Sec. 45.  And it was evident to him, that the Essences of those sensible Bodies, which are in this sublunary World, had some of them more Qualities superadded to their Corporeity, and others, fewer.  Now he knew that the Understanding of the fewer, must needs be more easie to him, than the Understanding of those which were more in number.  And therefore, he endeavour’d to get a true Notion of the Form of some one thing, whose Essence was the most simple and uncompounded.  Now he perceiv’d that the Essence of Animals and Plants consisted of a great many Properties, because of the great variety of their Operations; for which reason, he deferr’d the enquiring into their Forms.  As for the Parts of the Earth, he saw that some of them were more simple than others, and therefore resolv’d to begin his Enquiry with the most simple of all.  So he perceiv’d that Water, was a thing, whose Essence was not compounded of many Qualities, which appear’d from the Paucity of those Actions which arise from its Form.  The same he likewise observ’d in the Fire, and Air.

Sec. 46.  Now he had a Notion before, that all these four might be chang’d one into another; and therefore there must be some one thing which they jointly participated of, and that this thing was Corporeity.  Now ’twas necessary, that this one thing which was common them all, should be altogether free from those Qualities, by which these four were distinguish’d one from the other; and be neither heavy nor light; hot nor cold; moist nor dry; because none of these Qualities were common to all Bodies, and therefore could not appertain to Body as such.  And that if it were possible to find any such Body, in which there was no other Form superadded to Corporeity, it would have none, of these Qualities, nor indeed any other but what were common to all Bodies, with what Form soever endu’d.  He consider’d therefore with himself, to see if he could find any one Adjunct or Property which was common to all Bodies, both animate and inanimate; but he found nothing of that Nature, but only the Notion of Extension, and that he perceiv’d was common to all Bodies, viz.  That they had all of them length, breadth, and thickness.  Whence he gather’d, that this Property belong’d to Body, as Body.  However, his Sense could not represent to him any Body existent in Nature, which had this only Adjunct, and was void of all other Forms:  For he saw that every one of them had some other Quality superadded to the said Extension.