1167 



— 252o C. For the measurements between those limits owing to the 

 lesser constancy of the temperature in the vapour cryostat the 

 accurac} must not be estimated higher than .02 of a degree. 



Tables 1 and II contain the results of the measurements of the 

 two gold and the two platinum wii-es. The fii-st and second columns 

 give the temperatures at which the measurements were made, both 

 corrected to the Kklvin scale. The tiiird column conlaius (he resistance 

 in ohms, and the fourth its ratio to the resistance at 0° C. 



^ 4. Discussion. 



The above data which include both for gold and for platinum 



W 

 values of w =r --— for different wires, measured at equal tempera- 



' 



tares, may be used to investigate the laws governing the change 

 of the differences of resistance of tvvo wires with temperature and 

 in particular to find over which domain and with which accurticy 

 Nernst's and Hknning's relations hold for platinum and for gold. 



A. Platinum. 



Table III gives the difference L iv = lo,^ — 7^,^ between the two 

 platinum wires Ft — 21 (this wire is also called /^^igi^/ and afterwards 

 Ftxxi) and Ft—2Q (this wire is also called P/1915 17 and afterwards 

 Ptxxvi) together with the value of (1 — ?^, j. 



In fig. 1. Lw is represented as a function of (1 — //?,g) (curve A). 

 Attention may be drawn to the sudden bend which the curve shows 

 at low temperatures. It appears from the figure that Henning's 



Fig. 1. 



