66 
INDUCTION SHOCKS 
supporting collar, e (Fig. n), is fastened into a trian- 
gular sheet of brass, / (Fig. 12), from whose apex pro- 
ject horizontally two brass arms, w and w'\ these are 
bent at right angles at 
their outer ends, as shown 
in Fig. 13. From the tip 
of each of these arms a 
coiled spring, / and I' (Fig. 
12), extends down to the 
end of a lever, k and k'. 
Each spring consists of 
twenty-seven turns of 
spring brass wire, 0.6 mm. 
in diameter. The length 
of the spring is about 16 
mm., and the outside di- 
ameter of the coil 5 to 6 
FIG. 13. Diagram of the operating mm The depression of 
device for the knife-blade key; 
horizontal view. Significance of either lever puts the spring 
letters the same as in Figs. 1 1 and connecting with it under 
12. s, cavity in base for holding 
short-circuiting device. tension and tends to draw 
downward the correspond- 
ing arm, rotating the vulcanite blade with it. To pre- 
vent movement of the blade until the spring has been 
put under a certain degree of tension, two slits, g and g', 
are cut into the lower edge of the triangle, /. A re- 
leasing device, i, is pressed upward against the lower 
