644 
MR. H. B. DIXON" OX CONDITIONS OF CHEMICAL CHANGE 
pieces of platinum wire into small glass beads, Bunsen constructed a chain of alternate 
links of metal and glass, each piece of platinum being insulated from its neighbours bv 
a glass bead round which the spark passed when the two ends of the chain were 
connected with an electrical machine. This chain was fastened to two platinum wires 
fused through the glass near the top and bottom of the eudiometer. The object of 
this mode of ignition was to prevent the formation of an “ air-wave ” down the tube 
and the consequent compression of the still unburnt gases by the expansion of the 
burning gases above. The results obtained in this way by Bunsen agree well with 
those obtained by Horstmann. My experiments show a greater proportion of carbonic 
oxide burnt in every case. 
Table VII. — Explosion of dry carbonic oxide and electrolytic gas. 
No. 
Combustible gases contain in 
100 vols. 
1 
Ratio of carbonic acid to water formed =k!h 
H ; 0 
Carbonic oxide. 
Hydrogen. 
Dixon. 
1 
Horstmann. 
Bunsen. 
(new experiments.) 
1 
837 
163 
2-07 
2 
81-8 
18-2 
177 
1-52 
3 
80-8 
19-2 
1-62 
1-43 
4 
781 
21-9 
1-29 
174 
115 
5 
77-6 
22-4 
1-27 
1-09 
172 
6 
777 
22-6 
1-31 
1-08 
171 
7 
75'8 
24-2 
1-08 
•95 
1-01 
8 
75'5 
24-5 
1-05 
•94 
•99 
9 
73-4 
26-6 
•97 
•88 
•89 
10 
72-6 
27-4 
1-00 
•81 
•84 
11 
69-3 
307 
74 
70 
74 
12 
68-9 
311 
73 
•69 
*73 
13 
667 
33'3 
74 
•63 
70 
14 
53'5 
46-5 
■42 
•41 
The chief differences in the condition of the gases in the three series of experiments 
tabulated above lay in the initial pressure under which they were exploded, and in the 
length of the path traversed by the flame from the point of ignition. In my experi¬ 
ments the pressures were between 200 millims. and 300 millims.; in Horstmann’s 
experiments the pressures were between 360 millims. and 480 millims.; and in Bunsen’s 
between 600 millims. and 650 millims. To determine what difference, if any, is pro¬ 
duced in the division of the oxygen by a variation of (1) the initial pressure, and (2) 
the length of the column of gases along which the explosion is propagated, a 
fresh series of experiments was begun in the autumn of J 877. 
