Henry Cavendish 83 



The second of the two electrical papers which Cavendish 

 communicated to the Royal Society attracted considerable 

 attention, and though it does not deal with any matter which 

 we should now consider of fundamental importance, it shows 

 how far Cavendish was in advance of his time in appreciating 

 electrical matters correctly. The shocks which certain fishes, 

 such as the torpedo, 1 are capable of giving to those who touch 

 them had been known for some time, and John Walsh, a 

 Member of Parliament and Fellow of the Royal Society, had 

 described some experiments showing the conditions under 

 which the shocks were received. He suggested that they 

 were of an electrical character. The idea was not generally 

 accepted, and was even laughed at on the ground that a 

 fish immersed in sea water, which conducts electricity, could 

 not be electrically charged. In answer to this objection, 

 Cavendish actually constructed an imitation torpedo and 

 demonstrated to an assembly of scientific friends the possi- 

 bility of obtaining shocks even when it was immersed in salt 

 water. 



Maxwell remarks that this is the only recorded occasion 

 on which Cavendish admitted visitors to his laboratory. 



Henry Cavendish was born in 1731 ; he entered Peterhouse, 

 Cambridge, in 1749, and left that University four years later 

 without taking his degree. He was elected a Fellow of the 

 Royal Society in 1760 and died in 1810. His father, Lord 

 Charles Cavendish, third son of William, second Duke of 

 Devonshire, was interested in scientific subjects and published 

 a paper on the capillary depression of mercury in glass tubes, 

 which was highly spoken of by Franklin; he was also the 

 first to construct maximum and minimum thermometers, 

 and received the Copley medal of the Royal Society for the 

 invention of these useful instruments. We may infer 

 that the mind of Henry Cavendish was first directed towards 

 science by his father's example. He lived on an allowance 

 of 500 until he was about forty years of age, when through 

 the death of an uncle he acquired a fortune which made him 



1 The word " torpedo " comes from the Italian, and is derived 

 from "torpor;" the name was given to the fish on account of the 

 numbness caused by the electric shock felt on touching it. The 

 torpedo is not now generally associated with torpor. 



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