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

AIR. Constituents of The chief constituents of atmospheric air and their proportions are: — Atmospheric 1 1 1 Atr' Nitrogen........................ 79.1 per cent, by volume. Oxygen ....................... 20.9 Carbon Dioxide (C O2)........ .03 „ Aqueous vapour is also present in varying quantity. Nitrogen has neither taste nor smell nor colour, and, although it is non- poisonous, it will support neither life nor combustion. Its chief use appears to be to dilute the Oxygen which is the life-supporting component of the atmosphere, and is also odourless, tasteless and colourless. its Weight. The WEIGHT of the atmosphere is about iglbs. to the square inch ; thus, in speaking of one atmosphere we mean i51bs. on the square inch; two atmospheres ßolbs., and so on. Temperature Fahrenheit Temperature Centigrade x 9 --------------------------------- + 32 5 Temperature Centigrade = Temperature Fahrenheit—32 - 9 Column of A column of mercury 30 inches high = 1 atmosphere = say idbs. pressure. Mercury. . , A column of mercury 2 inches high = say ilb. pressure. Expansion. Air expands T|g- of its volume for every increase of 1 deg. F., and its volume varies inversely as the pressure. Quantity of Normally, the volume of air breathed by an average healthy adult male Air breathed . . . . . . . . by man. is about 30 cubic inches per inhalation x 15 inhalations = 450 cubic inches = about .25 cubic feet = 7.3 litres per minute. Exhaled air contains on the average 79.1 per cent, of nitrogen, 16.5 per cent, of oxygen, 4.4 per cent, of carbonic acid (C O2). The “dead space” formed by the larger air tubes is about 10 cubic inches. The air in the lung contains about i4%O2and 5% to 6% C 0.2. SUPERFICIAL AREA AND DISPLACEMENT OF A DIVER. Superficial The superficial area of an ordinary sized man’s body is about 2,160 square area of a A J j i naked man’s inches, so that in atmospheric air the total pressure on the man’s body is 2,160 x body and the pressure i^lbs. = 32,4oolbs. At a depth of 33 feet of sea water, the total pressure would thereon. be 64,800 lbs. So long as the pressure is equally distributed throughout the body by the body fluids, it has no effect. Weight of a The total weight of a diver’s equipment (i.e., the part which he actually Diver fully , r ...... , ,, . r <• , equipped. wears, and exclusive of his air pipe) is about 175IDS. ; therefore a diver (say a 12-stone man), fully equipped, would have a total weight of 3431bs. 94