a 
132 On the Measure of 
- Qn the other hand, Dr. Milner, of Cam- 
bridge, holds, “ that it is plain, that if any one 
contends for the equality of action and re- 
_ action, and explains those terms by the change 
_ produced in the absolute forces of bodies, the 
dispute is not merely verbal.”* And again, 
he says, “some writers have considered this 
question as entirely verbal, and have affected 
to treat the advocates on both sides with the 
greatest contempt. Such persons save them- 
selves a great deal of trouble, and have the 
credit of seeing farther into the controversy 
than others; but after all, I am afraid the 
practical mechanic will receive little intorma- 
tion or security from such speculations.” + 
Dr. Wollaston’s opinion is, that “the con- 
ception of a quantity dependent on the continu- 
ance of a given vis motria for a certain time 
may have its use, when correctly applied, in 
certain philosophical considerations ;. but the 
idea of a quantity resulting from the. same 
force exerted through a determinate space is 
of greater practical utility, as it occurs daily 
in. the usual occupations of men.’{ And 
he concludes his lecture on the Force 
of Percussion thus: “In short, whether we 
* Philosophical Trans, 1778, p. 377." + Ibid p. $78. 
t Philos, Trans. 1806; p. 15. 
