VOL. LXVI.] PHILOSOPHICAL TRANSACTIONS- 25 



will pass through the person's body. Some fluid also will pass through him, 

 even though he does not touch either electric organ, but has his hands on any 

 two parts of the fishes body whatever, provided one of those parts is nearer to 

 the upper surface of the electric organs than the other. On the same principle, 

 if the torpedo is immersed in water, the fluid will pass through the water in all 

 directions, and that even to great distances from its body ; but it must be ob- 

 served, that the nearer any part of the water is to the fishes body, the greater 

 quantity of fluid will pass through it. Also, 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 sup- 

 posed it to be touched when out of the water, some fluid will pass through his 

 body ; but evidently less than when the animal is held in the air, as a great pro- 

 portion 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. 



The second difficulty is, that no one has ever perceived the shock to be ac- 

 companied with any spark or liglit, 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 

 fish's body before the circuit was completed, and consequently the person would 

 receive no sliock. 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. 



I took several jars of different sizes, and connected them to the same prime 

 conductor, and electrified them in a given degree, as shown 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, before the jars would 

 .discharge themselves. I then electrified the same jars again in the same degree 

 as before, and separated all of them from the conductor except one. It was 

 found, that tlie distance to which the knobs must be approached to discharge this 

 single jar, was not sensibly less than the former. It was also found, that the 



VOL. XIV. E 



