Put in a vessel half a pound of powdered sugar, with one quart of cold water; grate in the rind of a large lemon, or of two small ones, squeezing in the juice of three good-sized ones, or of four if small, and with the spatula beat well together for five minutes. Have a syrup-weigher, place it in the centre of the preparation, and if it be twenty-one degrees it is correct; if not, add a little more powdered sugar; remove the weigher, mix a little more, and then strain through a sieve into the freezer, putting on the cover, and proceed to freeze it precisely the same as for vanilla ice-cream (No. 68), serving the same.