Interesting article...from the illustration it does look like the plug pins are of round section, rather than flat.
It was common in Australia up until the 1950's to still be powering appliances from a light socket. Often there was only one power point in the house and that was for a fridge. Smaller appliances like radios and shavers were plugged into a light socket by means of a bayonet plug. A bayonet double adaptor was available if the light bulb was required at the same time.

[This message has been edited by aussie240 (edited 09-05-2005).]