C 2C09 ) 
ftrument, but Motion $ whofe Nature therefore and Laws 
he inveftigateth, -zz/z). 
1. Two Equal Bodies, moved with e^ual celerity, if they 
meet one another^wil! refled", without loofing any thing of 
their celerity* 
2. Two Equal Bodies, moved with w«e^«^/ celerity, if 
they meet one another^that which mo veth more flowly^ can 
give nothing of its celerity to the other. 
3. Neither can thatjwhichmoveth with greater celerity^ 
communicate its whole motion to the other. 
4. If two Equal Eocjies, moved with umqual celerity, 
meet one another^they will refleft , and the motion which 
the Body,thatmoveth more fwiftly^ communicateth to the 
lefsfwiftjiliall be to its whole motion, as celerity is to ce- 
lerity. 
f . If there be two Equal Bodies, whereof the one mo« 
vethinfinitelyfwifter^ after their mutual encounter, that 
which moved more fwiftly^fhall be quiefcexit^ by communi- 
eating all its motion to the other. 
6. Iftwo Bodies be «^^e^^/z^/^and the leflerdoraoveinthat 
proportion, wherein the other exceeds it inbignefs , they 
lhall refledt after the encounter^ fo as to loofe no degree of 
celerity. 
7* If two Bodies be to one another in any Proportion 
given^but the lelftr move iofinitely fwifter ^ if the other be 
quiefctntjit iliall impell it^how big (bever it be. 
8. If there be a proportion of Equality^ the moved Body 
will be quiefcent by communicatiog its whole motion to the 
other. 
9. But if that which is movedjbe lefTer^it will be refieded 
loofing a part of its celerity^ which it will impart to the o* 
then 
icBut if it be greater/it will move the fame way, loofing 
alfo a part of its celerityj which the other will receive* 
