IX. 



The substance crystallises in bloodred crystals, and 

 melts at 85° C. At higher temperatures it is very volatile. 

 Above 180° C. the liquid becomes gradually darker by 

 oxydation and decomposition; thus the,determinations were 

 no longer continued. (Added in the English translation.) 



Molecular weight : 138.1 Radius of the Capillary tube : 0.04777 cm. ; 



with the measurements indicated by * it 



was: 0.04'^39 cm. 



Depth : 0.1 mm. 

 Under a pressure of 759 mm. the boilingpoint is 206° C. In a refrigerant 

 mixture it solidifies rapidly, and melts then again at -|-22° C. At the boiling 

 point / will have about the value : 19.9 Erg pro cm-. The specific gravity at 

 25^ C. was: 1.0812; at 50° C. : 1.0570; at 75° C. : 1.0325; at /^ : fi?4o = 1.1051 — 

 0.00095 / — 0.00000024 f-. 



The temperature-coefficient of ." is between 0° and 30' C. very great : 3.47 

 Erg; between 30^ and 150° it remains fairly constant, or only slowly decreasing 

 from 2.42 to 2.36 Erg. Between 150^ and 176^ it decreases: 1.98 Erg, and 

 between 176° and 196° C. : 1.66 Erg. The curve thus is slightly concave. 



