106 On the Measure of 
that the argument respecting the measure of 
the force of a body im motion, was merely 
a dispute about terms, and that, though the 
force in question may be variously estimated, 
according to circumstances, it is most natu- 
rally and consistently expressed by the product 
arising from the mass being multiplied into its 
velocity. 
Although scientific men have, for more 
than half a century, been generally satisfied 
on this question, it must nevertheless be 
acknowledged that considerable difficulties 
have occurred in the practical application of 
their measure of force; and, it is remarkable, 
that the measure which they have rejected, 
appears to have been first suggested to Hooke 
and Huygens, by their practical observations 
on the motion of pendulums, and was after- 
wards adopted by Smeaton, as a rule for the 
great operations in which he had so much 
experience. 
It is much to be regretted that theory should 
appear to be at variance with practice, or that 
any ambiguity should remain on a question of 
such general application in mechanics. 
{t has often been asserted, indeed, that 
practical operations need not be affected by 
differences of opinion about the measure of 
force ; for, there being no disputed facts, the 
A 
