« AnteriorContinuar »
I do not remember any, experiment by sun's surface, with a swiftness so prodigious ! which it appeared that high rectified spirit Must not the smallest particle conceivable will not conduct; perhaps you have made have, with such a motion, a force exceeding such. This I know, that wax, rosin, brim- that of a twenty-four pounder, discharged stone, and even glass, commonly reputed elec- from a cannon ? Must not the sun diminish trics, per se will, when in a fluid state, con- exceedingly by, such a waste of matter; and duct pretty well. Glass will do it when only the planets, instead of drawing nearer to red hot. So that my former position, that him, as some have feared, recede to greater only metals and waters were conductors, and distances through the lessened attraction. other bodies more or less such as they par- Yet these particles, with this amazing motook of metal or moisture, was too general. tion, will not drive before them, or remove,
Your conception of the electric fluid, that the least or lightest dust they meet with: and it is incomparably more subtle than air, is un- the sun, for aught we know, continues of his doubtedly just. It pervades dense matter ancient dimensions, and his attendants move with the greatest ease; but it does not seem in their ancient orbits. to mix or incorporate willingly with mere May not all the phenomena of light be air, as it does with other matter. It will not more conveniently solved, by supposing uniquit common matter to join with air. Air ob-versal space filled with a subtle elastic fluid, structs, in some degree, its motion. An elec- which, when at rest, is not visible, but whose tric atmosphere cannot be communicated at vibrations affect that fine sense in the eye, as so great a distance, through intervening air, those of air do the grosser organs of the ear? as through a vacuum. Who knows then, but We do not, in the case of sound, imagine that there may be as the ancients thought, a re- any sonorous particles are thrown off from a gion of this fire above our atmosphere, prevent- bell, for instance, and fly in strait lines to the ed by our air, and its own too great distance ear; why must we believe that luminous parfor attraction, from joining our earth? Per- ticles leave the sun and proceed to the eye? haps where the atmosphere is rarest, this fluid Some diamonds, if rubbed, shine in the dark, may be densest, and nearer the earth where without losing any part of their matter. I the atmosphere grows denser, this fluid can make an electrical spark as big as the may be rarer; yet some of it be low enough flame of a candle, much brighter, and, thereto attach itself to our highest clouds, and fore, visible further; yet this is without fuel ; thence they becoming electrified, may be at- and I am persuaded, no part of the electric tracted by, and descend towards the earth, fluid flies off in such case to distant places, and discharge their watery contents, together but all goes directly, and is to be found in the with that ethereal fire. Perhaps the aurore place to which I destine it. May not difboreales are currents of this fluid in its own ferent degrees of the vibration of the above region, above our atmosphere, becoming from mentioned universal medium, occasion the aptheir motion visible. There is no end to con-pearance of different colours ? I think the elecjectures. As yet we are but novices in this tric fluid is always the same; yet I find that branch of natural knowledge.
weaker and stronger sparks differ in appaYou mention several differences of salts in rent colour, some white, blue, purple, red; electrical experiments. Were they all equal. the strongest, white; weak ones, red. Thus ly dry? Salt is apt to acquire moisture from different degrees of vibration given to the air a moist air, and some sorts more than others. produce the seven different sounds in music, When perfectly dried by lying before a fire, analagous to the seven colours, yet the meor on a stove, none that I have tried will con- dium, air, is the same. duct any better than so much glass.
If the sun is not wasted by expenditure of New flannel, if dry and warm, will draw the light, I can easily conceive that he shall electric fluid from non-electrics, as well as otherwise always retain the same quantity of that which has been worn.
matter; though we should suppose him made I wish
had the convenience of trying of sulphur constantly flaming: The action of the experiments you seem to have such ex- fire only separates the particles of matter, it pectations from, upon various kinds of spirits, does not annihilate them. Water, by heat salt, earth, &c. Frequently, in a variety of raised into vapour, returns to the earth in rain; experiments, though we miss what we ex- and if we could collect all the particles of pected to find, yet something valuable turns burning matter that go off in smoke, perhaps out, something surprising, and instructing, they might, with the ashes, weigh as much as though unthought of.
the body before it was fired: and if we could I thank you for communicating the illustra- put them into the same position with regard tion of the theorem concerning light. It is to each other, the mass would be the same as very curious, But I must own I am much in before, and might be burnt over again. The the dark about light. I am not satisfied with chymists have analysed sulphur, and find it the doctrine that supposes particles of mat- composed, in certain proportions, of oil, salt, ter called light continually driven off from the and earth; and having, by the analysis, disco
vered those proportions, they can, of those in-only to the surface of the earth, but could disgredients, make sulphur. So we have only to cover no difference. suppose, that the parts of the sun's sulphur, I placed the needle of a compass on the separated by fire, rise into his atmosphere, and point of a long pin, and holding it in the atthere being freed from the immediate action mosphere of the prime conductor, at the disof the fire, they collect into cloudy masses, tance of about three inches, found it to whirl and growing, by degrees, too heavy to be longer round like the flyers of a jack, with great rasupported, they descend to the sun, and are pidity. burnt over again. Hence the spots appear I suspended with silk a cork ball, about the ing on his face, which are observed to dimi- bigness of a pea, and presented to it rubbed nish daily in size, their consuming edges being amber, sealing-wax, and sulphur, by each of of particular brightness.
which it was strongly repelled; then I tried It is well we are not as poor Galileo was, rubbed glass and china, and found that each of subject to the inquisition for philosophical he- these would attract it, until it became elecresy. My whispers against the orthodox trified again, and then it would be repelled as doctrine, in private letters, would be danger- at first; and while thus repelled by the rubous; but your writing and printing would be bed glass or china, either of the others when highly criminal. As it is, you must expect rubbed would attract it. Then I electrified some censure, but one heretic will surely ex- the ball, with the wire of a charged phial, cuse another.
and presented to it rubbed glass (the stopper I am heartily glad to hear more instances of a decanter) and a china tea-cup, by which of the success of the poke-weed, in the cure it was as strongly repelled as by the wire; of that horrible evil to the human body, a can- but when I presented either of the other rub
You will deserve highly of mankind for bed electrics, it would be strongly attracted, the communication. But I find in Boston and when I electrified it by either of these, they are at a loss to know the right plant, till it became repelled, it would be attracted some asserting that it is what they call Me by the wire of the phial, but be repelled by choachan, others other things. In one of its coating. their late papers it is publicly requested that These experiments surprised me very much, a perfect description may be given of the and have induced me to infer the following plant, its places of growth, &c. I have mis- parodoxes. said the paper, or would send it to you. I 1. If a glass globe be placed at one end of thought you had described it pretty fully.* a prime conductor and a sulphur one at the
B. FRANKLIN. other end, both being equally in good order,
and in equal motion, not a spark of fire can
be obtained from the conductor; but one globe E. Kinnersley, at Boston, to Benjamin Franklin.
will draw out, as fast as the other gives in.
2. If a phial be suspended on the conNew Experiments.--Paradoxes inferred from ductor, with a chain from its coating to the
them.-Difference in the Electricity of a Globe table, and only one of the globes be made use of Glass charged, and a Globe of Sulphur.. of at a time, 2) turns of the wheel for instance, Difficulty of ascertaining which is positive and which negative.
will charge it; after which, so many turns of February 3, 1752.
the other wheel will discharge it; and as I have the following experiments to com- many more will charge it again. municate: I held in one hand a wire, which
3. The globes being both in motion, each was fastened at the other end to the handle having a separate conductor, with a phial susof a pump, in order to try whether the stroke pended on one of them, and the chain of it from the prime conductor, through my arms,
fastened to the other, the phial will become would be any greater than when conveyed charged; one globe charging positively, the
4. The phial being thus charged, hang it in * As the poke weed, though out of place, is introduced here, we shall translate and insert two extracts of like manner on the other conductor; set both translator of a small collection of his works, on the of turns that charged it before, will now disletters from Dr. Franklin to M. Dubourg, the French wheels a going again, and the same number same subject.
“ LONDON, March 27, 1773. charge it; and the same number repeated, “ I apprehend that our poke-weed is what the botan: will charge it again. ists term phytolacca. This plant bears berries as large as peas: the skin is black, but it contains a crimson 5. When each globe communicates with juice. It is this juice, thickened by evaporation in the the same prime conductor, having a chain some persons were said to have been cured. I am not hanging from it to the table, one of them, quite certain of the facts; all that I know is, that Dr. when in motion (but which I cannot say) will Colden had a good opinion of the remedy.". “LONDON, April 23, 1773.
draw fire up through the cushion, and disYou will see by the annexed paper by Dr. Solander, charge it through the chain; the other will that this herb, poke-weed, in which has been found a draw it up through the chain, and discharge specific remedy for cancers, is the most common species of phytolacca. (Phytolacca decandria L.”)
it through the cushion.
I should be glad if you would send to my From these experiments one may be certain house for my sulphur globe, and the cushion that your 2d, 3d, and 4th proposed experibelonging to it, and make the trial; but mustments, would succeed exactly as you suppose, caution you not to use chalk on the cushion, though I have not tried them, wanting time. some fine powdered sulphur will do better. I imagine it is the glass globe that charges If, as I expect, you should find the globes to positively, and the sulphur negatively, for charge the prime conductor differently, I hope these reasons: 1. Though the sulphur globe you will be able to discover some method of seems to work equally well with the glass one, determining which it is that charges posi- yet it can never occasion so large and distant tively.- I am, &c. E. KINNERŠLEY. a spark between my knuckle and the conductor,
when the sulphur one is working, as when the
glass one is used; which, I suppose, is occaB. Franklin to E. Kinnersley. sioned by this, that bodies of certain bigness Probable Course of the different Attractions and cannot so easily part with a quantity of elec
Repulsions of the two electrified Globes mention- trical fluid they have and hold attracted witked in the two preceding Letters.
in their substance, as they can receive an adPHILADELPHIA, March 2, 1752. ditional quantity upon their surface by way I THANK you for the experiments commu- of atmosphere. Therefore so much cannot be nicated. I sent immediately for your brim- drawn out of the conductor, as can be thrown stone globe, in order to make the trials you on it. 2. I observe that the stream or brush desired, but found it wanted centres, which I of fire, appearing at the end of a wire, conhave not time now to supply; but the first nected with the conductor, is long, large, and leisure I will get it fitted for use, try the ex- much diverging, when the glass globe is used, periments, and acquaint you with the result. and makes a snapping (or rattling) noise :
In the mean time I suspect, that the differ- but when the sulphur one is used, it is short, ent attractions and repulsions you observed, small, and makes a hissing noise; and just proceeded rather from the greater or smaller the reverse of both happens, when you hold quantities of the fire you obtained from differ- the same wire in your hand, and the globes are ent bodies, than from its being of a different worked alternately: the brush is large, long, kind, or having a different direction. In diverging, and snapping (or rattling) when haste,
B. FRANKLIN. the sulphur globe is turned; short, small, and
hissing, when the glass globe is turned.
When the brush is long, large, and much diB. Franklin to E. Kinnersley. verging, the body to which it joins seems to Reasons for supposing, that the glass Globe me to be throwing the fire out; and when the
charges positively, and the Sulphur negatively. contrary appears, it seems to be drinking in. -Hint respecting a leather Globe for Experi- 3. I observe, that when I hold my knuckle bements when travelling.
fore the sulphur globe, while turning, the PHILADELPHIA, March 16, 1752. stream of fire between my knuckle and the Sir, -Having hrought your brimstone globe globe seems to spread on its surface, as if it to work, I tried one of the experiments flowed from the finger; on the glass globe it you proposed, and was agreeably surprised to is otherwise. 4. The cool wind (or what was find, that the glass globe being at one end of called so) that we used to feel as coming from the conductor, and the sulphur globe at the an electrified point, is, I think, more sensible other end, both globes in motion, no spark when the glass globe is used, than when the could be obtained from the conductor, unless sulphur one. But these are hasty thoughts. when one globe turned slower or was not in As to your fifth paradox, it must likewise be so good order as the other; and then the true, if the globes are alternately worked ; spark was only in proportion to the difference, but if worked together, the fire will neither so that turning equally, or turning that slow- come up nor go down by the chain, because est which worked best, would again bring the one globe will drink it as fast as the other proconductor to afford no spark.
duces it. I found also, that the wire of a phial charged I should be glad to know, whether the efby the glass globe, attracted a cork ball that fects would be contrary if the glass globe is had touched the wire of a phial charged by solid, and the sulphur globe is hollow ; but I the brimstone globe, and vice versa, so that the have no means at present of trying. cork continued to play between the two phials, In your journeys, your glass globes meet just as when one phial was charged through with accidents, and sulphur ones are heavy the wire, the other through the coating, by and inconvenient-Query. Would not a thin the glass globe alone. And two phials charg- plane of brimstone, cast on a board, serve on ed, the one by the brimstone globe, the other occasion as a cushion, while a globe of leaby the glass globe, would be both discharged ther stuffed (properly mounted) might reby bringing their wires together, and shock ceive the fire from the sulphur, and charge the the person holding the phials.
conductor positively! Such a globe would be
in no danger of breaking* I think I can con mingled with a little hail, fell from the cloud, ceive how it may be done; but have not time without either thunder or lightning ; this to add more than that I am,
cloud being, according to all appearance, only B. FRANKLIN. the consequence of a storm, which happened
elsewhere.--I am, with a profound respect, The early LETTERS of Dr. Franklin on elec- your most humble and obedient servant,
G. MAZEAS. tricity having been translated into French, and printed at Paris ; the Abbe Mazeas, A more particular Account of the Circumin a letter to Dr. Stephen Hales, dated St. Germain, May 20, 1752, gives the follow
stances and Success of this extraordinary ing Account (printed in the Philosophical
Experiment was laid before the Royal Transactions) of the Experiment made at
Academy of Sciences at Paris, three days Marly, in pursuance of that proposed by
afterwards, in a Memorial by M. d'Alibard, Dr. Franklin
viz. The Philadelphian experiments, that Mr. Extrait d'un Memoire de M. D’Alibard. Lu Collinson, a member of the Royal Society,
a l'Academie Royale des Sciences, le 13 Mai,
1752. was so kind as to communicate to the public, having been universally admired in France,
“En suivant la route que M. Franklin nous the king desired to see them performed a tracée, j'ai obtenu une satisfaction comWherefore the duke d’Ayen offered his ma
plette. Voici les préparatifs, le procédé et
le succès. jesty his country-house at St. Germain, where M. de Lor, professor of experimental philoso
“ 1. J'ai fait faire à Marly-la-ville, située à phy, should put those of Philadelphia in exe
six lieues de Paris au milieu d'une belle cution. His majesty saw them with great sa- plaine dont le sol est fort élevé, une verge de tisfaction, and greatly applauded Messieurs fer ronde, d'environ un pouce de diametre, Franklin and Collinson. These applauses of longue de 40 pieds, et fort pointue par son his majesty having excited in Messieurs de extrémité supérieure; pour lui ménager une Buffon, d'Alibard, and de Lor, a desire of pointe plus fine, je l'ai fait armer d'acier verifying the conjectures Mr. Franklin, trempé et ensuite brunir, au défaut de dorure, upon the analogy of thunder and electricity, pour la préserver de la rouille ; outre cela, they prepared themselves for making the ex
cette verge de fer est courbée vers son experiment.
trémité inférieure en deux coudes à angles M. d'Alibard chose for this purpose a gar éloigné de deux pieds du bout inférieur, et le
aigus quoiqu'arrondis; le premier coude est den situated at Marly, where he placed upon an electrical body a pointed bar of iron, of second est en sens contraire à trois pieds du forty feet high. On the 10th of May, twenty
premier. minutes past two in the afternoon, a stormy
“ 2. J'ai fait planter dans un jardin trois cloud having passed over the place where the grosses perches de 28 à 29 pieds, disposées en bar stood, those that were appointed to ob- triangle, et éloignées les unes des autres serve it, drew near, and attracted from it d'environ huit pieds; deux de ces perches sparks of fire, perceiving the same kind of sont contre un mur, et la troisieme est au-decommotions as in the common electrical expe- semble, l'on à cloué sur chacune des entre
dans du jardin. Pour les affermir toutes enriments.
M. de Lor, sensible of the good success of toises à vingt pieds de hauteur; et comme le this experiment, resolved to repeat it at his grand vent agitoit encore cette espéce dé'dihouse in the Estrapade, at Paris. He raised fice, l'on a attaché au haut de chaque perche a bar of iron ninety-nine feet high, placed up
de longs cordages, qui tenant lieu d'aubans, on a cake of rosin, two feet square, and three répondent par le bas à de bons piquets forteinches thick. On the 18th of May, between ment enfoncés en terre à plus de 20 pieds des four and five in the afternoon, a stormy cloud perches, having passed over the bar, where it remain
“ 3. J'ai fait construire entre les deux pered half an hour, he drew sparks from the bar, ches voisines du mur, et adosser contre ce mur like those from the gun barrel, when in the une petite guérite de bois capable de contenir electrical experiments, the globe is only rub un homme et une table. bed by the cushion, and they produced the
“ 4. J'ait fait placer au milieu de la guérite same noise, the same fire, and the
une petite table d'environ un demi-pied de crackling. They drew the strongest sparks affermir un tabouret electrique. Ce tabouret
hauteur: et sur cette table j'ai fait dresser et at the distance of nine lines, while the rain,
n'est autre chose qu'une petite planche * The discoveries of the late ingenious Mr. Symmer, quarrée, portée sur trois bouteilles à vin; il on the positive and negative electricity produced by n'est fait de cette matiere que pour suppléer the mutual friction of white and black silk, &c. afford
au defaut d'un gâteau de résine qui me manhints for further improvements to be made with this
quoit. VOL. II....2M
“5. Tout étant ainsi préparé, j'ai fait elevernuée d'orage et de grêle ne fut pas plus d'un perpendiculairement la verge de fer au milieu quart-d'heure à passer au zénith de notre mades trois perches, et je l'ai affermie en l'attach- chine, et l'on n'entendit que ce seul coup
de ant à chacune des perches avec de forts cor- tonnerre. Sitôt que le nuage fut passé, et dons de soie par deux endroits seulement. qu'on ne tira plus d'étincelles de la verge de Les premiers liens sont au haut des perches, fer, M. le Prieur de Marly fit partir le sieur environ trois pouces au-dessous de leurs ex- Coiffier lui-même, pour m'apporter la lettre trémités, supérieures; les seconds vers la suivante, qu'il m'écrivit à la hâte. moitié de leur hauteur. Le bout inférieur de la verge de fer est solidement appuyé sur le Je vous annonce, Monsieur, ce que vous milieu du tabouret electrique, où j'ai fait attendez : l'expérience est complette. Aucreuser un trou propre à le recevoir. jourd'hui à deux heures 20 minutes après
“6. Comme il étoit important de garantir midi, le tonnerre a grondé directement sur de la pluie le tabouret et les cordons de soie, Marly ; le coup a été assez fort. L'envie de parce qu'ils laisseroient passer la matiéré vous obliger, et la curiosité m'ont tiré de mon électrique s'ils étoient mouillés, j'ai pris les fauteuil, où j'étois occupé à lire : je suis allé précautions nécessaires pour en empécher. chez Coiffier, qui déja m'avoit dépêché un enC'est dans cette vue que j'ai mis mon tabouret fant que j'ai rencontré en chemin, pour me sous la guérite, et que j'avois fait courber ma prier de venir ; j'ai doublé le pas à travers verge de fer à angles aigus; afin que l'eau un torrent de grêle. Arrivé à l'endroit où qui pourroit couler le long de cette verge, est placée la tringle coudée, j'ai présenté le ne pût arriver jusques sur le tabouret. C'est fil d'archal, en avançant successivement vers aussi dans le même dessein que j'ai fait clouer la tringle, à un pouce et demi, ou environ ; sur le haut et au milieu de mes perches, à il est sorti de la tringle une petite colonne trois pouces au-dessus des cordons de soie, des de fer bleuâtre sentant le soufre, qui venoit especes de boîtes formées de trois petites frapper avec une extrême vivacité le tenon planches d'environ 15 pouces de long, qui du fil d'archal, et occasionnoit un bruit sem couvrent par-dessus et par les côtês une pa- blable à celui qu'on feroit en frappant sur la reille longueur des cordons de soie, sans les tringle avec une clef. J'ai répété l'expétoucher.
rience au moins six fois dans l'espace d'envi“Il s'agissoit de faire, dans le tems de ron quatre minutes, en présence de plusieurs l'orage, deux observations sur cette verge de personnes, et chaque expérience que j'ai faite fer ainsi disposée ; l'une étoit de remarquer a dure l'espace d'un pater et d'un ave.
J'ai á sa pointe une aigrette lumineuse, semblable voulu continuer ; l'action du feu s'est ralentie à celle que l'on apperçoit à la pointe d'une peu peu ; j'ai approché plus près, et n'ai aiguille, quand on l'oppose assez prés d'un plus tiré que quelques étincellss, et enfin rien corps actuellement électrisé ; l'autre étoit de n'a paru. tirer de la verge de fer des étincelles, comme Le coup de tonnerre qui a occasionné cet on en tire du canon de fusil dans les expéri- évenément, n'a été suivi d'aucun autre ; tout ences électriques; et afin de se garantir des s'est terminé par une abondance de grele. piquûres de ces étincelles, j'avois attaché le J'étois si occupé dans le moment de l'expétenon d'un fil d'archal au cordon d'une longue rience de ce que voyois, qu'ayant été frappé fiole pour lui server de manche.... au bras un peu au-dessus du coude, je ne puis
“ Le Mécredi 10 Mai, 1752, entre deux et dire si c'est en touchant au fil d'archal ou à trois heures après midi, le nommé Coiffier, la tringle: je ne me suis pas plaint du mal ancien dragon, que j'avois chargé de faire les que m'avoit fait le coup dans le moment que observations en mon absence, ayant entendu je l'ai reçu ; mais comme la douleur contiun coup de tonnerre assez fort, vole aussitôt nuoit, de retour chez moi, j'ai découvert mon à la machine, prend la fiole avec le fil d'archal, bras en présence de Coiffier, et nous atons présente le tenon du fil à la verge, en voit apperçu une meurtrissure tournante autour sortir une petite étincelle brilliante, et en du bras, samblable à celle que feroit un coup entend le pétillement; il tire une seconde de fil d'archal, si j'en avois été frappé à nud. étincelle plus forte que la premiere et avec En revenant de chez Coiffier, j'ai recontré M. plus de bruit! il appelle ses voisins, et envoie le Vicaire, M. de Milly, et le maitre d'école, chercher M. le Prieur. Celuici accourt de à qui j'ai rapporté ce qui venoit d'arriver ; toutes ses forces; les paroissiens voyant la ils se sont plaints tous les trois qu'ils sentoient précipitation de leur curé, s'imaginent que le une odeur de soufre qui les frappoit davanpauvre Coiffier a éte tué du tonnerre; l'allarme tage à mesure qu'ils s'approchoient de moi : se répand dans le village; la grêle qui survi- j'ai porté chez moi la même odeur, et mes doent n'empèche point le troupeau de suivre mestiques s'en sont apperçus sans que je leur son pasteur. Cet honnête ecclésiastique ar- aye rien dit. rive près de la machine, et voyant qu'il n'y Voilà Monsieur, un récit fait à la héte, avoit point de danger, met luimême la main mais naif et vrai j'atteste, et vous pouvez asà l'auvere et tire de fortes étincelles. La surer que je suis prêt à rendre témoignage