1 26 Mr. henli’s Experiments and 
A fpecimen of gypfum> 
<+. -- k • 
ARTIFICIAL SUBSTANCES. 
Staffordfhire ware glazed ; China ware, 
s; Wedgwood’s ware glazed, s; whale’s 
fin prepared, w; writing-paper; parch- 
ment, s; fheep’s gut, 
Tobacco-pipe, s; Wedgwood’s ware 
unglazed ; elaftic gum, s ; hard under- 
cruft of a leaf; a tallow-candle, w; oiled 
filk ; painted paper, s ; filver, burnt into 
glafs, unburnifhed ; pearl-barley, w ; In- 
dian ink, w; blue vitriol, s, 
Dr. lewis’s glafs porcelain, 
Silver burnt into glafs, burnifhed, could not be excited 
either with the woollen or filk. It is fuppofed that the 
fubftances being fo intimately incorporated or blended 
together, the fridtion at the fame time excited both the 
fubftances, fo as to counteradl and deftroy the effedt of 
each other. 
In thefe experiments I have been affifted by Mr. ca- 
vallo and Mr. adams, who have carefully repeated 
them in mv prefence. It may be proper to obferve alfo, 
that the white pea, a fcarlet bean, and the thorn from 
the 
Wool. Silk. 
Neg. Pof. 
Pof. Pof. 
> Neg. Neg. 
Neg. Pof. 
3 
