132 



Fig. 4. Another view of the interior of 

 the cabinet 



In order to overcome the disadvantage 

 mentioned above and also to eliminate 

 the necessity of soldering the cells, the 

 writer designed a battery case in which 

 the cells are slipped in place from the 

 back and automatically make connec- 

 tion. There is also provided an extra 

 switch mounted on the case which 

 allows each cell to be tested out individ- 

 ually at any time, in a most convenient 

 way. 



Popular Science Monthly 



less. The method 

 of connecting 

 is shown in the 

 diagram on page 

 134. At the right 

 of the panel is 

 shown the testing- 

 switch, the two 

 levers of which 

 are connected to 

 the lamp shown 

 at the middle of 

 the panel. 

 The first two 

 points of this 

 switch, upon 

 which the lever is 

 shown at rest, are 

 arranged to be 

 "dead;" each of 



Fig. 6. Section through 

 high-tension switch 



Fig. 5. Sectional view of case taken 

 through testing-lamp 



The arrangement of switches on the 

 case is shown at Fig. i and Fig. 2 of the 

 accompanying diagrams. In Fig. i 

 there will I)e seen to the left of the panel 

 at the front of the case the usual high- 

 tension switcli. This is of the type 

 recently described in this magazine, and 

 in which, to prevent accidental short- 

 circuiting of the cells, there is provided 

 between each pair of live points an 

 extra point. All of ihe extra points are 

 connected together and act in i)lace of 

 the usual connection to the ii-nler of 

 the switch. The i)oints are so spaced 

 and till' width of the lever so calculated 

 that the lever cannot in any case co\'er 

 more than two points, thus making 

 connection but ])reventing short-cir- 

 cuiting. 



The spacing of the points is also such 

 that the switch is smooth and noiM- 



the other points is 

 connected with the corresponding point 

 on the other switch. Thus when the 

 testing-switch is turned and its two 

 levers brought into contact with any 

 pair of points, the corresponding cell is 

 brought into connection with the testing- 

 lamp and the relative brilliancy of the 

 lamp is a measure of the condition of the 

 cell. In order to prevent short-circuiting 

 of the cells by the use of this switch, the 

 arms thereof are normally kept out of 

 contact with the points by a spring at 

 the rear. By the use of a spring friction- 

 member, shown at the bottom of the 

 switch, it may be set above any pair 

 of points. Pressing the knob will then 

 make the desired connection with the 

 cell selected. The 

 binding posts at 

 t he extreme left are 

 for the wires which 

 lead to the audion 

 cabinet. 



An understanil- 

 ing of the interior 

 construction of the 

 case maybe gained 

 by an examination 

 of the drawings. 

 Fig. T, and I'^ig. 4. 

 l"ig.3isa\iewof the 

 case in which the 

 front or switch 

 panel has been re- 

 moved as well as 

 the top of the case. 

 In l*~ig. 4 the front 



Fig. 7. View 

 through the testing- 

 switch 



