TORPEDO. 



fevers, by tying down the patient to a table, and applying 

 the fifli fucceffively upon all hie members, which puts him 

 to cruel torment, but efFeftually removes his difeafe. Bel- 

 lonius affures us, that our own torpedos applied to the foles 

 of the feet, have proved fuccefsful againft fevers. 



Oppian, like Diphilus, diftinguilhes the parts where the 

 powers of the fifli pecuharly refide ; thefe he calls ^-xyon;, 

 the flanks, from which he imagined the animal had a faculty 

 of darting upon other fifhes certain fubftances, called by a 

 name xifKih-:, the meaning of which is obfcure. In the fix- 

 teenth century, fome members of the Academia del Ci- 

 mento availed themfelves of their vicinity to the fea to make 

 experiments on the torpedo. Redi began, and was after- 

 wards afTiiled by Borelli, and Stciio the Dane ; and Lo- 

 renzini, his fcholar, engaged in the fame purfuit, and pub- 

 Lihed a curious treatife upon the fubjed. Redi, having 

 endeavoured to diftinguifh between the real properties ot 

 the torpedo, and thofe erroneoufly afcribed to it, proceeded 

 to the anatomy of it ; and was the hrft who with any ac- 

 curacy defcribed tliofe crooked fubllances lying on each 

 fide of the fpine, near the liead, which he confidered as 

 mufcles (from thence named mufculi falcati) that projefted, 

 according to him, certain effluvia, occafioning the fenfation 

 of numbnefs more or lefs, as the animal was excited to put 

 thefe organs into aftion. Tliis hypothefis of the tranfmif- 

 fion of effluvia was immediately embraced by Lorenzini, 

 and afterwards by Claude Pei-rault. Borelli, not admitting 

 the emiflion of benumbing particles, referred the fenfation 

 produced by this fifh to a certain brillc undulation of the 

 parts touched, which the animal could excite at will. 



In 1 7 14, M. Reaumur, being on the coaft of Poitou, 

 took an opportunity of making fome experiments on the 

 torpedo, which, with the refult, he communicated to the 

 Roj-al Academy of Sciences at Paris. His hypothefis, 

 which was generally received by the ingenious naturalifts 

 over aU Europe, is not very different from that of Borelli ; 

 for inftead of the undefined vibrating parts of the latter, 

 M. Reaumur fubflituted mufcles (the mufculi falcali of 

 Redi and Lorenzini) which, by the vivacity of their adlion, 

 impreifed upon the hand, that touched thefe parts, a fenfa- 

 tion of numbnefs, owing to the ftoppage of the progreffion 

 of the nervous fluid, or a repulfion of the fame. But he 

 denied that this impreffion of numbnefs could be commu- 

 nicated through water, a net, or any other foft and yielding 

 fubftance ; nay, through a fl;ick, except a very fliort one ; 

 ■whereas, it is certain, that the (hocks of the torpedo are 

 not lefs conducted throvigh fuch media than thofe from a 

 charged eleftrical phial. 



We have been lately furniftied, by the experiments and 

 ohfervations of John Walfli, efq. with a theory, much more 

 plaufible and juft than any above recited, wliich confiders 

 the eleftric fluid as the efficient caufe of the amazing qua- 

 lities of the torpedo. We fhaU be led to a brief account 

 of the fafts on which this theory is founded by the follow- 

 ing preliminary remarks. 



Soon after the difcovery of the Leyden phial, the cele- 

 brated profeflbr Allemand apphed to M. s'Gravefande, go- 

 vernor of Eflequibo, for an account of a fifh in Surinam, 

 refembling a conger-eel, and poffeffing properties fimilar to 

 thofe of the torpedo ; this account was received in 1 754, 

 and publifhed in the fecond volume of the Tranfaftions of 

 the fociety at Haerlem. From this account it appears, 

 that the fhocks of the fifli, which were fo violent, when the 

 fifh was flrong and lively, as to throw a perfon who touched 

 it to the ground, were like thofe of the eledlrical fire, but 

 unaccompanied with fparks of fire ; and that the fifh was a 



fpecies of the gymnotus of Artedi. In the fixth volun\e of 

 the fame work, we have a more ample relation of the exer- 

 tions of this animal by M. Vander Lott, dated from Rio 

 ElTequibo, in 1 761. M. Adanfon, about the fame time 

 with the difcovery of M. s'Gravefande in America, met 

 with the fame or a fimilar fifh in the river of Senegal in 

 Africa. The earlieft account we have of this kind of eel 

 is by M. Richer, recorded by M. du Hamel, in his Hiftory 

 of the Royal Academy of Sciences for 1677. In the if- 

 land of Cayenne, fays M. du Hamel, there is a fifh, not 

 unlike a conger-eel, which, touched with the finger, or even 

 with the end of a flick, affefts the arm with a numbnefs, 

 and the head with giddinefs, and the eyes with a dimnefs of 

 fight, which M. Richer had himfelf felt upon making the 

 experiment. See Gymnotus. 



We are indebted to Mr. Walfh for not only the firft, but 

 for a numerous feries of experiments on the torpedo, in order 

 to afcertain its eleftrical nature ; together with fome correft 

 and elegant drawings of the entire animal, and of fome of its 

 principal organs that appeared upon diffeftion. Thefe expe- 

 riments were made in the year 1 772, partly at the ifle of Rlie, 

 and partly at Rochelle, in the prefence of the members of 

 the Royal Academy of Sciences at that place. They were 

 condutled in a fcientific manner, and properly diverfified, 

 and the refult of them fatisfaClorily eftabhfhed the torpedo 

 in the rank of an electrician, furnifhed with a power over 

 the eleftric matter ; by means of which he can, without 

 any foreign machinery', and almoft in an inflantaneous man- 

 ner, coUeft, condenfe, and at his will difpcnfe it to neigh- 

 bouring bodies, through any of thofe fubftances that are 

 known to be conduftors of the eleftric fluid. The fenfa- 

 tions occafioned by the torpedo and Leyden phial, in the 

 human frame, are precifely fimilar : not only the fhock, 

 but the numbing fenfation fometimes given by the ani- 

 mal, may be exaftly imitated with the phial, by means of 

 Lane's eleftrometer ; the regulating rod of whicli, to pro- 

 duce the latter effeft, mufl be brought almoft into con- 

 taft with the prime conduftor which joins the pliial. 

 The firfl experiment of Mr. Walfh difcovered the elec- 

 trical quality of the torpedo, by his conveying its effects 

 through the fame conduftors with his elettricity, fuch 

 as metals, water, and animal fluids, and by intercepting it 

 by the fame non-condu6lors, as gl?.fs and fealing-wax. Be- 

 fides, one of the mofl brilliant of his difcoveries was, that 

 this animal not only could accumulate in one part a large 

 quantity of eleftrical matter, but was furnifhed with a cer- 

 tain organization, difpofed in the manner of the Leyden 

 phial: thus, while one furface of the elec"lrical part {e.g. 

 that on the back ) was charged with tliis matter, or in a po- 

 fitive ftate ; the other furface (that on the belly) was de- 

 prived of it, or in a negative flate : fo that the equiUbrium 

 could be reftored, by making a communication between the 

 two furfaces by water, the fluids of tlie human body or 

 metals, in the fame manner as by forming a circuit between 

 the infide and outfide furfaces of the Leyden phial. A 

 living torpedo was laid on a table, upon a wet napkin ; 

 round another table flood five perfons infulated : and two 

 brafs wires, each thirteen feet long, were fufpended from 

 the ceiling by filken firings. One of the wires refled by 

 one end upon the wet napkin, the other end was immerfed 

 in a bafon full of water, placed on a fecond table, on 

 wliich ilood four other bafons full of water. The firft per- 

 fon put a finger of one hand into the water in which the 

 wire was immerfed, and a fintrer of the other hand into the 

 fecond ; and fo on fucceffively, till all the five perfons com- 

 municated with one another by the water in the bafons. In 



the 



