“And they’ve got the shells, too,” Collins muttered, “the shells that burst under water.”

Granet looked around.  They were playing the other end now.

“Listen!” he said.

They paused in the middle of the lawn.  Granet held up his handkerchief and turned his cheek seaward.  There was still little more than a floating breath of air but his cheek was covered with moisture.

“I have everything ready,” he said.  “Just before we go to bed to-night I shall swear that I hear an aeroplane.  You’re sure your watch is right to the second, Collins?”

“I am as sure that it is right,” the other replied grimly, “as I am that to-night you and I my young friend, are going to play with our lives a little more carelessly than with this china ball.  A good throw, that I think,” he went on, measuring it with his eye carefully.  “Come, my friend, you’ll have to improve.  My Scotch practice is beginning to tell.”

Geoffrey Anselman threw up the window and looked out.

“Pretty hot stuff, isn’t he Ronnie?” he asked.

Granet glanced at his opponent, with his bent shoulders, his hard face, hooked nose and thin gold spectacles.

“Yes,” he admitted quietly, “he’s too good for me.”

CHAPTER XXI

At about half-past ten that evening, Granet suddenly threw down his cue in the middle of a game of billiards, and stood, for a moment, in a listening attitude.

“Jove, I believe that’s an airship!” he exclaimed, and hurried out of the room.

They all followed him.  He was standing just outside the French-windows of the sitting-room, upon the gravel walk, his head upturned, listening intently.  There was scarcely a breath of wind, no moon nor any stars.  Little clouds of grey mist hung about on the marshes, shutting out their view of the sea.  The stillness was more than usually intense.

“Can’t hear a thing,” young Anselman muttered at last.

“It may have been fancy,” Granet admitted.

“A motor-cycle going along the Huntstanton Road,” Major Harrison suggested.

“It’s a magnificent night for a raid,” Dickens remarked glancing around.

“No chance of Zepps over here, I should say,” Collins declared, a little didactically.  “I was looking at your map at the golf club only this morning.”

They all made their way back to the house.  Granet, however, seemed still dissatisfied.

“I’m going to see that my car’s all right,” he told them.  “I left it in the open shed.”