102 REPORT —1905. 
The Merewrous Sulphate Paste.—Some cadmium sulphate crystals are 
ground in an agate mortar with a little cadmium sulphate solution ; about 
one-quarter their bulk of pure mercury is then added and two volumes 
of the acid-free mercurous sulphate, the whole being well mixed with 
cadmium sulphate solution so as to form a thin paste. 
The Form of Cell.The H form of cell due to Lord Rayleigh is the 
most convenient, and is in general use. Two patterns have been adopted. 
In fig. 1 a form is shown in which the electrodes are sealed into the lower 
ends of the two vertical limbs, while in the form shown in fig. 2 the 
electrodes pass through glass tubes into the lower ends of which they 
M = Mercury. S = Saturated solution of cadmium sulphate. 
A = Amalgam. K = Cork. 
P = Paste. G = Marine glue. 
C = Cadmium sulphate crystals. 
are sealed. Form 1 can be hermetically sealed, and is intended to be 
immersed in an insulating liquid. Form 2 is sealed with marine glue, 
and may be immersed in ice or water. The hermetical sealing of form 1 
was suggested by Lord Rayleigh ' and by Professor Carhart.? The glass 
tubes through which the electrodes are introduced in form 2 pass through 
corks which have been previously boiled in water and soaked in cadmium 
sulphate solution ; in addition to the hole allowing of the passage of the 
electrodes, a second hole is bored through these corks for the passage of 
small glass pipettes. After the cell is filled these additional holes are 
1 Phil. Trans., 176, § 42, 1886. ? St. Louis Congress, 1904. 
