( ) 
Body communicates its Motion to the Clay round abouti 
and therefore does not ftrike in fo deep as the fwifcer 
Body, which puts in Motion few Parts of the Clay, be- 
fides thofe that are before it, and which Parts have fo 
much lefs Time to oppofe this Body’s Motion, as its 
Velocity is greater than the other’s. To make this 
plainer. Let us fuppofe a Door half open, and moving 
very freely on its Hinges ^ if aPiftol be fir’d againfi it, 
the Ball will go thro* the Door without moving it out 
of its Place*, but if we take a large Weight of Lead, 
and throw it againft the fame Door, with the fame 
Force as the Pifiol Bullet mov’d, the Door will be re- 
mov’d from its Pofition, and carried out of the Place 
on its Hinges by the Stroke •, becaufc in the firft Cafe, 
the Motion of the Ball is communicated but to a few 
Parts of the Door, and in the laft it is diffus’d all 
over it. Nay, the Door will be mov’d by the Stroke, 
even tho’ there flaould be a prominent Part in the Lead, 
that fiiould be no bigger than a Piftol- Bullet, in order 
to ftrike the Door upon no more of its Surface, than 
the Bullet had done. 
For illujirating this farther I contriv'd the following 
Experiment, 
I caus’d a Machine to be made, as reprefented inP/.I. 
Fig, I. confifting of a Bafe of Wood AB, which could 
be fet horizontal by means of three Screws, fuch as 
SS : Upon this Board, or Bafe, there ftood upright two 
parallel Boards, about four Inches wide, and four In- 
ches afunder, with the Elbow-piece E F Aiding behind 
one of them, fo as to raife its upper End F to any 
Height defired. Between thefe Boards, fquare Frames 
of Wood GG &c, with Paper extended upon them, 
could Aide in, to the Number of Six, in an horizontal 
! Z z 2 Pofition, 
