All day the garrison and population of Irkutsk were on the alert. The measures to repel an attack on the points hitherto unassailed had been taken. The Grand Duke and General Voranzoff visited the posts, strengthened by their orders. Wassili Fedor’s corps occupied the North of the town, but with orders to throw themselves where the danger was greatest. The right bank of the Angara had been protected with the few guns possessed by the defenders. With these measures, taken in time, thanks to the advice so opportunely given by Ivan Ogareff, there was good reason to hope that the expected attack would be repulsed. In that case the Tartars, momentarily discouraged, would no doubt not make another attempt against the town for several days. Now the troops expected by the Grand Duke might arrive at any hour. The safety or the loss of Irkutsk hung only by a thread. On this day, the sun which had risen at twenty minutes to six, set at forty minutes past five, having traced its diurnal arc for eleven hours above the horizon. The twilight would struggle with the night for another two hours. Then it would be intensely dark, for the sky was cloudy, and there would be no moon. This gloom would favor the plans of Ivan Ogareff. For a few days already a sharp frost had given warning of the approaching rigor of the Siberian winter, and this evening it was especially severe. The Russians posted by the bank of the Angara, obliged to conceal their position, lighted no fires. They suffered cruelly from the low temperature. A few feet below them, the ice in large masses drifted down the current. All day these masses had been seen passing rapidly between the two banks. This had been considered by the Grand Duke and his officers as fortunate. Should the channel of the Angara continue to be thus obstructed, the passage must be impracticable. The Tartars could use neither rafts nor boats. As to their crossing the river on the ice, that was not possible. The newly-frozen plain could not bear the weight of an assaulting column. This circumstance, as it appeared favorable to the defenders of Irkutsk, Ogareff might have regretted. He did not do so, however. The traitor knew well that the Tartars would not try to pass the Angara, and that, on its side at least, their attempt was only a feint. About ten in the evening, the state of the river sensibly improved, to the great surprise of the besieged and still more to their disadvantage. The passage till then impracticable, became all at once possible. The bed of the Angara was clear. The blocks of ice, which had for some days drifted past in large numbers, disappeared down the current, and five or six only now occupied the space between the banks. The Russian officers reported this change in the river to the Grand Duke. They suggested that it was probably caused by the circumstance that in some narrower part of the Angara, the blocks had accumulated so as to form a barrier.