Wash fruit; remove peel in quarters, and cut rind into fine slivers. Add water and baking soda. Bring to a boil. cover and simmer 20 minutes, stirring occasionally. Dice pulp, discarding center membrane and seeds. Add pulp and juice to undrained rind. Cover. Simmer for 10 minutes. Measure 3 1/2 cups of the mixture into a large saucepan. Add sugar and mix well.

Place over high heat; bring to a full rolling boil and boil hard 1 minute, stirring constantly. Remove from heat; stir in pectin immediately. Skim off foam with a metal spoon; alternate stirring and skimming for 7 minutes. Ladle into hot sterilized jars and seal with paraffin.