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as draw off the electrical fire; lay a long sharp needle upon the shot, and you cannot electrise the shot so as to make it repel the cork-ball.-Or fix a needle to the end of a suspended gun-barrel, or iron-rod, so as to point beyond it like a little bayonet:* and while it remains there, the gun-barrel, or rod, cannot by applying the tube to the other end be electrised so as to give a spark, the fire continually running out silently at the point. In the dark you may see it make the same appearence as it does in the case before-mentioned.

The repellency between the cork-ball and the shot is likewise destroyed. 1. By sifting fine sand on it; this does it gradually. 2. By breathing on it. 3. By making a smoke about it from burning wood. 4. By candle-light, even though the candle is at a foot distance: these do it suddenly.-The light of a bright coal from a wood fire, and the light of a red hot iron do it likewise; but not at so great a distance. Smoke from dry rosin dropt on hot iron, does not destroy the repellency; but is attracted by both shot and cork ball, forming proportionable atmospheres round them, making them look beautifully, somewhat like some of the figures in Burnet's or Whiston's Theory of the Earth.

N. B. This experiment should be made in a closet, where the air is very still, or it will be apt to fail.

The light of the sun thrown strongly on both cork and shot by a looking-glass for a long time together, does not impair the repellency in the least. This difference between fire-light and sun-light is another thing that seems new and extraordinary to us.

We had for some time been of opinion, that the electrical fire was not created by friction, but collected, being really an element diffused among, and attracted by other matter, particularly by water and metals. We had even discovered and demonstrated its afflux to the electrical sphere, as well as its efflux, by means of little light windmill wheels made of stiff paper vanes, fixed obliquely, and turning

*This was Mr. Hopkinson's experiment, made with an expectation of drawing a more sharp and powerful spark from the point. as from a kind of focus, and he was surprised to find little or none.

We suppose every particle of sand, moisture, or smoke, being first attracted and then repelled, carries off with it a portion of the electrical fire; but that the same still subsists in those particles, till they communicate it to something else, and that it is never really destroyed. So when water is thrown on common fire, we do not imagine that the element is thereby de stroyed or annihilated, but only dispersed, each particle of water carrying off in vapour its portion of the fire,

which it had attracted and attached to itself.

1 This different effect probably did not arise from any difference in the light, but rather from the particles separated from the candle, being first attracted and then repelled, carrying off the electric matter with them; and from the rarefying of the air, between the glowing coal or red hot iron, and the electrised shot, through which rarefied air the electric fluid could more readily pass.

freely on fine wire axles. Also by little wheels of the same matter, but formed like water-wheels. Of the disposition and appli cation of which wheels, and the various phenomena resulting, I could, if I had time, fill you a sheet. The impossibility of electrising one's self (though standing on wax) by rubbing the tube, and drawing the fire from it; and the manner of doing it, by passing the tube near a person or thing standing on the floor, &c. had also occurred to us some months before Mr. Watson's ingenious Sequel came to hand, and these were some of the new things I intended to have communicated to you.-But now I need only mention some particulars not hinted in that piece, with our reasonings thereupon: though perhaps the latter might well enough be spared.

1. A person standing on wax, and rubbing the tube, and another person on wax drawing the fire, they will both of them (provided they do not stand so as to touch one another) appear to be electrised, to a person standing on the floor; that is, he will perceive a spark on approaching each of them with his knuckle.

2. But if the persons on wax touch one another during the exciting of the tube, neither of them will appear to be electrised.

3. If they touch one another after exciting the tube, and drawing the fire as aforesaid, there will be a stronger spark between them than was between either of them and the person on the floor.

4. After such strong spark, neither of them discover any electricity.

These appearances we attempt to account for thus: we suppose, as aforesaid, that electrical fire is a common element, of which every one of the three persons abovementioned has his equal share, before any operation is begun with the tube. A, who stands on wax, and rubs the tube, collects the electrical fire from himself into the glass; and his communication with the common stock being cut off by the wax, his body is not again immediately supplied. B, (who stands on wax likewise) passing his knuckle along near the tube, receives the fire which was collected by the glass from A; and his communication with the common stock being likewise cut off, he retains the additional quantity received.-To C, standing on the floor, both appear to be electrised: for he having only the middle quantity of electrical fire, receives a spark upon approaching B, who has an over quantity; but gives one to A, who has an under quantity. If A and B approach to touch each other, the spark is stronger, because the difference between them is greater; after

* These experiments with the wheels, were made and communicated to me by my worthy and ingenious friend Mr Philip Syng; but we afterwards discovered that the motion of those wheels was not owing to any afflux or efflux of the electric fluid, but to various circumstances of attraction and repulsion. 1750.

such touch there is no spark between either | there will be a small spark; but when their of them and C, because the electrical fire in lips approach, they will be struck and shockall is reduced to the original equality. If they ed; the same if another gentleman and lady, touch while electrising, the equality is never C and D, standing also on wax, and joining destroyed, the fire only circulating. Hence hands with A and B, salute or shake hands. have arisen some new terms among us; we We suspend by find silk thread a counterfeit say B, (and bodies like circumstanced) is spider, made of a small piece of burnt cork, electrised positively; A, negatively. Or ra- with legs of linen thread, and a grain or two ther, B is electrised plus; A, minus. And of lead stuck in him, to give him more weight; we daily in our experiments electrise bodies upon the table, over which he hangs, we plus or minus, as we think proper.-To elec- stick a wire upright, as high as the phial and trise plus or minus, no more needs to be wire, four or five inches from the spider; known than this, that the parts of the tube or then we animate him, by setting the electrisphere that are rubbed, do, in the instant of fied phial at the same distance on the other the friction, attract the electrical fire, and side of him; he will immediately fly to the therefore take it from the thing rubbing: wire of the phial, bend his legs in touching it, the same parts immediately, as the friction then spring off, and fly to the wire on the taupon them ceases, are disposed to give the ble, thence again to the wire of the phial, fire they have received, to any body that has playing with his legs against both, in a very less. Thus you may circulate it, as Mr. Wat- entertaining manner, appearing perfectly son has shown; you may also accumulate or alive to persons unacquainted: he will consubtract it, upon, or from any body, as you tinue this motion an hour or more in dry weaconnect that body with the rubber or with the ther. We electrify, upon wax in the dark, receiver, the communication with the common a book that has a double line of gold round stock being cut off. We think that ingenious upon the covers, and then apply a knuckle gentleman was deceived when he imagined to the gilding; the fire appears every where (in his Sequel) that the electrical fire came upon the gold like a flash of lightning; not down the wire from the ceiling to the gun- upon the leather, nor, if you touch the leather barrel, thence to the sphere, and so electrised instead of the gold. We rub our tubes with the machine and the man turning the wheel, buckskin, and observe always to keep the &c. We suppose it was driven off, and not same side to the tube, and never to sully the brought on through that wire; and that the tube by handling; thus they work readily machine and man, &c. were electrised minus; and easily, without the least fatigue, especii. e. had less electrical fire in them than things ally if kept in tight pasteboard cases, lined in common. with flannel, and sitting close to the tube.* This I mention, because the European papers on electricity frequently speak of rubbing the tube as a fatiguing exercise. Our spheres are fixed on iron axles, which pass through them. At one end of the axis there is a small handle, with which you turn the sphere like a common grindstone. This we find very commodious, as the machine takes up but little room, is portable, and may be inclosed in a tight box, when not in use. It is true, the sphere does not turn so swift as when the great wheel is used: but swiftness we think of little importance, since a few turns will charge the phial, &c. sufficiently.*

As the vessel is just upon sailing, I cannot give you so large an account of American electricity as I intended: I shall only mention a few particulars more.-We find granulated lead better to fill the phial with, than water, being easily warmed, and keeping warm and dry in damp air.-We fire spirits with the wire of the phial.-We light candles just blown out, by drawing a spark among the smoke between the wire and snuffers. We represent lightning, by passing the wire in the dark, over a china plate that has gilt flowers, or applying it to gilt frames of looking glasses, &c.-We electrise a person twenty or more times running, with a touch of the finger on the wire, thus: he stands on wax; give him the,electrised bottle in his hand; touch the wire with your finger, and then touch his hand or face; there are sparks every time.*-We increase the force of the electrical kiss vastly, thus: let A and B stand on wax; or A on wax, and B on the floor; give one of them the electrised phial in hand; let the other take hold of the wire;

By taking a spark from the wire, the electricity within the bottle is diminished; the outside of the bottle then draws some from the person holding it, and leaves him in the negative state. Then when his hand or face is touched, an equal quantity is restored to him from the person touching.

B. FRANKLIN.

To Peter Collinson, London. Observations on the Leyden Bottle, with Experiments proving the different electrical State of its different Surfaces.

PHILADELPHIA, Sept.1, 1747.

THE necessary trouble of copying long letters, which perhaps, when they come to your * Our tubes are made here of green glass, 27 or 30 inches long, as big as can be grasped. †This simple easily-made machine was a contri vance of Mr. Syng's.

hands, may contain nothing new, or worth | from the top, by touching the wire, unless an your reading, (so quick is the progress made equal quantity can at the same time get in with you in electricity) half discourages me from writing any more on that subject. Yet I cannot forbear adding a few observations on M. Muschenbroek's wonderful bottle.

1. The non-electric contained in the bottle differs, when electrised, from a non-electric electrised out of the bottle, in this; that the electrical fire of the latter is accumulated on its surface, and forms an electrical atmosphere round it of considerable extent; but the electrical fire is crowded into the substance of the former, the glass confining it.*

at the bottom. Thus, place an electrised bottle on clean glass or dry wax, and you will not, by touching the wire, get out the fire from the top. Place it on a non-electric, and touch the wire, you will get it out in a short time; but soonest when you form a direct communication as above.

So wonderfully are these two states of electricity, the plus and minus, combined and balanced in this miraculous bottle! situated and related to each other in a manner that I can by no means comprehend! If it were possible that a bottle should in one part contain a quantity of air strongly comprest, and in another part a perfect vacuum, we know the equili brium would be instantly restored within. But here we have a bottle containing at the same time a plenum of electrical fire, and a vacuum of the same fire; and yet the equilibrium cannot be restored between them but by a communication without! though the plenum presses violently to expand, and the hungry vacuum seems to attract as violently m order to be filled.

2. At the same time that the wire and the top of the bottle, &c. is electrised positively or plus, the bottom of the bottle is electrised negatively or minus, in exact proportion; i. e. whatever quantity of electrical fire is thrown in at the top, an equal quantity goes out of the bottom.f To understand this, suppose the common quantity of electricity in each part of the bottle, before the operation begins, is equal to 20; and at every stroke of the tube, suppose a quantity equal to 1 is thrown in; then, after the first stroke the quantity contained in the wire and upper part of the bottle will be 21, in the bottom 19. After the second, the upper part will have 22, the lower 18, and so on, till, after 20 strokes, the upper part will have a quantity of electrical fire equal to 40, the lower part none: and then the operation ends: for no more can be thrown into the upper part, when no more can be driven outed, a communication with the floor is necesof the lower part. If you attempt to throw more in, it is spewed back through the wire, or flies out in loud cracks through the sides of the bottle.

3. The equilibrium cannot be restored in the bottle by inward communication or contact of the parts; but it must be done by a communication formed without the bottle, between the top and bottom, by some non-electric, touching or approaching both at the same time; in which case it is restored with a violence and quickness inexpressible; or, touching each alternately, in which case the equilibrium is restored by degrees.

4. As no more electrical fire can be thrown into the top of the bottle, when all is driven out of the bottom, so in a bottle not yet electrised, none can be thrown into the top, when none can get out at the bottom; which happens either when the bottom is too thick or when the bottle is placed on an electric per

se.

5. The shock to the nerves (or convulsion rather) is occasioned by the sudden passing of the fire through the body in its way from the top to the bottom of the bottle. The fire takes the shortest course, as Mr. Watson justly observes: but it does not appear from experiment, that in order for a person to be shock

sary: for he that holds the bottle with one hand, and touches the wire with the other, will be shocked as much, though his shoes be dry, or even standing on wax, as otherwise. And on the touch of the wire, (or of the gun-barrel, which is the same thing) the fire does not proceed from the touching finger to the wire, as is supposed, but from the wire to the finger, and passes through the body to the other hand, and so into the bottom of the bottle.

Experiments confirming the above.

EXPERIMENT I.

Place an electrised phial on wax; a small cork-ball suspended by a dry silk thread held in your hand, and brought near to this wire will first be attracted, and then repelled: when in the state of repellency, sink your hand, that the ball may be brought towards the bottom of the bottle; it will be there instantly and strongly attracted, till it has part

Again, when the bottle is electrised, but little of the electrical fire can be drawn outed with its fire.

* See this opinion rectified in sect. 16 and 17 of the next letter. The fire in the bottle was found by subsequent experiments not to be contained in the nonelectric, but in the glass. 1748.

What is said here, and after, of the top and bot tom of the bottle, is true of the inside and outside sur faces, and should have been so expressed.

If the bottle had a positive electrical atmosphere, as well as the wire, an electrified cork would be repelled from one as well as from the other.

*See the preceding note, relating to top and bottom. † Other circumstances being equal

EXPERIMENT II.

FIG. 1. From a bent wire (a) sticking in the table, let a small linen thread (b) hang down within half an inch of the electrised phial (c). Touch the wire or the phial repeatedly with your finger, and at every touch you will see the thread instantly attracted by the bottle. (This is best done by a vinegar cruet, or some such bellied-bottle.) As soon as you draw any fire out of the upper part, by touching the wire, the lower part of the bottle draws an equal quantity in by the thread.

EXPERIMENT III.

FIG. 2. Fix a wire in the lead, with which the bottom of the bottle is armed (d) so as that bending upwards, its ring-end may be level with the top or ring-end of the wire in the cork (e) and at three or four inches distance. Then electrise the bottle, and place it on wax. If a cork suspended by a silkthread (f) hang between these two wires, it will play incessantly from one to the other, till the bottle is no longer electrised; that is, it fetches and carries fire from the top to the bottom* of the bottle, till the equilibrium is

restored.

EXPERIMENT IV.

FIG. 3. Place an electrised phial on wax; take a wire (g) in form of a C, the ends at such a distance when bent, as that the upper may touch the wire of the bottle, when the lower touches the bottom: stick the outer part on a stick of sealing-wax (h,) which will serve as a handle; then apply the lower end to the bottom of the bottle, and gradually bring the upper end near the wire in the cork. The consequence is, spark follows spark till the equilibrium is restored. Touch the top first, and on approaching the bottom with the other end, you have a constant stream of fire from the wire entering the bottle. Touch the top and bottom together, and the equilibrium will instantly be restored, the crooked wire forthing the communication.

EXPERIMENT V.

FIG. 4. Let a ring of thin lead, or paper, surround a bottle (i) even at some distance from or above the bottom. From that ring let a wire proceed up, till it touch the wire of the cork (k). A bottle so fixed cannot by any means be electrised: the equilibrium is never destroyed: for while the communication between the upper and lower parts of the bottle is continued by the outside wire, the fire only circulates: what is driven out at bottom, is constantly supplied from the top.† Hence a bottle cannot be electrised that is foul or moist on the outside, if such moisture continue up to the cork or wire.

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Lay two books on two glasses, back towards back, two or three inches distant. Set the electrified phial on one, and then touch the wire; that book will be electrified minus; the electrical fire being drawn out of it by the bottom of the bottle. Take off the bottle, and holding it in your hand, touch the other with the wire; that book will be electrified plus; the fire passing into it from the wire, and the bottle is at the same time supplied from hand. A suspended small cork-ball will play between these books till the equilibrium is restored.

EXPERIMENT IX.

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When a body is electrified plus, it will repel a positively electrified feather or small cork-ball. When minus (or when in the common state) it will attract them, but stronger when minus than when in the common state, the difference being greater.

EXPERIMENT X.

Though, as in Experiment VI, a man standing on wax may be electrised a number of times by repeatedly touching the wire of an electrised bottle (held in the hand of one standing on the floor) he receiving the fire from the wire each time; yet holding it in his own hand, and touching the wire, though he draws a strong spark, and is violently shocked, no electricity remains in him; the fire only passing through him, from the upper to the lower part of the bottle. Observe, before the shock, to let some one on the floor touch him to restore the equilibrium in his body; for in taking hold of the bottom of the bottle, he sometimes becomes a little electrised minus, which will continue after the shock, as would also any plus electricity, which he might have given him before the shock. For restoring the equilibrium in the bottle, does not at all affect the electricity in the man through whom the fire passes

that electricity is neither increased nor dimi-ed through the hook, will be discharged nished.

EXPERIMENT XI.

The passing of the electrical fire from the upper to the lower part of the bottle, to restore the equilibrium, is rendered strongly visible by the following pretty experiment. Take a book whose covering is filletted with gold; bend a wire of eight or ten inches long, in the form of (m) Fig. 5; slip it on the end of the cover of the book, over the gold line, so as that the shoulder of it may press upon one end of the gold line, the ring up, but leaning towards the other end of the book. Lay the book on a glass or wax,† and on the other end of the gold lines set the bottle electrised: then bend the springing wire, by pressing it with a stick of wax till its ring approaches the ring of the bottle wire, instantly there is a strong spark and stroke, and the whole line of gold, which completes the communication, between the top and bottom of the bottle, will appear a vivid flame, like the sharpest lightning. The closer the contact between the shoulder of the wire, and the gold at one end

of the line, and between the bottom of the bottle and the gold at the other end, the better the experiment succeeds. The room should be darkened. If you would have the whole filletting round the cover appear in fire at once, let the bottle and wire touch the gold in the diagonally opposite corners.

B. FRANKLIN.

To Peter Collinson, London. Farther Experiments, confirming the preceding Observations.-Leyden Bottle analysed.-Electrical Battery-Magical Picture-Electrical Wheel or Jack.-Electrical Feast.

PHILADELPHIA, 1748.

1. THERE will be the same explosion and shock if the electrified phial is held in one hand by the hook, and the coating touched with the other, as when held by the coating, and touched at the hook.

2. To take the charged phial safely by the hook, and not at the same time diminish its force, it must first be set down on an electric per se.

3. The phial will be electrified as strongly, if held by the hook, and the coating applied to the globe or tube; as when held by the coating, and the hook appliedt.

4. But the direction of the electrical fire being different in the charging, will also be different in the explosion. The bottle charg

i. e. From the inside to the outside.

† Placing the book on glass or wax is not necessary to produce the appearance; it is only to show that the visible electricity is not brought up from the common stock in the earth.

This was a discovery of the very ingenious Mr. Kinnersley, and by him communicated to me. VOL. II....21

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through the hook; the bottle charged through the coating, will be discharged through the coating, and not otherways; for the fire must come out the same way it went in.

5. To prove this, take two bottles that in each hand; bring their hooks near each were equally charged through the hooks, one other, and no spark or shock will follow; because each hook is disposed to give fire, and down on glass, take it up by the hook, and apply its coating to the hook of the other; then there will be an explosion and shock, and both bottles will be discharged.

neither to receive it. Set one of the bottles

6. Vary the experiment, by charging two phials equally, one through the hook, the coating which was charged through the hook, other through the coating: hold that by the and that by the hook which was charged through the coating: apply the hook of the first to the coating of the other, and there will be no shock or spark. Set that down on glass which you held by the hook, take it up ther: a spark and shock will follow, and both by the coating, and bring the two hooks togephials be discharged.

In this experiment the bottles are totally restored. The abounding of fire in one of the discharged, or the equilibrium within them hooks (or rather in the internal surface of one bottle) being exactly equal to the wanting of

the other; and therefore as each bottle has in itself the abounding as well as the wanting, the wanting and abounding must be equal in each bottle. See § 8, 9, 10, 11. But if a man. holds in his hands two bottles, one fully electrified, the other not at all, and brings their hooks together, he has but half a shock, and the bottles will both remain half electrified, the one being half discharged, and the other half charged.

7. Place two phials equally charged on a table at five or six inches distance. Let a cork-ball, suspended by a silk thread, hang between them. If the phials were both charged through their hooks, the cork, when it has been attracted and repelled by the one, will not be attracted, but equally repelled by the other. But if the phials were charged, the one through the hook, and the other* through the coating, the ball, when it is repelled from one hook, will be as strongly attracted by the other, and play vigorously between them, fetching the electric fluid from the one, and delivering it to the other, till both phials are nearly discharged.

8. When we use the terms of charging

* To charge a bottle commodiously through the coat. ing, place it on a glass stand; form a communication from the prime conductor to the coating, and another from the hook to the wall or floor. When it is charged, remove the latter communication before you take hold of the bottle, otherwise great part of the fire will es cape by it..

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