Page:Popular Science Monthly Volume 1.djvu/556

540 creature more than others might seem to require such preparation of its food, it is the cramp ray, the whole canal of whose intestine is not more than half as long as the stomach." This is certainly very curious, and, if it should be found that the same deficiency in point of digestive accommodation exists in the gymnotus and the other fishes of electric powers, the hypothesis would be converted almost into a certainty. In hunting up authorities to verify this curious fact, we find, in the article on the gymnotus in Chambers's Encyclopædia, that "all the gymnotidæ are remarkable for the position of the anus, which is so very far forward as, in the electrical eel, to be before the gill-openings" which would certainly seem to confirm Mr. Couch's supposition.

Of the tremendous powers which can be given off in one shock, it may be stated that Faraday, having made experiments with the specimen which was shown several years ago at the Adelaide Gallery, estimated that an average shock emitted as great a force as the highest force of a Leyden battery of fifteen jars, exposing 3,500 inches of coated surface.

There are five different fish endued with electrical powers. Of the torpedo there are two species—the old and new British torpedo; one of the Gymnotus electricus, or electric eel, as it is called; and two of the Malapterurus—viz., M. electricus of the Nile, called Raash, or thunder-fish, by the Arabs, and the Malapterurus Beninensis—the smallest of the electrical fishes, found in the Old Calabar River, which falls into the Bight of Benin, on the coast of Africa. The latter fish is a comparatively recent discovery, having been known to us only some fifteen or sixteen years. We have no very good account of either of these latter fish. A specimen of the last was sent to me three or four years ago. It is a curious little fish, about five or six inches in length, and very much resembles the Siluridæ in general appearance, about the head especially. It has long barbules, three on each side of the mouth, and has a very bloated, puffy appearance, caused, it is to be presumed, by the electric apparatus which is deposited between the skin and the frame of the fish. In the torpedo the electric battery is placed in two holes, one on either side of the eyes. Here a number of prismatic cells are arranged in the fashion of a honey-comb, the number being regulated by the age of the fish. These represent the jars in the battery, and they are capable of giving out a terrible shock, as many an incautious fisherman has experienced to his cost. We may trust also that the torpedoes with which our coasts and harbors are likely to be thronged will be capable of giving off even a severer shock; and though gunpowder and gun-cotton will be the shocking agents in these cases, yet electricity will play no unimportant part in their process. Formerly quacks galvanized their patients by the application of the natural torpedo, applying it to the joints and limbs for gout, rheumatism, etc. That the electricity is true electricity has been proved by a host of experiments. The electrometer has shown it,