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Received November 2 r, 1768, 
XLV. An eafy Method of making a Phof- 
phorus, that will imbibe and emit Light, 
like the Bolognian Stone ; with Experiments 
and Obfervations ; by John Canton,. 
M. A. and F. R. S. 
To make the Phosphorus. 
Read December 22, ✓C ALCINE fome common oyfter 
fhells, by keeping them in a 
good coal fire for half an hour ; let the pureft part of 
the calx be pulverized, and lifted ; mix with three 
parts of this powder one part of the flowers of ful- 
phur ; let this mixture be rammed into a crucible of 
about an inch and a half in depth, till it be almofl full ; 
and let it be placed in the middle of the fire, where 
it muff be kept red hot for one hour at leaft, and then 
fet by to cool : when cold, turn it out of the crucible, 
and cutting, or breaking it to pieces, fcrape off, upon 
trial, the brighteft parts ; which, if good phofphorus, 
will be a white powder 5 and may be preferved by 
keeping- it in a dry phial with a ground Hopple. 
The quantity of light a little of this phofphorus 
gives, when firfi: brought into a dark room, after it 
lias been expofed for a few feconds, on the outlide of 
a window to the common light of the day, is fuf- 
ficient to difcover the time by a watch, if the eyes 
Vol. LVIII. Xx have 
