O '^ 



CIENCE 



New Series 



Vol. LVI, No. 14.52 



Friday, October 27, 1922 



Annual Stjbsceiption, $6.00 

 Single Copies, 15 Cts. 



EDGAR PURDUM RAPID ELECTROLYSIS CELL 



According to Dr. Graham Edgar and R. B. Purdum 



See ]our. of Amcr. Chern. Soc, June, igsB 



This is a simple glass apparatus in which stirring" of 

 the electrolyte is effected by a current of air. Results have 

 been ■• obtained as rapid and accurate as those afforded by 

 t'he use of rotating electrodes. The apparatus consists of a 

 tube of Pyrex glass to which are sealed three glass "air lifts," 

 connecting in a single tube at the bottom, and entering sym- 

 metrically about half way up the wide tube, the upper seals 

 being made tangentially. When the apparatus is half filled 

 with liquid and a current of air is foi'ced ,(0r drawn by suc- 

 tion) through the injectors, stirring is effected in two ways. First a con- 

 tinuous current of liquid is carried upward by the air lifts.. Secondly, the 

 liquid (with the air bubbles) is delivered into the wide tube in such a way 

 as to cause rotational stirring. For electrolytic determinations the wide tube 

 is fitted with a rubber stopper carrying a glass tube and the electrodes. Deter- 

 minations have been made upon solutions of copper sulfate, also on copper 

 in the presence of zinc, lead, and other metals. 110 volts D. C. reduced by 

 resistance lamps is satisfactory. The use of this apparatus for the determina- 

 tion of lead in baking powders will be discussed at the convention of Official 

 Agricultural Chemists to be held in Washington, November 15-17. 



Write for Bulletin No. 201 which 

 gives details of the apparatus. 





iriEnd 



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