twelve
o'clock
Before this force was in motion a reply came back from General le Gallifet to the effect that all communication with the south and east was stopped , and that an aerostat , which had been on scout duty during the night , had returned with the news that the whole country appeared to be up in arms from Portsmouth to Dover . Corps of observation and a fleet of thirty aerostats had been sent out , and three army corps were already on the march to the south and east . Meanwhile , the hour for the surrender of London was drawing very near , and all the while the bells were sending their mingled melody of peals and carillons up into the clear frosty air with a defiant joyousness that seemed to speak of anything but surrender . As twelve o'clock approached the guns of all the batteries on the heights were loaded and trained on different parts of the city , and the whole of the forces left after the detachment of the armies that had been sent to engage the battalions of the Federation prepared to descend upon the devoted city from all sides after the two hours ' incessant bombardment that had been ordered to precede the general attack . It had been arranged that if the city surrendered a white flag was to be hoisted on the cross of St. Paul 's . Within a few minutes of twelve the Tsar ascended to the roof of the Alexandra Palace on Muswell Hill , and turned his field-glasses on the towering dome . His face and lips were bloodless with repressed but intense anxiety , but the hands that held his glasses to his eyes were as steady as though he had been watching a review of his own troops .