Separate the eggs. Beat the yolks well, add the cold water and beat again. Add the sugar gradually, a tablespoonful at a time, while beating and beat until the sugar is disolved. This requires a lot of beating. Fold in the sifted flour. Add salt to egg white, whip to a froth, add cream of tartar, whip until stiff and dry, fold in lightly. Fold in the vanilla. Bake in a slow, 325(deg), oven for one hour, or until the top springs back when touched. Remove from oven, invert pan until cake is cold. Ice with your favorite frosting.