428 Drs. Byattie and De Smolan on the Conductance 



metallic disk without touching it. This showed that an 

 exceedingly minute quantity of electricity had passed from D 

 to C when they were in contact. 



C was then diselectrified by being held in the flame. The 

 ends of C and D were again put together — D still having 

 the charge previously given to it — and in this position 

 were passed through the flame. They were tested with 

 their ends still pressed together, and it was found that 

 when held as near as possible to the metal disk without 

 touching it, no reading was produced on the electrometer. 

 After this they were separated and tested separately ; and it 

 was found that D, when held over the disk, gave a large 

 reading in the same direction as before the two with their free 

 ends together had been passed through the flame, and G 

 (which was previously non-electrified) gave a large reading 

 in the opposite direction. 



Exactly similar results were obtained with the two paraffin 

 sticks when Rontgen rays were substituted for flame, and 

 when glass or ebonite was used instead of paraffin. 



The explanation clearly is this : — The flame or the Rontgen 

 rays put the outer paraffin surfaces of G and D temporarily 

 in conductive communication with the tinfoils, but left the 

 end of D, pressed as it was against the end of C, with its 

 charge undisturbed. This charge induced an equal quantity 

 of the opposite electricity on the outer surfaces of the paraffin 

 of C and D between the tinfoils ; half on C, half on D. 



When the application of flame or of Rontgen rays was 

 stopped, this electrification of the outer paraffin surfaces 

 became fixed. D, presented to the electrometer, shewed the 

 effect of the charge initially given to its end, and an induced 

 opposite charge of half its amount on the sides between the 

 end and the tinfoil. C showed on the electrometer only the 

 effect of its half of the whole opposite charge induced on the 

 sides by the charge on D's end. 



We have here another proof that paraffin is not rendered 

 largely conductive by the Rontgen rays. Had it been made 

 so, then the charge given to the end would have leaked 

 through the body of the paraffin to the outside, and have 

 been carried away either by the tinfoil or by the conductive 

 air surrounding the non-tinfoiled parts. 



To show that the induced charges were fixed on the sides, 

 the two sticks, and D, were next coated with tinfoil 

 throughout their whole length, only one end of each being 

 uncovered. The uncoated end of D was then charged and 

 pressed against that of 0, and the two were held either in the 

 flame of a spirit-lamp or in the Rontgen rays. When taken 



