622 
MR. H. B. DIXON OX CONDITIONS OF CHEMICAL CHANGE 
‘ Gasometrische Metlioden,’ published in 1857, some further experiments were added, 
which are included in the following table :—* 
Table II.— Bunsen’s Experiments. 
No. oE 
experi¬ 
ment. 
Gases present before explosion. 
Oxygen divides itself, 
Ralio of carbonic acid to 
aq. vapour in the hydrates 
of carbonic acid. 
Temp. C. 
Pressure. 
Oxygen. 
Hydrogen. 
Carbonic 
oxide. 
To 
carbonic 
oxide. 
To 
bydrcgen. 
1 
22-3 
Millims. 
734 
100 
200 
794 
67 
33 
• 2CO„ H,0 - - 67 : 33. 
2 
3-3 
453 
100 
200 
595 
50 
50 
CO,, H,0 - - 50 : 50. 
3 
22-5 
395 
100 
200 
449 
49 
51 
4 
47 
381 
100 
200 
295 
34 
66 
C0 2 , 2R,0 - - 33 : 67. 
5 
22-6 
723 
100 
200 
147 
25 
75 
CO,, 3H,0 - - 25 : 75. 
6 
2-6 
352 
100 
200 
119 
24 
76 
7 
23 
344 
100 
200 
81 
19 
81 
CO„ 4H,0 - - 20 : 80. 
8 
22-0 
720 
100 
370 
315 
20 
80 
9 
7'0 
321 
100 
200 
74 
17 
83 
CO,, 5H,0 - - 17 : 83. 
These experiments remained without confirmation until 1874, when E. von 
Meyer published a paper on the “Incomplete Combustion of Gases,” + in which 
he pointed out that when mixtures of carbonic oxide and hydrogen were exploded 
with progressively increasing quantities of oxygen, the proportion in which the oxygen 
divided itself altered per saltum , and that this proportion might ahvays be expressed 
by whole numbers. 
v. Meyer regarded his experiments as confirming Bunsen’s law, but as Horstmann 
subsequently pointed out, the whole numbers, expressing the ratios between the 
amounts of carbonic acid and steam formed, were in some cases so large that the 
difference between one such whole number and the next above or below it, fell within 
the limits of experimental error. The ratio of the volume of steam formed per unit 
volume of hydrogen present to the volume of carbonic acid formed per unit volume 
of carbonic oxide present, was called by v. Meyer the coefficient of affinity of 
hydrogen for oxygen compared with that of carbonic oxide for oxygen. Taking the 
affinity of carbonic oxide for oxygen as the unit, the coefficient for hydrogen and 
oxygen is given by the equation 
HoO CO, 
This “ coefficient of affinity ” according to v. Meyer is not a constant, but varies per 
saltum within small limits on account of the discontinuous alteration in the proportion 
of carbonic oxide and hydrogen burnt. It is greatest when the quantity of oxygen 
* This table is affected by two or three small errors of calculation, which bring the numbers, 
expressing the ratio of carbonic acid to steam formed, nearer to the theoretical numbers than they 
should be. These errors are corrected in the second edition of Bunsen’s * Gasometrische Mcthoden.’ 
\ ‘ Journal fiir praktischc Chemie ’ (2), 10, 273. 
