336 



Mr. E. Wilson. Aluminium as an Electrode 



The temperature of this liquid portion did not fall below zero centi- 

 grade. The results are given in Table I HA. When comparing these 



Table HlA. 



with the results of Table III, one must remember that the areas 

 of the plates in the electrolyte are 17 square inches in Table IIlA 

 and 8 square inches in Table III. This paper does not deal with 

 the chemistry of the effect discussed. It is known that a clean 

 aluminium plate acquires this film, when simply submerged in alum 

 solution, in the presence of oxygen, without the passage of currents. 

 We have seen that with a given film time is required to develop the 

 effect. 



[Note added 19th May, 1898. 



The film on these plates has been examined by Mr. Herbert Jack- 

 son, of the Chemical Department, King's College, London, and the 

 following is his communication. 



" King's College, London, 



" May 12, 1898. 

 " DEAR WILSON, 



" I waited to send you the results of my examination of the 

 aluminium plates until I had looked at them carefully with the 



