in at half
speed. The air-ship stopped within three miles, and remained
suspended in air over the opening mouth of the Neva. Then the two
after guns were trained upon the fortress, and Colston and Arnold
fired them together.

The two shells struck at the same moment, one in each of two angles
of the ramparts. Their impact was followed by a tremendous explosion,
far greater than could be accounted for by the shells themselves.

"There goes one, if not two, of his powder magazines. Look! half the
fortress is a wreck. I wonder which fired the lucky shot."

The man who a year before had been an inoffensive student of
mechanics and an enthusiast dreaming of an unsolved problem, spoke of
the frightful destruction of life and the havoc that he had caused by
just pressing a button with his finger, as coolly and quietly as a
veteran officer of artillery might have spoken of shelling a fort.

There were two reasons for this almost miraculous change. One was to
be found in the bitter hatred of Russian tyranny which he had imbibed
during the last six months, and the other was the fact that the woman
for whom he would have himself died a thousand deaths if necessary,
was a captive in Russian chains, being led at that moment to slavery
and degradation.

As soon as they had seen the effects of the last two shots, Arnold
said with a grim, half-smile on his lips--

"I think it will be better if we don't show ourselves too plainly to
Petersburg. It will take some time for the news of the destruction of
Kronstadt to reach the city, and, of course, there will be the
wildest rumours as to the agency by which it was done, so we may as
well leave them to argue the matter out among themselves."

He signalled again to the engine-room, and with the united aid of her
planes and fan-wheels the _Ariel_ mounted up and up into the sky,
driven only by the stern-propeller and with the force of the other
engines concentrated on the lifting wheels, until a height of five
thousand feet was reached.

At that height she would have looked, if she could have been seen at
all, nothing more than a little grey spot against the blue of the
sky, and as they heard afterwards she passed over St. Petersburg
without being noticed.

From St. Petersburg to Tiumen, as the crow flies, the distance is
1150 English miles, and nine hours after she had passed over the
Capital of the North, the _Ariel_ had winged her way over the Ourals
and the still snow-clad fore