510 
MESSRS. W. DE LA RUE AND H. W. MULLER ON THE 
Space . 
Stratum 
Cell?. 
102 
9 
/ = 
= U05 
1 
Taking the mean of several other sets, the balance of the results is in favour of the 
potential being greatest when a stratum intervenes, for example :— 
Stratum, 
1-243 
1-327 
1-081 
Mean 1"243 
Space. 
1 
1 
1 
1 
A series of experiments were made with tube No. 362 having a hydrogen charge; a 
battery of 3600 cells being used, which gave a current of 0'04686 ampere through it. 
This tube has four idle wires a, b, c, d, as shown in fig. 28, 6, but only two were 
used, namely, c and d, 1 inch (2"54 centims.) apart; and a stratum or a space was 
made to intervene between them. The positive pole was connected to the terminal in 
the shape of a point, and the negative to the ring which was also connected to earth. 
The following are the results :— 
Tube potential 
Stratum ,, 
Divisions. 
Ceils. 
Division: 
= 192 
1443 
111 
Space 98 
137 
59 
84 
115 
132 
78 
133 
115 
129 
69 
74 
72 
146 
69 
102 
141 
132 
142 
Mean 118 = 
887 
96 
Cells. 
722 
These figures may be taken as fairly representing the whole series of observations. 
hj\ ; 8 -= 1 '229, which agrees well with the ratio before cited as that of the potential of 
a stratum to that of a space =1 ; and we think that it may be fairly assumed that 
the potential is really greater when a stratum is straddled than when a space is 
straddled. 
Eddies in an electric discharge through a vacuum tube. 
On testing the discharge between two idle wires distant -§ inch (1'6 centim.) with 
a Thomson galvanometer, the current was found sometimes to go in the reverse 
direction to that of the main current. In order to fix with certainty this pheno- 
