. ANALYSIS OP ft|jfLG,NESITE. Si7^ 



fiCOmmon tethperature, and some floccolent matter of a lig^t , »-, 



.reddish colour remains. By the assistance of heat the solu-. i 



tion proceeds a little more speedily, and is complete. If """^ 



> the bits of stone were of a tolerable size when thrown into 



^ the acid, the effervescence took place only at their edges, 



, or in a crack where two edges joined. The most remarkable 



. circumstance was, that the rnagnesitefell to pQwd^r,^ before 



,Jrt dissolved, which facilitated Its solution.^^r, : .**.;• 



. ., A. In order to ascertain the quantity of cartonic acid ^^^. . ^'*", 

 *' . , . , . , • f ; . . nmnauc acid* 



.contained m this stone, we took 100 grs ot magnesitein hne with 



powder, and threw them into thrice their weight of fuming 

 muriatic acid diluted with an equal quantity of water. The 

 ^ ipixture was made in a very tall vessel, previously weighed ; 

 ^ which could be heated by placing it on a plate of iron not 

 ^^sufficiently hot to raise any vapours. \Vhen the efferves- 

 v^cence had ceased, the loss was found to be 52 grs. A few 

 slight flocks, floating in the liquor, disappeared on raisiiig 

 the temperature. To avoid all errour, this experiment was and without 

 repeated without heat, in a very tall vessel stopped with a ^ * 

 perforated cork. In eight hours the effervescence had 

 ceased, and the solution was Corfiplete, except a few white 

 flocks, which disappeared during the night. The loss was 

 precisely 52 grs. 

 ' " e. On exposing 100 grs of magnesite to a red heat for an Exposed to a 

 hour in an open crucible, they also lost 52 grs. The resi- "^® ^'^*^' 

 duum, which was of a reddish white, was dissolved in sul- 

 phuric acid diluted with water, without the least efferves- 

 cence : a slight flocculent precipitate of oxide of manganese 

 remaining. This stone therefore contains no water ; knd 

 hence no doubt arises the tolerable degree of hardness it 

 possesses, as well as the slowness with which it dissolves in acids. 



d. The solution of experiment c was evaporated to dry- Sulphtulc 

 ness, and water poured on the residuum to the depth of two e^j,"po°^t,i 

 inches. The whole of the salt was redissolved, except a few- 

 slight flocks of oxide of manganese^ mixed with a little sul- 

 phate of lime. On evaporating, and crystallizing at several 

 periods, a little more sulphate of lime was deposited : buf 

 the whole, including .he oxide of manganese, did not 

 amount to a quarter of a grain. No silex was found in thi« 

 stone. 

 Vol. XXXI April, 1819. T *. To 



