476 PHILOSOPHICAL TRANSACTIONS. [aNNO 1773, 



conduction to be very imperfect. The parts which conduct the best, are the 

 2 great lateral fins bounding the organs outwardly, and the space lying between 

 the 2 organs inwardly. All below the double transverse cartilages scarcely con- 

 duct at all, unless when the fish is just taken out of water and is still wet, the 

 mucus, with which he is lubricated, showing itself, as it dries, to be of an 

 insulating nature. 



f The organs themselves, when uncharged, appeared to be, not interiorly we 

 might suppose, but rather exteriorly, conductors of a shock. An insulated 

 person touching 2 torpedos, lying near one another on a damp table, with 

 fingers placed, one on the organ of one fish, and another on the organ of the 

 otlier, was sensible of shocks, sometimes delivered by one fish, and sometimes 

 by the other, as might be discovered by the respective winking of their eyes. 

 That the organs uncharged, served some way or other as conductors, was con- 

 firmed with artificial electricity, in passing shocks by them ; and in taking sparks 

 from them, when electrified. The electric effect was never perceived by us to 

 be attended with any motion or alteration in the organs themselves, but was 

 frequently accompanied with a little transient agitation along the cartilages 

 which surround both organs: this is not discernible in the plump and turgid 

 state of the animal, while he is fresh and vigorous ; but as his force decays, from 

 the relaxation of his muscles, his cartilages appear through the skin, and then 

 the slight action along them is discovered. 



May we not from all these premises conclude, that the effect of the torpedo 

 proceeds from a modification of the electric fluid? The torpedo resembles the 

 charged phial in that characteristic point of a reciprocation between its 2 surfaces. 

 Their effects are transmitted by the same mediums; than which there is not 

 perhaps a surer criterion to determine the identity of subtile matter: they 

 besides occasion the same impression on our nerves. Like effects have like 

 causes. But it may be objected, that the effects of the torpedo, and of the 

 charged phial, are not similar in all their circumstances; that the charged phial 

 occasions attractive or repulsive dispositions in neighbouring bodies; and that its 

 discharge is obtained through a portion of air, and is accompanied with light and 

 sound; nothing of which occurs with respect to the torpedo. The inaction of 

 the electricity of the animal in these particulars, while its elastic force is so great 

 as to transmit the effect through an extensive circuit, and in its course to com- 

 municate a shock, may be a new phenomenon, but is no ways repugnant to the 

 laws of electricity; for here too, the operations of the animal may be imitated 

 by art. 



The same quantity of electric matter, according as it is used in a dense or 

 rare state, will produce the different consequences. For example, a small phial, 

 whose coated surface measures only 6 square inches, will, on being highly 



