288 



Prof. T. Carnelley. On the 



[Jan. 6, 



below, otherwise fusion occurs. When the heat is applied to the free- 

 surface of the ice, the layers may be much thicker. 



Fig. 3. 



Mercuric Chloride, 

 m. p. = 288°, re-solidifies at 270—275°, b. p. =303°. 



About 40 grs. of pure mercuric chloride were placed in the tube 

 (A, fig. 3), and a thermometer arranged with its bulb imbedded in the 

 salt. The drawn-out end of the tube was connected by stout india- 

 rubber tubing with one branch of the three-wayed tube B, whilst the 

 other was attached to the manometer C. B was connected with a 

 Sprengel pump, fitted with an arrangement for regulating the pressure. 



When the pressure had been reduced by means of the pump to below 

 420 millims., the mercuric chloride was strongly heated by the flame of 

 a Bunsen's burner, with the following results : — ■ 



Not the slightest fusion occurred, but the salt rapidly sublimed into 



