ON PRACTICAL STANDARDS FOR ELECTRICAL MEASUREMENTS. 47 
The Weston normal cell is a voltaic cell which has a saturated 
aqueous solution of cadmium sulphate (CdSO,.8/3 HO) as its electro- 
lyte. 
The electrolyte must be neutral to congo red. 
The positive electrode of the cell is mercury. 
The negative electrode of the cell is cadmium amalgam consisting 
of 12°5 parts by weight of cadmium in 100 parts of amalgam. 
The depolariser, which is placed in contact with the positive elec- 
trode, is a paste made by mixing mercurous sulphate with powdered 
crystals of cadmium sulphate and a saturated aqueous solution of 
cadmium sulphate. 
_ The different methods of preparing the mercurous sulphate paste 
are described in the notes.1. One of the methods there specified must 
be carried out. 
For setting up the cell, the H form is the most suitable. The leads 
passing through the glass to the electrodes must be of platinum wire, 
which must not be allowed to come into contact with the electrolyte. 
The amalgam is placed in one limb, the mercury in the other. 
The depolariser is placed above the mercury and a layer of cadmium 
sulphate crystals is introduced into each limb. The entire cell is filled 
with a saturated solution of cadmium sulphate and then hermetically 
sealed. 
The following formula is recommended for the u.m.¥F. of the cell 
in terms of the temperature between the limits O° C. and 40° C. :— 
E,=E,)—0-0000406(¢—20°)—0-00000095(t—20°)?-+ 0:00000001(¢—20°)’. 
SCHEDULE D. 
1. The Conference recommends that the various Governments 
interested establish a permanent International Commission for Elec- 
trical Standards. 
_ 2. Pending the appointment of the Permanent International Commis- 
sion, the Conference recommends? that the President, Lord Rayleigh, 
nominate for appointment by the Conference a Scientific Committee 
of fifteen to advise as to the organisation of the Permanent Commis- 
sion, to formulate a plan for and to direct such work as may be neces- 
Sary in connection with the maintenance of standards, fixing of 
values *, inter-comparison of standards, and to complete the work 
: Notes on methods pursued at various standardising laboratories will be issued 
ee etic Committee or the Permanent Commission, as an Appendix to this 
port. 
2 In accordance with the above, Lord Rayleigh has nominated the following 
Committee, which has been approved by the Conference, viz. :— 
Dr. Osuke Asano. Dr. H. Haga. Dr. E. B. Rosa. 
M. R. Benoit. D. L. Kusminsky. Dr. S. W. Stratton. 
Dr. N. Egoroff. Prof. St. Lindeck. Mr. A. P. Trotter. 
Prof. Eric Gérard. Prof. G. Lippmann. Prof. E. Warburg. 
Dr. R. T. Glazebrook. Prof. A. Roiti. Prof. Fr. Weber. 
* This will include the reconsideration from time to time of the E.M.F. of the 
Weston normal cell. 
