Twenty-eighth street to below Twenty-sixth street it is down grade, and the cars will run of their own gravitation, on being started, down to and below the buildings in which the troops were located. The first car fired was a car of coal, and, after being set on fire, it was started on the down grade with one of the mob on it, and he, on arriving at the round house, broke up the car and stopped it. Other cars were fired and run down against the first one, and there was soon a string of fire the whole length of the shops on the side next the tracks. The round house was well supplied with water, and the troops were enabled to keep the fire from communicating with the buildings during the night.

About one o'clock, on the morning of the 22d, (Sunday,) it was discovered that the mob had a field piece on Liberty street, ready to fire on the round house. By General Brinton's orders his men were stationed at the windows ready to fire, and the mob were notified to abandon the gun and not attempt to fire it, or they would be fired on. They paid no attention to the warning, and when one of them was seen with the lanyard in his hand ready to discharge the piece, orders were given the troops to fire, and several of the mob fell, and the rest ran away. Several attempts were made by the mob during the night to creep up and discharge the gun, but the soldiers kept close watch on it and allowed them no opportunity to do so. General Brinton succeeded in communicating with General Latta during the night by sending out one of his men, Sergeant Joseph F. Wilson, who, by disguising himself, succeeded in getting out and back twice, but would not undertake it again. He brought orders from General Latta to hold on as long as possible, that Guthrie had been ordered to report to him, and ought to reach him at five or six o'clock, but if compelled to escape at last, to do so to the eastward, to take Penn avenue if possible, and make for Colonel Guthrie, at Torrens. The scout, Wilson, brought in the last dispatch about two o'clock, A.M., the 22d, and this was the last communication that reached General Brinton while in the round house. The ordeal through which these men passed that night was fearful. Tired, hungry, worn out, surrounded by a mob of infuriated men, yelling like demons, fire on nearly all sides of them, suffocated and blinded by smoke, with no chance to rest, and but little knowledge of what efforts were being made for their relief, with orders not to fire on the mob unless in necessary self defense, the wonder is that they were not totally demoralized; but the evidence of all the officers is that the men behaved like veterans, obeyed all orders cheerfully and with promptness, and during the whole night but one company manifested any spirit of insubordination, and these proposed to lay down their arms and quit, as they were not allowed to use them on the mob, while the latter were taking every opportunity of shooting down the soldiers. This insubordination was quickly brought to an end as soon as the attention of the proper officer was called to it, and when the troops marched out in the morning, no one could tell by their actions which of the men had wavered during the night. About half-past seven, Sunday morning, the 22d instant, the machine shop caught fire in many places, the roof of the round house also was on fire, and it became necessary to evacuate the buildings. The two Napoleon guns could not be removed, and were spiked, and about eight, A.M., the command marched out into the street in good, order, taking their Gatling guns with them. The mob scattered in every direction at sight of the troops coming out, and no attempt was made to molest the soldiers until they began their march eastward by Penn avenue, in pursuance of the orders received from General Latta.

After marching two or three squares, the troops were harassed by a fire in their rear. They were fired at from second story windows, from the corners of the streets, and from every place where one of the mob could fire from under cover so as to be safe himself from a return fire. They were also fired at from a police station, where eight or ten policemen stood in uniform, as they passed, and when they were a convenient distance from the station, shots were fired at them from the crowd there assembled. It is hard to believe charges of this kind, but the evidence is too positive and circumstantial to leave room for doubt. At one point, just before reaching the United States arsenal, there was some confusion among the men in the rear of the column, caused by an attack by the mob that was following up, and a halt was made, and the Gatling guns used on the attacking party, which dispersed them, and this ended all attacks on the troops. In this retreat, three of the soldiers were killed and several wounded, one of whom, Lieutenant Ashe, died a few days afterwards, at the United States arsenal. On arriving at the arsenal several of the soldiers climbed over the fence, into the grounds, and General Brinton called on the commandant, Major Buffington, for leave to feed and shelter his troops there. General Brinton and Major Buffington disagreed as to what occurred between them at that time, which question of veracity the purposes of this report does not require us to decide, but General Brinton is corroborated by the testimony of one of his officers, and Major Buffington has no corroborating witness. The result of the conference was, that General Brinton and his well men went on, and his wounded were left, and well cared for, at the arsenal. General Brinton, hearing nothing from Colonel Guthrie, continued his march out to and through Sharpsburg, and finally brought up in the vicinity of the work-house, and encamped on the grounds near that institution, where he was furnished with rations for his men, and gave them a chance to get the rest they so much needed. These rations reached General Brinton's command during Sunday afternoon, through the personal exertions of A. J. Cassatt, who, from the time of the occupation of the round-house by the troops, had been unwearied in his endeavors to get provisions to them. The command was also furnished with blankets and other necessary camp equipments, by Colonel Thomas A. Scott, who had also been vigilant in looking after the welfare of the men, and all necessary transportation needed on their behalf, after their departure from Philadelphia, unprepared for a campaign, on account of the brief notice given them. To these two gentlemen, the friends of the National Guard owe a debt of gratitude for the personal interest taken by them, at all times, during the campaign, to render any service that lay in their power to make the men comfortable.

The destruction of the railroad property by the mob had been continued all night, the cars and goods contained in them that could not be carried off being burned as fast as they could be broken open, the goods thrown out and the cars set on fire. Crowds of men, women, and children were engaged in the work of pillage, and everything portable, of any value, was seized as fast as thrown from the cars, and carried away and secreted. One feature of the mob at Pittsburgh is new in this country. A large number of women were in the crowd at Twenty-eighth street, on Saturday, the 21st instant, and according to testimony, they talked to the sheriff, and others who tried to get the crowd to disperse, worse than the men, used viler epithets, and more indecent language, and did everything in their power to influence and excite the mob to resistance. They also, during Saturday night and Sunday, brought out tea and coffee for the men engaged in the destruction of property, and were the most active in carrying away the goods taken from the cars. This work of pillage and destruction continued all day Sunday, and the actual destruction was participated in by only thirty to fifty men, the citizens in the meantime standing looking helplessly on, and no effort made to stay the damage by the bystanders. There was a very large crowd in the vicinity of the burning, who were