416 
MK. W. R. CARR OX THE LAWS GOVERNING 
V. Experiments, in Carbon Dioxide. 
These further experiments were made with a view to corroborate the results 
already obtained in air and hydrogen. The same apparatus as had been used with 
these two gases again served for the experiments in carbon dioxide, and the distance 
between the electrodes was varied as before, so that readings were obtained at the 
five different distances 1, 2, 3, 5, and 10 millims. The carbon dioxide was prejiared 
by treating marble with hydrochloric acid, and was purified and dried by beinu- 
bubbled through a wash-bottle of water and passed through a tube tightly packed 
with phosphoric pentoxide before reaching the discharge apparatus. In each case 
the operation of exhausting the whole discharge apparatus to 1 millim., or less, of 
mercury, and then refilling with carbon dioxide was repeated five or six times, and 
finally the gas was allowed to stand as in both previous cases, in the presence of a 
bulb of phosphoric pentoxide for several hours. 
The complete set of results is given in Table V., and the corresponding curves 
set forth in fig. 6, and if we again compare the discharge pressures and spark 
lengths corresponding to any value of the applied potential, the same law is seen 
to hold here also with even greater rigidity than in the other cases. 
Table V.—Carbon Dioxide. 
Spark 
= 1 m 
Pressures 
in 
millims. 
of 
mercury. 
length 
illim. 
; Spark length 
1 =2 millims. 
' Spark length 
! =3 millims. 
Spark length 
= 5 millims. 
Spark length 
= 10 millims. 
Spark 
potential 
in 
volts. 
Pressures 
i 
millims. 
of 
mercury. 
Spark 
potential 
1 in 
volts. 
1 
' Pressures 
i 
millims. 
of 
1 mercury. 
Spark 
potential 
in 
volts. 
Pressures 
in 
millims. 
of 
mercury. 
Spark 
potential 
in 
volts. 
Pressures 
in 
millims. 
of 
merciu-y. 
Spark 
potential 
in 
volts. 
19-8 
516 
21 
3 
802 
8-75 
674 
9 
10 
790 
7^27 
993 
12-6 
480 
13 
8 
645 
5-57 
563 
5 
77 
1 674 
4^26 
790 
9-41 
443 
8 
76 
519 
3-55 
477 
3 
64 
579 
2^43 
656 
6 • 8ii 
425 
5 
41 
464 
2-25 
427 
0 
w 
33 
498 
1-44 
553 
5-86 
421 
4 
02 
439 
1-91 
420 
1 
45 
438 
■860 
473 
5-02 
419 
3 
46 
426 
1-63 
419 
1 
25 
423 
■612 
428 
4-31 
420 
2 
95 
421 
1-41 
425 
1 
07 
421 
■510 
423 
3-73 
427 
2 
52 
419 
1-20 
432 
919 
428 
■409 
440 
3 ■ l8 
443 
2 
15 
420 
1-02 
449 
786 
441 
■340 
470 
2-73 
475 
1 
84 
427 
■875 
487 
678 
464 
■280 
506 
2-34 
503 
1 
58 
443 
■758 
542 
572 
495 
■239 
563 
2-00 
559 
1 
34 
473 
■651 
599 
492 
533 
■196 
639 
1-72 
636 
1 
16 
525 
•558 
699 
419 
599 
■162 , 
761 
1-47 
763 1 
980 
605 
•482 
815 
360 
704 
■134 
973 
1-26 
916 ‘ 
848 
702 1 
■420 ‘ 
971 
310 : 
820 
■111 
1219 
1-08 
1127 ; 
728 
847 
■362 
1162 
266 
969 
•094 
1550 
■946 
1432 
625 
1026 
■314 
1445 
232 
1159 
■089 
1730 
•817 
1801 
536 
1258 
■274 
1756 
196 
1373 
- 1 
— 
455 f 
1574 
— 
_ 1 
169 
1662 
1 
421 1 
1 
1762 
1 
— 
— 
■ 
164 
1770 
— 
— 
