ANALYSIS OF MAONESITE. §7^ 



,thc lightest possibly, and very bulky; unless.thia fie pre* 

 vented by some mechanical operation,, as strong pressure, 

 which however does not alter its component parts. 



If, instead of operating with the solutions cpldl, they be 

 mixed at a boiling heat, 100 parts of th£j;:'9U'bgn^te ofpx&s-* 

 ni^sia produced will contain -oV-Wv vj- -sttr ' 



Magnesia «•••» ««^.« '49" -'c:i, : precipitated 



Carbonicacid ..>....^v..*, 85 ' a- ^°^» " 



Water • 23 



100. 



The carbonate of magnesia prepared by passing a stream 

 . of carbonic acid gas through water, holding carbonate of 

 magnesia in suspension, or by filtering and leaving to 

 spontaneous evaporation the liquor obtained after precipi- 

 tating one part of sulphate of magnesia by four parta of 

 subcarbonate of soda, contains in 100 partd 



Magnesia 30 saturated by 



Carbonicacid ..*. 30 exposure to 



,-r carboaic actd. 



Water • • 40 



■ 100. 



Here it appears, that the first and third processes ap- 

 proach near each other in the proportions Of magnesia and 

 carbonic acid ; and, if we leave the water out of the ques- 

 tion, they differ but little from the natural stone, though 

 this contains a still larger proportion of carbonic acid. 



J5. The second variety of magnesite greatly resembles 2<l nncji, 

 the first in* the colour and marbling; but it is harder, and 

 hot so heavy. It is also less adhesive to the tongue, and 

 emits a perceptible smell of alumine* 



a. 100 grains of this stone in whole pieces, treated as in Treated with 

 experiment A 6, left 51 grs. At first a brisk effervescence "*""**'* " 

 took place, after which the stone fell to powder. In twelve 



hours the whole was dissolved, except a few light f!ock», 

 which disappeared by agitation. 



b. By an hour's calcination this stone lost 52 gra. The Ex>>6sed to 

 pieces bad still a slight cohesion, but might easily be rub- ^^'* - 

 bed to powder* Their colour was a reddish white. 



T 2 c. After 



