AS OBSEEVED IN TOEEICELLIAN AND OTHEE VACUA. 143 
The discharges, whether from a or a! to h or b’, were at first luminous, filling the whole 
tube without stratifications. On the discharges being continued from a io b for a few 
Eig. 3. 
seconds, the stratifications appeared of the cloud-like form, increasing in brilliancy, and 
leaving a dark negative band 3^ inches in length. The positive terminal of the coil was 
then attached to a', and the discharge taken from a! io b; there was no alteration in the 
character of the stratifications; they remained as in the last experiment, clear and 
distinct. The negative terminal wire of the coil was then removed from b to b', the dis- 
charge (luminosity without stratifications filling the entire tube) returned ; the positive 
terminal wire of the coil was then removed from a to a'., with the same result. 
The apparatus was allowed to remain in this state for one hour, when the experiment 
was repeated with the same result. On continuing the discharge from a! to b', the 
stratifications appeared, and the tube now remains in this state. If b and b are con- 
nected together by a wire so as to form one negative terminal, the stratifications are 
clearer and better defined than when the discharge is made to either separately, but 
there is not any increase or alteration if the a a! are connected. From these experi- 
ments it would appear that with platinum terminals the character of the stratifications 
is much modified by the altered condition of the negative wire, which it undergoes 
shortly after the discharges take place. 
Stratified Discharge from both Terminals. 
75. On one occasion I obtained a result, which, although as yet I have not been able 
to repeat with other tubes, yet with our present imperfect knowledge of the causes of 
the stratifications, may be worth recording. The following is an extract of a note taken 
at the time : — 
In a short tube, 10 inches long. No. 13, the discharge presented the cloud-like strati- 
fications. From the long time this tube had been used, and the direction of the dis- 
charges having been often altered, much metallic deposit had taken place at both termi- 
nals. In this state one end of the tube was perforated by an electrical spark while 
connected with the coil ; as the discharges were continued, the stratifications gradually 
assumed greater distinctness, at first with a light fawn, and then of a slightly red colour, 
but they did not alter in their shape : after one hour the discharges were discontinued, 
and again renewed in about thirty minutes, when I observed that the red colour had 
increased, but the size of the stratifications remained unaltered. The discharges were 
further continued for about thirty minutes : during the whole of this experiment only 
one cell of the battery had been used. On trying the effect of ten cells, I observed two 
