Woman's Institute of Domestic Arts and Sciences, Woman's Institute Library of Cookery…
“ Baking powder, which is also an important leavening in cakes, should be of an approved brand that can be relied on to do the work expected of it. Soda and cream of tartar are sometimes used together, and, again, soda is used alone with molasses or sour milk. For every 3 eggs in a cake mixture, 1 teaspoonful of the baking powder called for in the recipe may be omitted. Altitude affects the amount of baking powder required in cakes. ”
