426" Drs. Beattie and De Smolan on the Conductance 



was charged, whether positively or negatively, the Rontgen 

 rays diselectrified it in about five seconds ; not, however, to 



R.L. 



the metallic zero, but to a zero depending on the nature of 

 the insulated metal and of the metal surrounding it. On the 

 other hand, if the interior insulated metal had initially no 

 charge given to it, yet when the Rontgen rays were played 

 on it through the walls of the surrounding aluminium cylinder, 

 the reading on the electrometer deviated to the same zero to 

 which in the previous case it had fallen, and there remained 

 steady. 



With paraffin between the aluminium cylinder and the 

 insulated metal within (see fig. 6) we found no perceptible 

 increase of conductance produced by the Rontgen rays above 

 the natural conductance of the paraffin when undisturbed by 

 them. If the insulated metal was not charged and the 

 Rontgen rays played on it through the aluminium and the 

 paraffin, no deviation from the metallic zero took place 

 when the two pairs of quadrants of the electrometer were 

 insulated from one another. 



To make a similar series of experiments with glass we used 

 a piece of glass tubing 9'5 millim. internal diameter, 

 70 centim. long, and 10 millim. external diameter. The 

 inside of this tube was coated with a deposit of silver, which 

 was placed in metallic connexion with the insulated terminal 

 of the electrometer. The outside of the glass was covered, 

 with wet blotting-paper connected to the case of the electro- 

 meter. No increase of conductance was produced in the 

 glass when the Rontgen rays were played on it. 



We next removed a part of the wet blotting-paper from 

 the outside of the glass, and, after charging the insulated 

 interior metal deposited on the inside of the glass, we heated 

 the exposed part with a spirit flame, in this way making the 

 glass a conductor. The charge was completely removed in 



