Automatic Action of the Generator.
The generator works best while hot. The gas cock on the generator should now be opened and the mixture allowed to flow into the gas chamber until it spurts out of the gas cock, which must then be closed. By this action all the air in the gas chamber is expelled, leaving it free to generate pure gas at once. This is a sure method of exhausting the air in the gas chamber. The acid then attacks the zinc, causing it to decompose the water and free the hydrogen contained in the acid.
This gas, by reason of its lightness, will rise to the surface of the acid, and as pressure increases it will force the acid back up through the acid supply pipe into the acid chamber, until the acid falls below the perforated bottom. When the acid and zinc cease to come in contact with each other the generation of gas stops until gas is used, which relieves the pressure; then more acid descends, and as it comes in contact with the zinc more gas is generated, replacing that which has been used. This action makes the generator automatic, unless clogging with sulphate of zinc takes place. This may happen at any time if the apparatus is not cleaned after each day's use.