45S PEOSE HALIEUTICS. 



When the torpedo is disposed to 'astonish^ any one^, she 

 furnishes to a carefal observer the following premoni- 

 tory indications of her intentions : the back, which — un- 

 like that of the cat — is gibbous and raised when she is in 

 good humour, flattens as she waxes angry, till the convex 

 surface, gradually drawn in, becomes at length slightly 

 concave; and at the same time the eyes, remarkably 

 prominent during the repose of the creature, are retract- 

 ed far back in the orbits : these are the precursory signals 

 that the phials of her wrath are about to be poured forth ; 

 the shock then instantly follows, and the fish as suddenly 

 swells out again, recoveriag its usual form, generally to 

 prepare for a new attack. These shocks follow in rapid 

 succession; she sometimes inflicts forty or fifty broad- 

 sides in the course of one minute, and they are sufficiently 

 powerful to destroy, as by lightning, small animals ex- 

 posed to their influence. Reaumur put a duck and a 

 narke into the same vessel of water, covered with a cloth 

 to prevent the bird using its wings. After some hours 

 he found it foudroye by repeated shocks of the enemy, 

 and quite dead.* 



* Dr. Gr. Sn'hfi llin g'a magnetic experiments on the narke are 

 not without their interest, though they do not 'furnish any addi- 

 tional insight into the electrical phenomena exhibited by the fish. 

 On holding a magnet capable of sustaining a weight of fortypounds 

 within a short distance of a very powerful narke, he found that the 

 body was much agitated, and when it was held still nearer, that the 

 fish made every eSbrt to escape. Placing it next in a direct con- 

 tact with the surface of the water, the narke was violently agitated 

 for about a quarter of an hour, after which it swam to the magnet 

 and stuck. On repeating the experiment with the same fish, the 

 result differed only in this : that whereas the ray in the first, 

 after its attraction, stuck persistently to the magnet, in this the 

 adhesion lasted only half an hour. The same experimenter ascer- 

 tained that the foetal numb-fish is electric, and that steel-filings 

 thrown into the water restore to an exhausted narke its electric 

 powers. 



