In discussing this the boys said that a 32-candle-power lamp used 110 watts, and that since 96 per cent. of the energy supplied to the lamps went into heat each lamp transformed 105 watts of electrical energy into heat. But 100 watts sufficed to raise one pint (one pound) of water five degrees in one minute. They used seven lamps or about one horse-power, and adjusted the flow so that the shower delivered one quart of lake water per minute warmed for a tepid bath.
Fig. 149
The next time I sauntered down to the mill the boys were working on what they called an electric shower bath. They had fastened upon the wall of the bath room an electric bell ([Fig. 149]), and placed on a shelf near by a battery of two dry cells, P. The switch which closed this primary circuit was on the wall by the side of the faucet and electric heating switch ([Fig. 148]). One of the wires, S, for the secondary circuit was carried up and connected to the pan A ([Fig. 148]). The other wire was fastened to a sheet of zinc about a foot square, which lay upon the floor of the shower bath. The idea was that when one was taking a shower bath, if he chose to vary his sensations he might step upon the sheet of zinc, close the switch in the primary circuit and let the secondary current pass through his body by way of the shower. They said that it was particularly prescribed for slow people.
Speaking of chores, of course the most insistent chore was to keep the storage batteries stored. This process gave rise to many questions, through which the information contained in the next chapter was brought out.