'The polka. Young people, who always dance, are ecstatic about it,
and old people, who have not danced for years, have begun to dance
again, on its account. All share the excitement. It arrived in
London only some few months ago--it is now all over the country. Now
this is your opportunity, my good Margery. To learn this one dance
will be enough. They will dance scarce anything else at that ball.
While, to crown all, it is the easiest dance in the world, and as I
know it quite well I can practise you in the step. Suppose we try?'

Margery showed some hesitation before crossing the stile: it was a
Rubicon in more ways than one. But the curious reverence which was
stealing over her for all that this stranger said and did was too
much for prudence. She crossed the stile.

Withdrawing with her to a nook where two high hedges met, and where
the grass was elastic and dry, he lightly rested his arm on her
waist, and practised with her the new step of fascination. Instead
of music he whispered numbers, and she, as may be supposed, showed no
slight aptness in following his instructions. Thus they moved round
together, the moon-shadows from the twigs racing over their forms as
they turned.

The interview lasted about half an hour. Then he somewhat abruptly
handed her over the stile and stood looking at her from the other
side.

'Well,' he murmured, 'what has come to pass is strange! My whole
business after this will be to recover my right mind!'