parapet and exploded with a time fuse of FIFTEEN SECOND. The effect of the explosion was very severe, and fragments of sap-rollers, gabions and pieces of timber were thrown into the air, and, I think, some of the enemy's sappers must have been burned and smothered. They continued their operations,, however, and established another line on July mous, as the crater made was at least 20 deep, 30 feet across in one direction and 50 in another. The earth up heaved was thrown many yards around, but little of it falling back into the crater. I learned from the enemy's engineer that they had 1,500 pounds powder in this mine. The original faces of the redan were almost completely destroyed, and the work, making in it almost a practicable breach for an assault. No repair damages as well as possible.

Lieutenant P. J. Blessing, who had been in charge of this work, was wounded during the day, and I directed Lieutenant [W. O] Flyn to report to Captain [D]. Wintter to take his place.

In addition to Lieutenant Blessing, wounded on this day, private Owen, and 7 negroes engaged in sinking a shaft were killed by the enemy's explosion.

Captain Winter with Lieutenant Flynn and Sergeants Ryan and McGinnis and Private St. Vigne, of Captain Winter's company, worked during the afternoon and night succeeding the explosion with an energy zeal, and coolness, under a most terrific fire, worthy of all praise, and by daylight the next morning the breach was filled and the redan still tenable.

To give some idea of the difficulties attending this work, I will state that the enemy had two 9-inch Dahlgrens, several heavy Parrotts and field pieces, and a Cohorn mortar playing upon this redan, in addition to as heavy a fire of musketry as I ever witnessed, to be so long continued. In the course of one hour that I remained in the work at least a dozen o its garrison were killed or wounded by the mortar alone. On the same night one of the enemy's sap-rollers on the right of the Jackson road was burned and the sappers driven off by hand-grenades.

On the night of the 2nd, captain Robinson exploded one of his mines in front of the railroad redoubt, but with little effect, the explosion being premature. On this night we had prepared the following mines, viz; One in front of work on Hall's Ferry road; two in front of Fort Green's left and three on General Shoups' line all of which would have been ready for the enemy by the time he came within the limits of their effects. These mines contained between 6 and 9 feet under the surface of the earth. The flag of truce however, on the 3rd, stopped all operations on both sides, and the efficiency of our preparations were not tested.

The following is a list of casualties among the engineer and my working force; Wounded severely, first Lieutenant E. McMahon, company sappers and miners; Acting Lieutenant Blessing, assistant engineer, William R. Goeble, clerk to Captain Winer. Killed, sergeant Cole, company sappers and miners, private J. Hardy and Private OWEN. Eight negroes wounded, 9 killed.

In concluding this report, I beg leave to call the attention of the lieutenant-general commanding to the fact that no one was called upon to perform more arduous and continuously duty than the engineer officers and