510 Proceedings of the Roy at Society 
when it begins to return, the compression is effected on the less 
rigid hydrogenium already formed on the other side, the elasticity 
of form being also probably relatively small. This is the general 
explanation of the motion of the plate, but it must be remembered 
that the smaller flexures produced by different forms and positions 
of the electrodes are the result of non homogeneity or excessive 
strain. This is one position, at least, of the palladium relatively 
to the other electrode, where the plate should have no lateral 
motion — that is, when it is at right angles to the surface of the 
positive plate; but all the attempts made with the small palladium 
plate at my disposal failed to prevent lateral motion, probably from 
want of uniformity of surface producing different rates of penetra- 
tion. 
Effect on the Current during the Formation of the Hydrogenium. 
In order to determine the effect on the current during the oc- 
clusion of the hydrogen and its reoxidation, two Bunsen’s cells 
were connected, through a tangent galvanometer, with a plate of 
palladium and platinum as poles in a cell containing acidulated 
water. The intensity of the current was determined — 1st, during 
the decomposition of the water, when the palladium pole evolved 
oxygen; then during the absorption of hydrogen, when the current 
was reversed; and lastly, when the oxidation of the occluded hydrogen 
was taking place. 
Angles on tangent ) 
galvanometer, J 
Tangents, 
Palladium. 
Positive Pole. 
23 0, 5 
0-4348 
Palladium. Hydrogenium. 
Negative Pole. Positive Pole. 
21°-5 40°-3 
0-3939 0-8541 
The diminution in the intensity of the current during the forma- 
tion of the hydrogenium arises from the strong current, generated 
in the decomposing cell by the secondary polarity of the electrodes, 
acting in the opposite direction, whereas the oxidation of the 
hydrogenium reduces a current acting in the same direction as the 
battery. The intensity of the current during the oxidation of the 
hydrogenium is nearly doubled, so that if we consider the resist- 
ance in the circuit to remain constant, the additional electro-motive 
force added by the oxidation of the hydrogen is equivalent to two 
cells of Bunsen. The great increase in the intensity of the cur- 
