And her hand came down on my back with a force that made me jump. "Only shows," she gurgled merrily, "how little Jack knows about you. Say, you'd better never tell _him_ about those black pajamas!" She spoke chokingly through a storm of laughter as she rocked there against my shoulder. "And say--the joke of it!" She banged me on the back with a clublike blow, incredible from that little hand. "The joke of it is, he thought I'd be so safe with you! Oh, mamma!" And off she went again. I shifted uneasily. I did not like it--her merriment over what was perfectly obvious and rational. Of course, Billings knew she would be safe. Why the deuce shouldn't he? But the matter of the pajamas was another thing. Her receiving me in them was a contingency I could not possibly have anticipated and avoided, and yet a withdrawal because of them or even because of her presence here had been shown to be a course inexplicable to her. She was too innocent, too ingenuous, too _ingenue_ to understand that I was invading the sanctuary of her privacy. Yet to have taken any course that would have appeared to make correction of her error come from me would have been appallingly caddish and cruel. No, the best course had seemed to be to go right on--take no notice--and then, as soon as she retired, slip away to the club. That seemed the gentlemanly thing. Yet now her words implied a certain consciousness that her brother might frown upon her attire, might even visit me with reproach. I was troubled, and her next speech was not calculated to reassure me. "But I'll--I'll never say a word, Dicky," she said, coming out of her laughter and panting breathlessly. "Never! And don't _you_, Dicky--don't you ever! Understand? Mum's the word!" I looked up distressfully to protest, but her little head was shaking earnestly, the long, delicate hair wisps about her forehead wavering like tiny, curling wreaths of golden smoke. "No, sir," she emphasized soberly; "if you ever let _that_ cat out of the bag, it'll be all up with _me_--I mean Jack will never let me come again. You must promise me." "But--" "Oh, but me no 'buts'--_promise_!" "Why, then--er--of course, if you wish it." "That's right, because I want to come again--that is, if you _want_ me. But if Brother Jack was on to you, Dicky, as I am, he would sooner have me at a hotel, that's all." "But my dear Frances--" "I tell you I _know_, Dicky; he doesn't approve of young ladies in pajamas." She chuckled. "Not even black ones." She stood up, looking at herself and performing a graceful pirouette before the long pier glass. "Now, if they had been crimson," she proceeded, "he might have felt different. Old Jack's great on Harvard, and so am I." Of course. All Radcliffe girls were, I knew.