Who did know it? Whose duty was it to know it, and whose duty was it to report the fact to General Lee? And why was it not done?
General Pickett, if he had known it, would never, under the circumstances, have demurred to the charge. He would have died first.
General Lee does not say anything about General Longstreet not advancing his two divisions. If you will observe this map, which is a copy of the one carefully prepared by the Federals since the war, showing the positions of the Federal troops, you will observe that the largest mass of Federal troops seem to have been on that day—the 3d of July—posted between my left and Pickett's right, and at the place or near it where Longstreet's two corps—Hood's and mine—would have had to have attacked, if it had been intended they should, in order to have been of service in aiding Pickett's charge.
All along from Main Round Top on to Little Round Top and to its foot and extending to their right, the enemy's lines had been fortified during the previous night and strengthened with additional troops, rendering the few places which were assailable with some chances of success on the 2d entirely unassailable with any prospect of accomplishment on the 3d. So it would have been of no use to Pickett for Hood and myself to have made a direct assault on our direct front. But we would have had to have attacked about where you see that mass of troops is lying, or was, and in attempting it we would have exposed our flanks and rear to artillery and infantry fire, besides the resistance of the tremendous force which would meet us in front. The right of Pickett and my left were by no means in close proximity. There was a gap of a half mile between—it looked so to me—and I therefore do not believe that we could have effected anything, and if we had been repulsed as Pickett was, which would not have been at all improbable under the circumstances as above stated, and the enemy had then advanced their whole line, the consequences might have been more serious than they proved to be. I therefore do not think that it was ever expected by General Lee that Hood's and my division should take part in the charge unless we had been moved round and enveloped the enemy's left; and yet without more help than we had—more co-operation—it is difficult to conceive how Pickett could have been expected to be successful against the whole Federal army.
