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Mechanics,.

Hy the falling Body ; but this is proportional to the Ve-locity on two Accounts ; the first is, that every Particlewhich comes in Contact with the Striking Body, re-ceives a Stroke proportional to the Velocity, thereforealso the Number of Particles which each of these canmove, will be as the Force of the Stroke, or as the Ve-locity of the falling Body. Secondly, among yieldingParticles, the Number which the falling Body can applyto in a given Time, will be as the Velocity ; consequent-ly the whole Number of Particles which can be moved,both immediately by the Body itself, and bv the Motioncommunicated to the Particles, will be as the Square ofthe Velocity ; and therefore the Cavity will be in thefame Ratio also.

23. We hence observe, the fame Method of Reason-ing may be applied to soft and yielding Substances, ashas always been used in the Cafe of unelastic Fluids ;and for this Reason only, that in every Cafe of yieldingParticles, the Effect of a Body in striking them is notdestroyed momentaneously, but in Time, which Time(cater is paribus) will be as the Velocity ; and thereforeE being as T V, and T, in all these Cafes, being asV, it will be universally for all soft and yielding Sub-stances E : V \

24. 'Hence we may observe that as Bodies are more orless yielding or soft, so the Effect will be more or lessapproaching to the Ratio of the Square of the Velocity.This Consideration is of great Use in mechanical A stairs.Thus a Hammer with a double Velocity will producemuch more than a double Effect in driving a Na 1 ; the(ame may be said of a Rammer driving a Pile : Hencethe Reason why a small Hammer will by its Velocity domore Execution upon red hot Iron, than the large Ham-mer by its Momentum. In short, all these Things areso plain, and easy to be understood, that it is surprizingto think how such a Dispute could subsist so long, andoccasion so much to be said about it.

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