Chapter IX: Madam,

In my former, when I related your _Authors_ opinion, concerning Earthquakes, I forgot to tell you, that he counts the Doctrine of the Schools absurd, when they say that Air, or any Exhalation, is the cause of them: For, says he, _There is no place in the Pavements or soils of the Earth, wherein any airy body may be entertained, whether that body be a wind, or an airy exhalation._ But since I promised I would not offer to appoint or assign any natural causes of Earthquakes, I have only taken occasion hence to enquire, whether it may not be probably affirmed, that there is air in the bowels of the Earth: And to my reason it seems very probable; I mean not this Exterior air, flowing about the circumference of the Earth we inhabite; but such an airy matter as is pure, refined, and subtil, there being great difference in the Elements, as well as in all other sorts of Creatures; for what difference is there not between the natural heat of an animal, and the natural heat of the Sun? and what difference is there not between the natural moisture of an Animal, and the natural moisture of Water? And so for the Purity of Air, Dryness of Earth, and the like: Nay, there is great difference also in the production of those Effects: As for example; the heat of the Earth is not produced from the Sun, nor the natural heat in Animals, nor the natural heat in Vegetables; for if it were so, then all Creatures in one Region or place of the Earth would be of one temper. As for example: Poppy, Night-shade, Lettuce, Thyme, Sage, Parsly, &c. would be all of one temper and degree, growing all in one Garden, and upon one patch of Ground, whereon the Sun equally casts his beams, when as yet they are all different in their natural tempers and degrees. And so certainly there is Air, Fire, and Water, in the bowels of the Earth, which were never made by the Sun, the Sea, and this Exterior elemental Air. Wherefore those, in my opinion, are in gross Errors, who imagine that these Interior Effects in the Earth are produced from the mentioned Exterior Elements, or from some other forreign and external Causes; for an external cause can onely produce an external effect, or be an occasion to the production of such or such an effect, but not be the immediate efficient or essential cause of an interior natural effect in another Creature, unless the Interior natures of different Creatures have such an active power and influence upon each other, as to work interiously at a distance, such effects as are proper and essential to their Natures, which is improbable; for though their natures and dispositions may mutually agree and sympathize, yet their powers cannot work upon their Interior Natures so, as to produce internal natural effects and proprieties in them. The truth is, it cannot be; for as the Cause is, so is the Effect; and if the Cause be an exterior Cause, the Effect must prove so too: As for example; the heat of the Sun, and the heat of the Earth, although they may both agree, yet one is not the cause of the other; for the Suns heat cannot pierce into the bowels of the Earth, neither can the heat of the Earth ascend so far as to the Center of the Sun: As for the heat of the Earth, it is certain enough, and needs no proof; but as for the heat of the Sun, our senses will sufficiently inform us, that although his beams are shot forth in direct lines upon the face of the Earth, yet they have not so much force, as to pierce into a low Celler or Vault; Wherefore it is not probable, that the Earth hath its natural heat from the Sun, and so neither its dryness from the Air, nor its moisture from the Sea, but these interior effects in the Earth proceed from some other interior causes. And thus there may be great difference between the heat, cold, moisture, and drought which is in the Elements, and between those which are in Vegetables, Minerals, and Animals, not onely in their General kinds, but also in their Particulars: And not onely a difference in the aforesaid qualities of heat, cold, moisture, and drought, but also in all other motions, as Dilations, Contractions, Rarefactions, Densations, &c. nay, in their Mixtures and Temperaments: As for example; the temper of a Mineral is not the temper of an Animal, or of a Vegetable, neither is the temper of these the temper of the exterior Elements, no more then the temper of the Elements is the temper of them; for every Creature has a temper natural and peculiar to it self, nay, every particular Creature, has not onely different tempers, compositions, or mixtures, but also different productions; or else, if there were no difference in their productions, every Creature would be alike, when as yet there are seldom two that do exactly resemble each other. But I desire you to understand me well, _Madam_, when I speak of Particular heats, colds, droughts, and moistures; for I do not believe that all Creatures are made out of the four Elements, no more, then that the Elements are produced from other Creatures, for the Matter of all Creatures is but one and the same; but although the Matter is the same, nevertheless, the Tempers, compositions, Productions, Motions, &c. of particular Creatures, may be different, which is the cause of their different exterior figures, or shapes, as also of their different Interiour Natures, Qualities, Properties, and the like. And so, to conclude, there is no impossibility or absurdity in affirming, that there may be Air, Fire, and Water, in the bowels of the Earth proper for those Creatures, which are in her, although not such an Elemental Air, Fire and Water, as is subject here to our senses; but another kind of Air, Fire and Water, different from those. But this being a subject for Learned and Ingenious men to work and contemplate upon, better, perhaps, then I can do, I will leave it to them, and so remain,

Madam,

_Your constant Friend,_

_and faithful Servant._