150 ANNUAL OF SCIENTIFIC DISCOVERY. 



words for thunder (raad), and for the electric fish (ra'a'd), are different, and 

 that the latter signifies the " causer of trembling," or " convulser," so that 

 there are no grounds for computing to the ancient Egyptians, or even to the 

 Arabs, the identification of silurus-power with the electric force. In proof 

 of the generality of the practice of the zoo-electric machine at the present 

 day, the writer referred to the remedial application of the torpedo by the 

 Abyssinians, to that of the gymnotus by the South American Indians, and 

 to that of the recently discovered electric fish (Malapterurus Beninensis) by 

 the dwellers on the old Calabar Kiver, which flows into the Bight of Benin. 

 The native Calabar women were in the habit of keeping one or more of the 

 fishes in a basin of water, and bathing their children in it daily, with a view 

 to strengthen them by the shocks which they receive. These shocks are cer- 

 tainly powerful, for living specimens of the Calabar fish are at present in 

 Edinburgh, and a single one gives a shock to the hand reaching to the 

 elbow, or even to the shoulder. The usages referred to appear to have pre- 

 vailed among the nations following them from time immemorial ; so that 

 they furnish proof of the antiquity as well as of the generality of the prac- 

 tice under notice. The writer concluded by directing the attention of natur- 

 alists to the probability of additional kinds of electric fish being discovered, 

 and to the importance of ascertaining what the views of the natives familiar 

 with them arc in reference to the source of their power, and to their therapeu- 

 tic employment. 



Sir J. Richardson stated, that there were not less than eleven genera of 

 fishes known that had the power of giving electric shocks. There was one 

 peculiarity in all these fishes, and that was the absence of scales. In every 

 one of them an apparatus had been discovered, which consisted of a scries 

 of galvanic cells, put in action by a powerful system of nerves. He read 

 extracts from a letter from Dr. Baikie, now engaged in exploring the Niger, 

 in which that gentleman stated that he had met with an electric fish in 

 Fernando Po, and which Sir J. Richardson believed was identical with the 

 Malapterurus, which had been described by Dr. Wilson, from the coast of 

 Old Calabar. The natives called this fish the Tremble-fish. 



ON A NEW SOURCE OF ELECTRICAL EXCITATION. 



The following paper, by Mrs. Elisha Eoot, was presented to the Ameri- 

 can Association for the Advancement of Science, at its last meeting : 



I have ascertained that the compression or the expansion of atmospheric 

 air produces an electrical excitation. So far as I am aware this has not been 

 before observed, and it seems to me to have an important bearing in the ex- 

 planation of several atmospheric and electi'ical phenomena. 



The apparatus used was an ordinary air pump of rather feeble power and 

 adapted either to compress or exhaust the air. Its receiver was a glass 

 tube about twenty-two inches in height and three in diameter, with its ends 

 closed by brass caps cemented to it. At the bottom was a stop-cock and a 

 screw by which it was attached to the air pump. To the top were soldered 

 two copper wires, one hanging down within the tube, terminating in one or 



