264 
DR. HAROLD A. WILSON ON THE 
sodium amalgam contained in a test-tube. The test-tube was supported on asbestos 
wool in a thick brass tube DE, the lower end of which was closed by iron wire gauze. 
The gauze was heated by a small Bunsen dame and the temperature of the amalgam 
kept at about 280° C. At pressures above about 1 millim. a current from about 
400 cells could then be passed from the amalgam to the aluminium electrode, and 
sodium deposited, forming a metallic mirror in tlie upper parts of the tube C. The 
discharge in C was a brilliant yellow colour, giving the D line. It oxygen was 
present, sodium oxide was formed, and the brilliant yellow light did not appear so 
strongly at drst. This process did not appear to have any particular edect on the 
amount of leak obtained from the hot wire in hydrogen at any pressure, so that we 
may conclude that the increase of the leak due to letting in hydrogen is not due to 
the presence of impurities in the gas. 
