( ) 
tively affirm, that he bought the Small Pox when at 
School, and of Inch a Lady, now living, and gave her 
three Pence for the Matter contained in ix Puftules. 
That hundreds in this Country have had the Small 
Pox this way is certain ; and it cannot produce one 
fingle Inftance of their ever having them a lecond 
time. 
Haver ford Wef^ 
Feb. 15*. 171^. 
(^chard Wright, 
IX. An Account of fome Experiments made to prove y 
that the Force of Moving ^Bodies is proportionable 
to their Velocities: {or rather that the Momen- 
tum of' Moving Bodies is to he found by muU 
tiplying the Majfes into the Velocities) In Anfwer 
to Juch ioho have Jometime ago affirm dy that that 
Force is proportionable to the Sepiare of the Velo- 
city ^ and to thofe who Jiill defend the fame Opimon. 
By the BeVerend]ohn Theophilus Defaguliers, 
LL,V,F,^S, 
A S far as I can learn, Monfieur Leibnitz was the 
firft that oppos’d the receiv’d Opinion, con- 
cerning the Quantity of the Force of moving Bodies ; 
by faying, that it was to be eflimated by multiplying 
the Mafs of the Bodies, not by their Velocity, but by 
the Square of it. But, infteadof Ihewing any Para- 
logifm, in the mathematical Demonftrations, which 
U arc 
