High Temperatures. 



181 



The Observations with the first Platin-iridium Bulb. — The 

 earlier observations (loc. cit. Tab. IX, p. 189) with the first 

 bulb (80 Pt, 20 Ir), which were calculated with a constant 

 coefficient of expansion, can now be corrected for the increase 

 in the expansion with the temperature. The corrected values 

 are contained in Table XIV, the numbers printed in italics in 

 Table IX being here omitted. They were made with a uni- 

 formly wound oven coil, and a comparatively large (former 

 paper, Table YIII, p. 189) fall in temperature along the bulb, 

 roughly corrected with the help of the thermo-elements. 



Table XIV. 

 Platin-iridium Bulb I (80 Pt, 20Ir). Gas-Nitrogen. 



After 







Obs.— 



After 







Obs.— 



filling. 



t 



e 2 (MV) 



Calcul. 



filling. 



t 



e 2 (MV) 



Calcul. 



2d day 



529-1° 



4429 



-{-0-3° 



22d day 



1052-8° 



10073 



—o-i° 





614-8 



5289 



+0-1 





1102-5 



10653 



4-0-4 





1008-8 



9555 



-j-0-6 



















24th " 



541-2 



4552 



+0-1 



20th " 



625-6 



5401 



—o-i 





542-8 



4569 



— 0-2 





812-1 



7356 



+0-6 





615-5 



5297 



o-o 





907-3 



8396 



+1-2 





717-3 



6343 



+0-7 





1014-8 



9622 



-j-0-9 





814-3 



7385 



— 0-2 





1113-9 



10770 



+1-7 





919-7 

 1017-6 



8550 

 9661 





-0-2 



-o-i 



22d " 



511-8 



4252 



+1-1 





1106-6 



10700 





-0-4 





512-7 



4268 



-f-0 "2 













551^5 



4655 



— 0-2 



25th " 



516-4 



4304 



4-0-2 





659-3 



5754 



— 0-8 





616-3 



5303 



—o-i 





703-8 



6217 



— 0-9 





721-3 



6382 



+0-7 





757-0 



6775 



— 0-5 





821-9 



7462 



+1-6 





859-4 



7881 



— 0-3 





913-4 



8458 



4-1-8 





949-2 



8890 



— 0-6 





1026-0 



9756 



-j-0-5 





1001-5 



9496 



— 1-6 





1134-5 



11031 



+0-7 





1050-4 



10044 



—o-i 











The temperatures t are raised by the new coefficient of ex- 

 pansion 0-7° at 500°, 4-9° at 1000° and 7-5° at 1150°. 



In the recalculation a small correction has also been added 

 for the slight over-compensation of the heating coil (Table 

 YIII)— 13 microvolts at 500°, and 5 at 1150°. This corre- 

 sponds to the measured temperature distribution according to 

 which the junction of T 2 opposite the middle of the bulb reads 

 smaller than the integral temperature — at 620° 1*2° smaller, at 

 820° 1-0°, at 1010° 0-5° and at 1150° 0-4°. 



Observations below 500°. — After the observations in the 

 electric oven between 500° and 1150° were completed, the 

 thermo-element T 2 was compared with the gas thermometer 



