Granet resumed his seat and lit the cigarette which she insisted upon his smoking.

“Well,” he observed, “it does seem hard upon you, Miss Worth.  On the other hand, it really is rather interesting, isn’t it, to think that your father is such a man of mysteries?”

The girl sighed.

“I suppose so,” she admitted, “but then, you see, father is almost brutal about taking any one into his confidence.  He never tells even me a thing, or encourages me to ask a question.  I think for that reason I have grown rather to resent his work and the ridiculous restriction he places upon my freedom because of it.”

A parlourmaid entered with tea, a few minutes later, and Granet moved to his hostess’ side upon the sofa.  He showed no more interest in outside happenings.  He was an adept at light conversation and he made himself thoroughly agreeable for the next hour.  Then he rose quickly to his feet.

“I must go,” he declared.

She sighed.

“It has been so nice to have you here,” she said, “but if you only knew how difficult it was to arrange, it, you’d understand why I hesitate to ask you to come again.”

“Why shouldn’t you come and lunch with me to-morrow at the Golf Club?” he asked.

She hesitated.  It was obvious that the suggestion appealed to her.

“I believe I could,” she assented.  “Captain Chalmers has a small motor-car he’d lend me, and if I go out with my golf clubs it would be all right.  Very likely father will sleep out there and we sha’n’t see anything of him until to-morrow.”

Granet stepped once more to the window.  The mists had rolled up more thickly than ever and the queer little structure was almost invisible.  A bright light, however, fell upon the water a little distance away.

“Your father has electric light out there,” he remarked.

“Yes, they have a wire from the shed,” she told him.  “Whatever he’s trying to do, he needs a very intense and concentrated light at times.”

Granet drew a little sigh.

“Well, I hope it’s something that’ll do us a bit of good,” he said.  “We need it.  The Germans are miles ahead of us with regard to all new-fangled ideas.”

She opened her lips and closed them again.  Granet, who had suddenly stiffened into rigid attention, felt a quick impulse of disappointment.

“I have rung the bell for my own maid,” she said.  “She will show you out of the place.  Don’t let any one see you, if you can help it.”

“And to-morrow?” he asked.  “You will lunch with me?”

“I will be at the Golf Club,” she promised, “at one o’clock.”

Granet was conducted almost stealthily down the stairs and into the avenue.  Half-way to the gate he paused to listen.  He was hidden from sight now by the gathering twilight and the rolling mists.  From behind the house came the softly muffled roar of the tide sweeping in, and, with sharper insistence, the whirr of machinery from the boathouse.  Granet lit a cigarette and walked thoughtfully away.  Just as he climbed into the car, a peculiar light through the trees startled him.  He stood up and watched.  From the top of the house a slowly revolving searchlight played upon the waters.