Steam Engine. 55 
Tempe- 
rature 
on Fahr. 
Force of | 
aqueous j 
Vapour. I 
Tempe- 
rature 
on Fahr. 
Force of 
aqueous 
Vapour 
60=^ 
•0333 
212^^ 
1-000 
90 
•0453 
220 
i-i66 
100 
•0620 
230 
1-391 
no 
•0843 
240 
1-655 
120 
•1110 
250 
1-^40 
130 
•1446 
260 
2-257 
140 
•1913 
270 
2-5 5 
150 
•2473 
280 
2.958 
160 
•3153 
290 
3-337 
i:o 
•4043 
300 
3-727 
180 
•5050 
310 
4-117 
190 
•6333 
315 
4-309 
200 
•7880 
320 
4-500 
210 
•96;3 
325 
4-690 
The preceding experiments and calculations of Bet- 
tancourt, are certainly valuable ; but they require to be 
checked by the very important paper of Mr. Dalton, of 
Manchester, of which the following is an extract so far 
as it relates immediately to the theory of the Steam En- 
gine. 
Extract from experimental Essays on the Constitution of 
mixed Gases ; on the force of steam or vapour from wa- 
ter and other liquids in different temperatures^ both in 
a Torricellian V ucuum and in air ; on evaporation ; and 
on the expansion of gases by heat. By Jo h isr D a l t o . 
5 Manch. Trans. 241. GNich. Phil. 257. 
THE progress of Philosophical knowledge is adv anced 
by the discovery of new and important facts ; but much 
more when those facts lead to the establishment of general 
