Miscellanies. 1 99 



wire, of which he made two double helices. One of these helices 

 was 0"' 44 in length, and had a diameter of 0"" 05?« ; the other was 

 0" 72 metres in length, and 0*" 03 in diameter, and was wound on 

 a horse shoe. In the interior of the two helices was placed a cylin- 

 drical bar of soft iron. With this arrangement, completed as above 

 described, Matteucci succeeded without fail in obtaining a bright 

 spark. One of the helices wound on a horse shoe sufficed to pro- 

 duce the same successful result. 



Matteucci attempted to obtain the electric spark by means of two 

 plates of brass, with short wires attached and inserted into mercury. 

 But, notwithstanding the employment of every means which could 

 insure success, he failed in obtaining any effect except the shock. 

 He therefore infers, since the spark is not obtained with a very short 

 wire, and on the contrary is easily obtained with the above described 

 helices, that the spark is produced where the discharge ceases, in 

 which case the current, by induction, adds to the primitive current. 



He has also ascertained, by means of a delicate galvanometer, 

 that the current passes from the back to the venter, and that the back 

 may be considered the positive pole and the venter the negative. 

 The discharge is effected in the same manner by the two organs 

 situated on the sides of the torpedo, and the current is produced in 

 the same directions when one of the needles of the galvanometer 

 touches the ventral part of the left organ and back part of the right, 

 or inversely. The deviation in the galvanometer is augmented if the 

 two needles of platinum are put m contact with two metallic plates 

 placed on the two sides of the fish, instead of a direct application 

 of the needles. A discharge can almost invariably be produced by 

 forcibly curving the torpedo, making the venter the interior of the 

 curve. A removal of the skin of the animal diminishes the devia- 

 tion, but does not entirely prevent it. If the outer of the three ner- 

 vous cords which proceed from the brain to the electric organs are 

 cut, the electric discharge may still continue. It ceases immediately 

 on cutting the intermediate one. 



Thesie experiments were tried with thirty six individuals, which M. 

 Matteucci obtained during a long residence at Cesenatico. — L'lnsti- 

 iut, JVo. 167. July, 1836. 



14. Fall of Fishes from the Atmosphere in India ; by M. Prin- 

 SEP. — The fact that fishes fall from the atmosphere in the rainy sea- 

 son, however incredible it may appear, has been so frequently attested 



