Whip the egg whites until foamy. Add cream of tartar, and continue beating until stiff. In a separate bowl, beat the egg yolks until lemon colored. Boil the sugar and water until it reaches the thread stage, 230 - 234 degrees F. Beat sugar and water mixture into egg whites. Fold in egg yolks. Fold in flour. Pour batter into an ungreased tube pan. Bake at 350 degrees F for 1 hour. Cool.