X aumentaban la conductividad aproximadamente en la misma medida que los rayos del radio.
Becquerel23 ha demostrado recientemente que la parafina sólida expuesta a los rayos β y γ del radio adquiere la propiedad de conducir la electricidad en pequeña medida.
Tras retirar el radio, la conductividad disminuye con el tiempo según la misma ley que para un gas ionizado. Estos resultados muestran que un dieléctrico sólido, así como uno líquido y gaseoso, se ioniza bajo la influencia de los rayos del radio.
121. Effect of temperature on the radiations.
Becquerel24, by the electric method, determined the activity of uranium at the temperature of liquid air, and found that it did not differ more than 1 per cent. from the activity at ordinary temperatures. In his experiments, the α rays from the uranium were absorbed before reaching the testing vessel, and the electric current measured was due to the β rays alone.
P. Curie25 found that the luminosity of radium and its power of exciting fluorescence in bodies were retained at the temperature of liquid air. Observations by the electric method showed that the activity of radium was unaltered at the temperature of liquid air.
If a radium compound is heated in an open vessel, it is found that the activity, measured by the α rays, falls to about 25 per cent. of its original value. This is however not due to a change in the radio-activity, but to the release of the radio-active emanation, which is stored in the radium. No alteration is observed if the radium is heated in a closed vessel from which none of the radio-active products are able to escape.
122. Movimiento del radio en un campo eléctrico. Joly26 descubrió que un disco, en el que una de sus caras está recubierta con unos pocos miligramos de bromuro de radio, muestra, cuando se le acerca