WALNUT HILLS, VICKSBURG, May 29, 1863.
My Dear Brother:
I received a few days since your most acceptable letter of May 7th, which met me here. You will now have a fine understanding of the whole move thus far. The move by way of Grand Gulf to secure a foothold on the hills wherefrom to assail Vicksburg, appeared to me too risky at the time, and General Grant is entitled to all the merit of its conception and execution.
In our route we consumed the fruits of the country, broke up the important railroad communications, whipped the enemy wherever encountered, and secured the Yazoo as a base, the object for which we have contended so long and so patiently. . . .
We have Vicksburg closely invested, and its fate is sealed unless the enemy raises a large force from Carolina and Tennessee and assails us from without. In that event we must catch them at the crossing of Black, and fight them desperately.
The place is very well fortified, and is defended by twenty thousand brave troops. We have assaulted at five distinct points at two distinct times, and failed to cross the parapet. Our loss was heavy and we are now approaching with pick and shovel. If we did not apprehend an attempt on our rear, we could wait patiently the slow process of besiegers; but as this danger is great, we may try and assault again. In the mean time we are daily pouring into the city a perfect storm of shot and shells, and our sharp-shooters are close up and fire at any head that is rash enough to show itself above ground.
SOURCE: Rachel Sherman Thorndike, Editor, The Sherman letters: correspondence between General and Senator Sherman from 1837 to 1891, p. 205-6