was necessary to depend on the pioneers already referred to for this dangerous work. The compactness of the alluvial soil making lining for mining galleris unnecessary, these galleris were formed with ease; as mines could not make an easier way into the enemy's line than existed already, their only use was to demoralize the enemy by their explosion at the moment of an assault. There were completed and several others begun during the siege. More importance was attached to them by officers and men that they deserved. The labor in the trenches was done by men of the pioneer companies of DIVISION, by details from the line, or by negroes. Several of the pioneer companies had negroes attached to them, who had come into our camps. These negroes were paid $ 10 per moth, in accordance with law, and proved to be very efficient labors when under good supervision. The labor performed by details from the line, as is usual in such cases, was very light in comparison with that done by the same number of pioneers of negroes. Without the stimulus of danger or pecuniary reward, troops of the line will not work efficiently, especially at night, after the novelty of the labor has worn off. The amount of night work done by a given detail depends very much on the discipline of the command from which it is taken and on the energy of its officers. Under average circumstances, such details do not in a given time accomplish half the work of which they are capable. The want of officers of engineers already been referred to, there being at no time more than there on engineer duty. Over a line so extended and ground so rough as that which surrounds Vicksburg, only peculiar characteristics, namely that many times, at different places, the work that should be done,, and the way it should be done, depended on officers, or even on men, without either theorical or practical knowledge of siege operations, and who had to rely upon their native god sense and ing a battery was to constructed by men who had never built one before, a sap-roler made by those who had never heard the name, or a ship's gun-carriage to be built, it was done, and, after a few trials, was well done. But, while stating the power of adaptation to circumstances and fertility of resources which our men possess in so high a degree, it must be recollected that these powers were shown at the expense of time, and while a relieving force was gathering in our rear. Officers and men had to learn to be engineers while the siege was going on. The assault, which was to have been made July 6 would probably have been successful, and in this case the siege would, have lasted from May 22, to July 6. That time was too long; we might have been as ready for an assault two or three weeks earlier, if there had been a sufficient supply of engineers officers to watch that no time was lost or useless work done; to see that every shovelful of earth thrown brought us nearer to the end, and pensionably to push and constantly supervise the special works to which they were assigned. Fortunately, Johnston' relieving force was strengthened so slowly that the delay cost us only time, not the raising of the siege.

LIST OF OFFICERS.

The following is a list of the engineer officers who were present during the siege on engineer duty: Captain F. E. Prime, chief engineer, forced by severe illness to leave

12 R R-VOL XXIV, PT. II