An account of the Electro- Magnetic Engine. 123 



and Jc k, are, as appears by the plate, connected with one another 

 by means of a copper wire. 



The action of the Commutator will be now readily understood. 

 The levers are in constant connexion with the plates, but touch the 

 metallic and isolating parts alternately. As they readily move round 

 their axes, they fly from the slightest inequality of surface, and the 

 friction which is thereby caused is very trifling. The spiral coils which 

 encircle the moveable bars are united to one wire, branches of which 

 (/ m) are soldered to the pairs of plates, a b and c d. The other spirals, 

 encircling the fixed bars, are similarly joined, and the ends n and o dip 

 the one into a vessel of quicksilver, p, which is connected with the voltaic 

 apparatus, and the other into the vessel k of the Commutator. Thus, by 

 means of the Commutator, the whole sixteen spirals form but one 

 connecting wire. The voltaic apparatus consists of four troughs of 

 copper, into which four plates of zinc dip. The direction of the current 

 is pointed out in figure 3, by the small darts. As soon as the large 

 wooden frame is turned by the power of the voltaic pile, the Com- 

 mutator, which is attached to the same axis, will be likewise set in 

 motion, and thus the reversal of the poles effected by means of the 

 machine itself, provided that the commutation plates be so constructed 

 that the extremities of the levers shall pass from one sector to the 

 other. 



In September, 1837, by advice of the Minister of Public Instruction 

 in Russia, a commission, consisting of Rear Admiral von Krusenstern, 

 the Academicians, Foss, Ostragradski, Kupfer, and Lenz, Colonel 

 Sololewski, and Lieutenant-Colonel Buratschock were appointed, un- 

 der the guidance of Professor Jacobi, of Dorpat, with a view to endea- 

 vour, by experiment, to render electro-magnetism applicable to the 

 working of machinery, and particularly to the propulsion of ships. 

 The object of this commission appears in part obtained, as on the 25th 

 of September, 1838, a vessel was set in motion on the Neva. An 

 eight-oared galley, such as is usual in the navy, was placed at the dis- 

 posal of the commission, 28 feet in length and 7| in breadth ; it was 

 provided with paddles similar to those of a steampacket, and the vari- 

 ous apparatus were put on board. The insufficiency of many' of the 

 arrangements which had been made, was then, for the first time, ap- 

 parent, and, in consequence, the first experiment was in a measure 

 proportionably unsuccessful. It had been intended to make experi- 

 ments only in still water, but they succeeded in propelling the vessel 

 on the Neva, even against the stream. The speed attained in still 

 water was three English miles per hour, and would have been greater 



