140 ME. GASSIOT ON THE STEATIFICATIOXS IN ELECTEICAL DISCHAEGES. 
gave a bluish grey. In some instances oxygen gave the reddish tinge, in others gi-ey. 
similar to hydi'ogen. This apparent anomaly I subsequently ascertained arose from the 
impurity of the oxygen. 
67. If the extremity of a vacuum-tube is presented to the prime conductor ol an elec- 
tric machine, or to one of the terminals of an induction coil, a spark can be taken and 
the glass will be perforated. The perforation is extremely minute, but sufficient under 
the pressure on the vacuum to admit air or gas ; but so slowly does the gas or am enter, 
that the experimentalist is enabled to note the gradual change which takes place diuing 
the progress of the discharges of the induction coil; the change (depending on the size 
of the perforation) sometimes occupied two or three hours. The extremity of a vacuum- 
tube after perforation was connected by means of tight-fitting gutta percha tubmg to a 
glass cylinder containing fused chloride of calcium, through which am, hydi'ogen, oxygen, 
or nitrogen was permitted to pass into the vacuum ; the result of many repeated experi- 
ments showed that with hydrogen or oxygen no change in the colour takes place ; with 
air or nitrogen the colour of the stratifications changes from bluish grey to a fawn, and 
ultimately to a deep red tinge ; and during this addition of gas or am, the cloud-like 
stratifications gradually close, becoming narrower and naiTower untfr they are entirely 
destroyed, passing to a mere luminosity filling the entme tube, and finally mto the 
wave discharge. 
Condition of Discho/rge ot Negative Terminal. 
68. In some instances several seconds elapsed, during which the induction coil was in 
action before any luminous effect could be produced in the tube, the ffist lummous 
discharge filling the entire tube without any stratifications, the negative wm-e bemg 
surrounded with a brilliant Uue phosphorescence ; if the discharges ai-e now contmued 
for a few seconds, the cloud-like stratifications appear gradually becommg clear, and 
distinctly separated, leaving the dark band near the negative terminal 3 to 6 niches 
in length. At this time, and before any black deposit from the negative platmum ume 
(which now becomes intensely red) is deposited on the glass, a brilliant white lummous 
discharge (which for the sake of reference 1 name the White-tongue Dischai-ge) is lasibie 
close to the negative wire; this tongue has a tendency to rotate round the pole ot a 
magnet, and consequently assumes the appearance of being repelled or attracted as eao.i 
pole is alternately presented ; while a long brilliant phosphorescent dischai-ge, proceednig 
from the upper part of the negative terminal towards the positive, is also similar y 
attracted or repelled by the magnet. This phosphorescent discharge can by manipula- 
tion be contracted or expanded by a magnet in a remarkable degree (for distinction 
name this the Blue-tongue Discharge). 
If the north pole of a magnet is placed close to the negative uire, and o\ ei the ue 
tongue discharge, the discharge will be elongated and repeUed, the end thereof bein 
forced on the opposite side of the tube, illuminating the portion on winch it impingt 
with a brilliant phosphorescent blue light. 
rjj CjQ 
