1904.] some Mercury Standards of Resistance, etc. 243 



The temperature coefficients of resistance of — 



(1) Mercury in Jena 16'" glass, 



(2) Mercury in verre dur glass, 



(3) A constant volume of mercury, 



have also been determined for a range of temperature 0° C. to 22° C. 

 The results are as follows : — 



(1) Mercury in 16'" glass — 



E T = R [1+0-00088018T + 0-00000105793T 2 ]. 



(2) Mercury in verre dur glass — 



R T = E [1 + 0-00088036T + 0-00000103094T 2 ]. 



(3) A constant volume of mercury — 



Deduced from (1), 



E T = E [l+0-00088788T + 0-0000010564T 2 ] 

 Deduced from (2), 



E T = E [1 + 0-00088776T + 0-0000010376T 2 ], 



T being the temperature on the hydrogen scale. 



The whole of the observations have been carried outjat the National 

 Physical Laboratory. To the director, the author has to express his 

 great indebtedness in all departments of the work. To his colleague, 

 Mr. B. F. E. Keeling, the success of the linear measurements is entirely 

 due. 



