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Degree of Velocity in a perpendicular Diredion, before 
its force is entirely fpent, provided you take care to 
alter the Diredions of the Motion in every Stroke 
but the lad, after -a certain manner: That had the 
fame Body moved but with one degree of Velocity in 
one Diredion, and that in a perpendicular one, it 
would have loll all its force at once, and bent but 
one of thofe Springs : Which is far trom proving the 
thing in Queftion. 
3. To make the Reafoning on this Head conclufive, 
the two Bodies ihould not only be equal in Quantity of 
Matter, but alike in that material Circumflance the 
Diredion of their Motions; fo that if one of the Bodies 
move in a perpendicular Diredion, the other ihould 
do fo too ; or if the one ftrikes in an oblique Dire- 
dion, the other fliould do the fame, and that in the 
fame degree of Obliquity; and laftly, if one moves 
in feveralDiredions, the other fhould do the fame. 
But in the cafe before us one is fuppofed to move but 
in one Diredion perpendicularly, and the other to 
move in three oblique Diredions, and but one perpen- 
dicular. 
4. Let therefore the fame Body move always in 
the fame Diredions, and with a fmall Alteration, the 
Argument ufed in this Demonftration will be fo far 
from proving that fide only of the Queftion for which 
it was brought, that it will equally ferve to prove the 
truth of the other, namely, that the Forces of the 
fame Body moving with different Velocities are as 
thofe Velocities. 
, Let therefore the fame Body, inffead of moving with 
two Degrees of Velocity, move but with one, and in 
the fame Diredions as above ; only let the Springs be 
capable of deftroying but half a Degree of Velocity 
in a perpendicular Diredion ; then by the fame flcps 
