Peel, quarter and core the pears. Cut the quarters into small slices, add sugar, chopped ginger and the strained juice of the lemons. Cut the lemon rind into long thin strips, and add to the fruit and mix. Cover and allow to stand in a cool place overnight. Stir over moderate heat until the sugar has dissolved, and then bring quickly to boil. Cook very slowly for three hours until clear and thick. Pour into jars and cover.