’ 
ON THE GASES EVOLVED FROM IRON FURNACES. 151 
II. Experiments with a eudiometer of larger dimensions, such as that used 
. in our experiments. 
5th Experiment, June 30. 
Temp. | Difference of 
Volume. Cent. level. Barometer. 
° m m 
Volume of hydrogen used........es++000++ 1461 71 0-2149 0:7460 
Volume after admission of air ...........- 313°0 17-1 0:0593 0°7460 
Volume after combustion ..........scc00ee- 2169 17-1 0°1506 0:7449 
6th Experiment, July 1. 
Volume of hydrogen used........... aE ES 1556 | 16:8 02069 |. 0-7447 
Volume after admission of air ............ 297-1 16:9 0:0750 0:7442 
Volume after combustion ........-..s..000« 2143 17-0 0:1528 0:7444 
III. Experiments with a large, long and wide eudiometer. 
7th Experiment, July }. 
Temp. | Difference of 
Volume. Gone tere: Barometer. 
° m ae m 
Volume of air used ........sscecescereceees 663°2 16:0 0-2301 0°7453 
Volume after admission of hydrogen ...| 881-3 16-2 0:0237 0°7453 
Volume after combustion ........s+s+..s00 7350 16°5 0-1658 0-7448 
8th Experiment, July 10. 
Volume of air used ...se.seseeessseeessenes 676'8 16:4 0:2160 0°7444 
Volume after admission of hydrogen ...|) 8787 | 16-5 0:0225 0-7444 
Volume after combustion ......+0...sseeees 716-6 16:2 0:1667 0:7444 
9th Experiment, July 12. 
Volume of air used ......secsesecseeeeese --| 657-2 16°8 0-2408 0-7457 
Volume after admission of hydrogen ...| 890-9 16:8 0-0099 0°7457 
Volume after combustion ..,.... asad aaa 752°8 16:8 0:1460 0°7449 
From the preceding experiments, the composition of air is as follows:— 
Nitrogen. Oxygen. 
78°92 21-08 
78:93 21:07 
78°98 21:02 
78:99 21-01 
7910 20 ame by a larger eudiometer, such as that 
Determined by the smallest eudiometer. 
79:09 20°91 : : 
7914 20°86 used in our experiments, ¥ 
7910 20:90 
7919 20°81 >Determined by the largest eudiometer. 
79°05 20°95 
The great agreement of these experiments with one another, and with the 
results obtained by the extremely careful experimental determination of the 
composition of air by Dumas, proves that the eudiometric analyses of gases 
admit of a degree of exactness which certainly is not surpassed by the most 
minute analytical methods; and they further show, that the presence of ni- 
