Prof. Ritchie on the Rotation of closed Voltaic Circuits. 13 



rotation; and if the battery be removed, the ends of the xtires 

 brought into metallic contact, and the same motions be ■pro- 

 duced by mechanical means, the conductor will have the same 

 electric state induced on it, as it had when connected with the 

 battery." 



V. On the continued Rotation of a closed Voltaic Circuit, by 

 another closed Circuit. By the Rev. William Ritchie, 

 LL.D., F.R.S., Professor of Natural and Experiment al Phi- 

 losophy in the Royal Institution of Great Britain, and in the 

 University of London*. 



MAMPE'RE has demonstrated that when a closed cir- 

 • cuit (or a conductor of voltaic electricity returning into 

 itself so as to form a complete circuit,) is acted upon by another 

 closed circuit, there is a determinate position in which stable 

 equilibrium takes place. Hence the impossibility of producing 

 continued rotation by the mutual action of two closed voltaic 

 circuits. Hence also the impossibility of producing con- 

 tinued rotation by the mutual action of two permanent mag- 

 nets f. But though continued rotation cannot be produced 

 by the action of closed circuits, when the voltaic influence is 

 exerted in a particular direction, I have succeeded in pro- 

 ducing such rotation by changing the direction of the voltaic 

 influence; a short account of which may not be unacceptable 

 to the readers of the Philosophical Magazine. 



The description of the method will be easiest understood 

 by reference to the annexed figure. 



Let A B represent the section of a circular piece of wood, 

 having a groove measuring about an inch in 

 its inner diameter, and half an inch broad, 

 for the purpose of holding mercury. The 

 groove is divided into two compartments 

 by small slips of wood fixed diametrically 

 opposite to one another. These compart- 

 ments may be connected by means of wires 

 with the plates of an elementary battery. 

 A glass rod, having a small cup, c, at the top, is cemented 

 into the centre of the sole of the apparatus. A fine copper 

 wire, covered with silk, is formed into a rectangular coil or 

 closed circuit, as in the figure, the ends of which, ah, dip 

 into the mercury contained in the compartments. The lower 

 horizontal branch of the rectangle has the wires separated so 



' ( 'ommunicated by the Author. 



T This property was not known a few years ago, and hence an ingenious 

 Scotch shoemaker contrived to gull the most eminent philosophers in 

 Scotland, l>y a pretended perpetual motion, alleged to he produced by the 

 mutual action of magnets. 



