MINERALOGY. 115 



gillaeeous earth, both becaufe they become brittle 

 in the fire, which is a proof that they harden, 

 and becaule they become more fufible by the ad- 

 mixtion of a martial earth : but the method na- 

 ture makes ufe of for this change is as unknown, 

 as it might perhaps in other refpe&s be necefiary, 

 not to force the earths together, for fome flight 

 reafon, within the compafs of a few orders. 



The Siberian Afbeftus, which may be confidered 

 as the principal and chief of the fibrous kind, is, 

 as it were, confumed by the flame of a blow- 

 pipe, and does not leave any more certain mark 

 of fufion j but it melts readily with borax to a 

 clear and colourleis glafs. 



The natural itore of this kind is in proportion 

 to its ©economical ufe, both being very inconfi- 

 derable. It is an eld tradition, that in former 

 ages they made cloaths of the fibrous afbefti, 

 which is faid to be expreffed by the word Byjfus ; 

 but it is not very probable, fince, if one may 

 conclude from fome trifles now-a-days made of it, 

 as bags, ribbons, and other things, fuch a drefs 

 could neither have an agreeable appearance, nor 

 be of any conveniency or advantage. It is more 

 probable that the Scythians dreffed their dead 

 bodies, which were to be burnt, in a cloth ma- 

 nufactured of this {lone ; and this has perhaps oc- 

 cafioned the above fable. 



Paper is likewife made from this flone, only to 

 (hew its fixity in the fire, and to procure iome 

 efteem and value to this curious fubftance. 



It was reported forne years ago, that the French 

 fearched for afbefti, in order to mix it with' the 

 tar for preferring houfes and fhips ; but the 

 queftion is, If the afbefti can be of more fervice 

 than pounded mica, or charcoal-duft employed to 

 the fame purpofe? 



1 2 SECT, 



