( 67 ) 
POST-SCR IPX 
A Bout a Week after I bad fent you the Letter* 
containing my Obfervations on Poknus's Experi- 
ment, I had the good Fortune to hear an excellent and 
learned Friend of yours, to whom you had been 
plealed to fliew my Letter, give a very curious and 
weighty Argument to confirm Sir Ifaac Nemoris. Senti- 
ment in relation to the Refinance of Fluids, which I 
had deduced from the above mentioned Experiment ; 
and as this very much pleafed me, 1 lliall here endea- 
vour to fend you an Account of it in the following 
manner .* - 
Suppofe pieces of fine Silk, or the like thin Sub- 
dance, extended in Parallel Planes, and fixt at fmall 
Didances from each other. Suppofe then a Globe to 
drike perpendicularly againd the middle of the outer- 
mod of the Silks, and by breaking through them to 
lofe part of its Motion. If the pieces of Silk be of 
equal Strength, the fame Degree of force will be re^ 
quired to break each of them ; but the Time, in which 
each piece of Silk refids, will be fo much fliorter as 
the Globe is fwifter ; and the lofs of Motion in the 
Globe confequent upon its breaking through each Silk, 
and furmounting the Refidance thereof, will be pro- 
portional to the Time, in which the Silk eppofes it- 
felf to the Globe’s Motion ; infomuch that the Globe 
by the Refidance of any one piece of Silk will lofe 
fo much lefs of its Motion as it is fwifter. But on the 
other Hand, by how much fwifter the Globe moves, 
Ox fo 
