A 
JOURNAL 
OP 
NATURAL PHILOSOPHY, CHEMISTRY, 
AND 
THE ARTS. 
SUPPLEMENT TO VOL. XXXVI. 
ARTICLE I. 
/ 
\ On the Measure of Moving Force. By iVr. Peter Ewart. 
{Concluded from p. 261.) 
^PnpiHIS principle of moving force may perhaps be illustrated Cases of diffi- 
-IP in some degree, by comparing the phenomena of force docm'nes^of 
'with those of heat. — Metals and fluids having been observed to uioviug force. 
<«xpand and contract according as their temperature is increased 
oor diminished, it was for a long time understood that (empera- 
tture was the measure of heat. After it had been proved by 
IDr. Black that bodies of equal temperatures contain unequal 
qquantities of heat, it was no longer contended that temperature 
rrould be taken generally as the measure of heat. Yet tempe- 
r.'ature is a most important property of heat, and in cases where 
Ihhe temperature and the heat increase and diminish in the same 
fatio, the temperature may be used as the measure of the 
Meat. — In cases of moving force, where the space described by 
1 1 constant pressure, and its duration increase in the same ratio, 
;hhe duration may be taken as the measure of the moving force. 
Of absolute motion or of absolute heat, we know little,--- 
A.ur researches are chiefly directed to relative heat and to relative 
Supplement.-— VoL.XXXVI. — No. i6p. Y motion. 
