7i 
Experiments upon Heat. 
holding water in solution is augmented by heat, and dimi- 
nished by cold, and that, if hot air is saturated with water, and 
if this air is afterwards cooled, a part of its water is necessarily 
deposed. I took a cylindrical bottle of very clear transparent 
glass, about 8 inches in diameter, and 12 inches high, with a 
short and narrow neck, and suspending a small piece of linen 
rag, moderately wet, in the middle of it, I plunged it into a 
large vessel of water, warmed to about ioo° of Fahrenheit's 
thermometer, where I suffered it to remain till the contained 
air was not only warm, but thoroughly saturated with the 
moisture which it attracted from the linen rag, the mouth of 
the bulb being well stopped up during this time with a good 
cork ; this being done, I removed the cork for a moment, to 
take away the linen rag, and stopping up the bottle again im- 
mediately, I took it out of the warm water, and plunged it into 
a large cylindrical jar, about 12 inches in diameter, and lb 
inches high, containing just so much ice-cold water, that, when 
the bottle was plunged into it, and quite covered by it, the jar 
was quite full. 
As the jar was of very fine transparent glass, as well as the 
bottle, and as the cold water contained in the jar was perfectly 
clear, I could see what passed in the bottle most distinctly ; and 
having taken care to place the jar upon a table near the win- 
dow, in a very favourable light, I set myself to observe the 
appearances which should take place, with all that anxious ex- 
pectation which a conviction that the result of the experiment 
must be decisive, naturally inspired. 
I was certain, that the air contained in the bottle could not 
part with its heat, without at the same time, that is to say, at 
the same mo?nent,and in the same place, parting with a proportion 
