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 Hotel Normandie
on the Rue de l'Echelle--'

"'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.

"'Oh, dear--why, because we are invisible.'

"I tried to repress a shudder. The professor gave Wilhelmina his arm,
and, as I studied his ensemble, I thanked Heaven that he was
invisible.

"At the gate of the station I hailed a four-seated cab, and we rattled
away through the stony streets, brilliant with gas-jets, and in a few
moments rolled smoothly across the Avenue de l'Opera, turned into the
Rue de l'Echelle, and stopped. A bright little page, all over buttons,
came out, took my luggage, and preceded us into the hallway.

"I, with Wilhelmina on my arm and the professor shuffling along beside
me, walked over to the desk.

"'Room?' said the clerk. 'We have a very desirable room on the second,
fronting the Rue St. Honore--'

"'But we--that is, I want three rooms--three separate rooms!' I said.

"The clerk scratched his chin. 'Monsieur is expecting friends?'

"'Say yes,' whispered Wilhelmina, with a suspicion of laughter in her
voice.

"'Yes,' I repeated, feebly.

"'Gentlemen, of course?' said the clerk, looking at me narrowly.

"'One lady.'

"'Married, of course?'

"'What's that to you?' I said, sharply. 'What do you mean by speaking
to us--'

"'Us!'

"'I mean to me,' I said, badly rattled; 'give me the rooms and let me
get to bed, will you?'

"'Monsieur will remember,' said the clerk, coldly, 'that this is an
old and respectable hotel.'

"'I know it,' I said, smothering my rage.

"The clerk eyed me suspiciously.

"'Front!' he called, with irritating deliberation. 'Show this
gentleman to apartment ten.'

"'How many rooms are there!' I demanded.

"'Three sleeping-ro