



Produced by R.G.P.M. van Giesen. Thank you, Iain Somerville!




[Illustration: cover art]




The Sea-girt Fortress




BY PERCY F. WESTERMAN

"No boy alive will be able to peruse Mr. Westerman's pages without a
  quickening of his pulses."--Outlook.

The Sea-girt Fortress: A Story of Heligoland. 3_s_. 6_d_.
  "Mr. Westerman has provided a story of breathless excitement, and
  boys of all ages will read it with avidity."--Athenaeum.

When East meets West: A Story of the Yellow Peril. 3_s_. 6_d_.
  "The book is an experience no boy should miss."--Outlook.
  "A remarkable, ingenious story."--Academy.

Captured at Tripoli: A Tale of Adventure. 2_s_. 6_d_.
  "We cannot imagine a better gift-book than this to put into the
  hands of the youthful book-lover, either as a prize or present."
  --Schoolmaster.

The Quest of the "Golden Hope": A Seventeenth-century Story of
Adventure. 2_s_. 6_d_.
  "The boy who is not satisfied with this crowded story must be
  peculiarly hard to please."--Liverpool Courier.

A Lad of Grit: A Story of Restoration Times. 2_s_. 6_d_.
  "The tale is well written, and has a good deal of variety in the
  scenes and persons."--Globe.


LONDON: BLACKIE & SON, LTD., 50 OLD BAILEY, E.C.




[Illustration: "HAND OVER HAND HE CLIMBED TILL HE REACHED A METALLIC
BEAM" _Frontispiece_]




The
Sea-girt Fortress

A Story of Heligoland


BY
PERCY F. WESTERMAN

Author of "When East Meets West" "Captured at Tripoli"
"The Quest of the _Golden Hope_"
"A Lad of Grit" &c.



_Illustrated by W. E. Wigfull_



BLACKIE AND SON LIMITED
LONDON GLASGOW AND BOMBAY




  Contents
  CHAP.

      I. MAN OVERBOARD
     II. THROUGH THE FOG
    III. A LOSS AND A FIND
     IV. ARRESTED
      V. A DISCOVERY
     VI. VON WITTELSBACH'S PLAN
    VII. OFFICIAL HINDRANCES
   VIII. SENTENCED
     IX. ON THE SCENT
      X. IN THE PRISON CELL
     XI. A NIGHT OF TOIL
    XII. INVESTIGATIONS
   XIII. AN EXPERIMENT WITH A ZEPPELIN
    XIV. THE SECOND NIGHT OF LIBERTY
     XV. RECAPTURED
    XVI. THE NEWS LEAKS OUT
   XVII. THE SANDINSEL TUNNEL
  XVIII. THE ERRANT AIRSHIP
    XIX. AT THE MERCY OF THE WINDS
     XX. HOMEWARD BOUND
    XXI. GOOD OLD HAMERTON!
   XXII. A MOMENTOUS DECISION
  XXIII. FIRST BLOOD
   XXIV. THE BATTLE OF THE GALLOPER SANDS
    XXV. THE FALL OF THE ISLAND FORTRESS




  Illustrations

  "HAND OVER HAND HE CLIMBED TILL HE REACHED A METALLIC BEAM"
    _Frontispiece_

  "WAITING TILL A WAVE BROUGHT THE MAN WITHIN ARM'S LENGTH, THE SUB
  CLUTCHED HOLD OF HIM"

  "'SPIES ARE NOT ENTITLED TO ANY CONSIDERATION OF THAT DESCRIPTION'"

  "'IT'S THE ROUNDS, BY JOVE!' WHISPERED THE SUB"

  "'GREAT SCOTT!' HE EXCLAIMED; 'IT'S HAMERTON'"

  "A SEAPLANE CONTRIVED TO DROP A BOMB ON THE _ROYAL SOVEREIGN'S_
  DECK"




THE
SEA-GIRT FORTRESS


CHAPTER I

Man Overboard


"WHERE are we now?" asked Oswald Detroit, emerging from the cabin of
the _Diomeda_.

"Ask me another," replied his chum, Jack Hamerton, with a merry
laugh. "We may be here, we may be there, for all I know. One thing I
