106 Dr Turner's Experiments on the Application of 
A mixture of 13 oxygen to 1 hydrogen was acted on by 
electricity and platinum, just as in the preceding case. 
A mixture of 1 5 volumes of oxygen and 1 hydrogen was 
electrified, without either detonation or decrease in volume. 
The ball No. 2. then caused a diminution, which indicated the 
exact quantity of hydrogen. 
These results with respect to the influence of electricity cor- 
respond exactly with the experiments of MM. de Humboldt 
and Gay Lussac, detailed in the Journal de Physique for 1805, 
I made various mixtures of oxygen and hydrogen, in which 
the latter was ^th, ^th, ^ th, ^th, of the whole mass, 
and in all these cases ball No. 2. caused a diminution, which 
indicated the quantity of hydrogen with much accuracy. In the 
two last experiments the ball was slightly warmed. 
7 volumes of hydrogen were mixed with 700 volumes of 
oxygen, being the exact proportion of 1 : 100. The ball No. 2, 
gently warm, was put into 138 volumes of this mixture. The 
process was conducted in a capacious jar ; the gases were care- 
fully transferred into the graduated tube at the end of 10 mi- 
nutes, and the diminution was 3 volumes. Hence 2 volumes of 
hydrogen were indicated, while 1.38 were present. 
Ball No. 2. was put into 186 volumes of the same mixture, 
which was allowed to remain in the graduated tube for half an 
hour, when the diminution amounted to 4 volumes. 2.6 vo- 
lumes of hydrogen were therefore indicated, while only 1.86 
were present. 
Though there is a very slight error of observation in both 
these experiments, we may nevertheless safely infer that hydro- 
gen may be detected in oxygen gas, and its quantity ascertained 
with accuracy by platinum, when it does not exceed T Joth °f 
the whole volume. To detect any unforeseen source of error, I 
performed the following experiment. No. 2. gently warm, was 
put into 187.5 volumes of atmospheric air, dried by fused pot- 
ash, and was left there three-quarters of an hour; after this in- 
terval the air measured 189, which is 187.5 + 1.5 the space oc- 
cupied by the ball. I had ascertained, by some preliminary 
trials, that platinum, though strongly heated, could not cause 
the combination of oxygen and nitrogen, as electricity does ; and 
this is confirmed by the foregoing experiment. It shows, too, 
