Drain beets and pineapple, reserving 1 1/2 cups of the combined liquids.
Dissolve gelatin in boiling water; stir in reserved liquid, lemon juice, and salt.
Chill till partially set, then fold in drained beets and pineapple.
Pour gelatin mixture into 6 1/2 cup mold or eight to ten 1/2 cup molds.
Chill till gelatin mixture is firm