Table 236. 217 



MELTING-POINTS OF THE CHEMICAL ELEMENTS. 



The metals in heavier type are often used as standards. 



The melting-points are reduced as far as possible to a common temperature scale which is the 

 one used by the United States Bureau of Standards in certifying pyrometers. This scale is de- 

 fined in terms of Wien's law with O2 taken as 14500, and on which the melting-point of platinum 

 is 1755'^ C (Nernst and Wartenburg, 1751 ; Waidner and Burgess, 1753; Holborn and Valentiner, 

 1770; see C, K. 148, p. 1177, 1909). Above 1100° C, the temperatures are expressed to the 

 nearest 5° C. Temperatures above the platinum point may be uncertain by over 50° C. 



Smithsonian TABLts. 



