ii^U ANALYSIS OF MAGNEsiTltf^ 



pTastic ttiagnesite, with the silicHerous carbonated maghe*» 

 sia-of Haiiy. But tlie meerschauin is nothing but a hydratfe 

 ofsilex, which maybe made smooth by friction ; and this 

 Brongniart gives as one of the characters of mag-nesite. He 

 is mistaken too when he makes the magnesite of Baudissero 

 and Castellamonte, nearTurin, a subvariety of plastic niag- 

 uesite ; for this substance belongs to the magnesite of 

 Mitchel. As to his magnesite of Vatlecas, it is a true 

 meerschaum, which we cannot join with Mitchers magne- 

 site ; from which it differs greatly in specific gravity, being 

 of 1 '6, and also in tefiacity. The plastic raaguesite of Sali- 

 nello of the same author is obviously a variety of steatite, as 

 its analysis shows. 



Haiiy. Fiaiiy appears to be utterly unacquainted with meer* 



schaum, for, in vol. IV, p^ 443, of his work, he confounds 

 it with the red Turkish clay, of which pipes are sometimes 

 made; but this is nothing but a bolar earth. 



Analyses. It is pleasing to see how nearly the analyses of magnesite 



made by Mitchel, Larapadius, Klaproth, and Euchblz^ 

 agree. This shows how greatly Wondraschek wag deceived, 

 when he ascribes to it 20 per cent of water. We perceive 

 too, that Giobert was mistaken in his analysis tf the stone 

 of Baudissero, or that it is not a magnesite. We must also 

 question the accuracy of the analysis of the magnesite of 

 Castellamonte, published by Guyion ; which consists, ac- 

 cording to liim of 46 carbonic acid, 12 water, 26 magnesia, 

 and 14 silex, yet is insoluble in water. 



Magnesite Magnesite is found in rounded pieces, sometimes as large 



desciibtd. gg ^ man's head, and of an earthy aspect. 



It is always dense, and formed of earthy particles, dull 

 and of a meagre feel; sometimes with fissures in its interior, 

 but never with rounded cavities ; and sometimes, but very 

 rarely, a siliceous nucleus rtseuibling chalcedony is found 

 in the centre. 



Specific The specific gravity of magnesite, when it has been suf- 



giavuy. feied to imbibe as much water as it will take up, is 2'881 ; 



otherwise only 2'456. Haiiy has found, that the magnesite 

 of Castellamonte, which contains 14 per cent ofsilex, was 

 of the specific gravity of 2-781, when thoroiiijhly soaked in 

 water, and of 2*175 previously. 



The 



