And on this occasion I cannot but take notice, that whereas the great Argument which the Chymists are wont to employ to vilify Earth and Water, and make them be look'd upon as useless and unworthy to be reckon'd among the Principles of Mixt Bodies, is, that they are not endow'd with Specifick Properties, but only with Elementary qualities; of which they use to speak very sleightingly, as of qualities contemptible and unactive: I see no sufficient Reason for this Practice of the Chymists: For 'tis confess'd that Heat is an Elementary Quality, and yet that an almost innumerable company of considerable Things are perform'd by Heat, is manifest to them that duly consider the various _Phaenomena_ wherein it intervenes as a principall Actor; and none ought less to ignore or distrust this Truth then a Chymist. Since almost all the operations and Productions of his Art are performed chiefly by the means of Heat. And as for Cold it self, upon whose account they so despise the Earth and Water, if they please to read in the Voyages of our English and Dutch Navigators in _Nova Zembla_ and other Northern Regions what stupendious Things may be effected by Cold, they would not perhaps think it so despicable. And not to repeat what I lately recited to You out of _Paracelsus_ himself, who by the help of an intense Cold teaches to separate the Quintessence of Wine; I will only now observe to You, that the Conservation of the Texture of many Bodies both animate and inanimate do's so much depend upon the convenient motion both of their own Fluid and Looser Parts, and of the ambient Bodies, whether Air, Water, &c. that not only in humane Bodies we see that the immoderate or unseasonable coldness of the Air (especially when it finds such Bodies overheated) do's very frequently discompose the _Oeconomie_ of them, and occasion variety of Diseases; but in the solid and durable Body of Iron it self, in which one would not expect that suddain Cold should produce any notable change, it may have so great an operation, that if you take a Wire, or other slender piece of steel, and having brought it in the fire to a white heat, You suffer it afterwards to cool leasurely in the Air, it will when it is cold be much of the same hardnesse it was of before: Whereas if as soon as You remove it from the fire, you plunge it into cold water, it will upon the sudden Refrigeration acquire a very much greater hardness then it had before; Nay, and will become manifestly brittle. And that you may not impute this to any peculiar Quality in the Water, or other Liquor, or Unctuous matter, wherein such heated steel is wont to be quenched that it may be temper'd; I know a very skillful Tradesman, that divers times hardens steel by