MODE IV. STEATITt. 



hard. To the last the following interesting ob- 

 servations of Patrin chiefly refer ; and they are 

 the more freely extracted, because his works, 

 like those of Saussure, though of the greatest 

 importance to the science, have never been 

 translated, and remain new to the mere English 

 reader. 



" There is often so little difference between 

 ollite and steatite, that Saussure* who was so 

 well acquainted with rocks, sometimes uses 

 these two denominations in speaking of the 

 same substance; or, at least, he calls steatite ste ;$f t e e ? nd 

 the substance which forms the base or the paste 

 of ollite. The greatest, or the only difference 

 which, in fact, exists between them is, that 

 steatite is a more simple and more homogenous 

 compound, and that it is also more unctuous, 

 than ollite. 



< It may be said, that steatite is to the ol* 

 lites what corncenne is to porphyries. It is a 

 paste which contains crystals, or, at least, dis- 

 tinct particles, of mica, talc, sometimes of as- 

 bestos or amianthus ; as the base of porphyries 

 contains crystals of felspar, schorl, and grains of 

 quartz. Steatite is even observed, as that of the 

 summit of Roth-horn, near Mount Rosa, which 

 contains grains of felspar; and this mixture also 

 forms ollite. 



