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* 1.1Though Gun-powder be a Body so inflamma∣ble, yet it evidently imparts a Coldness, if mixed with Water. If a small quantity of Oil of Vi∣triol be mixed with the Salt formerly made use of, before the Oil hath been mixed with Water, it acquires a considerable degree of Coldness.
* 1.2Potential Coldness is usually looked upon to be a Quality so absolute, as not to be explicable without the Doctrine of Substantial Forms: But it will easily appear, That it may, without any great difficulty, be clearly explained by Me∣chanick Principles; if we consider, that the Fi∣gure, Shape and Texture of Bodies may be so contrived as to lessen the usual and natural Agi∣tation of Humors about our Sensory, and con∣sequently, the Perception of this Imminution, may cause such a Sensation as is usually term'd Potential Coldness; which account being allow∣ed, it will follow, That Potential Coldness is only a relative Quality, depending on the dispersion of the Agents through the Bodies to be cooled by them: According to which Notion, the cold Fitts in Agues may easily be conceived to arise from an Intermixture of the Parts of some clam∣my Matter, which before a Dissolution, were unable to cause any considerable Effect in the Mass of Blood; but presently after being mixed with the Blood, produce such a change in the Motion of its Parts, as affects the Sensory with such a Sensation as is usually esteemed Potential Coldness; which Sensation may not only be so produced in Agues, but by a like Cause in other Distempers, and in several Parts of the Body, as in Hypochondriack and Hysterical Cases. To render which Account more probable, I shall subjoyn, That I have learnt by the Effects of Poysons, that the small Parts of them being in∣terpersed
through the Parts of Humors previ∣ously disposed, may cause a notable Refrigeration: And I my self have prepar'd a penetrating Chy∣mical Liquor, a Drop of which being given to an Animal, would cast him into a seeming Sleep; and a little larger Quantity, being by Mischance applyed to an akeing Tooth, gave the Person a sort of trembling, and almost an universal Re∣frigeration. And that Coldness may be produ∣ced by the Mixture of some subtile Parts of Mat∣ter with the Mass of Blood, appears from the following Histories. Famulum habui (says Be∣nivenius, Cap. 56. Abditorum apud Schenk. Lib. 7. de Venen. Obs. 24.) qui a Scorpione ictus, tam subito ac tam frigido Sudore toto Corpore perfusus est, ut algentissima Nive atque Glacie sese opprimi quere∣retur, verum cum algenti illi solam Theriacam, ex Vino potentiore exhibuissem, illico curatus est. And to this I shall add another, related by A∣matus Lusitanus, Cent. 6. Obs. Vir qui a Scorpi∣one in Manus digito punctus fuit, multum dolebat, & refrigeratus totus, contremebat & per Corpus dolores, Cute tota quasi aut puncta, formicantes pa∣tiebatur, &c.
* 1.3Whether such Refrigeration depends on a sort of Coagulation of the minute Parts of the Blood, or whether it may be produced by a dif∣ferent Determination of the motion of the Parts of those Liquors as to the Lines they move in, I shall not now examine; but shall rather offer it to be considered, since the internal Constituti∣ons of several Parts of the Body are different from each other, and since the Size and Textures of seve∣ral Agents are also various, whether they may not upon that account have different Effects upon
distinct Parts of the Body, for all the Qualities of such Agents do not wholly depend on the Acti∣on of the Corpuscles of the Medicine only; but depend on some adventitious Qualities, which they acquire by being mixed with particular Hu∣mors and which they may dispose to be more or less worked upon, by the other Efficients of Heat or Cold.
And these Conjectures may not be render'd a little probable, by observing, That tho' Spirit of Wine inwardly taken causes Heat; yet exter∣nally it abates the Heat of inflamed Parts; but hath different Effects on a tender Eye: And though internally five Grains of Camphire may diffuse Heat through the whole Body, yet ex∣ternally it is used in refrigerating Medicines.
How far these Observations may be of Service in determining whether Camphire, &c. be hot or cold, I shall leave to Physicians to consider, and shall here only offer in Proof, That Potential Coldness is only a relative Quality, the follow∣ing particulars, viz. That from the VI. and VII. Experiments it appears, that according to the Dispositions of Bodies to be worked on, the Agent may have different Qualities: As Fumes of Lead may coagulate Mercury, tho' it hath not a like Effect on other Liquors: And further, al∣though Sal-Armoniack and Nitre be, when sepa∣rate, cool, and tho' the latter melted in a Cru∣cible takes not Fire of it self, yet upon an addi∣tion of Sal-Armoniack it flashes vehemently. But I shall leave this Digression, and proceed to Ex∣periments about Cold.
The effect of Gun-pow∣der mixed with Water.
Potential Coldness Mechani∣cally ex∣plained.
What Re∣frigeration depends on.