HAMILTON SCIENTIFIC ASSOCIATION. 121 



It would be foreign to the purpose of this paper to enter 

 into a scientific description of the electrol3'te cell, suffice it 

 to say that the passage of the electric current through an 

 electrolyte produces certain chemical effects, and in case this 

 current is between the pipes and the rails the result is 

 that the metal of the pipe is gradually carried away. 

 Damage is also done to the rails. Although this paper deals 

 with the injurious effect of electrolysis, it would be well to 

 remind you that electrolytic action has been made of great 

 service in the arts and manufacturies, and is a most important 

 factor in electro plating. 



The amount of damage done by electrolysis depends on 

 the amount or volume of the electric current, the length of 

 its duration and the constituents of the soil. 



In all systems of electric propulsion where the return 

 current is by the rails, it is found that at certain points there 

 is an escape of electrical current from the rails to the adjacent 

 metallic conduits, whether gas or water pipes, and from them 

 back again to the rails and power house. It is where the 

 current leaves the pipes to return to the rails that damage is 

 chiefly done by electrolysis, the metal of the pipes being 

 carried away leaving pits in the surface of the pipes, 

 which in time pass through the entire thickness of the pipes 

 and thus cause leaks. Should the leak be in a gas main, gas 

 would of course escape and an explosion might occur. 

 Breaks in water pipes of a serious nature have occurred in 

 several cities ; Providence and Toronto being two examples. 



It will readily be understood that the pipes and rails are 

 the electrode and the soil and its alkali salts the electrolyte. 

 It is said, and has been proved, that the passage of a contin- 

 uous current of one ampere per second into the earth involves 

 a loss of 20 lbs. of iron from an iron pipe per annum, and a 

 loss of 70 lbs. from a lead pipe. Cast iron pipes contain a 

 large amount of graphite carbon, which is not attacked by 

 the nascent chlorine or oxygen of the electrolyte, and a pipe 

 of this metal often remains for some time strong enough to 

 resist the bursting pressure of the water in the pipe, although 



