From "The Joy of Cooking," ed. 1943. (I doubt you'll find it in later
editions!) I tried searching online first, but couldn't find anything
as simple as this.

Quite good.

MINT CUP

About 2 quarts

Remove the tips and the leaves from:

4 sprigs of mint

Add to them:
2 cups sugar
2 cups water

Boil these ingredients for 5 minutes. Strain the syrup. Add:
2 cups lemon juice
1/4 teaspoon salt

Chill these ingredients well. Immediately before serving add:

1 quart chilled ginger ale


Lenona.