196 Memoir on the Torpedo as imitated by electricity 



represent the section of its body, and the dotted lines the direction of the 

 electric fluid; but it must be observed, that the nearer any part of the 

 water is to the fishes body, the greater quantity of fluid will pass through 

 it. Moreover, if any person touches the fish in this situation, either with 

 one hand on the upper surface of an electric organ, and the other on the 

 lower, or in any other of those manners in which I supposed it to be touched 

 when out of the water, some fluid will pass through his body ; but evidently 



Fig. i. 



less than when the animal is held in the air, as a great proportion of the 

 fluid will pass through the water: and even some fluid will pass through 

 him, though he does not touch the fish at all; but only holds his hands 

 in the water, provided one hand is nearer to the upper surface of the 

 electric organs than the other. 



401] The second difficulty is, that no one hath ever perceived the 

 shock to be accompanied with any spark or light, or with the least degree 

 of attraction or repulsion. With regard to this, it must be observed, that 

 when a person receives a shock from the torpedo, he must have formed 

 the circuit between its upper and lower surface before it begins to throw 

 the electricity from one side to the other; for otherwise the fluid would 

 be discharged over the surface of the fishes body before the circuit was 

 completed, and consequently the person would receive no shock. The only 

 way, therefore, by which any light or spark could be perceived, must be 

 by making some interruption in the circuit. Now Mr Walsh found, that 

 the shock would never pass through the least sensible space of air, or even 

 through a small brass chain. This circumstance, therefore, does not seem 

 inconsistent with the supposition that the phenomena of the torpedo are 

 owing to electricity; for a large battery will give a considerable shock, 

 though so weakly charged that the electricity will hardly pass through 

 any sensible space of air; and the larger the battery is, the less will this 

 space be. The principle on which this depends will appear from the 

 following experiments. 



402] I took several jars of different sizes, and connected them to the 

 same prime conductor, and electrified them in a given degree, as shewn 

 by a very exact electrometer; and then found how near the knobs of an 

 instrument in the nature of Mr Lane's electrometer must be approached, 



