The ideal proportions for a sponge cake are given in the accompanying recipe and upon these proportions the other recipes are based.
Beat the eggs until they are thick and lemon-colored. Add the sugar gradually and continue to beat. Sift the flour several times and fold into the mixture. When the ingredients are thoroughly mixed, add the grated rind and the juice of the lemon, pour into a sponge-cake pan, and bake.
Woman's Institute Library of Cookery, Volume 4.