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Your explication of the crooked direction of be repelled from the then generally electrilightning appears to me both ingenious and fied surface of the sea, and fly away with solid. When we can account as satisfactori- them into the air. I thought too, that possily for the electrification of clouds, I think that bly the great mixture of particles electric branch of natural philosophy will be nearly per se, in the ocean water, might, in some complete.
degree, impede the swift motion and dissipaThe air, undoubtedly, obstructs the motion tion of the electric fluid through it to the of the electric fluid. Dry air prevents the shores, &c.—But having since found, that salt dissipation of an electric atmosphere, the den- in the water of an electric phial does not ser the more, as in cold weather. I question lessen the shock; and having endeavoured whether such an atmosphere can be retained in vain to produce thạt luminous appearance by a body in vacuo. A common electrical from a mixture of salt and water agitated; phial requires a non-electric communication and observed, that even the sea-water will from the wire to every part of the charged not produce it after some hours standing in a glass; otherwise, being dry and clean, and bottle; I suspect it to proceed from some filled with air only, it charges slowly, and principle yet unknown to us (which I would discharges gradually, by sparks, without a gladly make some experiments to discover, if shock : but exhausted of air, the communica- I lived near the sea) and I grow more doubttion is so open and free between the inserted ful of my former supposition, and more ready wire and surface of the glass, that it charges to allow weight to that objection (drawn from as readily, and shocks as smartly as if filled the activity of the electric fluid, and the reawith water : and I doubt not, but that in the diness of water to conduct) which you have experiment you propose, the sparks would not indeed stated with great strength and clearonly be near strait in vacuo, but strike at a ness. greater distance than in the open air, though In the mean time, before we part with this perhaps there would not be a loud explosion. hypothesis, let us think what to substitute in As soon as I have a little leisure, I will make its place. I have sometimes queried whethe experiment, and send you the result. ther the friction of the air, an electric per se,
My supposition, that the sea might possibly in violent winds, among trees, and against be the grand source of lightning, arose from the surface of the earth, might not pump up, the common observation of its luminous ap- as so many glass globes, quantities of the pearance in the night, on the least motion ; electric fluid, which the rising vapours might an appearance never observed in fresh water. receive from the air, and retain in the clouds Then I knew that the electric fluid may be they form ? on which I should be glad to have pumped up out of the earth, by the friction your sentiments. An ingenious friend of of a glass globe, on a non-electric cushion; mine supposes the land-clouds more likely to and that notwithstanding the surprising acti- be electrified than the sea-clouds. I send his letvity and swiftness of that fluid, and the non- ter for your perusal, which please to return me. electric communication between all the parts I have wrote nothing lately on electricity, of the cushion and the earth, yet quantities nor observed any thing new that is material, would be snatched up by the revolving sur- my time being much taken up with other afface of the globe, thrown on the prime con- fairs. Yesterday I discharged four jars ductor, and dissipated in air. How this was through a fine wire, tied up between two done, and why that subtle active spirit did not strips of glass: the wire was in part melted, immediately return again from the globe, into and the rest broke into small pieces from half some part or other of the cushion, and so into an inch long, to half a quarter of an inch. My the earth, was difficult to conceive; but whe- globe raises the electric fire with greater ease
, ther from its being opposed by a current set- in much greater quantities, by the means of ting upwards to the cushion, or from what- a wire extended from the cushion, to the iron ever other cause, that it did not so return pin of a pump handle behind my house, which was an evident fact. Then I considered the communicates by the pump spear with the separate particles of water as so many hard water in the well. spherules, capable of touching the salt only By this post I send to ****, who is curious in points, and imagined a particle of salt could in that way, some meteorological observations therefore no more be wet by a particle of wa- and conjectures, and desire him to communiter, than a globe by a cushion; that there cate them to you, as they may afford you might therefore be such a friction between some amusement, and I know you will look these originally constituent particles of salt over them with a candid eye. By throwing and water, as in a sea of globes and cushions; our occasional thoughts on paper, we more that each particle of water on the surface readily discover the defects of our opinions, or might obtain from the common mass, some we digest them better and find new arguments particles of the universally diffused much to support them. This I sometimes practise : finer, and more subtle electric fluid, and form- but such pieces are fit only to be seen by ing to itself an atmosphere of those particles, friends.
J. Boudoin to Benjamin Franklin. four glass jars had upon a fine wire, tied beEffect of Lightning on Captain Waddel's Com-tween two strips of glass, puts me in mind of a pass, and the Dutch Church at New York. very similar one of lightning, that I observed Read at the Royal Society, June 3, 1752.
at New York, October, 1750, a few days af
ter I left Philadelphia. In company with a Boston, March 2, 1752.
number of gentlemen, I went to take a view I HAVE received your favour of the 24th of of the city from the Dutch church steeple, in January past, enclosing an extract from your which is a clock about twenty or twenty-five letter to Mr. Collinson, and ****'s letter to feet below the bell. From the clock went a yourself
, which I have read with a great deal wire through two floors, to the clock-hammer of pleasure, and am much obliged to Your extract confirms a correction Mr. Kin- wire being perhaps about a quarter of an inch
near the bell, the holes in the floor for the nersley made a few days ago, of a mistake I diameter. We were told, that in the spring of was under respecting the polarity given to 1750, the lightning struck the clock hammer, needles by electrical fire, “ that the end which and descended along the wire to the clock, receives the fire always points north;" and melting in its way several spots of the wire, " that the needle being situated east and west from three to nine inches long, through one will
not have a polar direction.”. You find, third of its substance, till coming within a few however, the polarity strongest when the feet of the lower end, it melted the wire quite needle is shocked lying north and south; through, in several places, so that it fell down weakest when lying east and west; which in several pieces; which spots and pieces we makes it probable that the communicated magnetism is less, as the needle varies from a few off to the hinge of a door, shattered the
When it got to the end of the wire, it north and south situation. As to the needle door, and dissipated. In its passage through of captain Waddel's compass, if its polarity, the holes of the floors it did not do the least was reversed by the lightning, the effect of damage, which evidences that wire is a good lightning and electricity, in regard of that, conductor of lightning (as it is of electricity) seems dissimilar ; for a magnetic needle in a provided it be substantial enough, and might, north and south situation (as the compass nee
in this case, had it been continued to the dle was) instead of having its power revers- earth, have conducted it without damaging ed, or even diminished, would have it confirm
the building. * ed or increased by the electric fire. But per Your information about your globe's raising haps the lightning communicated to some the electric fire in greater quantities, by means nails in the binnacle (where the compass is of a wire extended from the cushion to the: placed) the magnetic virtue, which might dis- earth, will enable me, I hope, to remedy a turb the compass. This I have heard was the case; if so, the lect the fire with the electrifying glass I use,
great inconvenience I have been under, to colseeming dissimilarity vanishes: but this re- which is fixed in a very dry room, three stories markable circumstance (if it took place). I from the ground. When you send your meshould think would not be omitted in captain teorological observations to ****, I hope I shall Waddel's account.
have the pleasure of seeing them. I am very much pleased that the explica
J. BOWDOIN. tion I sent you, of the crooked direction of lightning, meets with your approbation. As to your supposition about the source of
Proposal of an experiment to measure the lightning, the luminous appearance of the sea
time taken up by an Electric Spark in in the night, and the similitude between the
moving through any given space. friction of the particles of salt and water, as
James Alexander, of New York.-Read at you considered them in their original sepa the Royal Society, Dec. 26, 1756. rate state, and the friction of the globe and cushion, very naturally led you to the ocean, If I remember right, the Royal Society as the grand source of lightning: but the ac- made one experiment to discover the velocity tivity of lightning, or the electric element,
* The wire mentioned in this account was replaced and the fitness of water to conduct it, toge- by a small brass chain. In the summer of 1763, the ther with the experiments you mention of lightning again struck that steeple, and from the clocksalt and water, seem to make against it, and fore done the wire, went off to the same hinge, and to prepare the way for some other hypothesis. again shattered the same door. In its passage through Accordingly you propose a new one, which the same holes of the same floors, it did no damage to
the floors, nor to the building during the whole extent is very curious, and not so liable, I think, to of the chain. But the chain itself was
destroyed, being objections as the former. But there is not, as partly scaltered about in fragments oftwo or three links yet, I believe, a sufficient variety of experi- duced to smoke, and dissipated. (See an account of the ments to establish any theory, though this same effect of lightning on a wire at Newbury, p. 296.] seems the most hopeful of any i have heard of. The steeple, when repaired, was guarded by an iron
The effect which the discharge of your spindle down the outside of ihe building, into the earth.
of the electric fire, by a wire of about four | Answer to the foregoing.–Read at the Royal miles in length, supported by silk, and by turn
Society, Dec. 25, 1756. ing it forwards and backwards in a field, so SUPPOSE a tube of any length open at both that the beginning and end of the wire were ends, and containing a moveable wire of just at only the distance of two people, the one the same length, that fills its bore. If I atholding the Leyden bottle and the beginning tempt to introduce the end of another wire of the wire, and the other holding the end of into the same tube, it must be done by pushthe wire and touching the ring of the bottle; ing forward the wire it already contains; and but by this experiment no discovery was made, the instant I press and move one end of that except that the velocity was extremely quick. wire, the other end is also moved, and intro
As water is a conductor as well as metals, ducing one inch of the same wire, I extrude, it is to be considered whether the velocity of at the same time, an inch of the first, from the the electric fire might not be discovered by other end of the tube. means of water; whether a river, or lake, or If the tube be filled with water, and I insea, may not be made part of the circuit ject an additional inch of water at one end, I through which the electric fire passes ? in- force out an equal quantity at the other in the stead of the circuit all of wire, as in the above very same instant. experiment.
And the water forced out at one end of the Whether in a river, lake, or sea, the elec- tube is not the very same water that was forced tric fire will not dissipate and not return to in at other end at the same time, it was the bottle ? or, will it proceed in strait lines only in motion at the same time. through the water the shortest courses possi T'he long wire, made use of in the experible back to the bottle ?
ment to discover the velocity of the electric If the last, then suppose one brook that falls fluid, is itself filled with what we call its nainto Delaware doth head very near to a brook tural quantity of that fluid, before the hook of that falls into Schuylkill, and let a wire be the Leyden bottle is applied to one end of it. stretched and supported as before, from the The outside of the bottle being at the time head of the one brook to the head of the other, of such application in contact with the other and let the one end communicate with the end of the wire, the whole quantity of electric water, and let one person stand in the other fluid contained in the wire is, probably, put in brook, holding the Leyden bottle, and let an- motion at once. other person hold that end of the wire not in For at the instant the hook, connected with the water, and touch the ring of the bottle.-- the inside of the bottle, gives out ; the coatIf the electric fire will go as in the last ques-ing or outside of the bottle, draws in a portion tion, then will it go down the one brook to of that fluid. Delaware or Schuylkill, and down one of them If such long wire contains precisely the to their meeting, and up the other brook; the quantity that the outside of the bottle detime of its doing this may possibly be observ- mands, the whole will move out of the wire able, and the further upwards the brooks are to the outside of the bottle, and the over quanchosen, the more observable it would be.
tity which the inside of the bottle contained, Should this be not observable, then suppose being exactly equal, will flow into the wire, the two brooks falling into Susquehanna and and remain there, in the place of the quantity Delaware, and proceeding as before, the elec- the wire had just parted with to the outside of tric fire may, by that means, make a circuit the bottle. round the North Cape of Virginia, and go But if the wire be so long as that one tenth many hundred miles, and in doing that, it (suppose) of its natural quantity is sufficient would seem it must take some observable time. to supply what the outside of the bottle de
If still no observable time is found in that mands, in such a case the outside will only reexperiment, then suppose the brooks falling ceive what is contained in one tenth of the the one into the Ohio, and the other into Sus- wire's length, from the end next to it; though quehanna, or Potowmac, in that the electric the whole will move so as to make room at fire would have a circuit of some thousands the other end for an equal quantity issuing, at of miles to go down the Ohio to Mississippi, the same time, from the inside of the bottle. to the Bay of Mexico, round Florida, and
So that this experiment only shows the exround the South Cape of Virginia; which, I treme facility with which the electric fluid think, would give some observable time, and moves in metal; it can never determine the discover exactly the velocity.
velocity. But if the electric fire dissipates, or weak And, therefore, the proposed experiment ens in the water, as I fear it does, these ex-|(though well imagined, and very ingenious) periments will not answer.
of sending the spark round through a vast
length of space, by the waters of Susquehanna, The newspapers have mentioned, that in 1765, the or Potowmac, and Ohio, would not afford the lightning fell a third time on the same steeple, and was satisfaction desired, though we could be sure safely conducted by the rod, but the particulars are not that the motion of the electric fluid would be
come to hand.
in that tract, and not under ground in the wet stand. Then electrising the stand, I had the earth by the shortest way.
pleasure of seeing what I expected; the B. FRANKLIN. wooden needle turned round, carrying the
pins with their heads foremost. I then elecMr. Kinnersley to B. Franklin.
trised the stand 'negatively, expecting the Experiments on boiling water, and glass heated tremely disappointed, for it went still the
needle to turn the contrary way, but was exby boiling water.--Doctrine of repulsion in elec
When the stand was trised bodies doubted.--Electricity of the atmo. same way as before. sphere at different heights.-Electrical Horse- electrised positively, I suppose that the narace.- Electrical thermometer.— In what cases tural quantity of electricity in the air being the electrical fire produces heat.-Wire length increased on one side, by what issued from ened by Electricity.--Good effect of a rod on the points, the needle was attracted by the the house of Mr. West, of Philadelphia.
| lesser quantity on the other side. When PAILADELPHIA, March 12, 1761.
electrised negatively, I suppose that the naHAVING lately made the following experi- tural quantity of electricity in the air was diments, I
very cheerfully communicate them, minished near the points; in consequence in hopes of giving you some degree of plea- whereof, the equilibrium being destroyed, the sure, and exciting you to further explore your needle was attracted by the greater quantity favourite, but not quite exhausted subject, elec- on the opposite side. tricity.
The doctrine of repulsion, in electrised boI placed myself on an electric stand, and, dies, I begin to be somewhat doubtful of. I being well electrised, threw my hat to an think all the phenomena on which it is foundunelectrised person, at a considerable dis- ed, may be well enough accounted for withtance, on another stand, and found that the out it. Will not cork balls, electrised negahat carried some of the electricity with it; for, tively, separate as far as when electrised posiupon going immediately to the person who re- tively? And may not their separation in both ceived it, and holding a flaxen thread near him, cases be accounted for upon the same princiI perceived he was electrised sufficiently to ple, namely, the mutual attraction of the naattract the thread.
tural quantity in the air, and that which is I then suspended, by silk, a broad plate of denser or rarer in the cork balls ? it being metal, and electrised some boiling water one of the established laws of this fluid, th under it at about four feet distance, expect- quantities of different densities shall mutually ing that the vapour, which ascended plenti- attract each other, in order to restore the fully to the plate, would, upon the principle equilibrium. of the foregoing experiment, carry up some I can see no reason to conclude that the of the electricity with it; but was at length air has not its share of the common stock of fully convinced, by several repeated trials, electricity, as well as glass, and perhaps, all that it left all its share thereof behind. This other electrics per se. For though the air I know not how to account for; but does it will admit bodies to be electrised in it either not seem to corroborate your hypothesis, that positively or negatively, and will not readily the vapours
of which the clouds are formed, carry off the redundancy in the one case, nor leave their share of electricity behind, in the supply the deficiency in the other, yet let a common stock, and ascend in the negative person in the negative state, out of doors in state?
the dark, when the air is dry, hold, with his I put boiling water into a coated Florence arm extended, a long sharp needle, pointing flask, and found that the heat so enlarged the upwards, and he will soon be convinced that pores of the glass, that it could not be charged. electricity may be drawn out of the air; not The electricity passed through as readily, to very plentifully, for, being a bad conductor, all appearance, as through metal ; the charge it seems loth to part with it, but yet some of a three-pint bottle went freely through, will evidently be collected. The air near without injuring the flask in the least. When the person's body having less than its natural it became almost cold, I could charge it as quantity, will have none to spare; but, his usual. Would not this experiment convince arm being extended, as above, some will be the Abbé Nollet of his egregious mistake? collected from the remoter air, and will apFor while the electricity went fairly through pear luminous, as it converges to the point of the glass, as he contends it always does, the the needle. glass could not be charged at all.
Let a person electrised negatively present I took a slender piece of cedar, about eigh- the point of a needle, horizontally, to a cork teen inches long, fixed a brass cap in the mid- ball, suspended by silk, and the ball will be dle, thrust a pin horizontally and at right an- attracted towards the point, till it has parted gles, through each end (the points in contrary with so much of its natural quantity of elccdirections) and hung it, nicely balanced, like tricity as to be in the negative state, in the the needle of a compass, on a pin, about six same degree with the person who holds the inches long, fixed in the centre of an electric needle; then it will recede from the point, be
ing, as I suppose, attracted the contrary way | lowing description, you will readily apprehend by the electricity of greater density in the air the construction of it. (See the Plate.) behind it. But, as this opinion seems to de A B is a glass tube, about eleven inches viate from electrical orthodoxy, I should be long, and one inch diameter in the bore. It glad to see these phenomena better accounted has a brass ferrule cemented on each end, for by your superior and more penetrating ge- with a top and bottom part, C and D, to be nius.
screwed on, air-tight, and taken off at pleaWhether the electricity in the air, in clear sure. In the centre of the bottom part D, is dry weather, be of the same density at the a male screw, which goes into a brass nut, in height of two or three hundred yards, as near the mahogany pedestal E. The wires F and G the surface of the earth, may be satisfactorily are for the electric fire to pass through, dartdetermined by your old experiment of the ing from one to the other. The wire G exkite. The twine should have throughout a tends through the pedestal to H, and may be very small wire in it, and the ends of the wire, raised and lowered by means of a male screw where the several lengths are united, ought on it. The wire F may be taken out, and the to be tied down with a waxed thread, to pre- hook I be screwed into its place. K is a glass vent their acting in the manner of points. Itube, with a small bore, open at both ends, cehave tried the experiment twice, when the mented in the brass tube L, which screws air was as dry as we ever have it, and so into the top part C. The lower end of the clear that not a cloud could be seen, and tube K is immersed in water, coloured with found the twine each time in a small degree cochineal, at the bottom of the tube A B. (I electrised positively. The kite had three used, at first, coloured spirits of wine, but in metalline points fixed to it: one on the top, one experiment I made, it took fire.) On the and one on each side. That the twine was top of the tube K is cemented, for ornament, electrised, appeared by the separating of two a brass ferrule, with a head screwed on it, small cork balls, suspended on the twine by which has a small air-hole through its side, fine flaxen threads, just above where the silk at a. The wire b, is a small round spring, was tied to it, and sheltered from the wind, that embraces the tube K, so as to stay wherThat the twine was electrised positively, ever it is placed. The weight M is to keep was proved, by applying it to the wire of a strait whatever may be suspended in the tube charged bottle, which caused the balls to se-A B, on the hook I. Air must be blown parate further, without first coming nearer through the tube K, into the tube A B, till together. This experiment showed, that the enough is intruded to raise, by its elastic electricity in the air, at those times, was force, a column of the coloured water in the denser above than below. But that cannot tube K, up to c, or thereabouts; and then, be always the case; for you know we have the gage-wire b, being slipt down to the top frequently found the thunder-clouds in the ne- of the column, the thermometer is ready for gative state, attracting electricity from the use. earth: which state, it is probable, they are I set the thermometer on an electric stand, always in when first formed, and till they with the chain N fixed to the prime conducthave received a sufficient supply. How they or, and kept it well electrised a considerable come afterwards, towards the latter end of the time; but this produced no sensible effect; gust, to be in the positive state, which is some which shows, that the electric fire, when in a times the case, is a subject for further in- state of rest, has no more heat than the air, quiry.
and other matter wherein it resides. After the above experiments with the When the wires F and G are in contact, a wooden needle, I formed a cross, of two large charge of electricity sent through them, pieces of wood, of equal length, intersecting even that of my case of five and thirty bottles each other at right angles in the middle, hung containing above thirty square feet of coated it horizontally upon a central pin, and set a glass, will produce no rarification of the air light horse with his rider, upon each extre- included in the tube A B; which shows that mity; whereupon, the whole being nicely the wires are not heated by the fire's passing balanced, and each courser urged on by an through them. electrised point of a pair of spurs, I was enter When the wires are about two inches apart, tained with an electrical horse-race.
the charge of a three pint bottle, darting from I have contrived an electrical air thermo- one to the other, rarifies the air very evidentmeter, and made several experiments with it, ly; which shows, I think, that the electric that have afforded me much satisfaction and fire must produce heat in itself, as well as in pleasure. It is extremely sensible of any al- the air, by its rapid motion. teration in the state of the included air, and The charge of one of my glass jars (which fully determines that controverted point, will contain about five gallons and a half, Whether there be any heat in the electric wine measure) darting from wire to wire, fire? By the enclosed draught, and the fol- will, by the disturbance it gives the air, re