Feb.y 26th 1863.
Admiral,
I have changed the signal to the following. One rocket will denote the presence, in sight, of a rebel boat; two guns the presence of more than one. The same signals with the addition of a single gun that they are passing up stream above Warrenton and rapid firing that they are passing the batteries. Three rockets will indicate that rebel boats have turned back and followed by a single gun afterwards that. they have come to anchor below. Entire silence after three rockets will indicate that they have passed out of sight.
Very respectfully
U. S. GRANT
Maj. Gen.