I think this will sufficiently shew the Existence of this Fire in the Air; and, if any Regard be had to what I think its Power and Use is in the World, that it will intrude itself and force its Way into any Thing where less of it is, and so join itself to it by being in a greater Quantity; as has been shewn by many electrical Experiments.
You may suppose a Person sitting, as it is too frequently found they are, near a Door, or in a Window, when they are in a warm Temperature, and in Perspiration; if you believe that there can be any Probability in the Conjecture I have offer’d to your Consideration, is it not natural for any of this Fire, which passes as frequently through the Air in the Daytime (though unobserved) as when it is seen in the Night; I say, Why is it not natural for it to force its Entrance into any Person or Thing? especially as it comes then with the Assistance of the Stream of Air the Person sits in, and with which it is driven.
In order to make this Mischief the more to be regarded, I will endeavour to shew the natural State of the Air itself.
Many Writers about it chuse to divide it into two Sorts; the first is the pure Æther, which is supposed to be moving above our Atmosphere; the second is the common Air, which is supposed to be within our Atmosphere. I confess, the Feats attributed to the mighty Weight of our Atmosphere, in causing Siphons and Pumps, &c. to operate, I never could understand; but if I were to account for their Operations, as well as that of a Barometer, by the Elasticity of the Air, I think I could more easily and more naturally shew it.
Notwithstanding what has been advanced concerning the Æther, which is believed to inhabit above our Atmosphere, I chuse rather to suppose, that the Air is an Element as well as Fire, and that the Difference in it is only betwixt heavy and foul Air, and clean and light Air. That which comes on the highest Mountains is clean, and free from our Fogs and Putrefactions, and, consequently, more elastic.
As a Proof of this, I would recommend the following Experiment: Fill a Bladder with this clean Air; then press it with a Weight just sufficient to make it give way; and you will find, that, by reason of its Elasticity, it will yield much further, than if it were fill’d with the other Air, which is impregnated with foggy and aqueous Particles.
Now if, as in a Barometer, the Quicksilver is suspended by the Air on the Top of the Tube, which was extracted or emerged out of the Quicksilver, by the Weight of the said Quicksilver, and as that Air in the Barometer cannot but have a Communication with the ambient Air, the Air within the Barometer must thence be affected, by its becoming less elastic also.
But this is not so much to my present Purpose, as to consider the Air loaded not only with Vapours, but with poisonous Effluvia from the Steams of various Minerals, as well as with the Salts of dead Insects and Animals, which, in the Season of Autumn, may probably occasion so many Agues, and putrid Fevers, as are met with.
Now, if you further consider the Air as loaded with any or all of these Vapours and Effluvia, and demanding Entrance with the Authority of Fire, its Companion, is it any Wonder, that the Rheumatism, and many other bad Effects, which frequently happen, in unguarded Seasons, to Mankind, may be owing to the Cause here treated of?
I remember that a Person, riding in an open Chaise, in an Easterly Wind, receiv’d a Stroke upon one of his Scapula’s, with as great Pain, and with the same kind of Sensation, as if he had been stuck with a Dagger. Upon which he instantly said to his Friend in the Chaise, He expected a violent Rheumatism from it. Which accordingly happen’d; for he was not able to quit his Bed for Three Weeks after.—I think this cannot be better accounted for, than to suppose it proceeded from a pointed Body of this kind of Fire, and the Effluvia which accompanied it.