596 On the Expansion of Elastic Fluids by Heat. 
thollet and Monge did not sufficiently accord 
with each other; and that it would be of impor- 
tance to determine not only the whole expan. 
sion of each gas from two distant points, such 
as the freezing and boiling, but likewise whether 
. that expansion be uniform in every part of the 
scale, they instituted a set of experiments exs 
pressly for those purposes. The result of which 
was, that betwixt the temperatures of 32° and 
212°, the whole expansion of one gas differs 
much from that of another, it being in one 
instance about +s of the original, and in others 
more than 12 times that expansion; and that 
the expansion is much more for a given num- 
ber of degrees in the higher than in the lower 
part of the scale. These conclusions were so ex- 
tremely discordant with and even contradictory 
to those of others, that I could not but suspect 
some great fallacy in them, and found it in re- 
ality to be the fact: I, have no doubt it arose 
from the want of due care to keep the apparatus 
and materials free from moisture. 
My method of experimenting on this subject 
is simple, and therefore less liable to error. A 
straight manometer tube, such as has been men- 
tioned, is duly divided into equal portions of 
capacity; it is then dried by a wire and thread, 
and the open end inserted through a cork into 
a phial containing sulphuric acid, in order that 
