While there, he learned that the Confederate force occupying Columbus had evacuated the town and fortified themselves on Island No. 10. They numbered about 8,000 and were under the command of General Mackall, from Beauregard's army. Foote transferred his flag to the ironclad _Benton_ and advanced against the powerful works that had been erected on the island. The bombardment was continued for three weeks, without inflicting serious damage, and there was little prospect of capturing the place from the river, when General Pope arrived with a large land force; but to reach the fort it was necessary for him to get his troops across the river, and he had not a single transport to use for that purpose. Pope's arrival below made it necessary to send a gunboat down to him, for until that was done he could make no movement against the rebel force there. The all-important question was whether any one of the gunboats could run the terrific gauntlet of the batteries that lined the shore. It looked as if the attempt must result in the inevitable destruction of any craft before half the distance could be accomplished. At a council of the officers it was agreed that it was too hazardous to try to run one of the gunboats past the batteries. Such was the opinion of every man except Henry Walke, commander of the _Carondelet_, who volunteered to try the seemingly impossible task. Captain Foote reluctantly gave his consent. It was understood that Walke was to make the attempt on the first rainy or foggy night. In the event of success, he was to cooperate with Pope, and, when he moved, to assist in the attack on the fortifications. Captain Foote closed his instructions to his faithful aide with the following impressive words: On this delicate and somewhat hazardous service to which I assign you I must enjoin upon you the importance of keeping your lights secreted in the hold or put out, keeping your officers and men from speaking at all, when passing the forts, above a whisper, and then only on duty, and of using every other precaution to prevent the rebels suspecting that you are dropping below their batteries. If you successfully perform this duty assigned to you, which you so willingly undertake, it will reflect the highest credit upon you and all belonging to your vessel, and I doubt not but that the government will fully appreciate and reward you for a service which, I trust, will enable the army to cross the river and make a successful attack in the rear, while we storm the batteries in front of this stronghold of the rebels. Commending you and all who compose your command to the care and protection of God, who rules the world and directs all things, I am, respectfully, your obedient servant, A.H. Foote.