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common matter has not (generally) more than it can contain; otherwise all loose portions of it would repel each other, as they constantly do when they have electric atmospheres.
The form of the electrical atmosphere is that of the body which it surrounds. This shape may be rendered visible in a still air, by raising a smoke from dry resin dropped into a hot teaspoon under the electrified body, which will be attracted and spread itself equally on all sides, covering and concealing the body. And this form it takes, because it is attracted by all parts of the surface of the body, though it cannot enter the substance already replete. Without this attraction it would not remain round the body, but be dissipated in the air.
The atmosphere of electrical particles surrounding an electrified sphere is not more disposed to leave it, or more easily drawn off from any one part of the sphere than from another, because it is equally attracted by every part. But that is not the case with bodies of any other figure. From a cube it is more easily drawn at the corners than at the plane sides, and so from the angles of a body of any other form, and still most easily from the angle that is most acute, and, for this reason, points have a property of drawing on, as well as throwing off, the electrical fluid, at greater distances than blunt bodies can.
From various experiments recited in our author's treatise, to which the curious may have recourse, the preceding observations are deduced. You will observe how much they coincide with and support these which I some time since communicated to the Society upon the sime subject.
To give iven the shortest account of all the experiments contained in Mi. Franklin's book, would exceed greatly the time allowed for these purposes by the Royal Society; I shall content myself, therefore, with laying a few of the most singular ones before you.
The effects of lightning, and those of electricity, appear very similar. Light n lag has often been known to strike people blind. A pigeon, struck dead to appearance by the electrical shock, recovering life, drotped several days, ate nothing, though crumbs were thrown to it, but declined and died. Mr. Franklin did not think of its being derived of sight; but afterwards a pullet, struck dead in like manner being recovered by repeatedly blowing into its lungs, when set town on the floor, ran headlong against the wall, and on examinatim appeared perfectly blind; hence he concluded, that the pigeoi also had been absolutely blinded by the
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shock. From this observation we should be extremely cautious, how in electrizing we draw the strokes, especially in making the experiment of Leyden, from the eyes, or even from the parts near them.
Some time since it was imagined, that deafness had been relieved by electrizing the patient, by drawing the snaps from the ears, and by making him undergo the electrical commotion in the same manner. If hereafter this remedy should be fantastically applied to the eyes in this manner, to restore dimness of sight, I should not wonder, if perfect blindness were the consequence of the experiment.
By a very ingenious experiment our author endeavours to evince the impossibility of success, in the experiments proposed by others of drawing forth the effluvia of non-electrics, cinnamon, for instance, and by mixing them with the electrical fluid, to convey them with that into a person electrified; and our author thinks, that, though the effluvia of cinnamon and the electrical fluid should mix within the globe, they would never come out together through the pores of the glass, and thus be conveyed to the prime conductor; for he thinks, that the electrical fluid itself cannot come through, and that the prime conductor is always supplied from the cushion, and this last from the floor. Besides, when the globe is filled with cinnamon, or other non-electrics, no electricity can be obtained from its outer surface, for the reasons before laid down. He has tried another way, which he thought more likely to obtain a mixture of the electrical and other effluvia together, if such a mixture had been possible. He placed a glass plate under his cushion, to cut off the communication between the cushion and the floor; he then brought a small chain from the cushion into a glass of oil rf 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 chan 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 from each other, the oil of turpentine baween. Now the globe, being turned, could draw no fire from the flcor through the ma- chine, the communication that way being cut of by the thick glass plate under the cushion; it must then draw it through the chains, whose ends were dipped in the oil of turpentiie. And, as the oil of turpentine, being in some degree an electric per se, would not conduct what came up from the floor, the electricity was obliged to jump from the end of one chain to the *nd of the other, which
he could see in large sparks; and thus it had a fair opportunity of seizing of the finest particles of the oil in its passage, and carrying them off with it; but no such effect followed, nor could he perceive the least difference in the smell of the electrical effluvia thus collected, from what it had when collected otherwise; nor does it otherwise affect the body of the person electrified. He likewise put into a phial, instead of water, a strong purging 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 his 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 the phial had been charged with water. He has also smelt the electrical fire, when drawn through gold, silver, copper, lead, iron, wood, and the human body, and could perceive no difference; the odor being always the same, where the spark does not burn what it strikes; and therefore he imagines, that it does not take that smell from any quality of the bodies it passes through. There was no abridging this experiment, which I think very well conceived, and as well conducted, in a manner to make it intelligible; and therefore I have laid the author's words nearly before you.
As Mr. Franklin, in a letter to Mr. Collinson some time since, mentioned his intending to try the power of a very strong electrical shock upon a turkey, I desired Mr. Collinson to let Mr. Franklin know, that I should be glad to be acquainted with the result of that experiment. He accordingly has been so very obliging as to send an account of it, which is to the following purpose. He made first several experiments on fowls, and found, that two large thin glass jars gilt, holding each about six gallons, and such as I mentioned I had employed in the last paper I laid before you upon this subject, were sufficient, when fully charged, to kill common hens outright; but the turkeys, though thrown into violent convulsions, and then, lying as dead for some minutes, would recover in less than a quarter of an hour. However, having added three other such to the former two, though not fully charged, he killed a turkey of about ten pounds' weight, and believes that they would have killed a much larger. He conceited, as himself says, that the birds killed in this manner eat uncommonly tender.
In making these experiments, he found, that a man could, without great detriment, bear a much greater shock than he imagined; for he inadvertently received the stroke of two of these jars through his arms and body, when they were very near fully charged. It
seemed to him a universal blow throughout the body from head to foot, and was followed by a violent, quick trembling in the trunk, which went gradually off in a few seconds. It was some minutes before he could recollect his thoughts, so as to know what was the matter; for he did not see the flash, though his eye was on the spot of the prime conductor, from whence it struck the back of his hand; nor did he hear the crack, though the by-standers said it was a loud one; nor did he particularly feel the stroke on his hand, though he afterwards found it had raised a swelling there of the bigness of half a swan-shot or pistol-bullet. His arms and the back of his neck felt somewhat numbed the remainder of the evening, and his breast was sore for a week after, as if it had been bruised. From this experiment may be seen the danger, even under the greatest caution, to the operator, when making these experiments with large jars; for it is not to be doubted, but that several of these fully charged would as certainly, by increasing them in proportion to the size, kill a man, as they before did the turkey.
Upon the whole, Mr. Franklin appears in the work before us, to be a very able and ingenious man; that he has a head to conceive, and a hand to carry into execution, whatever he thinks may conduce to enlighten the subject-matter, of which he is treating; and, although there are in this work some few opinions, in which I cannot perfectly agree with him, I think scarce anybody is better acquainted with the subject of electricity than himself.
LETTER FROM THE ABBE* NOLLET TO BENJAMIN FRANKLIN.*
A Monsieur Benjamin Franklin, Auteur du Livre intitulé "Expériences et Observations sur F Electricité, faites à Philadelphie en Amérique."
Monsieur, Lorsqu'on fit paraître en Français vos Lettres sur l'Electricité, je m'empressai de les lire, et j'y trouvai, comme l'annoncent vos Editeurs, des faits nouveaux et intéressants, des expériences bien imaginées et conduites avec intelligence, des vues fort ingénieuses et des conjectures plausibles. Si ce témoignage, qui est très-sincère de ma part, étoit capable de vous flatter, je vous le rends avec d'autant plus d'empressement et de plaisir, que des gens peu instruits de mes vrais sentiments, m'ont accusé très-mal-à-propos de penser d'une autre façon. Cela vient apparemment de ce que j'ai mis quelques restrictions à mes applaudissements, et de ce qu'en parlant de vos opinions, j'en ai cité quelques-unes comme me paraissant incompatibles avec certaines vérités bien établies, et d'autres comme des nouveautés dont j'aurois voulu trouver les preuves plus solides. Mais cette liberté que j'ai osé prendre, et que je crois bien permise en pareille matière, doit-elle m'attirer des reproches que je n'ai pas mérités? Voudrait-on, en dissimulant les bornes que je mets à ma critique, laisser à penser que je désapprouve tout ce qui est dans votre ouvrage, afin qu'on me croie un homme peu au fait de la matière, ou mal intentionné? Ou bien s'offenseroit-on de ce que je ne souscris pas pleinement aux éloges illimités qu'on lui donne, comme si quelques restrictions de ma part portoient préjudice au discernement de ceux qui n'ont point usé de la même réserve? C'est à vous-même, Monsieur, qui êtes à mille cinq cent lieues de ces tracasseries, et aux personnes judicieuses qui se tiennent à l'écart pour juger sans prévention et sans partialité, que je m'adresse pour dire tout naturellement ce que je pense sur des questions auxquelles j'ai droit de m'interesser plus
* This letter is the first of a series written by the Abbé Nollet to Dr. Franklin, and serves to explain the grounds of the controversy, which the Abbé set on foot in regard to the Franklini&n theory of electricity. — Editor.
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