60 Elements of Mineralogy. 



thicknefs, and is the fubftance of which the 

 large Turkey tobacco-pipes are formed : it is 

 probably found alfo in North America^ being 

 the fubftance called in Canada^ Terre a chalu- 

 mean. It is of a white or yellow colour, 

 foapy feel, and moderately hard. It hardens 

 eafily in fire without requiring a great heat. 

 In the ftate in which we receive it, .that is 

 baked, it does not effervefce with acids, and 

 is difficultly foluble therein. 



According to Mr. Wiegletfs analyfis, it 

 confifts of equal parts, magnefia and filex. 

 5 Crell. Nev. Entdeck, p. 3. 



II. VARIETY. 



Mixed *witb Calcareous Earth and, Iron. 



It appears like an olive-coloured, or blue 

 clay : the olive-coloured contains no argilla- 

 ceous Earth : the blue fort contains moft cal- 

 careous Earth, alfo iron, a little argill, and 

 petrefa&ions. Both are found near Jhion- 

 <uille. The former fort is ufed in pottery. 

 13 Roz. p. 60. 



III. VARIETY. 



Mixed *uuith Clay^ Talc, and Iron. 



This is a greenifh yellow, loofe Earth, 

 of a greafy feel, found in Silefia. It con- 

 tains 



