Sec. 39. Then considering with himself, what that common thing must be, in which the _Sameness_ of the Animals and Plants did consist he saw that it must be some _Body_, like those Bodies, which had a Threefold Dimension, _viz_, Length, Breadth, and Thickness; and that whether it were Hot or Cold, it was like One of those other Bodies which have neither Sense nor Nutrition, and differ'd from them only in those Operations which arise from the Organical parts of Plants and Animals. And that, in, all likelihood, those Operations were not Essential, but deriv'd from something else. So that if those Operations were to be communicated to those other Bodies, they would be like this. Considering it therefore abstractedly, with regard to its Essence only, as stript of those Operations, which at first sight seem'd to flow from it, he perceiv'd that it was a _Body_, of the same kind, with those other Bodies; upon which Contemplation, it appear'd to him that all Bodies, as well those that had Life, as those that had not, as well those that mov'd, as those that rested in their Natural places were _One_; Only there were some Actions in some of them, which proceeded from their Organical Parts; concerning which Actions he could not yet determine whether they were Essential, or deriv'd from something without. Thus he continu'd, considering nothing but the Nature of Bodies, and by this means he perceiv'd, that whereas at first sight, _Things_ had appear'd to him innumerable and not to be comprehended; _Now,_ he discovered the whole Mass and Bulk of Creatures were in Reality only _One_. Sec. 40. He continu'd in this Opinion a considerable time. Then he consider'd all sorts of Bodies, both Animate and Inanimate, which one while seem'd to him to be _One_; and another, _a great many_. And he found that all of them had a Tendency either upward, as Smoak, Flame, and Air, when detain'd under Water; or else downward, as Water, pieces of Earth, or Parts of Animals and Plants; and that none of these. Bodies were free from one or other of these Tendencies, or would ever lye still, unless hinder'd by some other Body, and interrupted in their course; as when, for instance, a Stone in its fall is stopp'd by the solidity and hardness of the Earth, when 'tis plain it would otherwise continue still descending; so Smoak still continues going upwards, and if it should be intercepted by a solid Arch, it would divide both to the right and left, and so soon as it was freed from the Arch, would still continue ascending; and pass through the Air, which is not solid enough to restrain it. So when a Leathern Bottle is fill'd with Air and stopp'd up close, if you hold it under Water; it will still strive to get up, till it returns to its place of Air; and then it rests, and its reluctancy and propensity to ascend, ceases.