In face of so fundamental a resemblance no tactician can afford to ignore the sailing system merely because the method of propulsion and the nature of the material have changed.

It is not the principles of tactics that such changes affect, but merely the method of applying them.
Of even higher present value is the process of thought, the line of argument by which the old tacticians arrived at their conclusions good and bad.

In studying the long series of Instructions we are able to detach certain attitudes of mind which led to the atrophy of principles essentially good, and others which pushed the system forward on healthy lines and flung off obsolete restraints.

In an art so shifting and amorphous as naval tactics, the difference between health and disease must always lie in a certain vitality of mind with which it must be approached and practised.

It is only in the history of tactics, under all conditions of weapons, movement and material, that the conditions of that vitality can be studied.
For a civilian to approach the elucidation of such points without professional assistance would be the height of temerity, and my thanks therefore are particularly due for advice and encouragement to Admiral Sir Cyprian Bridge, Vice-Admiral Sir Reginald Custance, Rear-Admiral H.S.H.Prince Louis of Battenberg, and to Captain Slade, Captain of the Royal Naval College.