172 Mr. F. C. Webb on an Electrical Experiment 



The room was about 8 feet by 9 and about 8 feet high. 

 The floor was of wood^ and the sides of wooden framework 

 covered with calico and with pieces of tinfoil pasted about it 

 to make it a good conductor. It had a door and two windows 

 of wire gauze. A small table was placed in it, and a frictional 

 electrical machine was placed on this. The room was suspended 

 by four double parts of half-inch-round gutta-percha band to a 

 wooden frame, the floor being about 4 feet from the ground. 

 The gutta perch a was covered with paraffin ; and the whole room 

 was tested for insulation with five hundred DanielFs elements 

 with a delicate astatic Thomson^s reflecting-galvanometer, and 

 gave no perceptible loss. A Peltier electrometer was placed 

 on the ground outside ; and a wire from the brass knob of this 

 was connected to the gauze of the window. The table was con- 

 nected with the tinfoil that was pasted about the surfaces of 

 the room, so that when the rubber or prime conductor was con- 

 nected to the table it was in connexion with the sides of the 

 room. Thus arranged, the machine acted to all appearance 

 exactly the same as in an uninsulated room. When the rubber 

 was connected to the table, on turning the glass disk the prime 

 conductor was charged so as to give off sparks the same as when 

 the room was uninsulated ; and the conductor was completely 

 discharged when touched to the insulated room. Not the slightest 

 effect was produced on the electrometer, even when sparks were 

 flashing from the prime conductor to the wire gauze of the win- 

 dows to which the wire from the electrometer was attached. 

 Connecting the room to the earth made no difference. A sphere 

 about a foot in diameter was then charged when the room was 

 insulated, and then handed out by an insulating handle, when the 

 electrometer immediately diverged to about 50", showing that 

 the outer surface of the room had become negative. On taking 

 the sphere back into the room, the electrometer fell to zero. 



These results agree exactly with what I have suggested would 

 occur under such circumstances iu my treatise on Electrical 

 Accumulation published in 1862 ; audit is impossible to recon- 

 cile these results with the explanation of the action that takes 

 place in charging and discharging as given and republished in 

 most works. Take, for instance, the following from Noad''s 

 Student^s Text-book : — '^ Thus, in order to get any develop- 

 ment of electricity, there must be either with the rubber or with 

 the prime conductor, electrical communication with the earth 

 as the great natural reservoir of electricity.-'^ (P. 29.) 



This is about the same language as that used by Lardner, 

 De la Rive, Daniell, Gavarret, and later by Deschenelle. 



According to the views 1 have advocated, the accumulation 

 on the prime conductor depends on the resistance of what I have 

 termed the inductive circuit, which in the case of charging the 



