about it. If it had
been meant for that, it would hardly have been put half-way from the
top! I can't make it out! A hole like that in any chimney must surely
interfere with the draught! I must get a ladder!"

"Let me climb on your shoulders, Mr. Grant," said Davie.

"Come then; up you go!" said Donal.

And up went Davie, and peeped into the horizontal slit.

"It looks very like a chimney," he said, turning his head and thrusting
it in sideways. "It goes right down to somewhere," he added, bringing
his head out again, "but there is something across it a little way
down--to prevent the jackdaws from tumbling in, I suppose."

"What is it?" asked Donal.

"Something like a grating," answered Davie; "--no, not a grating
exactly; it is what you might call a grating, but it seems made of
wires. I don't think it would keep a strong bird out if he wanted to
get in."

"Aha!" said Donal to himself; "what if those wires be tuned! Did you
ever see an aeolian harp, my lady?" he asked: "I never did."

"Yes," answered lady Arctura, "--once, when I was a little girl. And
now you suggest it, I think the sounds we hear are not unlike those of
an aeolian harp! The strings are all the same length, if I remember.
But I do not understand the principle. They seem all to play together,
and make the strangest, wildest harmonies, when the wind blows across
them in a particular way."

"I fancy then we have found the nest of our music-bird!" said Donal.
"The wires Davie speaks of may be the strings of an aeolian harp! I
wonder if there could be a draught across them! I must get up and see!
I must go and get a ladder!"

"But how could there be an aeolian harp up here?" said Arctura.

"It will be time enough to answer that question," replied Donal, "when
it changes to, 'How did an aeolian harp get up here?' Something is here
that wants accounting for: it may be an aeolian harp!"

"But in a chimney! The soot would spoil the strings!"

"Then perhaps it is not a chimney: is there any sign of soot about,
Davie?"

"No, sir; there is nothing but clean stone and lime."

"You see, my lady! We do not even know that it is a chimney!"

"What else can it be, standing with the rest?"

"It may have been built for one; but if it had ever been used for one,
the marks of smoke would remain, had it been disused ever so long. But
to-morrow I will bring up a ladder."

"Could you not do it now?" said Arctura, almost coaxingly. "I should so
like to