Critical Phenomena of Ether. 825 



Appendix. 



A Vapour Thermostat for work on Critical Phenomena. 



In connexion with the vapour jacket shown in fig. 3 an 

 arrangement was employed for maintaining the vapour at 

 constant pressure, so that constant temperature was secured 

 (fig. 8). 



The vapour jacket communicates, through a large ballon 

 B, with the closed mercury manometer C. The manometer 



Ficr. 8. 



is fitted with a Topler siphon-tube, so that the vacuum may 

 be tested and, if necessary, renewed. In the short arm of 

 the manometer is a float E, which makes electrical contact 

 with a platinum-tipped needle F. The float consists of a light 

 Phil. Mag. S. 6. Vol. 20. No. 119. Nov. 1910. 3 I 



