rately. The topics so
treated fell naturally and, indeed, necessarily within the scope of the
present volume. To exclude them because I had discussed them elsewhere
was impossible. Wherever I found I could improve the language previously
employed in the direction of greater lucidity and precision I have done
so to the best of my ability, so that the passages in question are close
paraphrases rather than mere transcripts of those which occur elsewhere.
But I have not attempted to disguise or weaken by paraphrase any
passages which still seemed to me to convey my meaning better than any
other words I could choose.

Changes in the methods, though not in the principles, of naval warfare
are in these days so rapid and often so sudden that one or two topics
have emerged into public prominence even since the present volume was in
type. I desire therefore to take this opportunity of adding a few
supplementary remarks on them. The first, and possibly in the long run
the most far-reaching of these topics, is that of aviation, which I have
only mentioned incidentally in the text. That aviation is still in its
infancy is a truism. But to forecast the scope and direction of its
evolution is as yet impossible. For the moment it may perhaps be said
that its offensive capacity--its capacity, that is, to determine or even
materially to affect the larger issues of naval warfare--is
inconsiderable. I say nothing of the future, whether immediate or
remote. Any day may witness developments which will give entirely new
aspects to the whole problem. In the meanwhile the chief functions of
aircraft in war will probably be, for some time to come, those of
scouting, observation, and the collection and transmission of
intelligence not obtainable by any other means. Offensive functions of a
more direct and formidable character will doubtless be developed in
time, and may be developed soon; but as I am no prophet I cannot attempt
to forecast the direction of the evolution, to determine its limits, or
to indicate its probable effects on the methods of naval warfare as
expounded in the following pages. I will, however, advance two
propositions which will not, I believe, be gainsaid by competent
authorities. They are true for the moment, though how long they may
remain true I do not know. One is that no aircraft yet constructed can
take or keep the air in all conditions of weather. The number of days in
the year in which it can do so in safety can onl