340 Description of a Rotatory Multiplier. 



parts of the orbits described by the pins. Lastly, a second needle, 

 furnished with pins in like manner, being fastened at right angles 

 to the first, so as to form with it a cross, as represented in the en- 

 graving, each needle is made to receive two impulses during every 

 revolution. Hence one of Danell's sustaining batteries, as made 

 by Newman, is quite adequate to cause a revolution as rapid as 

 consistent with a due degree of stability in the mercurial globules 

 employed. 



One end of each coil, by means of the branching wire A, com- 

 municates with one pole of the galvanic pair; the other ends of 

 the coils terminate in mercurial globules contained in cavities on 

 opposite sides of the wooden disc G, upon the centre of which the 

 spindle of the magnetic needle rests. The branches of the wire 

 K proceeding from the other galvanic pole, terminate in globules 

 situated in the vicinity of those above mentioned, so that as the 

 needles revolve, the pins proceeding therefrom perpendicularly 

 may touch a pair of the globules first on one side and then on the 

 other. Whenever this contact takes place, the circuit is comple- 

 ted, and a discharge is effected through one or the other of the 

 coils of the multiplier. 



vSupposing E and P to be north poles, a discharge through one 

 of the coils will cause E to move off" a quarter of a circle, or more. 

 As this ensues, the pins of F will come in contact with the glob- 

 ules which those of E touched before. Of course F will be pro- 

 pelled so as to cause the pins of E to reach the pair of globules at 

 G, which, completing the circuit of a coil wound in a way the 

 opposite of that first mentioned, concurs with that coil in its influ- 

 ence, so as to promote the rotation previously induced. The same 

 result ensues when the pins proceeding from F come in contact 

 with the globules situated at G, and when E returns to its original 

 starting point. It follows, that by a repetition of the process the 

 galvanic action is sustained. The phenomenon is as well illus- 

 trated by employing the single needle, N, N, as by two, but the 

 most pleasing and energetic effect is produced by the crossed nee- 

 dles. In this simple form the spindle on which the needle rests 

 and revolves is represented at S ; the pins at P, P. Each coil, 

 consisting of copper bell wire, is about thirty feet in length, and 

 is contained in the groove C. The frame of the multiplier is con- 

 structed of mahogany and is levelled by the milled headed screws, 

 on the ends of which it is supported. 



