Baking powder

Is composed of soda and cream of tartar in definite, correct proportions, mixed with small quantity of dry material (flour or corn-starch) to keep action from taking place. If found to contain alum or ammonia, it is impure. In using baking powder, allow two teaspoons baking powder to each cup of flour, when eggs are not used; to egg mixtures allow one and one-half teaspoons baking powder. When a recipe calls for soda and cream of tartar, in substituting baking powder use double amount of cream of tartar given.