“I don’t care if I do,” he answered, after a moment’s reflection:  “a moonlight bath in the sea would be something out of the common; and there seems to be just surf enough to make it enjoyable.”

“Yes; and my bathing-suit is in the bath-house yonder.  I can be ready in five minutes.”

“Can you?  So can I; we’ll go in if only for a few minutes.  Won’t you go with us, Lulu?”

“I’d like to,” she said, “but I can’t without leave; and I know papa wouldn’t give it, for I had a bath this morning, and he says one a day is quite enough.”

“I was in this morning,” said Bob; “Betty, too, I think, and—­I say, Bet, it strikes me I’ve heard that it’s a little risky to go in at night.”

“Not such a night as this, I’m sure, Bob; why, it’s as light as day; and if there is danger it can be only about enough to give spice to the undertaking.”

With the last word she started for the bath-house, and Bob, not to be outdone in courage, hurried toward another appropriated to his use.

Lulu stood waiting for their return, not at all afraid to be left alone with not another creature in sight on the beach.  Yet the solitude disturbed her as the thought arose that Bob and Betty might be about to put themselves in danger, while no help was at hand for their rescue.  The nearest she knew of was at the cottages on the bluff, and for her to climb those long flights of stairs and give the alarm in case anything went wrong with the venturesome bathers, would be a work of time.

“I’d better not wait for them to get into danger, for they would surely drown before help could reach them,” she said to herself, after a moment’s thought.  “I’ll only wait till I see them really in, and then hurry home to see if somebody can’t come down and be ready to help if they should begin to drown.”

But as they passed her, presently, on their way to the water, Bob said:  “We’re trusting you to keep our secret, Lulu; don’t tell tales on us.”

She made no reply, but thought within herself, “That shows he doesn’t think he’s doing exactly right.  I’m afraid it must be quite dangerous.”

But while his remark and injunction increased her apprehensions for them, it also made her hesitate to carry to their friends the news of their escapade till she should see that it brought them into actual danger and need of assistance.

She watched them tremblingly as they waded slowly out beyond the surf into the smooth, swelling waves, where they began to swim.

For a few moments all seemed to be well; then came a sudden shrill cry from Betty, followed by a hoarser one from Bob, which could mean nothing else than fright and danger.

For an instant Lulu was nearly paralyzed with terror; but rousing herself by a determined effort, she shouted at the top of her voice, “Don’t give up; I’ll go for help as fast as ever I can,” and instantly set off for home at her utmost speed.