PRACTICAL STANDARDS FOR ELECTRICAL MEASUREMENTS, 33 
system as that on which to base any nomenclature of magnetic units, but 
are of opinion that a system of nomenclature is not called for.’ 
electro-magnetic and absolute electrostatic systems of units, and express 
the opinion that no system of prefixes should be employed in which each 
prefix does not bear some definite numerical signification. 
In view of the work still necessary with regard to the Ampére 
balance, the cadmium cell, and the platinum standard of temperature, 
the Committee recommend that they be reappointed, with a grant of 
50/., that Lord Rayleigh be Chairman, and Dr, R. T. Glazebrook 
Secretary. 
APPENDIX I. 
On Anomalies of Standard Cells. By F. E. Smrru. 
From the National Physical Laboratory. 
The Committee disagree with Dr. Kenelley’s prefixes for the absolute 
During the past two years certain anomalies of Clark and of cadmium 
cells have been under investigation at the National Physical Laboratory. 
The work is still far from completion, but the essential results so far 
obtained are given in this paper. 
In March 1902 some experiments at Bushy House resulted in the 
isolation of the depolariser employed in both standards as the great 
disturbing element. Lord Rayleigh, in his paper in the ‘ Phil. Trans.’ for 
1885, § 44, had shown this to be the case, and Mr. Swinburne arrived at 
the same conclusion in 1891,' while recently in America Professor H. 8. 
Carhart and Mr. G. A. Hulett have traced the variations in E.M.F. of 
the cadmium cell to the same source. A new specification of the mode 
of manufacture of the paste was thought to be desirable, and this 
problem was the first to receive attention. 
Im order to be independent of the variations of the other elements, 
cells were constructed of a type indicated by the arrangement 
Hg— Paste — Solution and Crystals — Paste — Hg, 
(4) (2) 
where a and 4 represent pastes made with different samples of mercurous 
sulphate. The Rayleigh H form of vessel was employed. Preliminary 
observations showed that when the same paste occupied the two limbs, 
‘such a cell had no measurable E.M.F. 
In addition a cell typified by the arrangement 
Amalgam 
é Sol | z 
mo Solution  & | 
ts and Crystals a o 
a | fae 
~S wa 
Paste (B) 
| 
Hg 
was largely employed, a four-limb vessel, similar to two Rayleigh H form 
of vessels crossed, being used to set up the standard. In this case there 
1 See B.A. Report, Cardiff, 1891. 
1904. D 
