256 L iterary and Philosophical Society. 



he conceives not to be explicable according to the prin- 

 ciples maintained by the advocates of the opposite mea- 

 sure of moving force to that which he adopted ; and if 

 the difference between them had been as great in reality 

 as it was in words, there is little doubt his conclusion 

 would have been just. Both parties seemed to be right, 

 and to obtain correct results, when they reasoned consis- 

 tently with their hypothesis ; but there required a little 

 adjustment between them. The arguments for adopting, 

 under some distinct denomination, the product of the 

 quantity of a pressure by the space through which it acted 

 were very strong. It was evident that such a measure of 

 effect produced would have a most extensive application. 



This measure had been used by Watt to estimate the 

 effects of steam engines ; it had long before been adopted 

 by Smeaton ; and writers on mechanics had become pre- 

 pared, both in this country and on the Continent, for the 

 introduction of such a value. It has, therefore, been 

 adopted by the most eminent writers on mechanics, both 

 theoretical and practical ; and without making any change 

 in the received definitions of momentum and moving force, 

 which depend on the mass multiplied by the velocity. 



