arranged signal to the others to do the same, and by the time they
had overtaken the flagship they also came to a standstill. As soon as
they were within speaking distance Arnold hailed the _Orion_ and the
_Ariel_ to come alongside.

After communicating to Tremayne and Mazanoff the orders of Natas, he
said to the latter--

"You will take Professor Volnow to present the Tsar's letter to the
Admiral in command of the fleet. Fly the Russian flag over a flag of
truce, and if he acknowledges it say that if the _Lucifer_ is given
up we shall allow the fleet to go on its way unmolested and without
asking any question.

"The cruiser that has her on board must separate from the rest of the
fleet and allow two of your men to take possession of her and bring
her up here. The lives of the four traitors are safe for the present
if the air-ship is given up quietly."

"And if they will not recognise the authority of the Tsar's letter,
and refuse to give the air-ship up, what then?" asked Mazanoff.

"In that case haul down the Russian flag, and get aloft as quickly as
you can. You can leave the rest to us," said Arnold. "Meanwhile,
Tremayne, will you go down to two thousand feet or so, and keep your
eye on that big cruiser a bit ahead of the rest of the fleet. I fancy
I can make out the _Lucifer_ on her deck. Train a couple of guns on
her, and don't let the air-ship rise without orders. I shall stop up
here for the present, and be ready to make things lively for the
Admiral if he refuses to obey his master's orders."

The _Ariel_ took the Professor on board, and hoisted the Russian
colours over the flag of truce, and began to sink down towards the
fleet. As she descended, the Admiral in command of the squadron,
already not a little puzzled by the appearance of the three
air-ships, was still more mystified by seeing the Russian ensign
flying from her flagstaff.

Was this only a ruse of the Terrorists, or were they flying the
Russian flag for a legitimate reason? As he knew from the experience
of the previous night that the air-ships, if their intentions were
hostile, could destroy his fleet in detail without troubling to
parley with him, he concluded that there was a good reason for the
flag of truce, and so he ordered one to be flown from his own
masthead in answer to it.

The white flag at once enabled Mazanoff to single out the huge
battleship on which it was flying as the Admiral's flagship. The
fleet was proceeding in fo