The cell is filled with a ten-per-cent solution of caustic soda.
The following table gives the names, elements, fluids, voltage, etc., of the most useful batteries, all of which may be easily constructed by the experimenter.
Secondary or Storage Batteries
The storage battery is a very convenient means of taking energy at one time or place and using it at some other time or place.
Small storage batteries are used in automobiles to supply current for the headlights and spark-coils. Many automobiles are now equipped with "electric starters," consisting of a dynamo-motor and a storage battery. Throwing a switch will cause the current from the storage battery to drive the motor and "crank" the engine. After the engine is started, the motor acts as a dynamo and generates a current for recharging the storage battery.
Storage batteries are also used to drive electric vehicles and cars.
Many central lighting and power stations employ storage batteries to supply the extra current demanded during rush hours. In the middle of the day, when the "load" is light, the surplus current of the dynamos is used to recharge the storage batteries.
What is really effected in the storage battery is the electrical storage of energy, not the storage of electricity. Properly speaking, the energy is put into the form of chemical energy, and there is really no more electricity in the cell when it is charged than after it is discharged.
