200 Mr. cavendish on the Torpedo. 
his hands in the water, provided one hand is nearer to 
the upper iurface of the eleCtric organs than the other. 
The fecond difficulty is, that no one hath ever per- 
ceived the lhock to be accompanied with any fpark or 
light, or with the lead; degree of attraction or repulfion. 
With regard to this, it muft be obferved, that when a 
perfon receives a fhock from the torpedo, he muft have 
formed the circuit between its upper and lower furface 
before it begins to throw the electricity from one fide to 
the other; for otherwife the fluid would be difcharged 
over the furface of the fifties body before the circuit ivas 
compleated, and confequently the perfon w r ould receive 
no fhock. The only way, therefore, by which any light 
or fpark could be perceived, muft be by making fome 
interruption in the circuit. Now Mr. walsh found, that 
the lhock would never pafs through the leaft fenfible 
fpace of air, or even through a fmall brafs chain. This 
circumftance, therefore, does not feem inconfiftent with 
the fuppofition that the phenomena of the torpedo are 
owing to elecftricity ; for a large battery will give a con- 
fiderable fhock, though fo weakly charged that the elec- 
tricity will hardly pafs through any fenfible fpace of air; 
and the larger the battery is, the lefs will this fpace be. 
The principle on which this depends will appear from 
the following experiments. 
I took feveral jars of different fizes, and connected 
them to the fame prime conductor, and electrified them 
in a given degree, as fhewn by a very exaCt electrome- 
ter ; and then found how near the knobs of an inftrument 
m 
