Cake flour by John Spottiswood.

4 1/2 cups cake flour = 1 pound

pastry flour (This has more protein than cake flour but less than all-purpose flour. Cakes made with pastry flour tend to be a bit less delicate and crumbly.) OR all purpose flour (Substitute 7/8 cup all-purpose flour for each cup of cake flour and add 2 tablespoons of cornstarch for every 7/8 cup all-purpose flour used. Cakes made with all purpose flour tend to be less delicate and crumbly.)