MINERALOGY, 85 



tin calx might by klclf take a fphenca! poiygbnal 

 figure, at its induration, as well as the garnet. 

 The white tin grains, (Sect, ccx.) out of which 

 no tin, but only iron, is to be got,, might with 

 more radon be placed here, if it was not fb ex- 

 ceffively refractory in the fire, and if it did 

 not, at lad, melted either by itfelf, or with borax, 

 give a clear and colourlefs glafs, contrary to whit 

 the garnet does, which difference artfes from the 

 different fufibility of thefe two fubftances. 



1 he garnet and cockle are not yet known to 

 me in form of an earth or clay, taken in the 

 common idea we have of thole bodies* It is 

 true, that there is a bole found at Swappawari, 



Lapland, which has the fame figure as the gar- 



: •> and the hornblende, (Sect, lxxxviii.) which 

 is fomewhat harder than this bole, has often the 



pearance of a cockle. We cannot, however, do 

 more than problematically fuppofe them to be 

 the neareit related to the garnet kind- as we have 

 not yet difcovefed a method how to feparate 



ths from the contained metals, without de- 

 ftroying their natural form, and efpecially from 

 iron, when it is ib ftrongly united" with them, as 



it had a part in their formation itfelf. - 



SEC T. LXXVIL 

 The F c u r t n Order, 



The Argillaceous Kind, Argitlaceau 



The principal character whereby thefe may 

 be d : . I from other earths, b, that they 



harden in the fire, and are compounded of very 

 minute particles, by which they receive a dead or 



ill appeal rhen broken. 



G 3 More- 



