176 
MESSRS. W. DE LA RUE AND H. W. MULLER ON THE 
and from time to time narrower strata introduced themselves between those 
first formed, as shown in 18, fig. 43. The introduction of 900,000 ohms caused 
the strata to widen out and to fill the space occupied bj the secondary strata. 
24. — After 10 cistern-fulls had run through it required a potential of 2400 cells 
to pass, the strata were 1^ inch wide, and a sort of hour-glass luminosity 
appeared at the negative, as shown in 20, fig. 45. At times the luminosity 
left the centre of the negative ring and jumped towards the wall of the tube, 
as shown in 22, fig. 45. 
Fig. 45. 
25. — At the 12th cistern-full the strata became 1-| inch wide, but at times 
divided into two ; one peculiarity observed was that the pink was on the 
convex side towards the negative and not as before noticed on the concave 
side.'"' The luminosity at the negative hugged the wall of the tube whether 
the point or the ring was positive. The phenomena are showm in 22, fig. 45. 
After a while 2400 rod cells only faintly illuminated the tube, and it required 
3600 to continue the phase. 
26. — At the 13th cistern-full 3600 cells would scarcely pass, only causing a faint 
glow in the tube, and it required 5880 to produce any strata ; without 
The phase was subsequently reproduced at a pressure of O' 390 m.m., 513 Mi O. 0'01451 W 
