While this long delayed force was on its way the little garrison at the fort had its hands full to maintain its position. On the 30th of August a large body of Indians made a bold raid on the post, and succeeded in stampeding and running off nearly two hundred head of cattle and one hundred head of horses and mules which were grazing on the prairie. Some fifty of the cattle afterwards escaped, and were restored to the post by a scouting party. This band of marauders did not, however, attack the fort. No one who has not experienced it can appreciate the mortification of seeing an enemy despoil you of your property when you are powerless to resist. An attack was made on the fort on the 3d of September, and some stacks burned and a few horses captured. Several men were killed on both sides, and Captain Van der Horck was wounded in the right arm from an accidental shot from one of his own men. On September 6th a second attack was made by a large force of Indians, which lasted nearly all day, in which we lost two men and had several wounded. No further attack was made until the 26th of September, when Captain Freeman's company was fired on while watering their horses in the river. These Indians were routed and pursued by Captain Freeman's company, and a squad of the Third Regiment men, with a howitzer. Their camp was captured, which contained quite an amount of plunder. A light skirmish took place on the 29th of September, in which the enemy was routed, and this affair ended the siege of Fort Abercrombie. CAMP RELEASE. Colonel Sibley's command made Camp Release on the 26th of September. This camp was in the near vicinity of a large Indian camp of about 150 lodges. These Indians were composed of Upper and Lower Sioux, and had generally been engaged in all the massacres that had taken place since the outbreak. They had with them some 250 prisoners, composed of women and children, whites and half-breeds. Only one white man was found in the camp, George Spencer, who had been desperately wounded at the Lower Agency, and saved from death by an Indian friend of his. The desire of the troops to attack and punish these savages was intense, but Colonel Sibley kept steadily in mind that the rescue of the prisoners was his first duty, and he well knew that any demonstration of violence would immediately result in the destruction of the captives. He therefore wisely overruled all hostile inclinations. The result was a general surrender of the whole camp, together with all the prisoners. As soon as the safety of the captives was assured, inquiry was instituted as to the participation of these Indians in the massacres and outrages which had been so recently perpetrated. Many cases were soon developed of particular Indians, who had been guilty of the grossest atrocities, and the commander decided to form a military tribunal to try the offenders. TRIAL OF THE INDIANS.