when sudden caving began at several points, and thereby so arrested the excavation remaining to be made that the rapidly falling river had in the next left the bottom of the cut-off some feet above the river's level. Thus I am chagrined to report that after the great labor of an average excavation of 18 feet in width and 13 feet deep, we have encountered at least a temporary failure. My purpose now is (if not interrupted by the enemy) to collect an additional force of blacks, shovels, axes, carts, wheelbarrows, scrapers, &c. to my present force of 1,500 blacks, with nearly as many shovels and axes, few wheelbarrows, no scrapers, and no carts, and make a real canal, carrying it, if necessary, to the depth of the greatest fall of the river at this point, say some 35 to 40 feet; a labor which, with sufficient force-that is, with as much force as can be profitably worked-will take three months.
A sketch and estimate is inclosed, showing the work contemplated; but the present cut-off (if reports be true of the landing of rebel forces below us, opposite Grand Gulf) may not be without its uses as a temporary line of defense, and it is therefore now being made available for that purpose. I would remark that as the water of the river falls below its banks the gunboats become less and (daily) of a protection practically; therefore my own field guns must ere long furnish my only direct or flank artillery defense. Morally, however, in any case the Navy are a great support.
The health of the troops has been much impaired by the absence of proper shelter. The quarters on board the transports are hot and crowded and those on shore are no protection against rain. Tents or boards are indispensable for shelter for the well and the sick-a rapidly increasing list. The large force of negroes also require shelter. Store-tents are required. My brigade quartermaster inclose an estimate to-day for lumber, store-tents for men.
These subjects, all of urgent interest are enhanced if it were possible, by the presence under the guns of Vicksburg and in view of our two fleets of the rebel ram (iron-clad) Arkansas. I inclose a sketch* of her. Hearing she was near completion up the Yazoo, Commodores Farragut and Davis sent two gunboats (one an iron-clad) and one of Colonel Ellet's rams, in the morning of July 14, at 5 o'clock, to reconnoiter and ascertain what other naval and co-operating land force would suffice for her capture or destruction and the destruction or capture of the land batteries and the land force protecting her. To accompany the reconnaissance as sharpshooters I furnished two parties, of an officer and 20 men each-Captain J. W. Lynn and 20 Wisconsin, men and Lieutenant A. E. Fiske and 20 Massachusetts men.
In the encounter about to be reported I regret to announce the death of Captain Lynn and 5 of his men and the wounding of 5 other men-all by the exploding of one of the enemy's shells.
The reconnaissance had proceeded on its way to within about a mile of the mouth of the Yazoo (see sketch*) when it encountered, at 6 o'clock in the morning, the rebel ram steaming down, and at once engaged her, our gunboat (Tyler) in the lead firing first, followed by the ram Queen of the West and the iron-clad gunboat Carondelet. The Tyler, Queen of the West, and Carondelet all engaged, joining the rebel ram as she passed and coming down with her; but the Queen of the West, they say, fired but failed to ram, though signaled to ram, while our iron-clad (Carondelet) lay side by side with the rebel ram some 5 miles exchanging broadsides, when some sudden break in steer-