The action brought home to her with a shock that there was a letter which she, in her turn, must write, must write and post in that glass letter-box, oh, without any hesitation or error, this very evening.  She thought upon it with repugnance, but it had to be written and done with.  It was the consequence of her own folly, her own vanity.  Harry Luttrell returned to her but he did not remark the trouble in her face.

“When I left England,” he said slowly, “people were dancing the tango.  That is—­one couple which knew the dance, was dancing it in the ball-room, and all the others were practising in the passage.  That’s done with, I suppose?”

“Quite,” said Joan.

Harry Luttrell heaved a sigh.

“I should have liked to have practised with you in the passage,” he said ruefully.

“Still, there are other dances,” Joan Whitworth suggested.  “The one-step?”

“That’s going for a walk,” said Harry Luttrell.

“In an unusual attitude,” Joan added demurely.  “Do you know the fox-trot?”

“A little.”

“The twinkle step?”

“Not at all.”

“I might teach you that,” Joan suggested.

“Oh, do!  Teach it me now!  Then we’ll dance it in the passage.”

“But every one will be dancing it in the ball-room,” Joan objected.

“That’s why,” said Harry Luttrell, and they both laughed.

Joan looked towards the gramophone in the corner of the room.  She was tempted, but she must have that letter written first.  She would dance with Harry Luttrell with an uneasy mind unless that letter were written and posted first.

“Will you put a record ready on the gramophone, whilst I write a note,” she suggested.  “Then I’ll teach you.  It’s quite a short note.”

Joan sat in her turn at the writing table.  She wrote the first lines easily and quickly enough.  But she came to explanations, and of explanations she had none to offer.  She sat and framed a sentence and it would not do.  Meanwhile the gramophone was open and ready, the record fitted on to the disc of green baize and her cavalier in impatient attendance.  She must be quick.  But the quicker she wanted to be, the more slowly her thoughts moved amongst awkward sentences which she must write.  She dashed off in the end the standard phrase for such emergencies.  “I will write to you to-morrow,” addressed and stamped her letter and dropped it into the letter box.  The letter fell in the glass box with the address uppermost.  But Joan did not trouble about that, did not even notice it; a weight was off her mind.

“I am ready,” she said, and a few seconds later the music of “The Long Trail” was wafted to the astonished ears of the tennis players in the garden.  They paused in their game and then Dennis Brown crept to the window of the hall and looked cautiously in.  He stood transfixed; then turned and beckoned furiously.  The lawn-tennis players forsook their rackets, Lady Splay and Stella Croyle their croquet mallets.  Dennis Brown led them by a back way up to the head of the broad stairs.  Here a gallery ran along one side of the hall.  Voices rose up to them from the floor above the music of the gramophone.