Reo 7 On the Measure of 4 RE ene 
and velocity to A, the ends of the spring will 
not be brought to meet by the action of the — 
balls. In that case, when the balls are at rest, 
the distance between the ends of the spring 
will be to C D, as 1.1 to 6 nearly. 
7. Ifanon-elastic mass, A, (fig. 7.) moving 
with a given velocity, strike an equal non- 
elastic mass, B, at rest in free space; both 
balls will move on together, with half the 
velocity of A. Upon the principle of the 
moving forces being as the quantities of mo- 
tion, and the quantities of motion as the masses 
into their velocities ; it is held that the moving 
force of A is equal to that of Aand B, moving 
together with half the original velocity of A. 
If the ball B, have a spring attached to 
it, furnished with a toothed catch C, to retain 
the spring in the form to which it may be 
compressed ; it will then represent a perfectly 
non-elastic body. Let A strike the spring and 
compress it to E, and let A and B move on 
together, with half the original velocity of A. 
Let the spring be then removed in its com- 
pressed state, and placed between two other 
balls, C and D, equal in their masses to A and 
B, and at rest in free space; let the catch C, 
be then disengaged ; the spring will resume its 
original shape, and the balls, C and D, will 
: each move off with half the original velocity 
