Ogareff, motionless near the window, and invisible in the shade did not answer. The Grand Duke was therefore informed that the Czar's courier was not at that moment in the palace.

Two o'clock struck. Now was the time to cause the diversion agreed upon with the Tartars, waiting for the assault. Ivan Ogareff opened the window and stationed himself at the North angle of the side terrace.

Below him flowed the roaring waters of the Angara. Ogareff took a match from his pocket, struck it and lighted a small bunch of tow, impregnated with priming powder, which he threw into the river.

It was by the orders of Ivan Ogareff that the torrents of mineral oil had been thrown on the surface of the Angara! There are numerous naphtha springs above Irkutsk, on the right bank, between the suburb of Poshkavsk and the town. Ogareff had resolved to employ this terrible means to carry fire into Irkutsk. He therefore took possession of the immense reservoirs which contained the combustible liquid. It was only necessary to demolish a piece of wall in order to allow it to flow out in a vast stream.

This had been done that night, a few hours previously, and this was the reason that the raft which carried the true Courier of the Czar, Nadia, and the fugitives, floated on a current of mineral oil. Through the breaches in these reservoirs of enormous dimensions rushed the naphtha in torrents, and, following the inclination of the ground, it spread over the surface of the river, where its density allowed it to float. This was the way Ivan Ogareff carried on warfare! Allied with Tartars, he acted like a Tartar, and against his own countrymen!

The tow had been thrown on the waters of the Angara. In an instant, with electrical rapidity, as if the current had been of alcohol, the whole river was in a blaze above and below the town. Columns of blue flames ran between the two banks. Volumes of vapor curled up above. The few pieces of ice which still drifted were seized by the burning liquid, and melted like wax on the top of a furnace, the evaporated water escaping in shrill hisses.

At the same moment, firing broke out on the North and South of the town. The enemy's batteries discharged their guns at random. Several thousand Tartars rushed to the assault of the earth-works. The houses on the bank, built of wood, took fire in every direction. A bright light dissipated the darkness of the night.

"At last!" said Ivan Ogareff.

He had good reason for congratulating himself. The diversion which he had planned was terrible. The defenders of Irkutsk found themselves between the attack of the Tartars and the fearful effects of fire. The bells rang, and all the able-bodied of the population ran, some towards the points attacked, and others towards the houses in the grasp of the flames, which it seemed too probable would ere long envelop the whole town.

The Gate of Bolchaia was nearly free. Only a very small guard had been left there. And by the traitor's suggestion, and in order that the event might be explained apart from him, as if by political hate, this small guard had been chosen from the little band of exiles.

Ogareff re-entered his room, now brilliantly lighted by the flames from the Angara; then he made ready to go out. But scarcely had he opened the door, when a woman rushed into the room, her clothes drenched, her hair in disorder.

"Sangarre!" exclaimed Ogareff, in the first moment of surprise, and not supposing that it could be any other woman than the gypsy.

It was not Sangarre; it was Nadia!

At the moment when, floating on the ice, the girl had uttered a cry on seeing the fire spreading along the current, Michael had seized her in his arms, and plunged with her into the river itself to seek a refuge in its depths from the flames. The block which bore them was not thirty fathoms from the first quay of Irkutsk.

Swimming beneath the water, Michael managed to get a footing with Nadia on the quay. Michael Strogoff had reached his journey's end! He was in Irkutsk!

"To the governor's palace!" said he to Nadia.