﻿during the Formation of Graham's Hijdrogenium. 427 



The electrodes of palladium and platinum were firmly clamped 

 in the little vice represented by D, and arranged as shown in the 



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figure, where A represents the palladium and B the platinum. 

 To the lower edge of the palladium plate a narrow strip of the 

 same metal is fused by the oxyhydrogen blowpipe ; the strip is 

 of such a length as to project above the level of the acid liquid 

 when the plate is immersed. To the end of the strip of palla- 

 dium a thread of glass is fused so as to have a radius in all of 40 

 or 50 centims. ; the arc of a divided circle of the same radius on 

 a piece of cardboard is supported by a stand at the extremity of 

 the index. By this apparatus the small deflection of the palla- 

 dium plate is greatly magnified, and the direction of motion well 

 defined. Suppose the palladium plate A in the figure is con- 

 nected with the negative pole of the battery, the glass index, 

 after a short time, begins to move from left to right on the plane 

 of the diagram to the extent of 8 or 10 centims. on the scale. 

 As the saturation goes on, the index begins to move backwards 

 from its first position, going towards the left, even to a greater 

 extent than its first deflection towards the right. Continuing 

 the action, it again returns to near its original position. The 

 power of being able to return to the position it had at starting 

 seems to depend on the condition of the plate, as regards the 



