"'Wilhelmina,' I faltered, 'do you mean to say that that guard could
not see you?' "She began to look so serious again that I merely added, 'Never mind,
I don't care whether you are invisible or not, dearest.' "'I am not invisible to you,' she said; 'why should you care?' "A great noise of bells and whistles drowned our voices, and, amid the
whirring of switch-bells, the hissing of steam, and the cries of
'Paris! All out!' our train glided into the station.

"It was the professor who opened the door of our carriage. There he
stood, calmly adjusting his yellow night-cap and drawing his
dressing-gown closer with the corded tassels.

"'Where have you been?' I asked.

"'On the engine.' "'In the engine, I suppose you mean,' I said.

"'No, I don't; I mean on the engine--on the pilot. It was very
refreshing. Where are we going now?'

"'Do you know Paris?' asked Wilhelmina, turning to me.

"'Yes. I think your father had better take you to the Hôtel Normandie
on the Rue de l'Échelle--' "'But you must stay there, too!'

"'Of course--if you wish--''

She laughed nervously.

"Don't you see that my father and I could not take rooms--now? You
must engage three rooms for yourself.' "'Why?' I asked, stupidly.