nd in command of various areas, and their work was of the
greatest possible value. A few of those with whom I came into personal
contact during the year 1917 were the late Captain F. Bird, C.M.G.,
D.S.O., who was most conspicuous in command of the drifters of the Dover
Patrol; Captain W. Vansittart Howard, D.S.O., who commanded the Dover
Trawler Patrol with such ability; Commander Sir George Armstrong, Bart.,
who so successfully inspired the minesweeping force working from Havre;
and Commander H.F. Cayley, D.S.O., whose services in the Harwich
minesweeping force, working under his brother, Rear-Admiral C.G. Cayley,
were invaluable.

So much for the patrol craft. The great work carried out by the
minesweepers can be best judged by quoting a few figures for 1917,
during which year the mine menace attained its maximum intensity, owing
to the large increase in the number of German submarine minelayers.

During the year 1916 the average number of mines swept up per month was
178.

Statistics for 1917 show the following numbers of mines swept up per
month:

January 250
February 380
March 473
April 515
May 360
June 470
July 404
August 352
September 418
October 237
November 184
December 188

making the average per month in 1917 355 mines.

It will be noticed how rapidly the figures rose in the early part of the
year, and how great was the diminution in the figures for the later
months. This decrease was due to the fact that the extension of
anti-submarine measures was beginning to take effect, and the
destruction of German submarines, and especially of submarine minelayers
of the U.C. type, was becoming considerable.

The heavy work involved a great strain on the minesweeping service, and
the greatest possible credit is due to the personnel of that service for
the fine response made to the call for additional exertions and heavier
risks.

At the same time the organizing work achieved at Headquarters by the
minesweeping section of the Naval Staff should not be forgotten. At the
head of this section was Captain Lionel G. Preston, C.B.; he had
succeeded to the post of Head of the Minesweeping Service early in 1917,
after two and a half years of strenuous and most successful minesweeping
work in the Grand Fleet flotillas, and he at once grappled with the task
of dealing with the large number of mines then being laid by German
submarines.

Instructions were issued to