320 



EEPORT 1886. 



drying, whereas the solutions containing organic salts were liable to serious 

 error, probably in consequence of the inclusion of the solution in the pores of the 

 deposit. 



It was originally intended to use only those experiments from which the loss of 

 the anode was obtained equal to the gain of the cathode. It was found, however, 

 that the possibility of weighing tlie loss of tlie anode was simply fortuitous, the action 

 of the solution upon the silver always producing a sort of honeycomb formation, 

 and ultimately leaving smaller particles which fell off in washing. This was the 

 case even when a silver crucible was used as the anode. It was therefore decided 

 to use the gain of the cathode only. The form of silver cell adopted is that of 

 Poggendorft"s voltameter in which a platinum crucible standing on a copper plate 

 is the cathode and a silver rod the anode. The crucibles were about H inch in 

 diameter and 2 inches high, and the silver rod forming the anode was about half 

 an inch in diameter. 



The method of drying the deposit was to wash in distilled water by filling up 

 the crucible several times and allowing it to stand for some time, then after 

 thoroughly rin.sing, to wash it out with alcohol and di'y in a hot air-bath at about 

 260° C. 



As the crucibles were very different in size from those used by Lord Rayleigh 

 some experiments were made to determine their behaviour. 



The following are the results : — 



Comparison of Two Crucibles of Different Sizes 



