Robert Walker, of this city, has invented a new machine for extracting the hulls and impurities from coffee, for which he has taken measures to secure a patent. The important features of the invention consist in an arrangement by which one cylinder is made to revolve within another—the external surface ot the smaller and the internal surface of the larger being covered with wire gauze or cloth, by which the hulls are scoured from the kernels by the revolution of the cylinder; a series of beaters are also placed upon the periphery of the revolving cylinder, which, serve to break the hulls from the coffee, and also to drive it from the end of the cylinder where it is introduced,to the opposite end. The external cylinder is stationary and nearly air-tight, so that a current of air may be drawn through between the cylinders, and the impurities ot the coffee extracted and conveyed to a remote place of deposit, instead of being thrown into the room to in]ure the lungs of the occupant.