On the Chemical Co^npositioti of Harmoiome. 35 



(c.) The liquid from which the silica had been separated was 

 precipitated by ammonia. The precipitate, after being collect- 

 ed on a filter and duly washed, was dried and ignited. It then 

 weighed 2.53 grains. It was dissolved in muriatic acid, and left 

 a residue of .03 of silica. The muriatic solution was then boiled 

 with caustic potash. What remained undissolved by the potash 

 was collected and washed, and then treated with muriatic acid. 

 A residue of .02 of silica was left by the acid. The muriatic 

 solution was boiled with nitric acid, neutralized by ammonia, 

 and precipitated by benzoatc of ammonia. The benzoate of 

 iron was burned with a little nitric acid, and the peroxide of 

 iron thus got weighed .03. The residual fluid boiled with car- 

 bonate of potash gave an insignificant white precipitate, too 

 small to weigh or examine. There thus remained of alumina, 

 dissolved by the caustic potash, 2.45 grains. 



(d.) The liquid which had been precipitated by ammonia, 

 together with the washings of the precipitate concentrated by 

 evaporation, was heated, and carbonate of ammonia added to it 

 whilst hot. The precipitate which fell, weighed, after being 

 washed and ignited, 4.36 grains. It was dissolved in dilute 

 muriatic acid, and left .01 of silica. The solution by evapora- 

 tion afforded tabular crystals of muriate of baryta. '■> 

 (e.) The crystals of muriate of baryta were washed with al- 

 cohol. The alcohol was separated, mixed with water, and eva- 

 porated to dryness, when a little deliquescent matter was left. 

 This was re-dissolved in water, and the solution precipitated by 

 oxalate of ammonia. The precipitate by calcination afforded 

 .03 of carbonate of lime, equivalent to .0168 of lime. By sub- 

 tracting from the amount of the precipitate by carbonate of am- 

 monia, the substances afterwards separated from it, we get 

 4.32 of carbonate of baryta, equivalent to 3.3517 of baryta. 



(y.) The liquid which had been precipitated by carbonate of 

 ammonia, in (d) was evaporated to dryness, and the ammoniacal 

 salt driven off by heat. The residue, after ignition, weighed .5. 

 Dissolved in water it left .02 of silica, giving .48 for the soluble 

 residue. The solution by evaporation gave cubical crystals. 

 Re-dissolved, the liquid was plentifully precipitated by muriate 



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