In a saucepan, thoroughly mix the contents of one envelope unflavored gelatin with sugar and salt. Add 1/2 cup water. Stir over low heat until gelatin is dissolved. Remove from heat and stir in 3/4 cup water and 1 can frozen concentrated fruit juice (orange, grapefruit or tangerine). Chill to slightly thicker than unbeaten egg white consistency. Add 2 unbeaten egg whites and beat with an electric beater until mixture begins to hold its shape, or beat with rotary beater until mixture is light and fluffy, about 7 minutes. Spoon into dessert dishes and chill until firm. Eat Fruit Juice Snow dessert.