In 2-quart saucepan, combine sugar, corn syrup, 1/4 teaspoon salt, and 1/2  cup water. Cook to hard ball stage (260°) stirring only till sugar dissolves. Meanwhile, beat egg whites to stiff peaks. Gradually pour syrup over egg whites, beating at high speed on electric mixer. Add vanilla and beat till candy holds its shape, 4 to 5 minutes. Quickly drop from a teaspoon onto waxed paper. Makes about 40 pieces.