L G. DOLMAGE, M.A., D.C.L., LL.D., F.R.A.S.

3. SCIENTIFIC IDEAS OF TO-DAY.
By C. R. GIBSON.

4. BOTANY OF TO-DAY.
By Professor G. F. SCOTT ELLIOT, M.A., B.SC.

6. ENGINEERING OF TO-DAY.
By T. W. CORBIN.

7. MEDICAL SCIENCE OF TO-DAY.
By WILLMOTT EVANS, M.D.

8. MECHANICAL INVENTIONS OF TO-DAY.
By T. W. CORBIN.

9. PHOTOGRAPHY OF TO-DAY.
By H. CHAPMAN JONES, F.I.C., F.C.S., F.R.P.S.

10. SUBMARINE ENGINEERING OF TO-DAY.
By C. W. DOMVILLE-FIFE.

11. GEOLOGY OF TO-DAY.
By Professor J. W. GREGORY, F.R.S.

12. AIRCRAFT OF TO-DAY.
By CHARLES C. TURNER, Lieut., R.N.V.R.

SEELEY, SERVICE & CO., LTD., 38 Great Russell St.

=Dedicated=

TO THE MEMORY OF

THE LATE LIEUT. WALTER PRICE, R.N.V.R.

A TRUE FRIEND AND A

GALLANT OFFICER

AUTHOR'S NOTE

I DESIRE simply to say that I commenced taking an active interest in
submarines in 1904. I wrote my first book on the subject, _Submarines of
the World's Navies_, in 1910, and I have watched and written of the rise
of these and kindred weapons for the past fifteen years of rapid
development in peace and war, finally taking a humble part in the defeat
of the great German submarine armada during the years 1914-1918.

C. D.-F.

1919.

INTRODUCTION

WHILE Great Britain remains an island, with dominion over palm and pine,
it is to the sea that her four hundred millions of people must look for
the key to all that has been achieved in the past and all that the
future promises in the quickening dawn of a new era.

Not only over Great Britain alone, however, does the ocean cast its
spell, for it is the free highway of the world, sailed by the ships of
all nations, without other hindrances than those of stormy nature, and
navigated without restriction from pole to pole by the seamen of all
races. It was the international meeting-place, where ensigns were
"dipped" in friendly greeting, and since the dawn of history there has
been a freemasonry of the sea which knew no distinction of nation or
creed.

When the call of humanity boomed across the dark, storm-tossed waters
the answer came readily from beneath whatever flag the sound was