798 



ANNUAL REGISTER, 1804. 



Mith elcflricit)-, and being inter- 

 cepted by the same non-condu6tors 

 as glass and sealing-wax. The back 

 and the breast of the animal ap- 

 pear to be in different states of elec- 

 tricity, I mean in particular the 

 upper and lower surfaces of the 

 two assemblages of pliant cylinders 

 engraved in the works of Loren- 

 zini*. By the knowledge of this 

 circumstance we have been able to 

 direft his shocks, though the} Mere 

 small, through a circuit of four 

 persons, all feeling it, and likewise 

 through a considerable length of 

 •wire held by two insulated persons, 

 one touching his lower surface and 

 the other his upper. When the 

 wire was exchanged for glass or 

 sealing wax no cfi"c6l could be ob- 

 tained ; but as it was resumed the 

 two persons became liable to the 

 shock. These experiments have 

 been varied many ways, and re- 

 peated times without number, and 

 they all determined the choice of 

 conductors to be the same in the 

 torpedo as in the Lcyden phial. 

 The sensations likewise, occasioned 

 by the one and the other in the hu- 

 man frame, are precisely similar. 

 Not only the shock, but the numb- 

 ing sensation, which the animal 

 sometimes dispenses, expressed in 

 French by tlic words cngourdisse- 

 mcnt and Journiillemeiit, may be 

 exactly imitated with the phial, by 

 means of Lane's clc'^rometor ; the 

 regulating rod of which, to produce 

 the latter eflect, must be brought 

 almost into contaft with the prime 

 condui'^or which joins the phial. It 

 is a singularity that the torpedo, 

 when insulated, should be able to 

 give us, insulated likewise, forty 

 or lifty successive shocks from nearly 



the same part ; and these with lit- 

 tle, if any diminution of their force. 

 Each etfort of the animal to give the 

 shock is conveniently accompanied 

 by a depression of his eyes, by 

 which even his attempts to give it to 

 non-conductors can be observed : 

 in respedt to the rest of his body he 

 is in a great degree motionless, 

 though not entirely so. I have 

 taken no less than fifty of the above- 

 mentioned successive shocks from 

 an insulated torpedo in the sp^ce of 

 a minute and a half. All our expe- 

 riments confirm that the electricity 

 of the torpedo is condensed, in the 

 instant of its explosion, by a sud- 

 den energy of the animal ; and as 

 there is no gradual accumulation, 

 or retention of it, as in case of 

 charged glass, it is not at all sur- 

 prising that no signs of attradtion 

 or repulsion were perceived in the 

 pith balls. 



In short, the effect of the torpedo 

 appears to arise from a compressed 

 elastic fluid, restoring itself to its 

 equilibrium in the same way, and by 

 the same mediums, as the elastic 

 fluid compressed in charged glass. 

 The skin of the animal, bad conduc- 

 tor as it is, seems to be a better con- 

 ductor of his electricity than the 

 thinnest plate of elastic air. Not- 

 Avithstanding the weak spring of the 

 torpedinal electricity, I was able, in 

 the public exhibitions of ray experi- 

 ments at La Rochelle, to convey it 

 through a circuit formed from one 

 surface of the animal to the other, 

 by two long brass wires, and four 

 persons, which number, at times, 

 was increased even to eight. The 

 several persons were made to com- 

 municate with each other, and the 

 two outermost with the wires, by 



* Obscrvazioni iutorno alle torpediiii, 1678. 



. means 



