Manchester Memoirs, Vol. liii. (1909), No. |<). 3 



that electrical heating had been used before for this 

 purpose. S. L. Bigelow {Ainer. Cheni. Joiirn., vol. 22, p. 280, 

 1899) first used the method, and demonstrated its usefulness. 

 Later the subject was fully discussed by E. Beckmann in 

 his paper : " Fehler der ebulHoskopischen Verfahren und 

 Versuche zu deren Beseitigung." {Zeii. Phys. Chem., 

 vol. 63, p. 177, 1908.) 



Both these experimentors state that the method is not 

 applicable for use with aqueous solutions. 



Thus, Bigelow says : — " Electric heating is not applic- 

 able for use with water solutions, for difficulties due to 

 electrolysis would surely be encountered." 



Beckmann found that a solution of potassium bromide 

 was instantly turned brown when a current of 2 amperes 

 was passed through the heating coil ; and this, even when 

 alternating current was used. 



We repeated the experiment with KBr in our appara- 

 tus with a direct current of 7 amperes, and not a trace of 

 bromine was liberated. In view of this fact we were led 

 to compare the physical constants of Bigelow's and Beck- 

 mann's apparatus with those of our own. 



Bigelow and Beckmann both used a heating coil of 

 5 ohms resistance. The current used by Beckmann to 

 produce the necessary heating effect was : — 



li amperes for low boiling solvents. 

 2 „ high 



The drop in potential across the coil would therefore 

 be yh to 10 volts. 



In our apparatus the resistance of the heating coil at 

 lOO'C. was 0"47 ohms. 



Current used 6'5 am[)eres. 



Drop in potential across wire 3 volts only. 



Evidently the electrolysis will depend on the drop 

 in potential across the heating coil, and when this is 



