But the river might be crossed both above and below the town, and consequently, Irkutsk ran a risk of being attacked on its east side, on which there was no wall to protect it.
The whole population were immediately set to work on the fortifications. They labored day and night. The Grand Duke observed with satisfaction the zeal exhibited by the people in the work, whom ere long he would find equally courageous in the defense. Soldiers, merchants, exiles, peasants, all devoted themselves to the common safety. A week before the Tartars appeared on the Angara, earth-works had been raised. A fosse, flooded by the waters of the Angara, was dug between the scarp and counterscarp. The town could not now be taken by a coup de main. It must be invested and besieged.
The third Tartar column--the one which came up the valley of the Yenisei on the 24th of September--appeared in sight of Irkutsk. It immediately occupied the deserted suburbs, every building in which had been destroyed so as not to impede the fire of the Grand Duke's guns, unfortunately but few in number and of small caliber. The Tartar troops as they arrived organized a camp on the bank of the Angara, whilst waiting the arrival of the two other columns, commanded by the Emir and his allies.
The junction of these different bodies was effected on the 25th of September, in the Angara camp, and the whole of the invading army, except the garrisons left in the principal conquered towns, was concentrated under the command of Feofar-Khan.
The passage of the Angara in front of Irkutsk having been regarded by Ogareff as impracticable, a strong body of troops crossed, several versts up the river, by means of bridges formed with boats. The Grand Duke did not attempt to oppose the enemy in their passage. He could only impede, not prevent it, having no field-artillery at his disposal, and he therefore remained in Irkutsk.
The Tartars now occupied the right bank of the river; then, advancing towards the town, they burnt, in passing, the summer-house of the governor-general, and at last having entirely invested Irkutsk, took up their positions for the siege.
Ivan Ogareff, who was a clever engineer, was perfectly competent to direct a regular siege; but he did not possess the materials for operating rapidly. He was disappointed too in the chief object of all his efforts--the surprise of Irkutsk. Things had not turned out as he hoped. First, the march of the Tartar army was delayed by the battle of Tomsk; and secondly, the preparations for the defense were made far more rapidly than he had supposed possible; these two things had balked his plans. He was now under the necessity of instituting a regular siege of the town.
However, by his suggestion, the Emir twice attempted the capture of the place, at the cost of a large sacrifice of men. He threw soldiers on the earth-works which presented any weak point; but these two assaults were repulsed with the greatest courage. The Grand Duke and his officers did not spare themselves on this occasion. They appeared in person; they led the civil population to the ramparts. Citizens and peasants both did their duty.
At the second attack, the Tartars managed to force one of the gates. A fight took place at the head of Bolchaia Street, two versts long, on the banks of the Angara. But the Cossacks, the police, the citizens, united in so fierce a resistance that the Tartars were driven out.
Ivan Ogareff then thought of obtaining by stratagem what he could not gain by force. We have said that his plan was to penetrate into the town, make his way to the Grand Duke, gain his confidence, and, when the time came, give up the gates to the besiegers; and, that done, wreak his vengeance on the brother of the Czar. The Tsigane Sangarre, who had accompanied him to the Angara, urged him to put this plan in execution.
Indeed, it was necessary to act without delay. The Russian troops from the government of Yakutsk were advancing towards Irkutsk. They had concentrated along the upper course of the Lena.