C 490 3 
very fmall white and fhining filaments, which have a 
flocculent or downy appearance, and is therefore 
the fame fait which was heretofore known under the 
name of alumen plumojum. Some kinds of ajbeftos , 
from their refetnblance to this fait, have alfo, though 
very improperly, obtained the name of alumen plu- 
moj'um. This fait has the diftinguifhing tafte of 
alum, though fomewhat more harfh and rough, 
owing either to fome ftnall mixture of vitriol of 
iron, which feems to fhoot out along with the alum ; 
or elle, becaufe mod of the alum prepared for lale 
has urine, kelp, and other mixtures, added to the 
lixivium during its codtion, which may render the 
fait lb prepared lefs harfh and ftyptic than the native 
alum. The Hone on which the native alum, here 
exhibited, germinates is black and fhining, and has 
ib much bitumen mixed with it, that it burns flowly, 
and leaves a white afh, when let on fire in large heaps. 
N. B. From the top of thefe heaps, I have col- 
jcdted confiderable quantities of brimftone that was 
fublimed from this bituminous ftone, while burning 
in this How manner. 
N° 18. Large pieces of the fame native alum, 
very pure ; on the outiide it has got a yellowilh call 
by being expofed two years to the open air lince it 
was taken from the mine ; when broken, it ap- 
pears on the infide more fhining, and has a blueifh 
call. 
N° 19. An earth found in confiderable quantities 
near the above fpecimens of alum. From its ex- 
tremely harfh, rough, and fiyptic tafte, like that of 
burnt alum, it feems to be an aluminous earth. It 
3 ■ may 
