Statistics for occurrence #1 of “Fort Donelson” in chapter 15 of Admiral David D. Porter, The Naval History of the Civil War.:
...o the enemy.
General Grant, being under the impression at least that Foote's flotilla could not assist him immediately, instructed Commander Walke to proceed without delay to commence the attack on Fort Donelson in connection with our Army before the enemy could receive re-enforcements or could strengthen his position.
The following is the letter referred to, preceding the battle of Fort Donelson.
† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.