Beat the whites of five eggs till they are solid, add the yolks to them, stirring very gently; grate the rind of a small lemon and squeeze in the juice of half. Sift in eight ounces of powdered sugar, and four of sifted flour, add a pinch of salt. Stir very gently after the flour is added, and only enough to mix it. Line a tin with buttered paper, and pour the cake into it; bake forty-five minutes in a brisk oven. Cover the cake the first half hour. When you take it out keep it from all drafts, or it will fall.