I come now to consider the Terrestrial Bodies; I shall say nothing of the whole Body of the Earth in general, because I reserve that as one of the Particulars I shall more carefully and curiously examine.
Terrestrial Bodies according to our Method before propounded are either inanimate or animate, and the inanimate either simple or mixt: Simple, as the four Elements, Fire, Water, Earth, and Air; I call these Elements in compliance (as I said before) with the vulgarly received Opinion; not that I think them to be the Principles or component Ingredients of all other sublunary Bodies: I might call them the four great Aggregates of Bodies of the same Species, or four sorts of Bodies of which there are great Aggregates. These notwithstanding they are endued with contrary Qualities, and are continually encroaching one upon another, yet they are so balanced and kept in such an aequilibrium, that neither prevaileth over other, but what one gets in one place it loseth in another.
First, Fire cherisheth and reviveth by its Heat, without which all things would be torpid and without Motion, nay without Fire no Life; it being the vital Flame residing in the Blood that keeps the bodily Machine in motion, and renders it a fit Organ for the Soul to work by. The Uses of Fire (I do not here speak of the Peripateticks Elementary Fire in the concave of the Moon, which is but a mere Figment, but our ordinary Culinary) are in a manner infinite for dressing and preparing of Victuals baked, boyled and roast; for melting and refining of Metals and Minerals; for the fusion of Glass, a Material whose Uses are so many that it is not easie to enumerate them, it serving us to make Windows for our Houses, drinking Vessels, Vessels to contain and preserve all sorts of fermented Liquors, destilled Waters, Spirits, Oils, Extracts, and other Chymical Preparations, as also Vessels to destil and prepare them in; for Looking Glasses, Spectacles, Microscopes and Telescopes, whereby our Sight is not only relieved, but wonderfully assisted to make rare Discoveries: For making all sorts of Instruments for Husbandry, mechanick Arts and Trades, all sorts of Arms or Weapons of War defensive and offensive; for fulminating Engines; for burning of Lime, baking of Bricks, Tiles, and all sorts of Potters Vessels or earthen Ware; for casting and forging metalline Vessels and Utensils; for Destillations, and all Chymical Operations hinted before in the use of Glass. For affording us Light for any Work or Exercise in winter Nights; for digging in Mines and dark Carvens: And finally by its comfortable Warmth securing us from the injuries of Cold, or relieving when we have been bitten and benummed with it. A Subject or Utensil of so various and inexplicable use, who could have invented and formed, but an infinitely wise and powerful Efficient?
Secondly, The Air serves us and all Animals to breath in, containing the fewel of that vital Flame we spake of, without which it would speedily languish and go out. So necessary is it for us and other Land-Animals, that without the use of it we could live but very few minutes: Nay Fishes and other Water-Animals cannot abide without the use of it: For if you put Fish into a Vessel of a narrow mouth full of Water, they will live and swim there not only days and months but even years. But if with your Hand or any other cover you stop the Vessel so as wholly to exclude the Air, or interrupt its communication with the Water, they will suddenly be suffocated; as Rondeletius affirms he often experimented: If you fill not the Vessel up to the top, but leave some space empty for the Air to take up, and then clap your hand upon the mouth of the Vessel; the Fishes will presently contend which shall get uppermost in the Water, that so they may enjoy the open Air; which I have also observed them to do in a Pool of Water that hath been almost dry in the Summer-time because the Air that insinuated itself into the Water did not suffice them for Respiration. Neither is it less necessary for Insects than it is for other Animals but rather more, these having more Air-vessels for their Bulk by far than they, there being many Orifices on each side their Bodies for the admission of Air, which if you stop with Oil or Hony, the Insect presently dies, and revives no more. This was an Observation of the Ancients, though the reason of it they did not understand (Oleo illito Insecta omnia exanimantur. Plin.) which was nothing but the intercluding of the Air; for though you put Oil upon them, if you put it not upon or obstruct those Orifices therewith whereby they draw the Air, they suffer nothing: If you obstruct only some and not others, the parts which are near and supplied with Air from thence are by and by convulsed and shortly relaxed and deprived of Motion, the rest that were untoucht still retaining it. Nay more than all this, Plants themselves have a kind of respiration, being furnished with plenty of Vessels for the derivation of Air to all their parts, as hath been observed, nay first discovered by that great and curious Naturalist Malpighius. Another use of the Air is to sustain the flight of Birds and Insects. Moreover by its gravity it raises the Water in Pumps, Siphons and other Engines, and performs all those feats which former Philosophers through Ignorance of the Efficient Cause attributed to a Final, namely Natures abhorrence of a Vacuity or empty space. The Elastick or expansive faculty of the Air, whereby it dilates itself, when compressed (indeed this lower Region of it by reason of the weight of the superincumbent is always in a compressed State) hath been made use of in the common Weather-glasses, in Wind guns, and in several ingenious Waterworks, and doubtless hath a great Interest in many natural Effects and Operations.