miled as he said:

"Oh, I feel very well, sir."

He need not have spoken, for the mountain air had worked wonders.
Nature was proving the best doctor, and the enforced stay in that clear
pure air, with the incessant exercise, had completely changed the lad.

CHAPTER FORTY FOUR.

THE EVASION.

Three months had passed away, and though the hopes of the prisoners had
been raised several times by the commencement of a thaw, this had been
succeeded again and again by heavy falls of snow, and by repeated frosts
which bound them more closely in the stronghold.

But at last the weather completely changed. The wind came one day
cloud-laden, and with a peculiar sensation of warmth. Thick mists hid
the mountain tops, and filled up the valleys, and a few hours later the
professor and his companions had to make a rush for the shelter of the
great hall that was their prison, for a terrific downpour commenced, and
for the next fortnight continued almost incessantly.

The change that took place was astounding; the mountain sides seemed to
be covered with rills, which rapidly grew, as they met, into mountain
torrents, which swirled and foamed and cut their way through the dense
masses of snow, till they were undermined and fell with loud reports;
every now and then the loosened snow high up began to slide, and
gathered force till it rushed down as a mighty avalanche, which crashed
and thundered on its course, bearing with it rock and tree, and quite
scraping bare places that had been covered with forest growth.

At first the prisoners started up in alarm as they heard some terrible
rush, but where they were placed was out of danger; and by degrees they
grew used to the racing down of avalanche, and the roar of the leaping
and bounding torrents, and sat talking to Yussuf all through that wet
and comfortless time about the probabilities of their soon being able to
escape.

"The snow is going fast," he said; "but for many days the mountain
tracks will be impassable. We must wait till the torrents have
subsided: we can do nothing till then."

Nearly four months had passed, since they had met the brigands first,
before Yussuf announced that he thought they might venture to make a new
attempt. The snow had pretty well gone, and the guards were returning
to their stations at the great gate. There was an unwonted hum in the
settlement, and when the chief came he seemed to take more interest in
his prisoners, as if they were