wrtyy = 
Force of Steam. 3 
accompanies Mr. Dalton’s interesting Paper 
on this subject, in the 5th vol. of the Society’s 
Memoirs!” In a valuable Essay on the article 
“ Steam,” published in the 17th vol. of the 
Encyclopedia Brit. and in the account of 
Mr. Betancourt’s experiments on the same 
subject, the force of steam over water is stated 
to increase in a still greater ratio with respect 
to the temperature; but I rely on Mr. Dalton’s 
table, which seems to have been constructed 
with great accuracy. When I first began to 
consider this subject, the question that natur- 
ally occurred to me, was, How does this com- 
paratively small addition of temperature pro- 
duce so remarkable an increase of force? I 
could find no satisfactory answer to this ques- 
tion in the papers that had been published ; nor 
did the information I obtained from such of my 
friends, as were most conversant with the sub- 
ject, supply the defect. I was told, that Mr. 
Watt had made experiments; but could not 
learn the nature of them, or the precise results. 
It was supposed, however, that, as steam over 
water increased in temperature, it continued 
to combine with a greater quantity of heat 
than what was indicated by the mere increase 
of temperature ;—so that steam of double the 
force of the atmosphere probably contained 
twice as much heat, in the same bulk, as 
A 2 
