An Essay to Shew the Cause of Electricity; and Why Some Things are Non-Electricable. / In Which Is Also Consider'd Its Influence in the Blasts on Human Bodies, in the Blights on Trees, in the Damps in Mines; And as It May Affect the Sensitive Plant, &c.

by John Freke

I am aware what Objection this is liable to; for, though it must be acknowleg’d that these Things are non-electricable, it may be asked, If they are not the most inflammable Things that can be imagined, and, consequently, susceptible of Fire; because Candles are made out of Wax, and Torches out of Pitch and Resin? To which I answer, That here it may be necessary to inquire, what occasions this Flame, which is produced either from the Candle or Torch? Can this Flame subsist one Moment, without the Passage of Air through it? I answer, No. Well then, as this Treatise is not intended merely to state Facts, but to account for the Nature of them, by the best Conjectures I can make, pray why does Air keep this Flame subsisting? If you will suppose, with me, that the Cause of all Heat, and the Appearance of all Fire in the World, is collected out of this universal Element of Fire; which, perhaps, will never increase nor diminish; it being dispersed where it is most invited; if therefore, I say, you will suppose with me, that this Air, which is full of a lambent Flame, when it has been invited by the Property supposed to be in it, that the biggest Body congregates the less; from these Considerations, I think it may be supposed, that the Flame of Fire is produced out of the Air, only; the Wax or Resin being a fatty sulphureous Matter, which, as Coals, may likewise be supposed to serve as a Pabulum, fitly adapted only to let this Element pass through it, for the Purposes here described.

The more of the Air that passes through them, the quicker they burn; as when the Snuff of a Candle is taken off, which hindered the Quantity to pass thro’ it, it increases the Flame; though, before, the same Materials were employ’d. The same may be said of clearing the Ashes from, and stirring the Fire; which impeded the Quantity of Air from leaving its Fire behind, in its Passage through the Coals.

If the Wax had any Inherency of Fire in its Nature, Why, if you turn a lighted Candle downwards, does the Wax extinguish the Flame? If this my Conjecture be difficultly conceiv’d, pray let me farther ask, Why does a Candle, which is lighted, and let down into a Mine where there is a Damp, go out? In a large Mine there is Space enough surely for a Candle to burn in, if there had been enough of that Pabulum Vitæ left in the stagnated Air which occupy’d that large Cavern.

Now, if you will suppose, with me, that this Air had been robb’d of its Fire, by its supporting and keeping alive such Things under-ground as its Business is to do every-where, and that Space was left full of stagnated Air, and therefore could not admit of fresh to enter, it became impossible for Fire, or any living Creature, to subsist there.

The Cure of this Evil is performed in Mines by a Horse-Mill, which works large Bellows, that drive fresh Air down a Shaft made for that Purpose.

I remember Dr. Halley told me, that he once try’d the Experiment of making a factitious Damp; which he did, by exhausting the Air out of the Receiver of an Air-Pump, and then luting to a Stop-cock a Gun-barrel; the other End of which he put into a Charcoal-Fire, and with the Air, which pass’d thro’ the Fire, he fill’d the Receiver again; he told me that it instantly kill’d a Mouse he put into it, and many other Animals, just as Damps did: Now how will you account for this, if you suppose not that its Fire was extinguish’d, and carried from it another Way?

Having thus far, I hope, prepared your Mind to understand what I apprehend the Element of Fire is, and what its Office seems to be, I will shew, if I can,

First, Why, in Electricity, Fire proceeds from an electrical Body, so as to light into a Flame many different Compositions.

Secondly, Why a Tube of Glass, when rubbed so as to be made electrical, will not only attract to it, but repel from it alternately, any light Body, as Leaf-Gold, Feathers, and the like: And also, why it will seem to send from it a Quantity of Wind, with a singing small Noise, if you hold it nigh to your Cheek and Ear.

Thirdly, Why, when any unelectrify’d Body touches any thing electrify’d, the Electricity breaks off with a smart Crack, and a Spark of Fire.