Some Curiosities. 175 



of metal rotated by a crank mounted on a 

 suitable stand. The electric circuit passes 

 through the disk to the hand of the operator 

 in contact with it, thence running through the 

 line-wire to the distant station. Now, if a 

 tune is played at that station, upon an elec- 

 trical key-board, as described in a previous 

 chapter, and the disk rotated \vith the fingers 

 in contact with it, the tune or other sounds will 

 be reproduced at the ends of the fingers. After 

 the telephone was invented and put into use I 

 used this revolving disk as a receiver for 

 speech as well as music, and by this means 

 persons may carry on an oral conversation 

 through the ends of their fingers. This appa- 

 ratus has been confounded in the minds of 

 SMIIIC people with Edison's electromotograph. 

 The phenomena of the electromotograph were 

 produced by chemical effects, while that of the 

 apparatus just described is electrostatic in its 

 action. The electrostatic disk was made in 

 the winter of 1873-4, while Edison's electro- 

 chemical discovery was made some time later. 



