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

Payerne and Lamival. Scott Russell's Boat. Caissons for Bridge Founda- tions. came in contact with a rock or other obstruction. The usual complement of men was nine, eight engaged in labouring in the work chamber (P), and the ninth in the chamber (L) to purify the air, receive the débris from the men working below, admit fresh air from the chambers (B B), which were necessary every hour, and to attend to the machine. The pump (E) was so arranged with pipes (H G) that the attendant could pump sea water into or out of the chamber (B B) and (C), or pump air from the chamber (B B) into the chamber (L) or (P), and it was also used for filling the chamber (B B) with compressed air when the machine was at the surface. Air cocks (F F) were also provided for supplying the chamber (L) with air from the chambers (B B) so long as the air pressure in the latter was in excess of that in the former. The descent and ascent of the machine was controlled by merely pumping water into the chamber (B B) and (C) when descending, and by pumping it out again for the purpose of ascending, and the machine could be slowly moved about along the bottom by poles used by the men in the work chamber (P). The work done by the machine was paid for by the French Government, according to the quantity of material excavated or masonry laid. The nine men could excavate somewhat less than one and a-half cubic yards of hard rock in six and a-half hours, besides ascending and descending twice in that time, chiefly to get rid of the débris which they had lifted into the chamber (L), but which might have been much more economically sent to the surface in iron cradles lowered to them for that purpose outside the machine. In general practice, the supply of fresh air was derived entirely from the reservoirs (B B), and the carbonic acid gas exhaled by the occupants, being heavy, fell to the bottom, and, if the machine was being used in running water, was absorbed and carried away by the current ; but as a small portion only of the gas would be absorbed in still water, the air was passed through a mixture of lime water with a little potash,* by means of a bellows, the operation being continued for every alternate quarter of an hour. The carbonic acid gas was thus completely absorbed by the lime and the atmosphere purified, so as in all cases to be amply sufficient for the day’s work of six and a-half hours. About ten years later, Payerne and his colleague, Lamival, were granted British letters patent for a submarine vessel similar to that already described, but provided with mechanical means of propulsion, and an arrangement for the introduction and discharge of water by means of pumps to enable the vessel to sink or rise in the water as required. During the Crimean War, the late Scott Russell built a submarine boat called the Nautilus, which it was intended to use against the enemy. This vessel was to have been propelled by divers, seated on platforms outside, and obtaining their air supply from compressed air cylinders carried in the vessel. Peace being declared before the final completion of the vessel, the project was abandoned, and she was subsequently broken up. Caissons for securing foundations were first used in this country by Hughes, about sixty years ago, in connection with a bridge over the Medway at Rochester, the depth in this case being about 60 feet. Subsequently Brunel used them for the bridge over the Wye, at Chepstow, and, later, at Saltash, the depth in the latter operations being 87 feet. * Payerne mentions an alkaline mixture consisting of about 2^ lbs. of water, \ lb of lime and 2oz of potash, and he says that a certain quantity of prepared oxygen may be admitted into the boat. I 70