The early type of German mask probably served as the model for the French A. R. S. mask. The facepiece was made of rubber, which was later replaced by leather because of the shortage of rubber. The following is a good description of a typical German facepiece: “The facepiece of the German mask was made of one piece of leather, with seams at the chin and at the temples, giving it roughly the shape of the face. The leather was treated with oil to make it soft and pliable, also to render it impervious to gases. The dressed surface was toward the inside of the mask. A circular steel plate, 3 inches in diameter, was set into the facepiece just opposite the wearer’s nose and mouth, with a threaded socket into which the drum containing the absorbents screwed. A rubber gasket (synthetic?) held in place by a sort of pitch cement, secured a gas-tight joint between the drum and the facepiece. There were no valves, both inhaled and exhaled air passing through the canister. The eyepieces were inserted by means of metal rims with leather washers, and were in two parts: (_a_) a permanent exterior sheet of transparent material (‘cellon’) resembling celluloid, and (_b_) an inner removable disc which functioned as an anti-dimming device. This latter appeared to be of ‘cellon’ coated on the side toward the eye with gelatin, and was held in position by a ‘wheel’ stamped from thin sheet metal, which screwed into the metal rim of the eyepiece from the inside. The gelatin prevented dimming by absorbing the moisture, but wrinkled and blistered and became opaque after a few hours’ use, and could not be changed without removing the mask. The edge of the facepiece all around was provided with a bearing surface consisting of a welt of finely woven cloth about one inch wide sewed to the leather. In some instances this welt was of leather of an inferior grade. The edge of the facepiece was smoothed over by a coat of flexible transparent gum, probably a synthetic compound.” [Illustration: FIG. 50.—German Respirator.] [Illustration: FIG. 51.—The German Respirator.] 1. Smoke Filter Extension. 2. Canister. 3. Ring for Protecting Eye Piece. 4. Anti-dimming Disc Envelope. 5. Carrying Case. 6. Cloth Wallet for Extra Canister (1918). 7. Can for Extra Canister (1916). 8. Assembled Respirator. 9. Face Piece. 10. Anti-dimming disc.