Beat 4 egg whites until foamy and add cream of tartar. Beat in slowly 1 cup sugar, a spoon at a time. Beat until stiff but not dry. Pour into buttered 9-inch glass pie pan, not over edge. Bake 1 hour plus 5 minutes in 250° oven. Cool. Beat 4 egg yolks, rind, juice and 1/2 cup sugar. Cook in double boiler. Cool. Whip 1/2 pint cream and combine with filling. Pour in meringue shell and keep refrigerated overnight. (Cover with Saran Wrap later.)