NATURAL PHILOSOPHY. 113 



and the discharge taken through the fluid, some curious effects take place, 

 modified according to which pole is immersed, but in each case the luminous 

 atmosphere exhibits singular corruscations. When the rheophores are sepa- 

 rated, so that the direct discharge cannot take place, the effects of the 

 luminous atmosphere are still more conspicuous. 



ELECTRICAL ACTION OF THE TORPEDO. 



From the results of some experiments recently published by M. Matteucei, 

 we learn that the electro-motive power of the organ of the torpedo exists 

 independently of the immediate action of the nervous system. If a section 

 of the electric organ of the torpedo which has been dead forty -eight hours, 

 or if the torpedo be exposed for the same number of hours to the action of 

 the open air, or left for twenty-four hours in a frigorific mixture, where it 

 may have hardened or become frozen, or if kept during the latter period in 

 water at a temperature from 104 to 122, be made to communicate with a 

 galvanometer, a great deviation will be produced. If the torpedo be killed 

 with the poison curare or woorali, it will present the same electro-motive 

 power as if it had. died naturally. In its operations as a nerve-discharging 

 battery, its electro-motive power is considerably increased under stimulated 

 action. When the nerves of the organs have been several times excited in 

 succession, that power for which the torpedo is so remarkable is greatly 

 increased, and will produce a greater number of discharges than it would in 

 its normal condition. For instance: Let two pieces of equal dimensions, 

 each containing a strong nervous filament, be prepared of one of the organs 

 of a torpedo; let them be placed on a piece of gutta-percha, with the two 

 nerves opposite to each other, and situated perpendicularly to the prisms of 

 a thermo-electric apparatus; on closing the circuit of the galvanometer, a 

 small differential current becomes apparent, but soon disappears. Then if 

 the nerve of a galvanoscopic frog be placed upon each organ, and the circuit 

 be broken under a mercury bath while the nerve of one of the pieces is 

 being irritated with the points of a fine pair of scissors, the frog then in 

 contact with that piece will exhibit violent convulsions. When after this 

 the nerve is left at rest, and the circuit of the galvanometer again closed, a 

 strong deviation, which lasts a long time, is perceived in the direction of the 

 excited organ. The electro-motive power of the organ of a torpedo is not 

 influenced by the nature of any gaseous medium in which it may be left 

 for twenty-four hours. This is proved by comparing, in opposition to each 

 other, two pieces preserved in different gases, such as hydrogen, oxygen, 

 carbonic acid, and atmospheric air more or less rarefied; when it will appear 

 that there is no constant difference between the electro-motive powers of the 

 two pieces. 



WEAVING BY ELECTRO-MAGNETISM. 



In the improvement of the old weaving machine, effected by Jacquard, 

 under the encouragement of the first Napoleon, the pattern of the design was 

 pricked on large perforated cards, which went in an endless chain round a 

 roller in the centre of the loom. All the threads of the warp were connected 

 with bars in the upper part of the loom, and these, by a movement of the 

 weaver's treadle, were piished against the perforated cards. Those which 

 faced the pattern holes, and therefore corresponded with them, remained 

 there, and so, when the lever was lowered, held up the threads which ought 



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