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XXI. A Continuation of the Experiments and Observations on 
the Light which is spontaneously emitted from various Bodies ; * 
with some Experiments and Observations on solar Light , when 
imbibed by Canton's Phosphorus. By Nathaniel Hulme, M. D. 
F. R. S. and A. S. 
Read June 18, 1801. 
SECTION XL 
The Effects of various aerial Fluids on spontaneous Light. 
INTRODUCTION-. 
The apparatus employed for experiments with any kind of 
air, unless otherwise expressed, consisted of the following parts : 
1. A tea-saucer, holding about three ounces of water. 2. A wide- 
mouthed phial, which would contain about ten ounces of liquid. 
* 3. A small wooden stand, composed of a slender pillar or pin, nearly 
four inches high, fixed into a round base, a little more than an 
inch in diameter, and half an inch thick. This stand was fastened 
by strong thread to the middle of a piece of flat lead, such as 
lines Chinese tea-chests, having holes in it to admit the thread; 
the lead was about three inches square, and doubled, to give it 
weight and stability. The top of the pillar was made pointed ; 
and a round piece of cork, about an inch in diameter and half 
an inch thick, was fixed upon it, by means of a superficial hole 
bored in its under part with a gimlet. 
* See Phil. Trans, for 1800, page 161. 
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