operators,
but they drilled the essentials of their practice into landward youths
in a few months--blessed them with a probationer's licence--and sent
them to sea. It is idle to speculate on what we could have done without
this communication with the beach: it is inconceivable that we could
have served the sea as we have done. Throughout the length of channel
waters, we were constantly in visual touch with the patrols, but in the
more open seas we relied on the wireless to keep us informed of enemy
activities. At first, we were lavish in its use. The air was scored by
messages--'back chat' was indulged in by the operators. An _S.O.S._ (and
they were frequent) was instant signal for a confusion of
inquiries--a battery of call and counter call--that often prevented the
ready succour of a vessel in distress. We grew wiser. We put a seal on
the switch. Regulations came into force to restrain unnecessary
'sparking'; we sat in to listen and record, and only to speak when we
were spoken to.

Codes were issued by the Admiralty for use at sea. Their early
cryptogram was easily decoded by friend and enemy alike. Knowing that
certain words would assuredly be embodied in the text of a message
(words such as, _from_--_latitude_--_report_--_submarine_--_master_), it
was not difficult to decipher a code of alphabetical sequence. There
were famous stories of traitors and spies, but our authoritative
simplicity was responsible for the occasional leakage of information. At
this date, 1915-16, wireless position-detectors came into use by the
enemy. A spark-group, repeated after an interval, could give a fair
approximation of distance and course and speed. More than ever it was
necessary to maintain silence when at sea. Withal, the air was still in
strong voice. At regular periods the great longshore radios threw out
war warnings to guide us in a choice of routes and warn us away from
mined areas. Patrols and war craft kept up an incessant, linking report.
Distress signals hissed into the atmosphere in urgent sibilance, then
faltered and died away. On occasion, the high note of a _Telefunken_ set
invited a revealing confidence that would lead us, 'chicky-chicky,' to
the block. We were well served by Marconi.

Extension of the power of enemy submarines brought new practice to our
seafaring. We had made the most of a passage by the land, steering so
close that the workers in the fields paused in their toil and waved us
on; but the new und