P OL YTECHNIC A SSO CIA TION Pr CEE DINGS. 995 



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. This influence was exhibited in an interesting series of experi- 

 ments by the aid of helices of wire, and the winding of a flat 

 copper strip or ribbon into a spiral, the greatest length of which 

 was ninety-six feet. With a large caloriniotor of eight pairs, 

 shocks were felt as far as the elbow. 



In the latter part of 1835, Dr. Neef, of Frankfort-on-the-Main, 

 published Poggendoi^^^s Annals, vol. 36, page 352, an account of 

 experiments for the purpose of obtaining a rapid succession of shocks 

 by a mechanical contrivance called a " lightning wheel," for making 

 and breaking rapidly the circuit with a voltaic pile, both with and 

 without the interposition of coiled conductors. The wheel con- 

 sisted of a circular table or disc of copper six and a half inches in 

 diameter, mounted to revolve on a vertical axis. The upper face of 

 this disc presented thirty-six strips of wood, or other non-conducting, 

 material, inlaid with strips of copper. A conductor resting upon 

 the upper face over the strips, was for connection with one pole 

 of the battery, the other pole being in connection with the bearings 

 of the wheel. As the wheel was turned, the circuit was broken 

 thirty-six times for every revolution. It was tried with a voltaic 

 pile, to obtain a rapid succession of contacts, and also with a coil 

 of wire surrounding a bar of soft iron, and was found to produce 

 novel and important physiological efiects due to the rapid succes- 

 sion of small shocks. It was contemplated by Dr. Neef for use for 

 medical purposes. The circuit-breaker was in reality a production 

 of Mr. Wao-ner, a friend of Dr. Neef. It is the first recorded 

 account of a mechanical circuit-breaker applied for this purpose. 

 The apparatus was, however, curnbrous; and as only a voltaic pile 

 was used and no secondary circuit around the electro-magnet em- 

 ployed, the action was too feeble and inconstant for practical 

 application and must have gone speedily into disuse. Dr. Neef 

 revived the su'bject in 1839, after his introduction of an automatic 

 circuit-breaker It is interesting to note, that Dr. Neef suggests 

 in this paper the use of galvanic baths, now so much in vogue. 

 Perhaps the experiments of M. Masson, of France, were in advance 

 of those of Dr. Neef, both as regards the coil, its physiological 

 efiects, and the use of a mechanical circuit-breaker. Du Moncel, ia 

 his Expose des Applications de VEctridte, 1856, says that"M. 

 Masson was one of the first who perfected the apparatus for volta- 

 electric induction. That in 1836 he employed a toothed wheel 

 {roue dentee) revolving against a metallic spring for breaking the 

 circuit with a coil, and obtained currents of some intensity," We 



