This had greatly perturbed them at the time, for up to then they had been in the easy position of the tipped rather than the tippers, and anyhow they had no idea what one gave stewardesses.  Neither, it appeared, had Aunt Alice; for, on being questioned, she said vaguely that as it was an American boat they were going on she supposed it would have to be American money, which was dollars, and she didn’t know much about dollars except that you divided them by four and multiplied them by five, or else it was the other way about; and when, feeling still uninformed, they had begged her to tell them why one did that, she said it was the quickest way of finding out what a dollar really was, and would they mind not talking any more for a little while because her head ached.

The tips they had seen administered during their short lives had all been given at the end of things, not at the beginning; but Americans, Aunt Alice told them, were in some respects, in spite of their talking English, different, and perhaps they were different just on this point and liked to be tipped at both ends.  Anna-Rose wanted to crane out her head and call up to Anna-Felicitas and ask her whether she didn’t think that might be so, but was afraid of disturbing the people in the opposite berths.

Anna-Felicitas was in the top berth on their side of the cabin, and Anna-Rose as the elder and accordingly as she explained to Anna-Felicitas, needing more comfort, in the lower one.  On the opposite side were two similar berths, each containing as Anna-Felicitas whispered after peeping cautiously through their closed curtains,—­for at first on coming in after dinner to go to bed the cabin seemed empty, except for inanimate things, like clothes hanging up and an immense smell,—­its human freight.  They were awed by this discovery, for the human freight was motionless and speechless, and yet made none of the noises suggesting sleep.

They unpacked and undressed as silently and quickly as possible, but it was very difficult, for there seemed to be no room for anything, not even for themselves.  Every now and then they glanced a little uneasily at the closed curtains, which bulged, and sniffed cautiously and delicately, trying to decide what the smell exactly was.  It appeared to be a mixture of the sauce one had with plum pudding at Christmas, and German bedrooms in the morning.  It was a smell they didn’t like the idea of sleeping with, but they saw no way of getting air.  They thought of ringing for the stewardess and asking her to open a window, though they could see no window, but came to the conclusion it was better not to stir her up; not yet, at least, not till they had correctly diagnosed what was the matter with her.  They said nothing out loud, for fear of disturbing whatever it was behind the curtains, but they knew what each was thinking, for one isn’t, as they had long ago found out, a twin for nothing.