2 ee he es ae So ee 
Chemistry and Physics. 387 
the resistances were varied. In all four telephones, tones were 
heard when the strength of the current and the values of ¢ were 
as follows: ; 
1 ; 2 3 4 
S 0:000100 0°000153. 0°000084 0°000066 
€ 0°00225 u 0°00133 0°00288 0°00237 
ith a movement equivalent to 71, of the wave-length of 
membrane and the magnet was filled with a cork. Bosscha thus 
shows that Professor Bell’s hypothesis that the movement of the 
plate was molecular is unnecessary. The currents which were 
hecessary to produce the red excursions of the style 
d red by Weber’s multipli- 
the true cause may not be found in a change 
William Thomson,* Professor Haughton,} Mr. George Darwin,} 
the Rev. L F, Twisden§ and others, and the result arrived at 
* British Association Report, 1876, part IT, p. 11. 
+ Proceedings of Royal Society, vol. xxvi, p. 51. 
