Chaf.IL PHILOSOPHY.

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which it sails, it shall have the very fame velocity, as it had inthe same place, when it ascended; and consequently shall comedown into the place, whence it first ascended, with the veloci-ty which was at first given to it. Thus if a body were thrownperpendicularly up in the line AB (infig. 11.) with such aforce, as that it should stop at the point B, and there beginto fall again ; when it shall have arrived in its descent to anypoint as C in this line, it shall there have the same velocity,as that wherewith it passed by this point C in its ascent; andat the point A it shall have gained as great a velocity, asthat wherewith it was first thrown upwards. As this is de-monstrated by the geometrical writers; so, I think, it willappear evident, by considering only, that while the body de-scends, the power of gravity must act over again, in an invert-ed order, all the influence it had on the body in its assent;so as to give again to the body the fame degrees of velocity,which it had taken away before.

2.2.. After the fame manner, if the body were thrownupwards in the oblique straight line CA (in fig. p.) from thepoint C, with such a degree os velocity as just to reach thepoint A; it shall by its own weight return again through theline A C by the fame degrees, as it assended.

2.Z. And lastly, if a body were thrown with any velocityin a line continually incurvated upwards, the like effect willbe produced upon its return to the point, whence it wasthrown. Suppose for instance, the body A (infig. 12 ..) werehung by a string A B. Then is this body be impelled any

I % way,