42 6 Dr. Hulme’s Experiments, Sic. 
P. S. In these experiments with solar light, the phosphorus 
was sometimes exposed to the direct rays of the sun, at other 
times to common day-light, in a northern aspect ; and it was 
remarked, that it became somewhat more luminous by mere 
day-light, than by the rays of the sun. 
It may also be proper to observe, that the above experi- 
ments were made with an improved preparation of Canton’s 
phosphorus. This improvement, which was first made by Dr. 
Higgins, consists in omitting the pulverization of the shells. 
His method was, after calcining the oyster-shells, to put the 
pieces, both great and small, in layers, into a crucible furnished 
with a cover, and to sprinkle flowers of sulphur between each 
layer. After they had remained some time in the furnace, they 
were taken out, suffered to cool, and then kept in a large bottle 
with a glass stopple. For this communication, I am indebted 
to Mr. Lewis of Holborn, near Southampton-street, who has an 
extraordinary dark room, where, at times, he amuses his friends 
with some beautiful appearances, arising from solar light im- 
bibed by phosphorus prepared as above directed. A still further 
improvement of this phosphorus, it appears to me, may be made 
by substituting precipitated sulphur for the flowers of sulphur ; 
and the experiments of this section were chiefly made with 
phosphorus so prepared. 
