Electrolysis
the decomposition of chemical compounds by electricity. This word is one of the many that have come into common use since electricity has played so important a part in eve every-day affairs, and means the condition which causes decomposition of gas and water pipes buried near the wires of electric railroads. As long ago as 1833 it was discovered that the earth could be used as a part of a circuit to carry electric currents, and until the introduction of electric cars the earth was almost wholly depended upon for the return current required by telephone and telegraph apparatus. Now the best telephone cirparatus. Now the best telephone cirthe return current. The interference with the telegraph is much less than with the telephone from this cause.
When electricity passes through moist earth it causes the decomposition of the water and the formation of oxygen and hydrogen gases. The oxygen, reaching metallic pipes, causes oxidation and ultimate destruction. The time required is, of course, wholly dependent upon the conditions, such as the volume of the current, the size of the conductor, and the amount of oxygen liberated.