to Of Simple Motion.

in the moving Bodies, and their Ce-lerities conjointly.

Let D ( = B) be moved with c,the Celerity of b y and let F y be it’sMomentum ; then (by Law zd.) be-cause c~e. D : b :: F: m. whenceD x m — b x F y and (by Law 4th.)because D == B. C : c : : M : F.whence C x F — c x M. and put-ting B in the Place of D y in the firstEquation, and multiplying it by thelast, you have B x 6 x m x F—b x cx Mx F y and dividing both Sides byF y the Equation is B xfx m — bx exwhich gives this Analogy M : m ::BxCibxc. %E.D.\

LA W VI.

C: ci’bx M: B xm. that is , The !Ratio of the Celerities is composed |of the direct Ratio of the Momenta, !and the inverse Ratio of the Quanti-ties of Matter. By j