1888.] on Electrical Influence Machines. 303 



the next set of plates gave negative electricity — as a consequence no 

 electricity passed the terminals. 



To overcome this objection, to dispense with the dangerously cut 

 j^lates, and also to better neutralise the revolving plate, throughout 

 its whole diameter, I made a large machine having twelve discs 2 feet 

 7 inches in diameter, and in it I inserted plain rectangular slips of 

 glass between the discs, which might readily be removed ; these slips 

 carried the paper inductors. To keep all the paper inductors on one 

 side of tl:e machine to a like excitement, I connected them together 

 by a metal wire. The machine so made worked splendidly, and your 

 late secretary, Mr. Spottiswoode, sent on two occasions to take note 

 of my successful modifications. The machine is now ten years old, 

 but still works splendidly. I will show you a smaller sized one at 

 work. 



The next machine on which I make observations, is the Carre. 

 It consists essentially of a disc of glass which is free to revolve with- 

 out touch or friction. At one end of a diameter it moves near to the 

 excited plate of a frictional machine, while at the opposite end of the 

 diameter is a strip of insulating material, opposite which, and also 

 opposite the excited amalgam plate, are combs for conducting the 

 induced charges, and to which the terminals are metallically 

 connected ; the machine works well in ordinary atmosphere, and 

 certainly is in many ways to be preferred to the simple frictional 

 machine. In my experiments with ii I found that the quantity of 

 electricity might be more than doubled by adding a segment of glass 

 between the amalgam cushions and the revolving plate. The current 

 in this type of machine is constant. 



The Voss machine has one fixed plate and one revolving plate. 

 UiDon the fixed plate are two inductors, while on the revolving plate 

 are six circular carriers. Two brushes receive the first portions of 

 the induced charges from the carriers, which portions are conveyed 

 to the inductors. The combs collect the remaining portion of the 

 induced charge for use as an outer circuit, while the metal rod with 

 its two brushes neutralises the plate surface in a line of its diagonal 

 diameter. When at work it supplies a considerable amount of 

 electricity. It is self-exciting in ordinary dry atmosj)here It freely 

 parts with its electricity from either terminal, but when so used the 

 current frequently changes its direction, hence there is no certainty 

 that a full charge has been obtained, nor whether the charge is of 

 positive or negative electricity. 



I next come to the type of machine with which I am more closely 

 associated, and I may preface my remarks by adding that the in- 

 vention sprang solely from my experience gained by constantly using 

 and experimenting with the many electrical machines which I 

 possessed. It was from these I formed a working hypothesis which 

 led me to make the small machine now before you. The machine is 

 unaltered. It excited itself when new with the first revolution. It 

 so fully satisfied me with its performance that I had four others 



