Wash pears. Do not peel. Slice. Add water just to cover. Cook until very soft. Press through sieve (strainer). To each cup pulp add 1/2 cup sugar. To each 3 cups of pulp add 1/2 teaspoon cinnamon. Cool on low heat until thick, stirring frequently to prevent scorching. Pour into sterilized jars and seal while still hot. Good on toast or hot biscuits.