Manciiester Memoirs, Vol. liii. (1909 J, No. 19. 



XIX. A Modification of the Beckmann Apparatus by 

 which Constant Readings are obtained in deter- 

 mining the Boihng Points of Aqueous Solutions. 



By Professor EDMUND Knecht, Ph.D., 



AND 



J. P. Batev, M.Sc.Tech. 



Read May 4tli, igog. Received for piibliiation May i8th, igog. 



In the course of a research into the condition of 

 certain dyes in aqueous solution, we desired to make 

 ebullioscopic determinations of their molecular weights 

 by determining the elevation which they produced in the 

 boiling point of water. Owing to the complex nature 

 and sparing solubility of these substances, it was only 

 possible to obtain a very small rise in the boiling point, 

 and it was found that with the types of Beckmann 

 apparatus at our disposal it was not possible to obtain a 

 sufficiently regular boiling point for our purpose. This 

 we supposed was due to superheating effects caused by 

 the cohesion of the liquid on the glass walls of the boiling 

 vessel. To avoid this we were led to try an electric 

 heating method in which the heat is supplied by a 

 platinum wire, in direct contact with the solution. 



A tube was made with a platinum heating coil inside, 

 while somewhat thicker wires, fused through the glass, 

 served for making the connections. 



When in use the apparatus rested in an outer cylin- 

 drical glass jacket which itself rested in a wide-mouthed 

 bottle, packed at the bottom and round the neck with 



Afay 28(h, igog. 



