PROFESSOR H. B. DIXON ON THE RATE OF EXPLOSION IN GASES. 171 
The apparatus being arranged as shown in fig. 7, the explosive mixture from the 
holder was driven through the washing vessel A, partly filled with boiled oil of 
vitriol, and through the two drying towers B, B, packed with pieces of asbestos 
saturated with boiled oil of vitriol. The gas then passed through a short length of 
black rubber tubing to the end piece C carrying the second bridge. From the end 
piece the mixture passed into the explosion tube coiled on a drum standing in the 
large iron water-bath D. A second clamp united the explosion tube to the firing 
piece E, carrying the first bridge at one end, and the firing wires f, f, sealed through 
Fig. 5. 
Fig. d 
Shows the construction of a second pair of bridge pieces and clamps used during the last two years. 
a stout glass tube, and a tap G at the other. The taps were made of hardened steel. 
After leaving the firing piece the gas passed by a glass tube M to a three-way tap H, 
by which it could be sent either to the testing tube I or by the pipe K to the window. 
In many of the experiments a sulphuric acid wash-bottle L was joined to the tube at 
M, and connected with a holder containing electrolytic gas. Before starting the 
experiment the air was displaced from the vessel L by a stream of electrolytic gas. 
When the explosion tube and firing piece were full of the explosive mixture, the tap 
H was shut, and a few bubbles of electrolytic gas were driven into the firing piece so 
as to fill about one-third of its length. This insured the explosion-wave being set up 
m the firing piece before the flame reached the first bridge, and was a convenient 
mode of firing mixtures—such as those containing cyanogen—which do not readily 
ignite. 
For experiments under increased pressure the arrangement shown in fig. 6 was 
