Experiments and Observations on Electricity Made at Philadelphia in America · Benjamin Franklin
_SIR_,
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 fair opportunity of seizing some of the finest particles of the oil in its passage, and carrying them off with it: but no such effect followed, nor could I perceive the least difference in the smell of the electrical 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 electrical 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 electrical 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 electrical fluid through the body of 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 electrical fluid, and relate the variety of little experiments we have try'd. I have already made this paper too long, for which I must crave pardon, not having now time to make it shorter. I shall only add, that as it has been observed here that spirits will fire by the electrical 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 EXPERIMENT, _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 outer Surface being always in a negative State of Electricity, when the inner Surface is in a positive State_. Place a thick plate of glass under the rubbing cushion, to cut off the communication of electrical fire from the floor to the cushion; then, if there be no fine points or hairy threads sticking out from the cushion, or from the parts of the machine opposite to 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, tho' 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 electrical 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.
Now if the fire discharged from the inside surface of the bottle through its wire, remained on the prime conductor, the balls would be electrified and recede from 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 charged, they continue so afterwards. If not, they are not electrified by that discharge. CORRECTIONS _and_ ADDITIONS _to the_ PRECEDING PAPERS. Page 2, Sect. 1. We since find, that the fire in the bottle is not contained in the non-electric, but _in the glass_. All that is after said of the _top_ and _bottom_ of the bottle, is true of the _inside_ and _outside_ surfaces, and should have been so expressed. _See Sect._ 16, p. 16. Page 6, Line 13. The equilibrium will soon be restored _but silently_, etc. This must have been a mistake. When the bottle is full charged, the crooked wire cannot well be brought to touch the top and bottom so quick, but that there will be a loud spark; unless the points be sharp, without loops.
Ibid. line ult. _Outside_: add, such moisture continuing up to the cork or wire. Page 12, line 14. _By candle-light_ etc. From some observations since made, I am inclined to think, that it is not the light, but the smoke or non-electric effluvia from the candle, coal, and red-hot iron, that carry off the electrical fire, being first attracted and then repelled. Page 13, line 15. _Windmil wheels_, &c. We afterwards discovered, that the afflux or efflux of the electrical fire, was not the cause of the motions of those wheels, but various circumstances of attraction and repulsion. Page 16, line 21. _Let_ A _and_ B _stand on wax_, &c. We soon found that it was only necessary for one of them to stand on wax. Page 19. in the title r. _on_. Page 24, line 12. r. contact, line 24. confined. Page 25, line 10. for _stand_ r. _hand_. Page 28, line 2. _The consequence might perhaps be fatal_, &c. We have found it fatal to small animals, but 'tis not strong enough to kill large ones. The biggest we have killed is a hen. Page 31, line 20. _Ringing of chimes_, &c. This is since done. Page 33, line 22. _Fails after ten or twelve experiments._ This was by a small bottle. And since found to fail after with a large glass. Page 40, sect. 50, 51. _Spirits must be heated before we can fire them_, &c. We have since fired spirits without heating, when the weather is warm.
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