ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. 187 
Tube 129, 9th Charge of Hydrogen. 
85. — Pressure 14T m.m., 18,533 M, 8040 cells, C. 0’00335 W. A glow from the 
positive extending for J- the length of the tube ; it began to taper down 
about half the length of the tube, and then great heat was developed at 
its extremity. 
86. — Pressure 12 m.m., 15,789 M. A luminosity formed on the positive, like 102, 
fig. 46 ; it then travelled nearly to the negative and returned slowly to 
the positive. After a while another luminosity partly stratified, formed 
behind the first at the positive, but ultimately disappeared. Finally the 
luminosity took the form of 104, fig 46, and was partially stratified, it moved 
towards the negative when the markings became more pronounced, but 
when returning to the positive the markings disappeared. 
87. — Pressure 2 m.m., 2632 M, 3600 cells, C. 0’01272 W. The phase was 
obtained which is shown in fig. 11, Plate 15, copied from a photograph taken 
in 7 seconds. 
The tube was accidentally broken on January 23rd, 1877, and although 
it has been successfully mended it has not been re-filled, as the pumps have 
been occupied with other experiments.* 
Tube 129, Air. 
88. — Pressure 8'7 m.m., 11,447 M, 8040 cells. A continuous nebulous discharge, 
most brilliant at the positive wire, a patch of nebulous light on the 
negative ring. 
89. — Pressure 5’5 m.m., 7237 M, 8040 cells. Three nebulous luminosities like 1, 
fig. 48. 
90. — Pressure 2*4 m.m., 3158 M, 4800 cells. A continuous glow extending 
from the positive to the negative, in which the rotating mirror did not 
show any structure, C. 0 ’02320 W. 
91. — Pressure 1*2 m.m., 1579 M, 3600 cells. Two or three strata formed at the 
extremity of the nebulous discharge near the negative. 
* May 20th, 1878. This tube has since been re-attached to the pump, and several of the foregoing 
experiments have been repeated. The effect of running successive cisternfulls of mercury through the 
pump after the pressure had attained 0T8 m.m. was found to be as follows : — 
1st cisternfull reduced the pressure to 0"085 m.m., 112 M, 3,600 cells, C. 0'01451 W, 21 strata. 
2nd 
„ 0-038 „ 
50 „ 
99 99 
„ -0-00631 , 
, 15 „ 
3rd 
„ 0-019 „ 
25 „ 
7,760 „ 
„ 0-02131 , 
, 20 „ 
5th 
„ 0-011 „ 
14 „ 
„ „ 
„ 0-01705 , 
, 17 „ 
8th 
„ 0-008 „ 
11 „ 
8,040 „ 
„ 0-01331 , 
, indistinct. 
9th 
„ 0-003 „ 
4 „ 
11,000 „ 
„ 0-01639 , 
, faint. 
10th 
„ 0-002 ,, 
3 „ 
55 j5 
„ 0-01840 , 
, ,, 
2 b 2 
