SR = 
PHYSICAL anv LITERARY. 65 
ferent forces of the fame body moving with 
different velocities. 
Jy being thus afcertained, that the force of 
- abody moving by the vis infita is always in 
proportion to its velocity; we have reafon to 
conclude, from analogy, that the fame rule 
holds where bodies move by the force of gra- 
vity. And accordingly this is alfo made evi- 
dent from a courfe of unexceptionable expe- 
riments. 
Tue German philofophers, in their experi- 
ments, have been mifled, by afcribing to the 
force of the moving body, effects which ob- 
vioufly refult from other caufes. Not to 
lengthen out this paper too much, 'I fhall fa- 
tisfy myfelf with giving an inftance or two. 
Itis a fact agreed upon, that a pendulum 
{wung upwards with a double velocity, will 
reach a quadruple height. . Hence it is. in- 
ferred by Leibnitz, and his followers, that 
the forces muft be as the {quares of the velo- 
_ eities; feeing the effects produced by the dif- 
ferent forces, viz. the {paces gone through, 
are as the fquares of the volocities. And 
could it be juftly maintained, that the fpace 
_ fun through is purely the effect of the mo- 
ebb or force, with which the body is 
_ thrown upwards, ‘the argument would be 
0) J con- 
