Manchester Memoirs, Vol. liv. (1910), No. 13. 2i 



and formed the transmitting portion of the system. The 

 messages, which were sent in the Morse code were received 

 by the operator who placed the left-hand in a vessel con- 

 taining dilute salt solution in which was immersed a 

 zinc rod to serve as an electrode. In the right-hand was 

 held a pencil wrapped round with tin-foil or contained in 

 a metal pencil-case. The pencil was connected to one 

 end of the line whilst the other end was placed in con- 

 nection with the zinc rod. A " dot " was represented by 

 a shock in the right-hand and a " dash " by one in 

 the left-hand. After a little practice Messrs. W. B. 

 Smith (of the P.O. Engineering Dept.) and A. Hodgson 

 and T. Alston (of the Manchester Postal Telegraphs) 

 were able to send and receive messages at the rate 

 of from 7 to 15 words per minute: the lower speed 

 being when the receiving operator actually made his 

 own record in writing, and the higher speed when 

 he dictated the message as received. When the message 

 is dictated it is better to receive with the right hand 

 also immersed in salt solution. The method may prove 

 to be one of value in practice in case of emergencies 

 where receiving instruments are not available. 



Dangers of Supply Ci)'ciiits. The resistance between 

 the hands wet with salt solution being with alternating 

 currents only about 800 ohms, the result of including the 

 body in an alternating supply of about 100 volts will be 

 excessively dangerous and probably will cause death. An 

 accident of this kind is recorded by A. Kolpen.*^ 



* Elcktrolech Z/sckr., 21, p. 133, Feb. I5t.h, 1900. The glow lamps of 

 some potash works near Prague were connected with one phase and the 

 neutral wire of a three-phase system giving I lo volts. A man standing on 

 an iron soda tank with his boots soaked with soda, accidentally touched one 

 of the bare wires of a lamp. Two of his lingers stuck to the wire and before 

 he could be released he was unconscious and all attempts to resuscitate 

 him failed. 



