Fig. 284.—Ray torpedo.
c, brain; m e, spinal chord; o, eye; e, electric organs; b, gills; np, nl, nerves; n, spinal nerve.
There is yet another fish known as the malapterurus; one species is called the thunder-fish. Professor Wilson has written a paper upon the electric fishes as applied to the remedy of disease, and considers them the “earliest electric machines ever known.”
Humboldt relates that the South-American Indians capture the gymnotus by driving horses into ponds which the electric eels are known to inhabit. The result is that the fish deliver shock after shock upon the unfortunate quadrupeds. Mules and horses have frequently been killed by these powerful eels, and even Faraday experienced a very great shock when he touched the head and tail of the captive gymnotus with either hand.
The malapterurus to which we have referred is an inhabitant of the African rivers, chiefly in the Nile and Senegal. Such a fish has been known with others for some hundreds of years; its electrical powers are not great. There are one or two other species of fish which possess electrical qualities, but none apparently to the same extent as the torpedo and the gymnotus.
Fig. 285.—The Malapterurus.
The electricity of plants also is in some cases very marked. Flashes have been seen to come from some flowers in hot and dry weather. Currents of electricity have been detected, and Wartmann investigated the subject closely. He says the currents in flowers are feeble, but in succulent fruits and some kinds of grain they are very marked. These currents depend upon the season, and are greatest in the spring, when the plant is bathed in sap. These experiences were confirmed by Bequerel in 1850, and he concludes that the rank vegetation in some parts of the world must exercise considerable influence on the electric phenomena of the atmosphere. M. Buff has more recently made experiments in this direction, and he examined plants and trees, and even mushrooms. M. de la Rive, after carefully summing up the various theories, comes to the conclusion that it is to chemical reactions that the traces of electricity are due.
The subject of atmospherical electricity properly belongs to meteorology, and under that heading we will treat of it more fully. But lightning is so identified with electricity, and being the most common form observable to all, we will say something about thunderstorms and the electric discharges accompanying them.
