Adams and Johnston — Standard Scale of Temperatures. 541 



The electromotive forces at the freezing points were reduced 

 to degrees with the aid of Table II ; the boiling points were 

 reduced to normal pressure by means of this table and the 

 formulas: for naphthalene, £ 760 = t — 0*058 (p — 760); for 

 benzophenone, t leo = £ — 0-063 (j> — 760). The freezing points 

 have been given to hundredths of a degree, as relative values 

 for purposes of comparison only ; their absolute accuracy is of 

 the order of 0-1°. 



This table shows that the boiling points are independent of 

 the apparatus and sample of material employed, and that the 

 freezing points can be reproduced satisfactorily on different 

 days and with varying set-up ; e. g., the results are independent 

 of the size and kind of tube — glass or porcelain — used to 

 protect the thermocouple from the metal, and of the size of 

 the charge. 



In order to make the data of Waidner and Burgess more 

 truly comparable with our own, we have reduced them to the 

 scale of temperature on which our own values are based 

 (cf . postea, Table V), and present these reduced values in the 

 last column of Table III. The differences between the values 

 for the adjacent freezing and boiling points are compared in 

 Table TV with the analogous differences derived from our 

 thermoelectric measurements. 



Table IV. 



-Comparison of Temperature Intervals as measured by Thermo- 

 elements and by the Eesistance Thermometer. 





Temperature difference as derived from 

 measurements with 



Interval 



Thermoelements 



Resistance Thermometer 





E* 



0, 



C 3 



Waidner 

 & Burgess 



Holborn 

 & Henning 



Sn-naphthalene 

 Cd-benzophenone, Merck 

 Cd-benzophenone, Kahlbaum 

 Pb-Cd 



13-9 



14-8 



15-0 



6-3 



13-78 



14-82 



15-02 



6-36 



13-T8 



14-82 



15-02 



6'38 



13-91 



14-81 



15*01 



6-43 



13-87 

 15'03 



The differences, therefore, as determined by us with platin- 

 rhodium and copper-constantan thermoelements in various 

 forms of apparatus on the one hand, and with resistance ther- 

 mometers at the Bureau of Standards or at the Reichsanstalt 

 on the other, agree very satisfactorily. This proves conclu- 



* When reading only to one microvolt, as we were, it is illusory to give the 

 readings of the platin-rhodium element closer than the nearest tenth of a 



degree. 



