Popular Science MontJdy 



133 



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panel with its wood pieces 

 has been removed and a piece 

 of the second or interior panel 

 broken away to show the ar- 

 rangement of the cellri in the 

 box. It will be seen that the 

 interior of the case is divided 

 into twelve compartments by 

 means of thin fiber strips and 

 at the front of each compart- 

 ment is a pair of contacts 

 against which the electrodes 

 of the battery are forced by 

 the sliding panel at the back 

 of the case. These two con- 

 tacts consist of a switch- 

 point and a spring, the 

 switch-point for making con- 

 tact with the long springlike 

 electrode of the cell and the 

 spring-contact making con- 

 tact with the short, stiff 

 electrode of the cell. 



By the diagonal arrangement of the 

 spring-contacts shown, the use of connec- 

 ting wires is obviated and an arrange- 

 ment made whereby all the cells are 

 inserted in the same position. In Fig. 4 

 these diagonal springs are shown as 

 suspended in mid-air in order to show 

 the method of making contact. The 

 switch-points further act as connections 

 for the leads to the high-tension switch. 

 Between the front panel and the interior 

 contact panel all the connecting wires 

 are neatly placed and well protected. 

 Fig. 5 is a sectional view taken on the 

 line of the testing-lamp and looking 

 toward the left in Fig. i. The arrange- 

 ment of contacts and the connecting 

 space at the back of the switches is here 

 clearly shown. It will be noted that 

 the switch panel with its wood backing 

 forms a cover for the battery holder, 

 and is secured to the latter by means of 

 the large screws shown at the right and 

 left-hand ends of the front panel. On 

 loosening these two ^screws, the cover 

 may be removed and the connections 



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Detail of the top and bottom of the case 



Details of ends of the case, sliding rear panel, front panel, etc. 



examined, yet cells may be inserted 

 from the back at any time without 

 disturbing a single connection. 



Fig. 6 is a section taken through the 

 high-tension switch and shows clearly the 

 arrangement of the switch parts. 



Fig. 7 is a section through the testing- 

 switch and shows the arrangement of 

 the parts of this switch and also more 

 clearly how the switch arms are normally 

 out of contact with the points. 



Consider now the details of con- 

 struction in diagrams on this and fol- 

 lowing page: Detail I is at the top and 

 bottom panels of the case. The narrow 

 transverse slots are for the fiber separa- 

 tors and may be carefully cut with a 

 hack-saw. The slot in which the sliding- 

 back of the case fits is shown at the 

 back and should be made smooth and 

 true. Detail 2 shows the ends of the 

 case, and 3 is the sliding-rear of the case. 

 At its right-hand end a recess should be 

 made to enable this piece to be slid out 

 easily. Detail 4 is at the top and bottom 

 of the cover or switch panel support, 

 while 5 shows the end-pieces of the same. 

 The fiber .separating pieces (6), should 

 be made a rather tight fit in the slots 

 provided for them. 



The front panel (7) should be very 

 carefully laid out before being drilled. 

 It may, after drilling, be rubbed down 

 with pumice stone and water to get 

 the dull finish so much desired. 



