608 
MESSRS. R. T. GLAZEBROOK AND S. SKINNER ON THE 
Table XI. 
Number. 
00 
>> 
13 
July 9. 
o 
r— 1 
13 
d 
July 11. 
o 
CO 
3 
July 21. 
July 22. 
July 23. 
July 30. 
80 
81 
- 25 
0 
- 24 
— 53 
- 26 
- 29 
- 23 
- 23 
- 19 
- 21 
Zinc amalgamated 
+ 2 
- 16 
+ 2 
- 15 
+ 2 
- 13 
+ 8 
- 20 
Since the result of amalgamation had been to bring No. 80 into agreement with the 
standard it was thought worth while to try the effect of amalgamating the zinc of one 
of the cells Nos. 42-47 now under consideration. On July 22 the zinc rod of No. 43 
which, as has been remarked, was covered with the grey deposit, was removed and 
amalgamated. After careful washing and drying it was restored to the cell which, 
since that date, has agreed well with our standard (see Table X.). 
On July 24 the zinc rod from No. 42 w~as removed and a new rod inserted in its 
place. There is some doubt as to whether this rod was amalgamated or not; the 
entry in the note book is not quite clear; the cell was still too low, although better 
than before. The rod which had been taken out was placed in some fresh Clark liquor, 
and the difference of potential between it and a well amalgamated rod measured. It 
proved to be 8 or 9 units lower than the amalgamated rod. 
Experiments were commenced on August 17 to test this point with a special form 
of cell. 
Fig. 5. 
A Clark cell was set up in a three-necked Woulfe’s bottle. Two of the apertures, a 
and b, contained the ordinary zinc and platinum of the cell. The third, e, was left 
free for the insertion of the zincs to be tested. In fig. 5, X represents this cell and 
Y the Clark cell, the contents of which are to be examined, d being the platinum and 
c the zinc pole of Y„ The plan of the experiment was to insert a well-amalgamated 
zinc in e, and compare the E.M.F. between a and b, e and b, respectively. These 
were practically the same, and equal to the standard Clark. The differences between 
