40 



BEPORTS ON THE STATE OF SCIENCE. 



amounting to less than three parts in 100,000 have been detected by 

 its aid. 



The results of the investigation on cadmium amalgams at the 

 National Physical Laboratory were incorporated in a paper read before 

 the Physical Society last February. It may be useful to give here the 

 limits of temperature between which various amalgams may be most 

 usefully employed in the Weston normal cell : — 



The degree of reproducibility which is now obtainable with the 

 Weston cell far surpasses what it was five years ago. At the National 

 Physical Laboratory sixty-seven cells were tested in 1909, and of these 

 sixty agreed with the Laboratory standards within one part in ten 

 thousand. What is not' understood at present is the occurrence of 

 strange hysteresis effects in a few cells. The e.m.f. of such cells may 

 be normal at first, but changes comparatively rapidly with time. 

 Indeed, a large hysteresis effect in a cell appears to be an indication 

 that the e.m.f. will not remain constant with time, whereas its absence 

 is in general an indication of constancy. 



In view of the fact that the republication of the Eeports is not yet 

 completed, the Committee recommend that they be reappointed, that 

 Lord Bayleigh be Chairman, and Dr. E. T. Glazebrook Secretary. 



APPENDIX. 



Order in Council relating to Electrical Standards. 



At the Court at Buckingham Palace, January 10, 1910. Present: 

 the King's Most Excellent Majesty in Council. 



Whereas by the ' Weights and Measures Act, 1889,' it is, among 

 other things, enacted that the Board of Trade shall from time to time 

 cause such new denominations of standards for the measurement of 

 electricity as appear to them to be required for use in trade to be made 

 and duly verified. 



And whereas by Order in Council dated the 23rd day of August, 

 1894, Her late Majesty Queen Victoria, by virtue of the power vested 

 in Her by the said Act, by and with the advice of Her Privy Council, 

 was pleased to approve the several denominations of standards set forth 

 in the Schedule thereto as new denominations of standards for electrical 

 measurement. 



