Ques. What must be done in such case?
Ans. The electrodes must be reformed.
Ques. How is the loss of film prevented?
Ans. By Removing the electrodes from the electrolyte and drying them.
Fig. 2,087.—The Fleming oscillation valve. It depends for its action on the well-known Edison effect in glow lamps. The valve consists of a carbon filament glow lamp with a simple central horseshoe filament. Around this filament inside the exhausted bulb is fixed a small cylinder of nickel, which is connected by means of a platinum wire sealed through the bulb to a third terminal. The valve is used as follows: The carbon loop is made incandescent by a suitable battery. The circuits in which the oscillations are to be detected is joined in series with a sensitive mirror galvanometer, the nickel cylinder terminal and the negative terminal of the filament of the valve being used. The galvanometer will then be traversed by a series of rapid discharges all in the same direction, those in the opposite direction being entirely suppressed.
Ques. What attention must be given to the electrolyte?
Ans. Water must be added from time to time to make up for evaporation.
This is necessary to keep the solution at the proper density.