92 



THE EXPLOSIVE WAVE. 



2. These arrangements will now be described in detail. 



The tube has sometimes been laid in a single horizontal 



straight line, and sometimes in a succession of parallel rows, as 



shown in Fig. 9. The tube is represented as fixed upon a 



vertical wooden frame. It is provided with two terminal taps, 



A and B, and an intermediate 

 interrupter, C. 



Fig. 10 represents one of 

 the terminal taps without 

 any additional mechanism. 



Fig. 11 represents a tap 

 with a lateral tube enclosing 

 an insulated metallic wire. 



Fig. 10. Terminal Tap. 



The spark is made to flash between the wire and the metallic 

 casing of this pipe. 



Fig. 12 shows the arrangement of one of the strips to be 

 broken by the explosion ; s s is the strip of tin, p p is the slip 



of paper on which 

 the tin is glued. 



The tin is ex- 

 posed at the point 

 V of the tube T, 

 which is shown in 

 section. 



The grain of ful- 

 minate is placed 

 at i. 



Fig. 13 repre- 

 sents the section of 



Fig. 11. Tap and Apparatus for igniting by 

 Electricity. 



the coupling at right angles to the axis of the tube. 



The coupling is marked C C C C. It is formed of four semi- 

 circular pieces facing each other in pairs, two only being shown 

 in the figure ; they are clamped together and round the tube T, 

 by means of the screws E E. 



Fig. 14 represents a section following the axis of the tube. 



The tube T T T T shown in this figure is not the tube of 

 gutta-percha itself, but a brass tube of the same section, on 

 which the gutta-percha tube is fitted, either on one side 

 only, or on both sides at once, as in Fig. 9. This arrange- 

 ment is necessary for clamping the coupling and fixing the 

 interrupters. 



C C C C are the four parts of the coupling, the screws not 

 being shown in order not to complicate the figure. The channel, 

 V V, serves for the passage of the gas. 



The strip of tin, s s, is held in position by small metallic 

 supports, r r, on which the wires conveying the electric current 

 are fixed. 



Between the portions of the coupling, C C, are the two discs 



