GASEOUS DIFFUSION. 265 



tions of current, passing, then suddenly as the salt liquefied 

 290°-300° C. a violent effervescence took place.* At the 

 positive electrode free iodine was liberated, and recognised 

 by its colour, and after a little time oily globules made their 

 appearance on the sides of the tube nearest the negative 

 electrode ; these proved, on opening the tube, to have the 

 characteristic odour of triethylphosphine ; powerful fuming 

 also took place on the admission of air. The salt itself 

 became of a dark red colour from the formation of polyio- 

 dide, by the combination of the free iodine with unde- 

 composed salt.t 



From the foregoing experiment the following facts are 

 established: — (1.) That fused tetraethylphosphoniura iodide 

 is an excellent conductor and a good electrolyte. (2.) On 

 electrolysis at 300° C. the salt sphts up into triethylphosphine, 

 butane (?), and free iodine. (3.) Apparently no chance of 

 obtaining the free radicle by electrolysis. 



In conclusion, there is no reason to doubt that all the salts 

 of organic bases that can be obtained in the molten condition 

 would be conductors and electrolytes. 



4.— LECTURE EXPERIMENT ON GASEOUS 

 DIFFUSION. 



By 3. B. KIRKLAND, F.C.S., Assistant Lecturer and Demonstrator 

 on Chemistry, University of Melbourne. 



An instructive lecture experiment on gaseous diffusion can 

 be made in the following manner: — Take a piece of ordi- 

 nary combustion tubing about 20 inches long ; into this 

 introduce a clean iron tube about 3 inches long and half an 

 inch in diameter ; close the ends with rubber stoppers 

 having connecting tubes. The tube with its contents is next 

 supported in such a manner that heat may be applied 

 directly under the iron tube. The air in the tube is then 

 displaced by slow current of dry hydrogen from a kipp, or 

 other form of gas generator, making the gas travel in the 

 direction of the empty part of the tube. (Note — the experi- 

 ment is more striking if the iron tube is placed near 

 hydrogen inlet). At the distal end the escaping gas is led 



• The battery current had to be diminished. 



t See Masson and Kirkland on the Salts of Tetraethylphosphoniuin. 

 J. Chemical Society, Vol. LV., 1889. 



