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.
1 tablespoon gelatin
1/4 cup cold water
1 teaspoon grated lemon rind
Beat egg yolks until thick and lemon colored; add 1/2 cup of sugar, lemon juice and salt. Cook in a double boiler until the consistency of custard. Soften gelatin in cold water for 5 minutes, then dissolve in hot custard. Add lemon rind. Cool until mixture begins to thicken. Beat remaining sugar into stiffly-beaten egg whites and fold into gelatin mixture. Blend well. Fill baked pastry shell. Chill until firm. Cover with whipped cream before serving. Makes 1 (9-inch) pie.
Orange Chiffon Pie: Use orange juice for lemon juice, omit lemon rind and add 1 tablespoon grated orange rind and 1 tablespoon lemon juice.
Lime Chiffon Pie: Use lime juice for lemon juice and grated lime rind in place of lemon rind.