Chap. It.] -Jibeftos. * 7 



names of daze s glimmer, or glift. Talk differs from 

 other micas in its laminae or filaments being much 

 tenderer and more brittle, but both have the metallic 

 luftre. 



5. The ASBESTOS, or amianthus, is a foflil agree- 

 ing with 'talk i'n having a regular ftrufturei in being 

 flexible, but differing in being compofed of fibres 

 iriftead of plates. When long expofed to air, it dif- 

 folves into a fort of downy matter, which has fome 

 degree of tonghnefs, but the fibres cannot be unra- 

 velled. Cloth and paper have been made of this fub- 

 ftance, which refift the fire. Afbeftos, however* 

 though unaffailable by common fires, has fubmitted to 

 the power of ftrong burning mirrors, and has under- 

 gone vitrification. The ancients are faid to have ma- 

 nufactured cloths of this foflil, in which they wrapped 

 their dead when they burned them* that the afhes 

 hiight be preferved. Several moderns have fucceedcd 

 in making this cloth j the chief contrivances which 

 are neceftary are to mix the mineral fibres with a large 

 proportion of flax, and to ufe oil freely j thefe matters 

 are afterwards confumed by expofing the cloth to 

 a red heat. Although the cloth of afbeftos when foiled 

 is reftored to its whitenefs by burning, yet it does lofe 

 fome part of its weight, as has been afcertained by ac- 

 curate experiments. The varieties of this curious 

 genus of fofiils are mountain leather or cork 5 moun- 

 tain flax, to which the name of amianthus is particu- 

 larly applied; common or unripe afbeftos, and moun- 

 tain wood. Thefe fubftances all confift nearly of the 

 fame component parts* and differ chiefly in colour, 

 folidity, or in the form and direction of their fibres. 

 Some fpecimens of the amianthus are fo light as to 

 float in water. When the fibres are parallel, it is 

 F a called 



