Signals employed.—The signalman is the responsible person, and must be very vigilant all the time the diver is down; occasionally he will give one pull on the life line, and the diver should return the signal by one pull signifying "all right;" if the signal be not returned, the diver must be hauled up, but if the diver wishes to work without being interrupted by signal, he gives one pull on the line, independently, for "All right; let me alone." If the signalman feels any irregular jerks, such as might be occasioned by the diver falling into a hole, he should signal to know if he is all right, and if he does not receive any reply, he should haul him up immediately. If the diver from any cause is unable to ascend the ladder, and wishes to be pulled up, he gives four sharp pulls on the life line. If while being hauled up the diver gives one pull, it signifies "All right; don't haul me any more." The diver should be hauled up slowly and steadily. If the signalman wishes the diver to come to the surface, he gives four sharp pulls on the line, on which the diver should answer "All right," return to the foot of the ladder, and signal to be hauled up.
One pull on the air-pipe signifies that the diver wants more air. Two pulls on the life line and two pulls on the air-pipe in rapid succession, signify that the diver is foul and cannot release himself, and requires the help of another diver; on receiving such a signal, no attempt should be made to haul the diver to the surface.
The above signals are to be invariably used; but other signals may be arranged as is most convenient for any particular work, as a great variety can be made with the life line and air-pipe. The diver can communicate with the surface by means of a slate.
Further information on this subject, especially with regard to the foregoing diving apparatus, will be found in Messrs. Siebe and Gorman's "Manual for Divers."
FOOTNOTES:
[V] In wrought iron there is always some residual magnetism; there is therefore no necessity to start the magnetism with a permanent magnet.
[W] Siemens' unit.