170 On the Measure of 
If it appear that I have insisted too much on 
this part of my subject, it should be recollected 
that many of the objections which I have been 
endeavouring to meet, apply not only to the 
particular cases under consideration, ie 
generally to the. whole question at issue. 
must acknowledge too, that I have felt more 
than ordinary solicitude that the experience 
‘and the conclusions of one who has long been 
looked up to, in this country, as the father of 
civil engineers, should be duly appreciated. 
But it is not necessary, I apprehend, to resort 
to complicated cases for the purpose of examin- 
ing the points in question. If the two first 
cases which I have stated, were once distinctly 
explained and agreed upon, no difficulty would 
remain in explaining their various and multi- — 
plied applications in machinery. 
Although these cases comprehend much of 
what relates, in this question, to rotatory mo- 
tion, the three following cases apply more 
particularly to that branch of the subject. 
In rotatory motion, it is universally admitted, 
that four times the force is necessary to generate 
the same angular velocity, or twice the abso- 
lute velocity, in the same body placed at twice 
the distance from the centre of motion; and 
it is but reasonable to enquire why we must 
have one measure for rotatory, and another for 
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