[ 4 ] 
Power 
.. t F 
••AVI 
A + 
3« — A 
4 A 
a X 3 a * — b 
4 A 1 
and if 
the Brachia are equal, i. e. if a — the weight : 
power :: y /7 — | : i, viz. 0,618 : i nearly when 
the effect is a maximum. And fo, in like manner, 
when by m and n are given, and a is made variable, 
it is eafy to fee that, indead of the load, the bed 
didance of the power from the fulcrum of the lever 
will be the refult of the procefs ; viz. a : b :: n -\- 
s/ r? -j- m n : m. But, this by the way. 
In the proportion here determined, the power m 
is a weight, and therefore ma — nb, which is the 
generating force, being partly employed to overcome 
the Inertia of the quantity of matter m, it is not 
wholly taken up in giving motion to the weight n 3 
and the relative velocity is continually decreafing. 
But, on the other hand, if m be the force of a fpring, 
as is that of our atmofphere, or if n can be uni- 
formly accelerated any how, in repeated vibrations, 
that there may be no fenfible diminution of the rela- 
tive velocity, the whole will be exerted on the 
weight to be raifed ; /. e. the tenlion of the rope or 
chain, by which the power is confined to a£t on the 
weight, will always be the fame as tho’ the Beam 
were at reftj and then, by expunging ma 1 out of 
the expreflion for the greated effe<d, n J 
becomes evidently enlarged to n J 
ma — nb 
111a — nb 
ma 2 - -f- n A“ 
The 
confequences are thefe. id, The greated efife<d of 
this engine when m is a fpring, will always exceed 
the cotemporary efFedt where m is a weight. 2dly, 
The proportion of the Power and weight will then 
be 
