Heat in a saucepan and cook until mixture just starts to boil:

4 slightly beaten egg yolks (save whites for later)
1./2 cup sugar
1 T. gelatin
2/3 cup water
1/3 cup lemon juice

Pour into bowl.
Refrigerate until mixture just starts to mound and not fall from a wooden spoon.

Meanwhile, fold in:

4 beaten egg whites
1/2 tsp. cream of tartar
1/2 cup sugar

Pour into 9 in. baked pie crust.