Soften gelatin in cold water for 5 minutes.
Combine beet and orange liquid and add enough water to make 1 1/4 cups.
Heat liquid to boiling and add gelatin; then add salt, onion, and vinegar or lemon juice (or combination of the two).
When mixture is slightly thickened, fold in beets and oranges.
Pour into 6 individual molds and chill until firm.
Unmold on lettuce and serve with mayonnaise with dash of celery salt.