of
Nature in her own secret and solitary places.

She would have faced a levelled rifle without flinching, but as she
looked at that frowning mass of rocks towering up into the sky, and
then down into the fearful depths below, where huge trees looked like
tiny shrubs, and vast forests like black patches of heather on the
earth, her heart stood still in her breast when she thought of the
frightful fate that would overwhelm the _Ariel_ and her crew should
she fail to rise high enough to clear the ridge, or if anything went
wrong with her machinery at the critical moment.

"Are you sure you can do it?" she asked almost involuntarily.

"Perfectly sure," replied Arnold quietly, "otherwise I should not
attempt it with you on board. The _Ariel_ contains enough explosives
to reduce her and us to dust and ashes, and if we hit that ridge
going over, she would go off like a dynamite shell. No, I know what
she can do, and you need not have the slightest fear!"

"I am not exactly afraid, but it _looks_ a fearful thing to attempt."

"If there were any danger I should tell you--with my usual lack of
dissimulation. But really there is none, and all you have to do is to
hold tight when I tell you, and keep your eyes open for the first
glimpse of Aeria."

By this time the _Ariel_ was more than ten miles away from the
mountains. Arnold, having now got offing enough, swung her round
again, headed her straight for the ridge between the two peaks, and
signalled "full speed" to the engine-room.

In an instant the propellers redoubled their revolutions, and the
_Ariel_ gathered way until the wind sang and screamed past her masts
and stays. She covered eight miles in less than four minutes, and it
seemed to Natasha as though the rock-wall were rushing towards them
at an appalling speed, still frowning down a thousand feet above
them. For the instant she was all eyes. She could neither open her
lips nor move a limb for sheer, irresistible, physical terror. Then
she heard Arnold say sharply--

"Now, hold on tight!"

The nearest thing to her was his own arm, the hand of which grasped
one of the spokes of the steering wheel. Instinctively she passed her
own arm under it, and then clasped it with both her hands. As she did
so she felt the muscles tighten and harden. Then with his other hand
he pulled the lever back to the full, and inclined the planes to
their utmost.

Suddenly, as though some Titan had overthrown it, the huge black wal