[ * 4 ° 3 , 
XXII. Experiments made to determine the pojitive and relative 
Quantities of Moifure abforbed from the Atmofphere by various 
Subfiances , under fimilar Circumfiances. By Sir Benjamin 
Thompfon, Knt. F. R. S. } communicated by Charles Blag- 
den, M. D, Sec. R. S, 
Read March 22, 1787. 
B EING engaged in a courfe of experiments, upon the 
condu&ing powers of various bodies with refpedt to heat, 
and particularly of fuch lubftances as are commonly made ufe 
of for cloathing, in order to fee if I could difcover any rela- 
tion between the conducting powers of thofe fubflances, and 
their power of abforbing moifture from the atmofphere, I made 
the following experiments. 
Having provided a quantity of each of the under mentioned 
fubftances, in a (late of the moft perfefl cleannefs and purity, 
I expofed them, Ipread out upon clean China-plates, twenty- 
four hours in the dry air of a very warm room (which had 
been heated every day for fevcral months by a German Rove), 
the laft fix hours the heat being kept up to 85° of Fahrenheit’s 
thermometer; after which I entered the room with a very 
accurate balance, and weighed equal quantities of thele various 
lubftances, as exprefled in the following table. 
This being done, and each fubftance being equally fpread 
out upon a very clean China plate, they were removed into a 
very large uninhabited room upon the fecond floor, where they 
were 
