as a voluminous precipitate, which by repose was 

 converted into crystalline grains; this was weighed, added to 

 the weight of uric acid previously obtained, and the loss was 

 estimated as organic matter: the solution of urate of ammo- 

 nia was evaporated, its weight ascertained, then ignited, and 

 the ashes, if necessary, analysed for lime and magnesia, in the 

 manner before described. 



The third division of the analysis was commenced by ascer- 

 taining, by means of potash, whether any uric acid or urate 

 of ammonia was present in the residue left undissolved by the 

 repeated boiling with water. If these substances were absent, 

 care being taken at the same time to note whether the residue 

 gave off' any ammonia when thus treated, and the presence or 

 absence of ammonio-phosphate of magnesia being thus ascer- 

 tained, (supposing no urate of ammonia nor uric acid existed in 

 the residue) a given weight of it was boiled with diluted muriatic 



