phosphorescent. Then I could follow your incandescent heel like that chap Byron wrote about — don’t you remember?”

He heard her appreciative gurgle in the dark, and then her: “Well, I’m going now.”

Unable to see the slightest glimmer, nevertheless, from the few sounds she made he knew she had turned over and gone down head first, and he was not beyond visioning with inner sight the graceful way in which she had done it — an anything but graceful feat as the average swimming woman accomplishes it.

“Somebody gave it away to you,” was Bert’s prompt accusal, when Graham rose to the surface of the tank and climbed out.

“And you were the scoundrel who rapped stone under water,”