of the soul considered.

XVII. Let us once more resume the ex-ample of a watch, or clock, that we maysee what is here asserted to be true, reallyeffected in a parrallel cafe. The immaterialimpulse of gravity or elasticity is the power:The constant action of this power is neces-sary to make the machine go. It is there-fore properly th e mover-, or, if we might sofay analogically, the living principle and soulof the engine. Yet the due configurationand disposition of the parts is also necessary:and, supposing that to be perfect in all theseveral pieces j it is still farther necessary,that there be no accidental impediments ;not only nothing wanting that should be there jbut nothing present that should not be there.And how many thousand ways may some-thing of this kind happen ? Or, how con-temptible a thing may prove the impediment,even in such rude mechanism ? a grain ofsand, the smallest hair. It is farther no lessnecessary that the machine be kept dry, andthe whole refreshed, (to speak still in theterms of an animal body) by winding up,once perhaps every four and twenty hours.These several things are all necestary, thatVol. I, E e there