At this signal all the enemy's batteries opened in succession, and for a space a storm of shot and shell tore through Sickles' lines with crushing effect. His own guns, posted partly in the orchard, partly along the cross-road, on the high knoll behind it,--that is to say, in the very spot selected by Lee in advance for his own,--began to lose both horses and men, nor were the infantry able to shelter themselves from the cross-fire of fifty-four pieces of artillery, some of which were killing men at both sides of the angle with the same shot.[63] Not many minutes had elapsed before every man on the ground, from general to private soldier, felt that a wretched blunder had been committed in thrusting them out there. [Illustration: Explanation--R., Round Top; L. R. T., Little Round Top; D., Devil's Den; P. O., Peach Orchard; P. H., Power's Hill; G., Gettysburg.] [Sidenote: See his Troops described, p. 26.] By and by the cannonade slackened. This was sufficient notice to old soldiers that something more was coming. Before its echoes had died away Longstreet's first assaulting column, led by Hood himself, came down with a crash upon Birney, three lines deep. The enemy was about to repeat his old tactics, employed at Chancellorsville with so much effect, of getting around the Union left and then rolling it up endwise.[64] That his calculations in this case were not quite accurate was soon made manifest. Since noon Longstreet had been working his way round through the woods toward Little Round Top, making a wide circuit to avoid discovery.[65] Having remonstrated in vain against this movement, he was probably in no great hurry to execute it. It was therefore four o'clock before he was ready to begin. But if slow he was sure. Longstreet's line crossed the Emmettsburg road at an acute angle with it, Hood's division stretching off to the right, McLaws' mostly to the left. Longstreet was thus about to throw eight brigades, or, by his own account, thirteen thousand men, against the three brigades of Ward, De Trobriand, and Graham, numbering about five thousand men. Hood was to begin by attacking from the wheat-field to the Devil's Den, McLaws to follow him up from the wheat-field to the orchard. It was not until they had got into line, however, that the Confederates were undeceived about the Union force before them. Until then they thought the Union left stopped at the orchard. At four o'clock the Union signal-station on Little Round Top saw and reported these movements to headquarters. The Confederate advance began soon after four. By the first fire Hood was wounded and had to leave the field almost before his troops had fairly come into action. [Sidenote: Combat at Devil's Den.]