Rejoining his regiment at Gloucester Point, Va., he was in Gen. Butler's expedition up the James River, towards Drewry's Bluff. Early in June, while the Army of the James was shut in the peninsula at Bermuda Hundred, Gen. Butler called for a volunteer scout--or quasi spy--to venture within the enemy's lines, and bring back information of his position and numbers. This call found a ready response in Manning's heart, and he volunteered for the undertaking. He found, as he said in writing to his home of his determination, peculiar satisfaction in the thought that he could now be of real service to the cause he loved. On the vedette-post, in the rifle-pit, or on the battle-line, he must stand or fall as one man, doing only what any lad might compass; but in this new mission, all his nervous energy and cautious shrewdness and consecrated purpose would tell in an effort worthy of a soldier, whether that effort brought success or failure. As expressive of his feelings, he enclosed to his friends the following lines he had clipped from some paper:-- "We must forget all feelings save the _one_; We must resign all passions save our purpose; We must behold no object save OUR COUNTRY, And only look on death as beautiful, So that the sacrifice ascend to heaven And draw down freedom on her evermore." It requires not a little moral courage and true nerve to deliberately leave one's military lines in the face of the enemy, and pass over into the encircling forces of the foe. But Henry Manning had counted the cost of his undertaking; and late on the evening of June 7, 1864, he glided stealthily down the steep right bank of the river James, and along the water's edge in the shade of the heavy foliage, until he had passed the rebel picket in front of the famous "Howlett Battery;" then cautiously, and with bated breath, he crept up the bank, and was within the enemy's intrenchments. Bayonets glistened, lights flashed, voices hummed about him: he was everywhere surrounded by sights and sounds of life, but he saw never a friendly look, heard never a friendly note. "He hears the rustling flag, And the armed sentry's tramp; And the starlight and moonlight His silent wanderings lamp. With slow tread and still tread, He scans the tented line; And he counts the battery guns By the gaunt and shadowy pine; And his slow tread and still tread Give no warning sound."