which consists of two main parts, the helmet and the dress proper. The helmet (Fig. 161) is made of copper. A breastplate, B, shaped to fit the shoulders, has at the neck a segmental screw bayonet-joint. The headpiece is fitted with a corresponding screw, which can be attached or removed by one-eighth of a turn. The neck edge of the dress, which is made in one piece, legs, arms, body and all, is attached to the breastplate by means of the plate P1, screwed down tightly on it by the wing-nuts N N, the bolts of which pass through the breastplate. Air enters the helmet through a valve situated at the back, and is led through tubes along the inside to the front. This valve closes automatically if any accident cuts off the air supply, and encloses sufficient air in the dress to allow the diver to regain the surface. The outlet valve O V can be adjusted by the diver to maintain any pressure. At the sides of the headpiece are two hooks, H, over which pass the cords connecting the heavy lead weights of 40 lbs. each hanging on the diver's breast and back. These weights are also attached to the knobs K K. A pair of boots, having 17 lbs. of lead each in the soles, complete the dress. Three glazed windows are placed in the headpiece, that in the front, R W, being removable, so that the diver may gain free access to the air when he is above water without being obliged to take off the helmet.
