252 Proceedings of Royal Society of Edinburgh. [sess. 
of salt solution. When the fingers are dipped into the salt 
solution, and the phonograph is set in motion, thrills are felt by 
the fingers corresponding to the intensity and rhythm of the 
music. 
Deeming it of interest to have some data regarding this experi- 
ment, I have modified it in the way shown in the diagram, and 
the E. M. E. of the battery employed and the resistances of the 
various pieces of the apparatus were measured. Into the circuit 
of the secondary coil, /, a resistance box, g , and a telephone, t , were 
introduced ; and the circuit was completed when the fingers were 
immersed in the salt solution h, i. When the phonograph was in 
action and gave out a well-known military march, the thrills 
could be felt in the fingers, and at the same time the telephone, 
which was fixed in a stand at the level of the ear, gave out the 
music. Resistance was then introduced into the secondary circuit 
until the “ thrills ” could be no longer felt, and it was observed 
that still the telephone could be heard. The measurements were 
as follows : — 
(1) 1 Obach cell used — Q pattern ; 
Internal resistance, 1 *37 ohms; 
E. M. F., 1*25 volts. 
(2) Resistance of primary of induction coil, 0T83 ohms. 
(3) Resistance of secondary of induction 
coil, ...... 726*3 ohms. 
(4) Resistance of telephone, . . . 1180 ohms. 
(5) Mean resistance of variable resistance 
transmitter, . . . . . 21 ohms. 
(6) With a finger in each beaker, mean resist- 
ance between terminals was . . 50,000 ohms. 
When the resistance-box was placed in the secondary circuit of 
the induction coil, the “ thrills ” were felt until an extra resistance 
of 12,220 ohms was introduced. With this resistance the tele- 
phone still gave out the music as distinctly as before, and it was 
not until a resistance equal to about 1,250,000 ohms had been in- 
troduced that the telephone ceased to be audible. Thus, variations 
of current intensity, corresponding to the loudness of the tones of 
