In training for one of the world’s most dangerous jobs - that of the London fire- man in wartime - the “smoke eaters” are drilled under conditions as much like those of an actual incendiary bomb raid as can be created. They are taught to grope their way into a smoke-filled building blindfolded, since in an actual fire the smoke makes vision impossible. In the first stages of training they are blindfolded and led by the voice of an instructor, learning caution in feeling their way around unseen obstacles. All firemen, too, must periodically check their gas masks in a testing chamber to be certain they are safe, and here also they are accustomed to working in masks.