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

The diver should signal for more air and stop moving about, resting quietly while the impure air in his helmet is swept out by a fresh supply from the pump, and in a minute or two he will be all right ag"ain, and able to continue his work. It can- not be pointed out too often that struggling or doing anything that requires an effort is the surest way of getting worse, and that, unless the air supply is very bad indeed, a couple of minutes’ rest with the valve comfortably adjusted, and with the pump heaving- fast, will restore the man to perfect comfort and efficiency. Panting is generally a sign that the air supply is insufficient, and the diver should not hesitate to ask for more air. In any case, the more air the diver has the better he is for it. The supply indicated on page 97 is not more than the diver can easily control with his valve. Coming up from Deep Water.—In coming up, after making the usual four pulls on the breast rope, the diver gives one pull on it, just as he starts up the shot-rope, as a signal that he is leaving the bottom. In ascending, the outlet valve should be screwed up until the diver is almost afloat ; he is then able to come up the rope without having to pull himself up or exert himself in any way. He should go up steadily hand over hand, keeping- the shot rope between his legs, and be on the look-out to stop directly he g-ets one pull on the air pipe. On being stopped, he can maintain himself in position on the shot rope by curling one leg round it, which will leave the other leg and both hands free. While waiting, he must keep his limbs in motion, and try to work every muscle in his body, bending' backward and forward, etc., but not so violently as to tire himself. The object of these gymnastics is to quicken the circulation temporarily, and so to assist in sweeping’ the excess of nitrogen out of the tissues of the body. Getting into the Boat. On reaching- the surface, and before letting go the shot rope, the diver should look up to see whether he has taken any turns with his air pipe or breast rope round it ; if so, he must take them out before going to the ladder. The attendant will then draw him to the ladder. In getting a footing on it, if there be any “sea” on, the diver should keep under water as much as possible in order to avoid being knocked about. If there is any tide, he must keep his dress empty and his feet down, for it is easy to get inflated and helpless on the surface. Since this is more likely to happen if the diver rolls over on his back, he should keep on his face whenever brought into a horizontal position. The following hints are meant for beginners rather than for experienced men :— In any difficulty a little quiet thought will generally save time in the end. Don’t take any steps under water without reflecting on their probable consequences. Keep cool. Distance-Line Lost.—Should the distance-line be lost in the dark, feel carefully all round you before moving. Don’t waste time by searching about for it. Signal 53