This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
Use an ungreased pan for sponge or angel cakes. If they are greased the batter cannot cling to the sides of the pan as it bakes and thus the cake does not reach its full height. Greasing also causes the cake to fall out of the pan during cooling, making it flat and soggy.
Baking Temperatures - True sponge and angel food cakes in which eggs are the only leavening are baked in a moderate oven (325° - 350° F.) to insure the best volume and texture. If baked too slow the results will be a coarse uneven cake; if oven is too hot the cake will be small in volume, fine grained and tough. It can be truly said of such a cake, "half the making is the baking." When baking-powder is used, a slightly higher temperature is desirable. The division of baking time is the same as for butter cakes.
When the cake is a light brown, and springs back when pressed with the finger, it is done. Remove it to a wire cake cooler, invert the tin and allow it to stand till the cake is cool. Then remove the cake from the tin. When serving, break it apart with two forks; cutting with a knife tends to crush the cake and make it appear heavy.