Trusting it may meet with your kind approval, we are,
Very sincerely yours,
Capt. Louis Sorcho,
Frances Namon Sorcho,
Deep Sea Divers.
HISTORY OF DEEP SEA DIVING.
Just how far back the art of sub-marine diving dates, is a matter of conjecture, but until the invention of the present armor and helmet in 1839, work and exploration under water was, at best, imperfect, and could only be pursued in a very limited degree. The armor of to-day consists of a rubber and canvas suit, socks, trousers and shirt in one, a copper breastplate or collar, a copper helmet, iron-soled shoes, and a belt of leaden weights to sink the diver.
The helmet is made of tinned copper with three circular glasses, one in front and one on either side, with guards in front to protect them. The front eye-piece is made to unscrew and enable the diver to receive or give instructions without removing the helmet. One or more outlet valves are placed at the back or side of the helmet to allow the vitiated air to escape. These valves only open outwards by working against a spiral spring, so that no water can enter. The inlet valve is at the back of the helmet, and the air on entry is directed by three channels running along the top of the helmet to points above the eye-pieces, enabling the diver to always inhale fresh air, whilst condensation on the glasses is avoided. The helmet is secured to the breastplate below by a segmental screw-bayonet joint, securing attachment by one-eighth of a turn. The junction between the waterproof dress and the breastplate is made watertight by means of studs, brass plates, and wing-nuts. A life or signal line enables the diver to communicate with those above. The air-pipe is made of vulcanized india-rubber with galvanized iron wire imbedded.