1892.] Determination of Low Tempeixitures . 



Table I. 



Thermo- 

 meter. 



Eeferences. 



n u A > liPhil. Trans. A. 1887, 

 Gallendar s. h 4. o p o 



sect. 2 & 3. 



Na. 

 Nb. 

 M,. 

 Mo. 

 H. 



iPhil. Trans. A. 1891,) 

 I pp. 151, 152. \ 



IjPhil. Trans. A. 1891,) 

 \\ pp. 132-136. \ 



JPhil. Trans. A. 1891, 

 \ p. 153. 



5-0845 



9-8558 

 5-9865 

 3-8749 

 4-2267 

 4-1732 

 13-5216 



Ej/Efl 



1-3460 



1-3484 

 1-3482 

 1-3480 

 1-3381 

 1-3383 

 1-3463 



1-46 



1-638 



1-648 



1-639 



1-57 



1-57 



1-474 



when E = 0. 



pt. 



289-04 



287-03 

 287-19 

 287-34 

 295-81 

 295-58 

 ■ 288-77 



- 274-12 



- 270-60 



- 269-60 



- 270-86 

 -279-15 



- 278-97 



- 273-71 



"Mean. 



273-86 



The above table seems to corroborate the conclusions arrived 

 at by Profs. Dewar and Fleming, and at the same time is a 

 valuable testimony to the accuracy of the method adopted by 

 Callendar and Griffiths in the papers referred to, for it did not 

 appear probable that their formulae could bear the strain of ex- 

 trapolating over a range of nearly 300°. This is more especially 

 the case when it is remembered that the wires used have different 

 resistance coefficients and different values for S ; the origin of 

 such differences is probably due to slight impurities in the 

 platinum. 



We have reason to believe, from some recent experiments 

 conducted by us, that the rise in temperature of the wire, caused 

 by the current necessary to determine its resistance, is greater 

 than is usually supposed. If the difference of potential at the 

 ends of the wire is kept constant, the effect of the error thus 

 introduced is to make the absolute zero too low ; if, however, 

 the current is kept constant, the absolute zero works out too 

 high. In the determination of the constants of thermometers N, 

 a rough attempt was made to keep the current constant ; but 

 in the remaining thermometers no alteration was made in the 

 electromotive force as the resistance of the coil, and thei'efore 



* Cf. with the vakie given by Joule and Thomson, -273°-7, Proc. Boy. Soc, 

 vol. X., p. 502. 



1—2 



