Soak gelatin in cold water. Put sugar, syrup and water into saucepan, stir until sugar is well dissolved, and cook to 240. Add gelatin, remove from heat, add vanilla and pour on well beaten egg whites beat vigorously until very stiff. Pour into metal pan, which has been dusted with powdered sugar. Sift powdered sugar over top of candy and allow to stand until firm. Cut into squares with knife, dipping knife in boiling water occasionally or cut with small cutter.