[ II ] 
III. Experiments on fome Mineral Subjlances. By Peter 
Woulfe, F. R. S. Communicated at the Dejire of Wil- 
liam Hunter, F. R. S. and Pbyfician extraordinary to 
the 'Queen, 
Read Nov. 19, 1778. 
On cryflal , quartz , and flint. 
T\/|’ONS. beaume, a member of the Royal Academy 
. "*■ of Sciences or Paris, has aflerted, that he obtained 
allum from cryftal, quartz, and flint. His method to 
obtain allum from thefe fubftances was to make a liquor 
fllicum , by melting them in a crucible with fixed allcaly, 
and letting the mixture run per deliquium ; any acid 
added to this deliquium precipitates the cryftal, quartz, 
or flint, which, by means of acid of vitriol, he diffolved, 
and obtained allum. I have often repeated this opera- 
tion on all thefe fubftances, but could never obtain a An- 
gle grain of allum : in lieu thereof I got a felenite, and 
was on that account convinced, that the bafts of thefe 
fubftances was a calcareous earth. Mr. beaume’s miftalce 
was, I am certain, owing to the Paris crucibles which he 
C 2 made 
