Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

GENERAL DESCRIPTION OF THE CONSTRUCTION OF THE DIVING APPARATUS AND ITS USE. A Set of the ordinary Diving Apparatus consists essentially of seven parts, viz. :—(a) A helmet with corselet. (6) A waterproof diving dress, (c) A length of flexible air tube with metal couplings, (c/) Pair of weighted boots, (e) Pair of lead weights for breast and back. (/) A lifeline, (g) An air pump. The Helmet, which is fully described on pages 26 to 29, and illustrated on page 28, is secured to the Corselet by segmental rings, the corselet being clamped water-tightly to the vulcanized rubber collar of the Diving Dress, which is a combination suit covering the whole body except the hands, which project through elastic cuffs (see page 32) which make a watertight joint at the wrists. Air is supplied to the diver through a non-return valve at the back of the helmet by means of a Flexible Tube connected with the Air Pump. The air escapes through a spring valve at the side of the helmet, this valve being adjustable by the diver. With this arrangement the pressure of the air in the helmet is always equal to, or slightly greater than, the water pressure at the outlet valve. It is absolutely necessary that the diver should breathe compressed air, otherwise his breathing would be instantly stopped and blood would flow from his nose and mouth. In order to enable him to sink and to stand firmly on the bottom, he carries a 40 lb. Leaden Weight on his chest and a similar weight on his back, and 16 lbs. of lead on each Boot. Altogether the weight of the equipment which he actually wears is about 175 lbs. (see pages 94 and 95 for particulars as to displacement, etc.). Besides the air pipe, the diver is usually connected with the surface by a signal, or Life-line, in which, in most cases, are embedded telephone wires. He usually descends by a rope (the 'shot'rope ) attached to a heavy weight which has been previously lowered to the bottom, and on reaching the bottom takes with him a line (the “ distance line ") attached to this weight, so that he can always find the shot>rope again. 6a