The result is that each dot and dash he makes is formed of a large number of separate currents, and as these flow through the reactance coil, it gives each one a little kick and sends it out into the water through the copper plates; the currents then spread out between and from the plates in closed lines which extend to very considerable distances, as shown in [Fig. 59].
When these electric currents reach the plates of the receiving apparatus on the submarine where the operator is listening in, they flow up the wires and through the primary winding of the telephone induction coil; these broken up direct currents flowing through the primary coil set up alternating currents in the secondary coil and also raise the low pressure currents into high pressure currents—that is, currents of a higher voltage, as it is called.
These alternating high pressure currents then flow through the telephone receiver, and by varying the strength of the magnet of the latter the dots and dashes of the sending station are reproduced and the receiving operator hears them as a musical buzz.
CHAPTER IX
THE CREW OF THE SUBMARINE
How the Crew of a Submarine is Signed, Slept and Fed. The Mother or Base Ship and Its Uses. The Complement of the Submarine; How New Men Are Trained, and the Duties of the Crew