f telegram to Banks:

"I am concentrating my forces at Grand Gulf; will send an army
corps Bayou Sara by the 25th, to co-operate with you on Port Hudson.
Can you aid me and send troops after the reduction of Port Hudson
to assist me at Vicksburg?"

This message, although Banks and Grant were then only about two
hundred miles apart, had to travel three thousand miles to reach
its destination. Banks received it just before marching from
Opelousas on the 5th of May, twenty-one days after it left Grant's
hands. As received, the message was in cipher and without a date.
As the prevailing practice was, in conformity with the orders of
the Secretary of War, the only persons in the Department of the
Gulf who held the key to the cipher were the Superintendent of
Military Telegraphs and such of his assistants as he chose to trust,
and Mr. Bulkley was at New Iberia, where the wires ended. The code
employed was the route cipher in common use in the service, and
with the help of the words "Bayou" and "Sara" as guides the meaning
was not hard to make out. Banks did not trust to this, however,
and waited until, late at night, he received from the Superintendent
an official translation, still without date, as indeed was the
original document received at headquarters from New Orleans. The
25th Banks naturally took to mean the 25th of May. Grasping eagerly
at the first real chance of effective co-operation, he at once
replied: "By the 25th probably, by the 1st, certainly, I will be
there." This despatch was not in cipher, because he had no code.
Captain Crosby carried it to the _Hartford_ at the mouth of Red
River. Captain Palmer, who was found in command, the Admiral having
crossed Fausse Point and joined his fleet below, at once forwarded
the despatch. Near Natchez Crosby met Captain Uffers of Grant's
staff and turned back with him bringing Grant's despatch of the
10th of May, written at Rocky Springs. This Banks received at
Alexandria on the 12th of May. From it he learned that Grant was
not coming. Having met the Confederates after landing at Grand
Gulf and followed on their heels to the Big Black, he could not
afford to retrace his steps; but he urged Banks to join him or to
send all the force he could spare "to co-operate in the great
struggle for opening the Mississippi River." The reasons thus
assigned by Grant for his change of mind were certainly valid; yet
it must be doubted whether in these hurried lines the