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Mechanics.

Will be found in A, as manifest the Falsity of this Hy-pothesis.

ix. Being driven from this Subterfuge, t’ .y seekanother in a critical Distinction between Force and Pres-sure. Pressure, fay they, is the Power with which Bo-dies act by Means of Instruments ; thus a Weight inOne Scale acts against the Weight in another by Pres-sure ; but the Power by which Bodies act on each otheralone, is properly called Force, as when one Stone strikesanother by falling on it, or a Hammer strikes an An-vil. The former they allow is proportional to the Ve-locity and Mass of Matter conjointly ; but the latter,they fay, is as the Mass multiplied by the Square of theVelocity.

12. But this Eclarcissement boots them as little as theformer, if they mean a momentary Impact or Stroke,or such whose Effect is produced in a Moment of Time.For in such a Case we say, the Stroke is in Proportionto the Mass of Matter, and also to the Degree of Ve-locity, and therefore as both conjointly ; but we denythere is any other Source of Power from whence a Bo-dy can derive any Force for producing a momentaryEffect: Nor have any of those Gentlemen been able toshew there is, though some (bewildered in the Laby-rinth) have attempted it; but in how weak and ridicu-lous a Manner may be seen in a Piece intituled De Con-ser-vatlone Virium vivarum, Scc. And it is worth theReader’s while to fee the jocular Confutation of thisludicrous Piece by Phileleutheris Londinenfis.

13. If they fay, they would not be understood ofmomentaneous Effects, but such as are produced inTime, then they have no Antagonists. And it is plainfrom their Experiments, that this is their Meaning afterall. For the Experiments which they so much insiston, are such as are made by letting Bodies fall on softSubstances, as Clay, Butter, &c. or by the Action ofBodies on yielding Springs, or springy Bodies ; in allwhich Cafes, the Effect is not produced instantaneously,but in Time ; the Clay takes Time to recede, theSpring to bend, £sV.

14. If the Time be taken into Consideration, thenfcvcry Body must know that the Effect will be propor-tional