( 288 ) . 
Pofition. Thefe Paper Diaphragms being thus plac’d, 
I fufpended an Ivory Ball of about one Inch and an half 
Diameter, weighing fomething more than an Ounce 
and an half, by a fhort Thread, under F, fo that its 
Center of Gravity hung four foot over the firft Dia- 
phragm^ then cutting the Thread, the Ball fell upon the 
Paper, and by its perpendicular Stroke broke thro’ that 
Diaphragm, and the three next under it. Then put- 
ting fo much Lead into the Ball abovemention’d, (which 
was made hollow for that Purpofe) as to make it weigh 
twice as much as it did before ^ and bringing down F, 
to let it fall but from one foot, it broke thro’ only two 
Diaphragms by its Fall. Making the Experiment fe- 
veral times with different Heights, but flill keeping the 
Proportion in Height of four to one, when the Balls 
were as one and two, the heavy and floweft Ball broke 
thro’ but half the Number of Papers. It happen’d 
indeed fometimes, that there was fome little difference, 
when the Papers were not equally flrong, or equally 
flretch’d, but the fwiftefl: Ball always broke through 
more Papers than the flow one. 
Now tho’ this Experiment does at firft feem to con- 
firm Potenus'^ Theory , yet, when duly weigh’d, it 
proves no fuch thing. For the lighter Ball does not 
break thro’ more Papers, becaufe it has more Force, or 
a greater Qu^antity of Motion, but becaufe each Dia- 
phragm has but half the time to refill the Ball, that 
falls with a double Velocity, and therefore their Refi- 
nance being as the time, as many more of them muft 
be broken by the fwift Ball, as by the flow one. 
P. S. To all the Objeftors, that allow the Force of 
moving Bodies, and their Cluantity of Motion to be the 
fame, what has been faid in this and my former Pa- 
per, feems to be a full Anfwer^ but as there are now 
fome Philofophers, who diftinguiflithat Force from the 
Qiiantity 
