Remove rind and seed from melons. Cut melon into small pieces. Add just enough water to prevent sticking. Boil until soft, then process through a sieve. Measure, add 1 to 1 1/2 cups sugar, 1 tablespoon lemon juice and 1 teaspoon cinnamon or other spices to each quart pulp. Boil until thick. Pour while hot into hot sterilized jars. Process 10 minutes in hot water bath; then complete seal.