ALL NIGHT PUDDING

Some years ago, I came across a recipe called an All Night Pudding. It was published in the Advocate in 1938 and contributed by Georgina Burgess (1886-1951) of Wynyard. The recipe calls for no precise measurement and therefore I have not been game to try it. Is anyone able to explain the difference between a small cup and a large cup in today's measurement? 

Sift one large cup flour, one small cup sugar and one teaspoon carbonate soda into a basin, and add one cup sultanas, then put a lump of butter into a cup and fill the cup with boiling water. Mix the pudding with the butter and water, and let it stand overnight. Next day break an egg into it and mix well. Put into a greased basin and steam for 2.5 hours. This is a very easy pudding and very rich.
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