a Cremona violin--a genuine
Stradivarius.

The moment Nils touched the strings with the bow, a thrill of rapture
went through him, the like of which he had never experienced. The divine
sweetness and purity of the tone that vibrated through those magic
chambers resounded through all his being, and made him feel happy and
exalted.

It occurred to him, while he was coaxing the intoxicating music from his
instrument, that tonight would be midsummer night. Now was his chance to
catch the Nixy's strain, for this exquisite violin would be capable of
rendering the very chant of the archangels in the morning of time.

To-night he would surprise the Nixy, and the divine strain should no
more drift like a melodious mist through his brain; for at midsummer
night the Nixy always plays the loudest, and then, if ever, is the time
to learn what he felt must be the highest secret of the musical art.

Hugging his Stradivarius close to his breast, to protect it from the
damp night-air, Nils hurried through the birch woods down to the river.
The moon was sailing calmly through a fleecy film of cloud, and a light
mist hovered over the tops of the forest.

The fiery afterglow of the sunset still lingered in the air, though the
sun had long been hidden, but the shadows of the trees were gaunt and
dark, as in the light of the moon.

The sound of the cataract stole with a whispering rush through the
underbrush, for the water was low at midsummer, and a good deal of it
was diverted to the mill, which was working busily away, with its big
water-wheel going round and round.

Nils paused close to the mill, and peered intently into the rushing
current; but nothing appeared. Then he stole down to the river-bank,
where he seated himself on a big stone, barely out of reach of the
spray, which blew in gusts from the cataract. He sat for a long while
motionless, gazing with rapt intentness at the struggling, foaming
rapids, but he saw or heard nothing.

Then all of a sudden it seemed to him that the air began to vibrate
faintly with a vague, captivating rhythm. Nils could hear his heart
beat in his throat. With trembling eagerness he unwrapped the violin and
raised it to his chin.

Now, surely, there was a note. It belonged on the A string. No, not
there. On the E string, perhaps. But no, not there, either.

Look! What is that?

A flash, surely, through the water of a beautiful naked arm.

And there--no, not there--but somewhere from out