an scientists who gave such ready help during the war,
the function of the naval officers working with the scientists being to
see that the effort was being directed along practical lines. They were
also greatly indebted to Captain Ryan, R.N., for the exceedingly
valuable work carried out by him at the experimental establishment at
Hawkcraig. Many brilliant ideas were due to Captain Ryan's clever brain.

I doubt whether the debt due to Admiral Duff and Captain Fisher and
their staff for their great work can ever be thoroughly appreciated, but
it is certainly my duty to mention it here since I am better able to
speak of it than any other person. In saying this I do not wish to
detract in the least from the value of the part performed by those to
whose lot it fell to put the actual schemes into operation. Without
them, of course, nothing could have been accomplished.

When the Anti-Submarine Division started in December, 1916, the earlier
devices to which attention was devoted were:

(1) The design and manufacture of howitzers firing shell fitted to
explode some 40 to 60 feet under water with which to attack submarines
when submerged.

(2) The introduction of a more suitable projectile for use against
submarines than that supplied at the time to the guns of destroyers and
patrol craft.

(3) The improvement of and great increase in the supply of smoke
apparatus for the screening of merchant ships from submarines attacking
by gunfire.

(4) A great increase in the number of depth charges supplied to
destroyers and other small craft.

(5) The development of the hydrophone for anti-submarine work, both from
ships and from shore stations.

(6) The introduction of the "Otter" for the protection of merchant ships
against mines.

(7) A very great improvement in the rapidity of arming merchant ships
defensively.

(8) The extended and organized use of air craft for anti-submarine work.

(9) A great development of the special service or decoy ship.

(10) The introduction of a form of net protection for merchant ships
against torpedo fire.

Other devices followed, many of which were the outcome of work in other
Admiralty Departments, particularly the Departments of the Director of
Naval Ordnance and the Director of Torpedoes and Mines, working in
conjunction with the Anti-Submarine or the Operations Division of the
Naval Staff. Some of the new features were the development of
depth-charge throwers, the manufacture and