a key to our codes.) It comes from the Cunarder, now out of
sight ahead. We figure the radius on the chart, and bear off six points
on a new course to keep well clear of the area. The Leyland liner is by
now well ahead and we note she has turned to steer west. There is a
slight difference in our courses and we draw together again as we steam
on. The wireless operator now reports that a vessel near at hand has
acknowledged the Cunarder's _allo_. Shortly a man-o'-war sloop appears
in sight and passes north at high speed, steering towards the position
we are avoiding.

The second officer keeps a keen look-out. He has had bitter experience
of the power of an enemy submarine and is anxiously desirous that it
should not be repeated. A 'check' on the distant sea-line (that we had
taken for the peak of a drifter's mizen) draws his eye. He reports a
submarine in sight--broad on the port bow. The circle of our telescope
shows the clean-cut horizon ruling a thread on the monotint of sea and
sky. Sweeping the round, a grey pinnacle leaps into the field of view.
It is over-distant for ready recognition. Only by close scrutiny,
observing a hair-line that rises and falls on either side of the grey
upstanding point, are we able to recognize our enemy. He is pressing on
at full speed, trusting to our casual look-out, that he may secure a
favourable position to submerge and attack. Our fine confidence with
which we have anticipated such a meeting gives place to a more sober
mood. Though not yet in actual danger, there is the former _allo_ to be
thought of--the possibilities of a combination. Quick on recognition, we
alter course, steering to the north again. The gun, already manned, is
brought to the 'ready,' and the intermittent crackle of the wireless
sends out an urgent warning. The Leyland steamer starts away at first
sight of our signals: ahead, grey smoke on the horizon marks where the
patrol sloop has gone hull-down.

A spurt of flame throws out from the distant submarine. He has noted our
sudden alteration of course and knows that he has now no prospect of
reaching torpedo range unobserved. His shell falls short by about a
thousand yards. We reply immediately at our extreme elevation, but
cannot reach him. The next exchange is closer--he is evidently
overhauling us at speed. Mindful of our limited fifty rounds, we
telephone to the gun-layer to reserve his fire until he has better
prospect of a hit. Two shots to our one; the ene