14 Mr. J. A. Harker and Mr. H. B. Dixon on the 



the great bulk of the acetylene was undecomposed. The 

 experiment was repeated with the same result. 



An apparatus was then fitted up, to test the action of 

 fulminate of mercury. It consisted of a steel cylinder or 

 'bomb,' holding about 400 cc, provided with a screw top, 

 through which passed insulated copper wires, and having a 

 tap for admission of gas. This was connected by a union 

 joint with a lead tube similar to that used in the last 

 experiment, having at its other end a strong glass tube and 

 steel tap. The bore through the joint was not less than 

 that of the tube itself. The fulminate used was procured 

 from the Roburite Explosives Company, in the form of 

 detonators containing one gram each. After each explosion 

 the bomb was immediately detached, and the end of the 

 leaden tube stopped by a cork till its contents could be 

 examined. In no case was there any flame in the glass 

 tube at the other end, and on testing the contents of the 

 tube, it was found that the gas was never decomposed down 

 the tube for more than about 1 5 cm. The acetylene in the 

 bomb itself was decomposed, and the sides of the bomb 

 were covered with a deposit of fine carbon. 



A second series of experiments was then made, in which 

 carbon bisulphide vapour was used instead of acetylene. 

 This gave a different result. On attaching to the bomb 

 described a strong glass tube I % metres long, instead of the 

 lead one, and filling the whole, by exhaustion, with vapour 

 of CSo, one of the same detonators produced complete 

 decomposition of the gas, and a deposit of carbon on the whole 

 of the inner surface of the glass. A repetition of the 

 experiment gave a similar result. An attempt was then 

 made to measure the rate of transmission of this explosion. 

 The passage of the flame down the tube was timed by 

 making it break in turn two silver ' bridges ' stretched 

 across the tube, each bridge being connected with a 

 magneto-electric style tracing a mark on a moving plate. 



