310 ELECTRICAL FISH. SECT. XXIX. 



ducting heat, while it acquires a capacity for conducting elec- 

 tricity in a high degree. M. Becquerel regards the production 

 of heat and that of electricity to be concomitant ; their depend- 

 ence being such, that when one is increased the other diminishes, 

 and vice versa, so that one may altogether disappear with the 

 increase of the other. For instance, when electricity circulates 

 in a metallic wire, the greater the heat produced, the less the 

 quantity of electricity which passes, and the contrary, so that 

 the affair proceeds as if electricity were converted into heat, and 

 heat into electricity. Again, in a closed galvanic circuit the 

 sum of the heat produced in the chemical action of the acidulated 

 water upon the zinc and in the conducting wire is constant, so 

 that the quantity of heat disengaged in the reaction is greater in 

 proportion as less electricity passes through the wire. These, 

 and other circumstances, prove such an intimate connexion be- 

 tween the production of heat and electricity, that in the change 

 of condition of substances the electrical effects might disappear 

 or be annulled by the calorific effects. 



The galvanic current affects all the senses : nothing can be 

 more disagreeable than the shock, which may even be fatal if the 

 battery be very powerful. A bright flash of light is perceived 

 with the eyes shut, when one of the wires touches the face, and 

 the other the hand. By touching the ear with one wire, and 

 holding the other, strange noises are heard ; and an acid taste is 

 perceived when the positive wire is applied to the tip of the 

 tongue, and the negative wire touches some other part of it. 

 By reversing the poles the taste becomes alkaline. It renders 

 the pale light of the glow-worm more intense. Dead animals 

 are roused by it, as if they started again into life, and it may 

 ultimately prove to be the cause of muscular action in the 

 living. 



Several fish possess the faculty of producing electrical effects. 

 The most remarkable are the gymnotus electricus, found in South 

 America; and the torpedo, a genus of ray, frequent in the 

 Mediterranean. The electrical action of the torpedo depends 

 upon an apparatus apparently analogous to the Voltaic pile, 

 which the animal has the power of charging at will, consisting of 

 membranous columns filled throughout with laminae, separated 

 from one another by a fluid. The absolute quantity of electricity 

 brought into circulation by the torpedo is so great, that it effects 



