Analysis of Limestone, 109 



6ly. The limestone containing magnesia, may be 

 reduced into an impalpable powder, and treated with 

 an equal weight of oil of vitriol, mixed with thrice its 

 quantity of water. When the limestone is well pow- 

 dered and sifted through fme muslin, and the super- 

 fluous acid driven off by heat, I believe this is as good 

 a method as any. 



In making the experiments of which I am about to 

 give the result, I proceeded in two ways. 



First, I took 100 grains of the stone powdered and 

 sifted, and treated it with muriatic acid diluted with 

 three waters by measure, stirring it frequently : after 

 four hours, the supernatant liquor was poured oft', and 

 the undissolved residuum washed with an equal quan- 

 tity of hot water as of the acid liquor, filtered, and dri- 

 ed in the heat of about 160 Fah. and then weighed. 



The solution, was then precipitated by a sufiicient 

 quantity of oil of vitriol cautiously added : it was left 

 to stand after stirring till the gypsum had formed. 

 Then filtered, and the separated gypsum put aside. 



This second filtered solution, contained, muriat of 

 magnesia, a small quantity of sulphat of magnesia, a 

 small quantity of sulphat of lime, and alumina, with 

 excess of acid. The alumina was thrown down in a 

 dirty-coloured floculent precipitate, by the cautious ad- 

 dition of carbonat of ammonia, and was separated by 

 the filter and washed, dried and weighed. The solu- 

 tion was then precipitated by hot carbonat of potash 

 which threw down the magnesia and the lime ; and fil- 

 tered. This precipitate was re- dissolved in sulphuric 

 ^cid, and left to stand. The sulphat of lime (general- 



