Manchester MeJiioirs, Vol. liv. (1910), No. 13 19 



Exp. 6. Dry finger tips on metal. D.C. 

 Resistance by galvanometer = 150,000 ohms. 



Physiological Effects. The various types of electronic 

 effects known to physiologists were manifest during these 

 experiments. The muscular contractions were made very 

 evident by the movement of* the reflection images at the 

 surface of the solution. With the hands immersed in salt 

 solution 1-2 volts gave a sensation on closing the circuit 

 with a key, the effect with 30 volts causing great dis- 

 comfort and vigorous contraction of the muscles. In- 

 voluntary muscular contractions took place on making 

 the circuit, with a minimum of 8 volts at the cathode and 

 of 1 1 volts at the anode. By placing the muscles in a 

 strained condition these numbers were reduced to 4 and 

 6 volts respectively. 



It was thought that the effect being greater at the 

 cathode this would furnish an easy method of dis- 

 tinguishing the polarity of circuit terminals. With dry 

 finger tips on brass terminals the following effects were 

 observed. 



Table VII.a. 



Voltage. 



230 ... Smart shock to end.s of fingers. More marked 



at the cathode. 

 150 ... Same effect. 



no ... Less shock. Distinctly greater at the cathode. 

 50 ... No effect with dry fingers. With wet fingers 

 the cathode contraction is very distinct. 



A number of observations concerning these interesting 

 sensation effects are appended in Table VIII. In the 

 following experiments the skin contact remained un- 



