“As a check on the quality on the final inspectors’ work a reinspection of 5 per cent of the passed masks was conducted. Where it was found that a particular inspector was making numerous mistakes, her eyes were examined to see whether it was due to faulty eyesight or careless work. Masks containing known defects were purposely sent to these inspectors to determine whether they were capable of continuing the inspection work. In this way the desired standard was maintained. “A daily report of the final inspection was sent back to each of the assembly departments involved so that defects might be eliminated immediately and the percentage of rejects kept as low as possible. “After the final inspection the masks were numbered, packed in knapsacks, and the filled knapsacks placed in packing cases, twenty-four to a case.” TISSOT MASK The French, as has already been pointed out, early recognized that certain classes of fighting men, as the artillerymen, needed the maximum of protection with the minimum decrease in efficiency. The result of this was the Tissot Mask. Before the United States entered the war, the British standard box respirator had reached a greater degree of perfection, with far greater ruggedness and portability. It was therefore adopted as the American standard. At the time of the invention of the British box respirator and practically up to the time the United States entered the war, masks were worn only during the sporadic gas attacks then occurring and only for a brief period at a time. As the war progressed, the men were compelled to wear their masks for much longer periods (eight hours was not uncommon). It was then seen that more comfort was needed, even at the expense of a little safety. The principle of the Tissot mask was correct so far as comfort was concerned, since it did away with the irritating mouthpiece and noseclip, but the chief danger in the French mask arose from the fact that the facepiece was made of thin, pure gum rubber. The Research Division, together with the Gas Defense Division, developed two distinct types of Tissot masks. The first of these was the Akron Tissot, the second the Kops Tissot. The best features of these have been combined in the 1919 Model. [Illustration: FIG. 60.—American Tissot Mask, Early Type.] [Illustration: FIG. 61.—American Tissot Mask, Interior View.] 1919 MODEL AMERICAN MASK