In top of double boiler, beat egg yolks until thick and lemon-colored. Add juices and mix well. Stir in sugar and salt. Cook over hot (not boiling) water until slightly thickened (about 10 minutes). Remove from heat; stir in lemon peel and gelatin. Chill until mixture begins to set (about 1 hour). Beat until smooth.
Beat egg whites until frothy. Gradually add ⅔ c. sugar, beating until glossy peaks are formed.
Whip cream and fold into egg whites. Then fold into thickened lemon mixture. Spoon into cool pie shell. Refrigerate several hours before serving.