272 iifiLirsis «f MAQ^^nt, 



in th« superior strata of the decomposed serpentine ^rcen 

 chalcedony and opal are found. 



The magnesite of Castellaradntej nearTtiTitt, is also found 

 in strata of serpentine and tale* 

 Its uses. This stone might be used fbr toan'ufacturirrs* fedlphate of 



magnesia. According to Giobertit is used Jo 'Pifedmont H 

 the porcelain manufactoryi We ate informed Jklso, that the 

 meerschaum of Vallecas in Spainis emjilftyedirt the Jjorce- 

 lain manufactory at Madrid. ri;. yi. ■ . 



Stones with Care must betaken, not to confound tnagtieSit^'^kH talc 

 be con- ™ °^ lithomargtl} and thongh Werner says, that Khere are 

 founded. some Varieties of magiiesite which are soft t6 ihe t*»uch, t 

 believe they are only fragments approachirig to sttatitfe, and 

 then they become smooth when rubbed. 

 Its carbonic W'e must likewise reject tfe^ opinion of Giobfert', li^ho 



sorbed from tliinks, that the magnesite of Baudissero contains no earbb- 

 the air. nic acid while it remains in the earth, but attracts it subse* 



quentjy from the air ; for hitherto no magnesia Cortibined 

 with water alotie has been discovered. If magnesia be found 

 pure, it is always intimately mixed with a large propbrtibn 

 of silex, as is the case in steatite, or speckstein. The ana- 

 lysis published by Giobert too must be considered as faflUy. 

 According to him magnesite is composed of ' 



Giobarfs ana- Magnesia , . jSCg. . 



*>«'*' Silex.... ••••••• ..^. lSt-$'' ' 



Carbonic acid ............. ..^ 12 , 



Water ♦, 3 



and casually it contains sulphate of lime.. I'd 



100*2 



Analyst. Chemicat analysis. 



IstTariety A. This first variety has the greatest specific gravity^ 



dejcribed. ^nd the slightest degree of cohesion ; emits no argillaceous^ 

 but a sliglit earthy smell ; is strongly adhesive to the tongue ; 

 has a yellowi«ih white colour, and little figures are observ- 

 able in it. Externally it is friable, and sometimes soilt 

 the hands. <^n touching it. 

 Action of acids «. When small bits of this stone nre thrown iilto sulphu- 

 *'^*'' fic, nitric, or muriatic acid, they dissolve but slowly at the 



commc>n 



