364 Intelligence and Miscellaneous Articles. 



the other is connected with a source of electricity which supplies 

 electricity slowly. When the potential has reached a certain limit 

 a scintilla passes between the two halves of the conductor; the 

 potential then falls rapidly, then increases again until a fresh 

 scintilla again diminishes it, and so on. If electrodynamic waves 

 produce electrical vibrations in the secondary conductor, the sparks 

 will obviously occur with a smaller accumulation of electricity than 

 otherwise; this is the fundamental idea of the new method of 

 observation. 



In practically carrying out the observation I connect the half of 

 the secondary conductor which is to be electrified with an ordinary 

 electroscope, which contains two aluminium leaves which hang 

 near each other. Each spark is then manifested by a sudden col- 

 lapse of the aluminium leaves : attention is to be directed to this 

 phenomenon. If electrodynamic waves act, the greatest angular 

 deflexion of the aluminium leaves diminishes. 



If the action of the electrodynamic waves is so violent that, even 

 without artificial electrification of the secondary conductor, scintillas 

 occur in its spark-gap, the aluminium leaves remain almost without 

 change. 



I used at first a water-electrification machine as source of elec- 

 tricity ; I now use a Wimshurst machine. A thread of proper 

 length connects one electrode with the half of the secondary con- 

 ductor which is to be electrified ; in order to avoid too high tensions 

 both electrodes are provided with points. If the machine is kept 

 at work for a few seconds and is then left to itself, the store of 

 electricity remaining in the Leyden jars is sufficient to keep up 

 the play of the phenomenon. 



The author points out the similarity of his method of observa- 

 tion to that of Boltzmann (Phil. Mag. [5] xxx. p. 126), which he 

 had only seen after his paper was sent off. He dwells on the very 

 distinct way in which his method illustrates the phenomena. — 

 Wiedemann's Annalen, vol. xl. p. 640 (1890). 



EXPERIMENTS. BY G. BARTANIEK. 



The author uses small incandescent lamps which have become 

 useless owing to a break in the carbon filament, and which he inserts 

 in the interval of Hertz's resonator. It is only necessary to connect 

 one wire with one sphere of the resonator. At the break small 

 green scintillas appear with an aureole. On touching the glass side 

 the light streams to the part touched, which acquires a green 

 phosphorescence. — BeibVdtter der Physik, vol. xiv. p. 654. 



