regard for Truth, and a love of my fellow Creatures, already offer'd four Pamphlets on the fame Subject to the Public.

My Intention at firft was only to afcertain Jome remarkable Cures performed on the buman Body by the electrical Virtue; remarkable I call them, fince feveral of the Maladies were deemed beyond the power of common Medicine, having baffled all the efforts of the fanative Art; and therefore I can affert with Truth, that they very much exceeded my most fanguine expectations.

What prompted me to apply thofe Experiments to human Disorders, was fome printed Accounts of the healing Virtues of Electricity; wherein a variety of extraordinary Cures were. Said to be performed, and which for the most part appeared well attefted.

That fuch a number of Cures, as I was about to publish, might be fixed on a folid Foundation ; and that fuch falutary Effects might be reasonably expected from this furprising Agent, just then difcovered, I was induced to publish my Sentiments concerning it; when, I openly declared my real opinion of it, without the least referve, viz. That it must be the fame ætherial Medium, which Sir Ifaac Newton had conjectured to exist in grofs Bodies, and which he had in his Optics and elsewhere defcribed.

This, I thought, I might very fafely affert; ince I was able to demonftrate from the moft convincing facts, that it exifted in the pores of

of grofs Bodies, and was endued with all the moft remarkable and effential qualities and properties, which he had afcribed to his fubtile Medium.

That part however of my Work met with a fevere animadverfion from the Authors of the monthly Review, as deviating too much from the language of the Newtonian Philofophers. This was the Caufe of my publishing a fecond part in Vindication of the first, wherein I maintained the exemption of this electrical Fluid from all Newtonian Laws, and appealed to the authority of Sir Ifaac Newton himself.Their Anfier to this was the Caufe of my third, and in like manner of a fourth, which put an end to the Controverfy.

But however irksome this difpute was, it had one good Effect, and was of fuck real use to me, that many Things which I only conjectur'd at first fetting out, were, by repeated Experiments, clearly demonftrated, and above all, that my Sentiments in the first part, concerning the identity of the two fuppofed Fluids, appeared to be for the most part juft and well founded.

I was perhaps the first, that ever maintained that the electrical Fluid and the Newtonian Æther were one and the fame, at least, of any who carried their Sentiments to any confiderable length; for foon after the discovery of the Leyden Experiment, and of others fubfequent to it, Bishop Berkeley's modern plan on Ether and Fire came to my Hand. Indeed I had taken

b z

a fuperficial View of it before, when it made no great Impreffion on me, it appearing at that Time no more than an ingenious Hypothefiss but now it appear'd in a Light, as much fupe rior to what it did before, as the Completion of a Prophecy does excel the Prediction; for what was foretold in that learned Treatife, was minutely realized and confirmed by the electrical Experiments. Soon after this, appeared the ingenious Dr. Franklin's Letters upon the fame Subject, which more and more confirmed me in my Opinion, fince there I found many accurate. Experiments which fo manifeftly proved the wonderful Elafticity, the exquifite fubtilty, and inconceivable force of this Fluid, that not one doubt remained any longer about the Identity of those (as fuppos'd) two fubtile Fluids. There the curious Reader may fee it demonftrated, to be a most powerful Fire, equal to that of Lightning, and as capable of producing the fame Effects, fuch as melting of Metals in an Inftant, &c. There likewife is difcovered the Method to collect the fame Fire from the Clouds, and to make all the Experiments from the Fire thus obtain'd, as with that collected at the electrical Apparatus; from which it may be irrefragably concluded, that Lightning and the electrical Fluid, are strictly and precifely the Same.

It hath ever been my wish, that fome Genius of Learning and establish'd Character in the philofophic World would, instead of myself, have

under

V

undertaken this Subject of Electricity, and from clear and repeated Experiments, deduc'd fuch obfervations, as might merit the attention, and gain the approbation of the Public.

A Report indeed has prevail'd, that a celebrated Profeffor in foreign parts, had attempted to have written an intelligible Syftem of it; but in the profecution, he met with infuperable difficulties, found many of the Experiments fo irreconcileable with each other, and fo little reducible to the known Rules or common Laws of Motion, that be was oblig'd to give over the Subject as altogether inexplicable.

Had this learned Profeffor been in earneft, He would not, furely, fo foon have defifted and been difcouraged; fince no natural Agent was ever more eafy of Accefs; none ever folicited, and, as it were, courted our examination in fo familiar and inviting a manner; it appearing actually to exist in almost every object we can fee or handle: And let me add to all this, that fo fimple an Inftrument as a common glafs Tube, when rubb'd with the Hand, is fufficient to effect Jome of the capital Experiments.

But

That this Electric matter is not fubject to the fame rules or laws of other Matter is moft certainly a Conceffion that will be very readily granted, and therefore, the common Poftulatum, that Matter differs from Matter in form only, having all other properties in common, must confequently be abfolutely falfe. For, let me afk, Can the primary Corpufcles of all

Matter

Matter differ from each other in figure or form only, and yet not be fubject to the fame Laws? Does not this at firft fight appear too unphilofophical, too abfurd to be admitted?

And although all terreftrial Matter may poffibly be of one Genus, and be endued with the fame properties, fince it is obferved to be inert and dead; yet every Electrician is well affured, that the electrical Fluid appears poffefs'd of real Activity, and that the particles contain'd in the Leyden Vial after being electrised, if carried Miles, will, without any additional Agitation, fhew most evident Effects of Force and Activity, and frequently retain them even till the next Day.

As to the following Effay, it is humbly propos'd only as a rough, artless Draught, in order to excite fome masterly Hand to exhibit a more perfect Model, whenever a true Genius fhall arife, free from the Biafs of Prejudice in favour of fuch Systems, that have totally excluded the fubtile Medium, which is here demonftrated to exift.The Cultivation of Electricity muft ultimately depend on unprejudic'd Obfervers; nor can it ever be eftablished in the World as an univerfal Ether, without meeting with the fame oppofition as all other new difcoveries in the works of Nature have before it.

In this Efay I have endeavour'd at the moft methodical difpofition of the feveral beads of Enquiry, of which I was capable; that the feveral Experiments and the reafoning founded

upon