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but moving on the approach of the rubbed tube, is explained. When an additional quantity of the electrical fluid is applied to the side of the vessel by the atmosphere of the tube, a quantity is repelled and driven out of the inner surface of that side into the vessel, and there affects the feather, returning again into its pores, when the tube with its atmosphere is withdrawn; not that the particles of that atmosphere did themselves pass through the glass to the feather. And every other appearance I have yet seen, in which glass and electricity are concerned, are, I think, explained with equal ease by the same hypothesis. Yet, perhaps, it may not be a true one, and I shall be obliged to him that affords me a better.

the cushion again, the outer surface delivers its overplus fire into the cushion, the opposite inner surface receiving at the same time an equal quantity from the floor. Every electrician knows that a globe wet within will afford little or no fire, but the reason has not before been attempted to be given, that I know of. 34. So if a tube lined with a non-electric be rubbed little or no fire is obtained from it; what is collected from the hand, in the downward rubbing stroke, entering the pores of the glass, and driving an equal quantity out of the inner surface into the non-electric lining and the hand in passing up to take a second stroke, takes out again what had been thrown into the outer surface, and then the inner surface receives back again what it had given to the non-electric lining. Thus the particles of electral fluid belonging to the inside surface go in and out of their pores every stroke given to the tube. Put a wire into the tube, the inward end in contact with the nonelectric lining, so it will represent the Leyden bottle. Let a second person touch the wire, while you rub, and the fire driven out of the inward surface when you give the stroke, will pass through him into the common mass, and return through him when the inner surface resumes its quantity, and therefore this new kind of Leyden bottle cannot be so charged. But thus it may: after every stroke, before you pass your hand up to make another, let a second person apply his finger to the wire, take the spark, and then withdraw his finger; and so on till he has drawn a number of sparks; thus will the inner surface be exhausted, and the outer surface charged; then wrap a sheet of gilt paper close round the outer surface, and grasping it in your hand you may receive a shock by applying the finger of the other hand to the wire: for now the vacant pores in the inner surface resume their quantity, and the overcharged pores in the outer surface discharge that overplus; the equilibrium being restored through your body, which could not be restored through the glass.f If the tube be exhausted of air, a non-electric lining, in contact with the wire, is not necessary, for in vacuo the electrical fire will fly freely from the inner surface, without a nonelectric conductor; but air resists in motion; for being itself an electric per se, it does not 36. Hence we see the impossibility of sucattract it, having already its quantity. So the cess in the experiments proposed, to draw out air never draws off an electric atmosphere the effluvial virtues of a non-electric, as cinfrom any body, but in proportion to the non-namon, for instance, and mixing them with electrics mixed with it: it rather keeps such the electric fluid, to convey them with that inan atmosphere confined, which, from the mu- to the body, by including it in the globe, and tual repulsion of its particles, tends to dissipation, and would immediately dissipate in vacuo.-And thus the experiment of the feather enclosed in a glass vessel hermetically sealed,

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35. Thus I take the difference between nonelectrics, and glass, an electric per se, to consist in these two particulars. 1st, That a nonelectric easily suffers a change in the quantity of the electric fluid it contains. You may lessen its whole quantity, by drawing out a spark, which the whole body will again resume: but of glass you can only lessen the quantity contained in one of its surfaces; and not that, but by supplying an equal quantity at the same time to the other surface: so that the whole glass may always have the same quantity in the two surfaces, their two dif ferent quantities being added together. And this can only be done in glass that is thin; beyond a certain thickness we have yet no power that can make this change. And, 2dly, that the electric fire freely removes from place to place, in and through the substance of a non-electric, but not so through the substance of glass. If you offer a quantity to one end of a long rod of metal, it receives it, and when it enters, every particle that was before in the rod pushes its neighbour quite to the further end, where the overplus is discharged; and this instantaneously where the rod is part of the circle in the experiment of the shock. But glass, from the smallness of its pores, or stronger attraction of what it contains, refuses to admit so free a motion: a glass rod will not conduct a shock, nor will the thinnest glass suffer any particle entering one of its surfaces to pass through to the other.

then applying friction, &c. For though the effluvia of cinnamon, and the electric fluid should mix within the globe, they would never come out together through the pores of the glass, and so go to the prime conductor, for the electric fluid itself cannot come through; and the prime conductor is always

one person, why should it stop on the skin of another?

But I shall never have done, if I tell you all my conjectures, thoughts, and imaginations on the nature and operations of this electric fluid, and relate the variety of little experiments we have tried. I have already made this paper too long, for which I must crave pardon, not having now time to abridge it. I shall only add, that as it has been observed here that spirits will fire by the electric spark in the summer time, without heating them, when Fahrenheit's thermometer is above 70; so when colder, if the operator puts a small flat bottle of spirits in his bosom, or a close pocket, with the spoon, some little time before he uses them, the heat of his body will communicate warmth more than sufficient for the purpose.

Additional Experiments :

Proving that the Leyden Bottle has no more electrical fire in it when charged, than before: nor less when discharged: that, in discharging, the Fire does not issue from the Wire and the Coating at the same time, as some have thought, but that the Coating always receives what is discharged by the Wire, or an equal quantity; the other Surface being always in a negative state of Electricity, when the inner Surface is in a positive state.

supplied from the cushion, and that from the floor. And besides, when the globe is filled with cinnamon, or other non-electric, nonelectric fluid can be obtained from its outer surface, for the reason before-mentioned. I have tried another way, which I thought more likely to obtain a mixture of the electric and other effluvia together, if such a mixture had been possible. I placed a glass plate under my cushion, to cut off the communication between the cushion and floor; then brought a small chain from the cushion into a glass of oil of turpentine, and carried another chain from the oil of turpentine to the floor, taking care that the chain from the cushion to the glass, touched no part of the frame of the machine. Another chain was fixed to the prime conductor, and held in the hand of a person to be electrified. The ends of the two chains in the glass were near an inch distant from each other, the oil of turpentine between. Now the globe being turned could draw no fire from the floor through the machine, communication that way being cut off by the thick glass plate under the cushion: it must then draw it through the chains whose ends were dipped in the oil of turpentine. And as the oil of turpentine, being an electric per se, would not conduct, what came up from the floor was obliged to jump from the end of one chain to the end of the other, through the substance of that oil, which we could see in large sparks, and so it had a PLACE a thick plate of glass under the rubfair opportunity of seizing some of the finest bing cushion, to cut off the communication of particles of the oil in its passage, and carry-electrical fire from the floor to the cushion, ing them off with it: but no such effect followed, nor could I perceive the least difference in the smell of the electric effluvia thus collected, from what it has when collected otherwise, nor does it otherwise affect the body of a person electrised. I likewise put into a phial, instead of water, a strong purgative liquid, and then charged the phial, and took repeated shocks from it, in which case every particle of the electrical fluid must, before it went through my body, have first gone through the liquid when the phial is charging, and returned through it when discharging, yet no other effect followed than if it had been charged with water. I have also smelt the electric fire when drawn through gold, silver, copper, lead, iron, wood, and the human body, and could perceive no difference: the odour is always the same, where the spark does not burn what it strikes; and therefore I imagine it does not take that smell from any quality of the bodies it passes through. And indeed, as that smell so readily leaves the electric matter, and adheres to the knuckle receiving the sparks, and to other things; I suspect that it never was connected with it, but arises instantaneously from something in the air acted upon by it. For if it was fine enough to come with the electric fluid through the body of

then if there be no fine points or hairy threads sticking out from the cushion, (of which you must be careful) you can get but a few sparks from the prime conductor, which are all the cushion will part with.

Hang a phial then on the prime conductor, and it will not charge though you hold it by the coating.-But,

Form a communication by a chain from the coating to the cushion, and the phial will charge.

For the globe then draws the electric fire out of the outside surface of the phial, and forces it through the prime conductor and wire of the phial into the inside surface.

Thus the bottle is charged with its own fire, no other being to be had while the glass plate is under the cushion.

Hang two cork balls by flaxen threads to the prime conductor; then touch the coating of the bottle, and they will be electrified and recede from each other.

For just as much fire as you give the coating, so much is discharged through the wire upon the prime conductor, whence the cork balls receive an electrical atmosphere.-But,

Take a wire bent in the form of a C, with a stick of wax fixed to the outside of the curve, to hold it by; and apply one end of

this wire to the coating, and the other at the same time to the prime conductor, the phial will be discharged; and if the balls are not electrified before the discharge, neither will they appear to be so after the discharge, for they will not repel each other.

If the phial really exploded at both ends, and discharged fire from both coating and wire, the balls would be more electrified, and recede farther; for none of the fire can escape, the wax handle preventing.

But if the fire with which the inside surface is surcharged be so much precisely as is wanted by the outside surface, it will pass round through the wire fixed to the wax handle, restore the equilibrium in the glass, and make no alteration in the state of the prime conductor.

Accordingly we find, that if the prime conductor be electrified, and the cork balls in a state of repellency before the bottle is discharged, they continue so afterwards. If not, they are not electrified by that discharge.

not but take notice of the large comazants (as he calls them) that settled on the spintles at the top-mast heads, and burnt like very large torches (before the stroke.) According to my opinion, the electrical fire was then drawing off, as by points, from the cloud; the largeness of the flame betokening the great quantity of electricity in the cloud: and had there been a good wire communication from the spintle heads to the sea, that could have conducted more freely than tarred ropes, or mats of turpentine wood, I imagine there would either have been no stroke, or, if a stroke, the wire would have conducted it all into the sea without damage to the ship.

His compasses lost the virtue of the loadstone, or the poles were reversed; the north point turning to the south.-By electricity we have (here at Philadelphia) frequently given polarity to needles, and reversed it at pleasure. Mr. Wilson, at London, tried it on too large masses, and with too small force.

A shock from four large glass jars, sent through a fine sewing-needle, gives it polarTo Peter Collinson, London. ity, and it will traverse when laid on water. Accumulation of the electrical Fire proved to be-If the needle, when struck, lies east and in the electrified Glass.-Effect of Lightning west, the end entered by the electric blast on the Needle of Compasses, explained.-Gun-points north.—If it lies north and south, the powder fired by the electric Flame.

PHILADELPHIA, July 27, 1750.

end that lay towards the north will continue to fire entered at that end, or at the contrary end. point north when placed on water, whether the

MR. WATSON, I believe, wrote his Observations on my last paper in haste, without having first well considered the experiments needle is struck lying north and south, weakThe polarity given is strongest when the related 17,* which still appear to me decisive in the question,- Whether the accumu- the force was still greater, the south end, enest when lying east and west; perhaps if lation of the electrical fire be in the electri-tered by the fire (when the needle lies north cal glass, or in the non-electric matter connected with the glass? and to demonstrate that it is really in the glass.

As to the experiment that ingenious gentleman mentions, and which he thinks conclusive on the other side, I persuade myself he will change his opinion of it, when he considers, that as one person applying the wire of the charged bottle to warm spirits, in a spoon held by another person, both standing on the floor, will fire the spirits, and yet such firing will not determine whether the accumulation was in the glass or the non-electric; so the placing another person between them, standing on wax, with a bason in his hand, into which the water from the phial is poured, while he at the instant of pouring presents a finger of his other hand to the spirits, does not at all alter the case; the stream from the phial, the side of the bason, with the arms and body of the person on the wax, being all together but as one long wire, reaching from the internal surface of the phial to the spirits.

June 29, 1751. In capt. Waddell's account of the effects of lightning on his ship, I could * See the paper entitled, Farther Experiments, &c.

and south) might become the north, otherwise it puzzles us to account for the inverting must always be found in that situation, and of compasses by lightning; since their needles entered the north and went out at the south by our little experiments, whether the blast end of the needle, or the contrary, still the end that lay to the north should continue to point north.

dles are sometimes finely blued like a watchIn these experiments the ends of the neespring by the electric flame. This colour given by the flash from two jars only, will wipe off, but four jars fix it, and frequenthave had their heads and points melted off by ly melt the needles. I send you some that our mimic lightning; and a pin that had its point melted off, and some part of its head and neck run. Sometimes the surface on the body of the needle is also run, and appears blistered when examined by a magnifying glass: the jars I make use of hold seven or eight gallons, and are coated and lined with tin-foil; each of them takes a thousand turns* of a globe nine inches diameter to charge it.

*The cushion being afterwards covered with a long flap of buckskin, which might cling to the globe; and

I send you two specimens of tin-foil melted | may seem to many a little extravagant to between glass, by the force of two jars only. suppose. So we are not got beyond the skill I have not heard that any of your European of Rabelais's devils of two years old, who, he electricians have ever been able to fire gun- humourously says, had only learnt to thunder powder by the electric flame. We do it and lighten a little round the head of a cabB. FRANKLIN. here in this manner:-A small cartridge is bage. filled with dry powder, hard rammed, so as to bruise some of the grains; two pointed wires are then thrust in, one at each end, the Queries and Answers referred to in the forepoints approaching each other in the middle of the cartridge, till within the distance of half an inch; then, the cartridge being placed in circuit, when the four jars are discharged, the electric flame leaping from the point of one wire to the point of the other, within the cartridge amongst the powder, fires it, and the explosion of the powder is at the same instant with the crack of the discharge.

B. FRANKLIN.

going Letter.

The terms, electric per se, and non-electric, improper.-New relation between Metals and Water-Effects of Air in electrical Experiments.-Experiments for discovering more of the Qualities of the electric Fluid.

Query. WHEREIN consists the difference between an electric and a non-electric body?

Answer. The terms electric per se, and nonelectric, were first used to distinguish bodies, on a mistaken supposition that those called elec

To Cadwallader Colden,* at New York, com- trics per se, alone contained electric matter in municated to Mr. Collinson.

Unlimited Nature of the Electric Force.
PHILADELPHIA, 1751.

I ENCLOSE you answers, such as my present hurry of business will permit me to make, to the principal queries contained in yours of the 28th instant, and beg leave to refer you to the latter piece in the printed collection of my papers, for farther explanation of the difference between what is called electrics per se, and non-electrics. When you have had time to read and consider these papers, I will endeavour to make any new experiments you shall propose, that you think may afford farther light or satisfaction to either of us; and shall be much obliged to you for such remarks, objections, &c. as may occur to you.-I forget whether I wrote to you that I have melted brass pins and steel needles, inverted the poles of the magnetic needle, given a magnetism and polarity to needles that had none, and fired dry gunpowder by the electric spark. I have five bottles that contain eight or nine gallons each, two of which charged are sufficient for those purposes; but I can charge and discharge them altogether. There are no bounds (but what expense and labour give) to the force man may raise and use in the electrical way; for bottle may be added to bottle in infinitum, and all united and discharged together as one, the force and effect proportioned to their number and size. The greatest known effects of common lightning may, I think, without much difficulty, be exceeded in this way, which a few years since could not have been believed, and even now

care being taken to keep that flap of a due temperature, between too dry and too moist, we found so much more of the electric fluid was obtained, as that 150 turns were sufficient.-1753.

This gentleman was afterwards lieutenant-governor of New York.

their substance, which was capable of being excited by friction, and of being produced or drawn from them, and communicated to those called non-electrics, supposed to be destitute of it: for the glass, &c. being rubbed, discovered signs of having it, by snapping to the finger, attracting, repelling, &c. and could communicate those signs to metals and water.

Afterwards it was found, that rubbing of glass would not produce the electric matter, unless a communication was preserved between the rubber and the floor; and subsequent experiments proved that the electric matter was really drawn from those bodies that at first were thought to have none in them. Then it was doubted whether glass, and other bodies called electrics per se, had really any electric matter in them, since they apparently afforded none but what they first extracted from those which had been called non-electrics. But some of my experiments show, that glass contains it in great quantity, and I now suspect it to be pretty equally dif fused in all the matter of this terraqueous globe. If so, the terms electric per se, and non-electric, should be laid aside as improper: and (the only difference being this, that some bodies will conduct electric matter, and others will not) the terms conductor and nonconductor may supply their place. If any portion of electric matter is applied to a piece of conducting matter, it penetrates and flows through it, or spreads equally on its surface; if applied to a piece of non-conducting matter, it will do neither. Perfect conductors of electric matter are only metals and water. Other bodies conducting only as they contain a mixture of those; without more or less of which they will not conduct at all.* This

This proposition is since found to be too general; Mr. Wilson having discovered that melted wax and rosin will also conduct.

(by the way) shows a new relation between | we concluded that the air's elasticity was not metals and water heretofore unknown. affected thereby.

To illustrate this by a comparison, which, however, can only give a faint resemblance. An experiment towards discovering more of Electric matter passes through conductors as water passes through a porous stone, or spreads on their surfaces as water spreads on a wet stone; but when applied to non-conductors, it is like water dropt on a greasy stone, it neither penetrates, passes through, nor spreads on the surface, but remains in drops where it falls. See farther on this head, in my last printed piece, entitled, Opinions and Conjectures, &c. 1749.

Query. What are the effects of air in electrical experiments?

Answer. All I have hitherto observed are these. Moist air receives and conducts the electrical matter in proportion to its moisture, quite dry air not at all: air is therefore to be classed with the non-conductors. Dry air assists in confining the electrical atmosphere to the body it surrounds, and prevents its dissipating; for in vacuo it quits easily, and points. operate stronger, i. e. they throw off or attract the electrical matter more freely, and at greater distances; so that air intervening obstructs its passage from body to body in some degree. A clean electrical phial and wire, containing air instead of water, will not be charged nor give a shock, any more than if it was filled with powder of glass; but exhausted of air, it operates as well as if filled with water. Yet an electric atmosphere and air do not seem to exclude each other, for we breathe freely in such an atmosphere, and dry air will blow through it without displacing or driving it away. I question whether the strongest dry north-wester would dissipate it. I once electrified a large cork-ball at the end of a silk thread three feet long, the other end of which I held in my fingers, and whirl'd it round, like a sling one hundred times in the air, with the swiftest motion I could possibly give it, yet it retained its electric atmosphere, though it must have passed through eight hundred yards of air, allowing my arm in giving the motion to add a foot to the semidiamater of the circle.-By quite dry air, I mean the dryest we have: for perhaps we never have any perfectly free from moisture. An electrical atmosphere raised round a thick wire, inserted in a phial of air, drives out none of the air, nor on withdrawing that atmosphere will any rush in, as I have found by a curious experiment accurately made, whence

*The cold dry wind of North America.

†The experiment here mentioned was thus made. An empty phial was stopped with a cork. Through the cork passed a thick wire, as usual in the Leyden experiment, which wire almost reached the bottom. Through another part of the cork passed one leg of a small glass syphon, the other leg on the outside came down almost to the bottom of the phial. This phial was first held a short time in the hand, which, warming, and of course ratifying the air within, drove a

the qualities of the electrical fluid. FROM the prime conductor, hang a bullet by a wire hook; under the bullet, at half an inch distance, place a bright piece of silver to receive the sparks; then let the wheel be turned, and in a few minutes, (if the repeated sparks continually strike in the same spot) the silver will receive a blue stain, nearly the colour of a watch-spring.

A bright piece of iron will also be spotted, but not with that colour; it rather seems corroded.

On gold, brass, or tin, I have not perceived it makes any impression. But the spots on the silver or iron will be the same, whether the bullet be lead, brass, gold, or silver.

On a silver bullet there will also appear a small spot, as well as on the plate below it.

Cadwallader Colden, New York.

Mistake, that only Metals and Waters were conductors, rectified.—Supposition of a region of electric fire above our atmosphere.-Theorem concerning Light.-Poke-weed a cure for Cancers.-Read at the Royal Society, of London, Nov. 11, 1756.

PHILADELPHIA, April 23, 1752.

IN considering your favour of the 16th past, I recollected my having wrote you answers to some queries concerning the difference between electrics per se, and non-electrics, and the effects of air in electrical experiments, which, I apprehend, you may not have received. The date I have forgotten.

We have been used to call those bodies

electrics per se, which would not conduct the electric fluid; we once imagined that only such bodies contained that fluid; afterwards that they had none of it, and only educed it from other bodies: but further experiments showed our mistake. It is to be found in all matter we know of; and the distinctions of electrics per se, and non-electrics, should now be dropt as improper, and that of conductors and non-conductors assumed in its place, as I mentioned in those answers.

red ink in a tea-spoon was applied to the opening of small part of it out through the syphon. Then a little the outer leg of the syphon; so that as the air within cooled, a little of the ink might rise in that leg. When the air within the bottle came to be of the same temperature of that without, the drop of red ink would rest in a certain part of the leg. But the warmth of a finger applied to the phial would cause that drop to descend, as the least outward coolness applied would make it ascend. When it had found its situation, and was at rest, the wire was electrified by a communication from the primè conductor. This was supposed to give an electric atmosphere to the wire within the bottle, which might likewise rarify the included air, and of course depress the drop of ink in the syphon. But no such effect followed.

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