At half-past six, the preconcerted signal of three shells went up, one after another, from a French battery, and the next instant the whole Allied batteries opened simultaneously. On the side of the British, seventy-three, and of the French, fifty-three, in all one hundred and twenty-six guns, one-half of which were of the very heaviest calibre, launched their thunders on the side of the Allies; while upwards of two hundred replied in one deafening roar from the Russian lines. Two long lines of belching flame and smoke appeared, and through the space between hurtled a shower of shot and shell, while the earth shook with the thunders of the deadly volleys. Distinctly amidst the din could be heard the immense Lancaster guns, which here, for the first time, gave evidence of their tremendous powers. Their sharp report, heard among the other heavy guns, was like the crack of a rifle among muskets. But the most singular thing was the sound of their ball, which rushed through the air with the noise and regular beat precisely like the passage of a rapid railway train at close distance--a peculiarity which, at first, excited shouts of laughter from the men, who nicknamed it the express-train. The effect of the shot was terrific; from its deafening and peculiar noise, the ball could be distinctly traced by the ear to the spot where it struck, when stone or earth were seen to go down before it. The first few minutes’ firing sufficed to show to each side, what neither had as yet accurately known, the actual strength of its opponents; and it now appeared, that even in the extent of the earthwork batteries thrown up since the siege began, the Russians immensely surpassed their besiegers. Besides their stone forts, and a long line of intrenchments, guns of heavy calibre had been planted on every ridge and height; and as fresh batteries were unmasked one after another, often in places totally unexpected, the Allied generals were completely taken by surprise at the magnitude of the defences. Opposite to the French lines, the main strength of the Russians lay in the Flag-staff batteries, erected upon a hill commanding the French works. They consisted of two tiers of intrenchments, each mounting about twenty-five guns, the upper of which tier of cannon was unknown to the besiegers until it opened fire; with several large mortars placed on the summit of the hill. And on the extreme right of the Russian lines was a ten-gun battery, most commandingly placed, so as to enfilade the French lines. In this quarter the Russians had not only a great advantage in point of position, but also their guns outnumbered those of the French, and it soon became evident that the French were fighting at a disadvantage, and were dreadfully galled in flank by the ten-gun battery.