inaBvoity o/Matter, &c. 165

and manner of operation had been betterknown before now (r). If then we considerthe quantity of matter to be moved by theforce impressed on this first part alone (noother force concurring by the supposition)which is often more than double the matterof the whole body, in cafes where a foreignweight is also to be moved, and that thispart which receives the whole impression is sominute and subtil; it follows that the quan-tity of matter in it bears scarce any propor-tion to that of the matter to be moved by it;and if we should suppose (which is the onlything to be supposed, to render the effect pos-sible) that their quantities of matter and ve-locities were reciprocally proportional (that is,that it as much exceeded the matter to bemoved in velocity, as it is less in quantity) torender their forces but barely equal; then itfollows that the velocity of this part wouldbe so inconceivably great, that it would pet-s' ! J Fateor me nonpercipere mechanicam operatianem, quatnotus Jpirituum in cerebra imperio valuntatis agitati, eosdirigont ad titillandos certos et determinatos muscuhs , Kf,ft velim manum extendere, fpiritus dirigantur nan ad nsr-‘vos pedum, aut thoracis , fed ferantur ad ess qui ad ma-ms pertingunt , tit eos titillent . At ft lalbutiends aliquidloqui vslimus , puts, &c. Ibid. Prop. 25.

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