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Tbefalea Deoth by ancients and
Account of the Torpedo. From It is affirmed by Pliny, that the tor.
or stick; can benumb the strongest THE torpedo has been cele. arm, and stop the swiftest foot.
It is well observed by Dr. Bloch, moderns for its wonderful faculty that these exaggerations, on the part of causing a sudden numbness or of the ancients, are the less to be painful sensation in the limbs of wondered at when we reflect on those who touch or handle it. This similar ones in modern times. Thus power the ancients, unacquainted when Muschenbroek happened acci. with the theory of electricity, were dentally to discover and feel the effect contented to admire, without at.. of the electric shock from what is tempting to explain ; and, as is called the Leyden phial, he representusual in similar cases, magnified edit of so terrible a nature as to affect into an effect little short of what is his health for several days afterwards, commonly ascribed to enchantment. and declared that he would not un. Thus we are told by Oppian, that dergo a second for the whole kingthe torpedo, conscious of his latent dom of France. Yet this is now faculty, when caught by a hook, the common amusement of philosoexerts it in such a manner that, phical curiosity. passing along the line and rod, it The observations of the learned benumbs the astonished fisherman, Redi and others of the seventeenth and suddenly reduces him to a state century, had tended, in some deof helpless stupefaction.
gree, to elucidate the peculiar ac
tions and anatomy of the torpedo ; The hook'd torpedo, with instinctive but it was reserved for more modern force,
times, and for our own ingenious Calls all his magic from its secret countrymen in particular, to ex. Quick thro' the slender line and polished the particulars of its history; and
plain in a more satisfactory manner wand It darts; and tingles in th’offending to prove that its power is truly hand.
electric. The first experiments of The palsied fisherman, in dumb sur this kind were made by Mr. Walsh, prise,
of the royal society of London, at Feels thro' his frame the chilling vapours Rochelle in France, in the year 1772.
“ The effect of the torpedo," Drops the lost rod, and seems, in stiff'ning pain,
says Mr. Walsh, “ appears to be Some frost fix'd wanderer on the polar absolutely electrical forming, its cir. plain. cuit through the same conductors
with electricity, and being inter- the same part; and these with lila cepted by the same non-conductors tle, if any diminution of their force. as glass and sealing-wax. The back Each effort of the animal to give the and the breast of the animal ap- shock is conveniently accompanied pear to be in different states of elec- by a depression of his eyes, by tricity, I mean in particular the which even his attempts to give it to upper and lower surfaces of the non-conductors can be observed : two assemblages of pliant cylinders in respect to the rest of his body he engraved in the works of Loren. is in a great degree motionless, zini*. By the knowledge of this though not entirely so. I bare circumstance we have been able to taken no less than fifty of the above. direct his shocks, though they were mentioned successive shocks from small, through a circuit of four an insulated torpedo in the space of persons, all feeling it, and likewise a minute and a half. All our expethrough a considerable length of riments confirm that the electricity wire held by two insulated persons, of the torpedo is condensed, in the one touching his lower surface and instant of its explosion, by a sud. the other his upper. When the den energy of the animal; and as 'wire was exchanged for glass or there is no gradual accumulation, sealing wax no effect could be ob or retention of it, as in case of tained; but as it was resumed the charged glass, it is not at all sure two persons became liable to the prising that no signs of attraction shock. These experiments have or repulsion were perceived in the been varied many ways, and re. pith balls. poated times without number, and In short, the effect of the torpedo they all determined the choice of appears to arise from a compressed conductors to be the same in the elastic fluid, restoring itself to it torpede as in the Leyden phial. equilibrium in the same way, and by The sensations likewise, occasioned the same mediums, as the elastic by the one and the other in the hu- fluid compressed in charged glass. man frame, are precisely similar. The skin of the animal, bad conduc- ! Not only the shock, but the numb. tor as it is, seems to be a better cos. ing sensation, which the animal ductor of his electricity than the sometimes dispenses, expressed in thinnest plate of elastic air. NotFrench by the words engourdisse. withstanding the weak spring of the ment and fourmillement, may be torpedinal electricity, I was able, ia exactly imitated with the phial, by the public exhibitions of my experimeans of Lane's electrometer; the ments at La Rochelle, to convey it regulating rod of which, to produce through a circuit formed from one the latter effect, must be brought surface of the animal to the other, almost into contact with the prime by two long brass wires, and four conductor which joins the phial. It persons, which number, at times, is a singularity that the torpedo, was increased even to eight. The when insulated, should be able to several persons were made to com. give us, insulated likewise, forty municate with each other, and the or fifty successive shocks from nearly two outermost with the wires, by
* Observazioni intorno alle torpedini, 1678.
means of water contained in basons, The effects produced by the torpedo properly disposed between them for resemble in every respect a weak that purpose. This curious and con
electricity. vincing experiment is thus related by This exhibition of the electric Monsieur Seignette, mayor of La powers of the torpedo, before the Rochelle, and one of the secretaries academy of La Rochelle, was at a of its academy; published in the meeting held for the purpose, in French gazettes, for the month of my apartments, on the 22d of July, October in the above year.
1772, and stands registered in the A live torpedo was placed on a journals of the academy.” table: round another table stood five Mr. Walsh, in his paper on this persons insulated : two brass wires, subject, in the Philosophical Transeach thirteen feet long, were sus actions, thus continues the account pended to the ceiling by silken of these interesting experiments : strings. One of these wires rested “ The effect of the animal, in the by one end on the wet napkin on above experiments, was transmitted which the fish lay; the other end through as great an extent, and va. was immersed in a bason full of wa- riety of conductors, as almost at any ter, placed on the second table, on time we had been able to obtain it, which stood four other basons like and the experiments included nearly wise full of water. The first person all the points in which its analogy put a finger of one hand in the ba. with the Leyden phial had been obson in which the wire was immersed, served. These points were stated and a finger of the other hand in a to the gentlemen present, as were second bason. The second person the circumstances in which the two put a finger of one hand in the last effects appeared to vary. It was likebason, and a finger of the other in a wise represented to them, that our third, and so on successively, till experiments had been almost wholly the five persons communicated with with the animal in air ; that its acone another, with the water in the tion in water was a capital desidera. bwsons. In the last bason one end tum, that indeed all as yet done was of the second wire was immersed, little more than opening the door to and with the other end Mr. Walsh inquiry ; that much remained to be touched the back of the torpedo, examined by the electrician, as well when the five persons felt a commo. as the anatomist : that as artificial tion which differed in nothing from electricity had thrown light on the that of the Leyden experiment, ex natural operation of the torpedo, .cept in the degree of force. Mr. this might, in return, if well consi. Walsh, who was not in the circle of dered, throw light on artificial elec.conduction, received no shock..- . tricity, particularly in those respects This experiment was repeated seve- in which they now seemed to differ. ral times, even with eight persons, The torpedo, in these experiments, and always with the same success. dispensed only the distinct, instanta. The action of the torpedo is com. neous stroke, so well known by the municated by the same medium as electric shock. That protracted but the electric fluid. The bodies which lighter sensation, that torpor or intercept the action of the one inter- numbness which
at times induces, .cept likewise the action of the other, and from which he takes his name,
was not then experienced from the the animal, when in an insulated and animal, but it was imitated with ar- unagitated state ; but, from the tificial electricity, and shewn to be quickness with which the immersions producible by a quick consecution were made, it may be presurned there of minute shocks. This, in the tor- were full twenty of these in a mi. pedo, may perhaps be effected by nute; from whence the number of the successive discharge of his nu- shocks in that time must have amerous cylinders, in the nature of a mounted to above an hundred.running fire of musquetry: the This experiment, therefore, while it strong single shock may be his gene. discovered the comparative force be. ral volley. In the continued effect, tween a shock in water and one in as well as the instantaneous, his air, and between a shock delivered eyes, which are usually prominent, with a greater degree of exertion on are withdrawn into their sockets. the part of the animal, and one with
“A large torpedo, very liberal of less, seemed to determine that the his shocks, being held with both change of his organs with eleetrici. hands, by electric organs above and ty, as well as the discharge, was af. below, was briskly plunged into fected in an instant. water to the depth of a foot, and “ The torpedo was then put into instantly raised an equal height in a flat basket, open at the top, but air, and thus continually secured by a net with wide meshes, plunged and raised, as quick as pos- and with this confinement was let sible, for the space of a minute. In down into the water about a foot the instant his lower surface touched below the surface; being there the water in his descent, he always touched through the meshes, with gave a violent shock, and another, only a single finger, on one of his still more violent in his ascent; both electric organs, while the other hand which shocks, but particularly the was held at a distance in the water, Jast, were accompanied with a writh. he gave shocks which were distinctly ing in his body, as if meant to force felt with both hands. an escape. Besides these two shocks
66 The circuit for the passage of from the surface of the water, which the effect being contracted to the fine may yet be considered as delivered ger and thumb of one hand, applied in the air, he constantly gave at least above and below to a single organ, two when in the air, and as con- produced a shock, to our sensation, stantly one, and sometimes two, of twice the force of that in the larger when wholly in the water. The circuit by the arms. shocks in the water appeared, as far " The torpedo, still confined in as sensation could decide, not to have the basket, being raised to within near a fourth the force of those which three inches of the surface of the took place at the surface of the wa. water, was there touched with a ter, nor much more than a fourth of short iron bolt, which was held, half those entirely in air.
above and half in the water, by one « The shocks received in a cer- hand, while the other hand was tain time were not, on this occasion, dipped, as before, at a distance in the counted by a watch, as they had water; and strong shocks, felt with been on a former, when fifty were both hands, were thus obtained delivered in a minute and a half, by through the iron.
801 " A wet hempen cord, being fas. faces, were all affected; two persons tened to the iron boit, was held in likewise, after the electricity had the hand above the water, while the passed through a wire into a bason bolt touched the torpedo, and the of water, transmitted it from thence shocks were obtained through both into two distinct channels, as their these substances.
sensation convinced them, into ano. “A less powerful torpedo, sus. ther bason of water, from whence it pended in a small net, being fre. was conducted, probably in an united quently dipped into water, and state, by a single wire. How much raised again, gave, from the surface farther the eticct might thus be diof the water, slight shocks through vided and subdivided into different the net to the person holding it. channels, was not determined ; but
66 These experiments in water it was found to be proportionately manifested, that bodies immersed in weakened by multiplying these cir. that element might be affected by cuits, as it had been by extending immediate contact with the torpedo; the single circuit." that the shorter the circuit in which The body of the torpedo is of a the electricity moved, the greater somewhat circular form, perfectly would be the effect; and that the smooth, slightly convex above, and shock was communicable, from the marked along each side of the spine animal in water, to persons in air, by several small pores or foramina: through some substances.
the colour of the upper surface is usu. “ How far harpoons and nets, ally a pale reddish brown, sometimes consisting of wood and hemp, could marked by five, large, equidistant, in like circumstances, as it has been circular dusky spots, with paler cenfrequently asserted, convey the ef- tres; the under surface is whitish, or fect, was not so particularly tried, flesh-coloured. The torpedo, howas to enable us to confirm it. I ever, is observed to vary consideramention the omission, in hopes some bly in the cast and intensity of its one may
be induced to determine the colours. The general length of the point by express trial,
torpedo seems to be about eighteen, “We convinced ourselves, on inches, or two feet, but it is occaformer occasions, that the accurate sionally found of far larger dimen. Kæmpfer, who so well describes the sions, specimens having been taken effect of the torpedo, and happily on our own coasts of the weight of compares it with lightning, was de- fifty, sixty, and even eighty pounds. ceived in the circumstance that it A specimen, weighing fifty-three could be avoided by holding in the pounds, was found, according to Mr. breath, which we found no more to Pennant, to measure four feet in prevent the shock of the torpedo, length, and two and a half in breadth: when he was disposed to give it, the head and body, which were inthan it would prevent the shocks of distinct, were ncarly round, about the Leyden phial.
two inches thick in the middle, atte“ Several persons, forming as ma- nuating to extreme thinness on the ny distinct circuits, can be affected edges: below the body, the ventral by one stroke of the animal, as well fins formed on each side one fourth as when joined in a single circuit. of a circle: the two dorsal fins were For instance, four persons touching placed on the trunk of the tail: the separately his upper and lower sur eyes were small, placed near each VOL. XLVI.