540 Adams and Johnston — Standard Scale of Temperatures. 



Freezing; Points of Metals. 











From Thermoelectric From Eesistance Ther- 











measurements Jmometer measurements 







Quantity 





(Adams & Johnston) (Waidner & Burgess) 



Metal 



Source 



of 



Thermo- 

















metal 



couple 1 









When re- 







grins. 





Microvolts 



Degrees 



| As given 

 by them 2 



duced to our 



scale 3 



Sn 



Kahlbaura 



1500 



c, 



10861' 



231*75] 











a 



c, 



10859- 



231-71 











a 



c s 



10863- 



231-79 











200 



c s 



10856* 



231-67 | 



231-92 



231-88 







200 



E 



1706- 



231-9 











u. 



a 



1706- 4 



231-9 











1500 



u 



1706- 



231-9 











u 



a 



1706* 



231*9 







Bi 



J.T.Baker 





0, 



13020- 

 13015- 



270-99/ 

 270-90^ 



. . . 



• • • 



Cd 



Kahlbaum 





o x 



15860- 



320-921 













c. 



15858' 



320-92 1 



321-01 



320-92 









E 



2502-5 



320-9 







Pb 



Kablbaum 





E 



2560-5 



327*2 j 

















M S97-9T 



327*19 









C 1 



16227' 



327-28 







i 







c 3 



16226- 



327-30J 







1 Couple E is of Pt — PtRh ; Ci, C 2 , C 3 , are of copper-constantan. 



2 Bull. Bur. Standards, vi, 173 (reprint No. 124). 



3 The values given in the last column have been reduced from those in the 

 column to the left by means of the differences between the scales as deter- 

 mined in a way to be described later (p. 543) ; i. e., these values are on the 

 basis that the b. p. of sulphur is 444*55°. 



4 Melting point. 



In Table III we present our results. In the boiling point 

 experiments, three forms of apparatus were used ; one (B in 

 the table) of glass,* with an aluminium shield for the thermo- 

 couple ; the second (A) of brass, with an inner tube of thin 

 copper to prevent radiation ; and the third (S) similar to the 

 second, but of slightly different dimensions. Four different 

 elements were used ; one (E) of platinum-platin-rhodium, the 

 other three (C, 

 0-25 mm diam.). 



C 2 , C 3 ) of copper-constantan (No. 30 wire= 



Lent to us by Dr. Burgess. 



