conquered the gravest danger which has ever faced the Empire.

There were at times inevitable set-backs as the enemy gained experience
of our methods, and new ones had then to be devised, and we were always
most seriously handicapped by the strain imposed upon the Fleet by our
numerous military and other commitments overseas, and by the difficulty
of obtaining supplies of material, owing to the pre-occupation of our
industries in meeting the needs of our Armies in equipment and
munitions; but, generally speaking, it may be said that in April, 1917,
the losses reached their maximum, and that from the following month and
onwards the battle was being slowly but gradually won. By the end of the
year it was becoming apparent that success was assured.

The volume describes the changes carried out in the Admiralty Staff
organization; the position of affairs in regard to submarine warfare in
the early part of 1917; and the numerous anti-submarine measures which
were devised and brought into operation during the year. The
introduction and working of the convoy system is also dealt with. The
entry of the United States of America into the war marked the opening of
a new phase of the operations by sea, and it has been a pleasure to give
particulars of our cordial co-operation with the United States Navy. The
splendid work of the patrol craft and minesweepers is described all too
briefly, and I have had to be content to give only a brief summary of
the great services of the Dover and Harwich forces.

Finally, an effort has been made to suggest the range and character of
the work of the Production Departments at the Admiralty. It is
impossible to tell this part of the story without conveying some
suggestion of criticism since the output never satisfied our
requirements. I have endeavoured also to indicate where it seemed to me