108 of the Newtonian system,

About the year 1666 , or the twenty-fourthyear of his age, he retired from Cambridgeinto the country, in order to avoid the plague,which, at that time, raged with great violence zand sitting one day in an orchard, under a tree,an apple, by chance, falling upon his head,caused him to enter into a number of reflections.The phænomena of falling bodies particularlyengaged his attention; and pursuing the ideaswhich presented themselves to his mind, he car-ried his researches from the earth to the heavens,and began to investigate the nature of motionin general. Because there is motion, said he,there must be a force which produces it; butwhat is this force ? That a body, when left toitself, will fall to the ground, is known to themost illiterate ; but if you alk them the reasonof its doing so, they will think you either a foolor a madman : the circumstance is too commonto excite their admiration, although philosophersare so much embarrassed with it, that they findit almost inexplicable.

Let us follow Newton, and examine this ques-tion a little. Does the cause of weight or gra-vity exist in the bodies themselves, or out ofthem ? It seems natural to conclude, that thepropensity which all suspended bodies have offalling to the earth, exists in the bodies them-selves. When I take a stone, and let it dropfrom my hand, it falls immediately to the

ground j