MOVING FORCE, 
93 
that any remarks, having that tendency, would ill become me. Cases of diffi- 
and could be of no avail in my argument. Anxious as I am to 
state distinctly the reasoning and the conclusions which appear to nioving force. 
me to be objectionable, I am not less anxious to state them fairly 
and respectfully. I am well aware of the disadvantages under 
which 1 labour ; the general prejudice against this subject 
being so strong, that a great national institution has absolutely 
proscribed the discussion of it*. That circumstance, however, 
enhances the value of the indulgence of which I now avail 
myself, in submitlir/ t to the consideration of this society. 
Proceeding now to the consideration of the particular cases 
which I have described, I may observe, that the first two case* 
, comprehend, I believe, the chief points at issue, as far as 
I they relate to force producing rectilinear motion by the inter- 
I vention of levers or wheels, and to motion produced about fixed 
. axles. 
That the forces of C and D, in the first case, are equal, cannot, 
I I think, be questioned ; and it is not less obvious that their 
« effect, if estimated by the masses into the squares of their 
1 velocities are also equal. 
In the second case, the force of P is twice that of Q, and 
I the effect of these forces, if measured by the masses into the 
! squares of their velocities, are respectively in the same propor- 
I tion. 
Mr. Atwood, (as we have already noticed at page 109) 
j admits, that the measure composed of the mass into the square 
t of its velocity obtains in all cases of rotatory motion about 
I fixed axes j and that the measure composed of the mass into 
I its velocity, when applied to the same cases, fails ; “ a given ’ 
I quantity of motion thus estimated, being alterable in any as- 
' signed ratio.” 
But authors on mechanics generally concur in the following 
« conclusion : that " a distinction is always to be made be- 
I tween the actions of bodies when at liberty, and when they 
t 
t Tlie Frrnch National Institute has, I nmlerstand, prohibited th* 
I reception of all dissertations *n the measure of force. 
revolve 
