English orange marmalade recipe

4 Oranges
1/2 Grapefruit
1/3 Lemon
Sugar
Remove seeds from fruit. Cut fruit into very thin slices. Cut each slice in quarters. Remove pithy inner portion from each section of fruit. Add 1 1/2 quarts water to each pound of fruit. Let stand 24 hours. Boil hard 1 hour. Add 1 pound sugar to each pound fruit and liquid. Boil slowly 45 minutes or until juice sheets from spoon.