# Page:Popular Science Monthly Volume 89.djvu/146

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��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

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