316 ILLINOIS STATE ACADEMY OF SCIENCE 



Each individual cell consists of a glass test tube, 1 to 

 11/4 inches in diameter, and 5 to 6 inches long, in which 

 are placed two strips of sheet lead and a quantity of di- 

 lute suljDhuric acid. To protect the electrolyte from 

 evaporation it is covered with a thin layer of oil which 

 also tends to prevent the acid from being thrown off in 

 spray Avhile charging the battery. A general idea of the 

 wooden tray and assembled cells may be obtained from 

 Fig. 1. The purpose of the two auxiliary tubes, next to 

 the binding posts and filled with oil, is to prevent the acid 

 from creeping. The oil also protects the soldered joints. 



The plates were made of sheet lead 1/8 inch thick. Af- 

 ter cutting it into strips of the desired width, they were 

 run through two corrugated rollers, giving them some- 

 what more surface, and also providing recesses to hold 

 the active material formed in charging. These strips 

 were then cut into the desired length, each length provid- 

 ing two plates when bent into shape. The strip thus bent 

 was placed astride two cells, one plate forming the posi- 

 tive electrode and the other the negative of the adjacent 

 cell. The lead plates being heavy, but little warping will 

 result; hence no separators are necessary. 



The manner of putting the cells together is clearly 

 shown in the figure. The time required for the forma- 

 tion of the lead plates may be considerably shortened by 

 treating them before assembling in strong nitric acid for 

 from four to six hours. The plates were then rinse'd in 

 water and placed in position. Dilute suljDhuric acid of 

 density 1.25 to 1.30 was used as the electrolyte, and a pro- 

 tecting film of oil was placed over it. The cells thus as- 

 sembled were allowed to stand for several days before 

 beginning to charge them. During this interval a coat of 

 lead peroxide formed on the plates. 



In the formation of the plates, a small current (about 

 1/10 of an ampere) was sent through each cell. Larger 

 currents caused excessive bubbling, which is objection- 

 able since it tends to prevent the formation of active ma- 

 terial on the plates. The charging was allowed to con- 

 tinue until they were all gassing freely, which required 

 about 8 hours. 



