366 Dr. Ure’s new experimental researches 
Table VI. 
Oil of Turpentine. 
Petroleum. 
Temp. 
Calculat. 
Observed. 
Temp. 
Calculat. 
Observed. 
310° 
320 
33 ° 
• 34 ° 
35 ° 
360 
37-7 
42.5 
47-7 
60.4 
33-5 
37.06 
42.1 
47-3 
53-8 
60.8 
3 20° 
33 ° 
34 ° 
35 ° 
360 
37 ° 
1 . 6.2 
41.2 
47.0 
53-6 
61. 1 
31 7 
364 
41.6 
46.86 
53-3 
60.7 
The whole of the preceding research is closely interwoven 
with a question of the first importance in chemical philosophy ; 
what are the relative portions of temperature denoted by the 
graduations of our thermometric scale? Mr. Dalton regards 
the progressive elasticities of aqueous and ethereal vapour as 
affording countenance, if not support, to his thermometric 
innovations. He affirms, that if our instrument for measur- 
ing heat were accommodated to his doctrine, the quan- 
tity of expansion of its mercury is as the square of the 
temperature from its freezing point; then “the force of 
“ steam in contact with water increases accurately in geome- 
“ trical progression to equal increments of temperature, 
“ provided these increments are measured by a thermometer 
“ of water or mercury, the scales of which are divided by 
“ the above mentioned law.”* 
Were this position true, it would certainly bring a powerful 
analogy in aid of his theoretical views. We are now 
furnished with data to verify, or refute it. The following tables 
show the correspondence between that principle and experi- 
ment. In the table of aqueous vapour, the first column pre- 
* New System, vol. i. p. n. 
