220 



ELEMENTS OF GENERAL SCIENCE 



228. The lead storage cell and some of its uses. It is quite 

 common in automobiles and other machines to observe elec- 

 tricity in use in appliances which are removed from the gen- 

 erators which supply the energy. This is made possible by 

 the storage cell (fig. 109). If the wires from the two plates 

 shown in the figure are attached to the binding posts which 

 are connected to the battery and the switch is closed, the 



10!>. Materials for studying the lead storage eel 



The solution in the cell contains 1 liter of water into which ^ liter of concentrated 

 sulphuric acid has been slowly poured. From left to right the materials shown 

 are three dry cells, an electric bell, two lead peroxide plates, two unused lead 

 plates, a commercial lead storage cell, a laboratory-made lead storage cell 

 connected with wires, and an Edison cell 



ammeter shows that a current is passing through the circuit, 

 and bubbles will be seen near the lead plates. This action 

 should be allowed to continue for a minute or more, and 

 then it may be interrupted by opening the switch. 



If the dry cells are now disconnected from the binding 

 posts, and an electric bell is inserted in the circuit (care 

 should be taken to reverse the connections on the ammeter 

 and voltmeter), the bell will ring when the switch is closed. 

 Since the two lead plates in the sulphuric acid would not 



