Buenos Ayres.

February 12th.—Public events here, for the last few days, have been more exciting in their progress, and more important in their issues, than any that have occurred on the Plata for many years. On the evening of the 4th inst., the Hon. Mr. Schenck arrived from Buenos Ayres on his return to Brazil. He boarded the Congress from the steamer in which he came, announcing, as he crossed the gangway, the utter overthrow of Rosas by Urquiza, “foot, horse and dragoons!” as he expressed it. This had occurred on the morning of the preceding day. He left the city the same evening, when thousands of mounted troops were pouring through it in rapid flight, before the victorious pursuers. It was not yet known whether Rosas had fallen in battle, was a prisoner, or had made a safe escape.

Before the arrival in Buenos Ayres of Mr. Schenck and Commodore McKeever, he had left for the camp, ten miles distant; and they did not see him. They were twice at Palermo, however, on visits to Doña Manuelita; once before any collision between the hostile forces had taken place; and again on the evening of the 1st inst., when it was known that an advanced guard of six thousand Buenos Ayrean troops, under General Pachecho, had been routed the day previous, and the general made prisoner: a foreboding shadow of the coming event. Till then, Manuelita had sustained her position with great spirit and energy; receiving all visitors—official, diplomatic, and private—as usual, in the saloons of the Quinta, and conducting with ability and despatch the affairs of the Home Department of the government. Toward the close of the last named evening, however, when surrounded by those only who were in her immediate confidence, tears might occasionally be seen trembling in her eye, or stealing down her cheek; but only to be dashed away on the approach of any from whom she would conceal the weakness. It was now well known to her that a general and decisive battle might at any hour take place; and that Palermo, immediately in the line of march from the point of contest to the city, was no longer a place of safety for her. The night was one of splendid moonlight in midsummer, and among others, Commodore McKeever and Mr. Schenck remained with her till a late hour of the evening. Before they left, a walk in the flower-garden was proposed by her; and, taking the arm of Mr. Schenck, she led the way to the rose-covered arbor mentioned in my visit last year. Standing within it in silence for a few moments, she said—“This is my choicest retreat at Palermo; it is here that I come alone, to be alone; and I am here now for the last time, perhaps forever!” adding, as the tears fell rapidly down her face, upturned to the moon, as if in appeal to Heaven for her sincerity, “I leave Palermo to-night! Whatever the issue of the morrow is to be, I know our cause to be just, and believe that God will give to it success!” In this, however, she was mistaken. That cause, the next day but one, was utterly defeated; and the following midnight witnessed her flight with her father disguised as an English marine, and she in the dress of a sailor boy—not from Palermo only, but from her city and country, without even a change of clothes, to find safety and a conveyance to distant exile, under the protection of the British flag.

But this is anticipating the order of events. Rumors of the defeat, on the 1st instant, of the vanguard of the army of Rosas, or some disaster of the kind, reached the city on Sunday evening, the 2d inst.—the night on which Manuelita forsook Palermo. It produced little impression on the public mind, however; and on Monday the shops were open, and general business transacted as usual. At daybreak on Tuesday, heavy cannonading was heard for several hours in the direction of the opposing armies. Early afterwards, whispers of a defeat were afloat; and a straggling cavalry soldier here and there, soon followed by others, in groups of three and four, began to enter the city. The excitement spread rapidly, till three guns from the citadel—the signal for martial law—confirmed the report of the overthrow, and led at once to the shutting up of every shop, and the closing of every door. The retreating cavalry now rushed through the town by hundreds, and soon by thousands, hastening from harm’s way to their homes in the pampas of the South. General Mancilla, the brother-in-law of Rosas, and governor of the city, despatched messengers to the foreign ambassadors, reporting the place to be defenceless, and soliciting their intervention with the approaching conqueror, for a halt in his march, till terms of capitulation could be presented. Permission was at the same time granted by him, for the landing of the marines attached to the different foreign squadrons in the harbor, to protect the lives and property of residents from their respective countries—British, American, French, and Sardinian. Forty American marines, including those from the Congress, were disembarked from the Jamestown, under the command of Captain Taylor and Lieut. Tatnall, and the crew of the captain’s gig, in charge of Midshipman Walker. These were distributed in the central and richest part of the town—at the Embassy and Consulate of the United States; at the residence of Mr. Carlisle of the house of Zimmerman, Frazer & Co., the head-quarters of Commodore McKeever; and one or two other principal American mercantile establishments. At the same time, a hasty consultation of the diplomatic corps led to the sending of a deputation from their number to the head-quarters of Urquiza, in behalf of the city. The chief member of this was Mr. Pendleton. Mr. Glover, the secretary of our commander-in-chief, an accomplished young man, well fitted for the service by his talents, and the facility with which he speaks the principal modern languages, formed one of the mission. The special object was to solicit from the victorious chieftain an order to restrain his troops from entering the city, till the authorities could make a formal surrender to him, and thus spare the inhabitants the violence and rapine they had reason to fear. Happily the exhaustion of the victors rendered such an order, for the time, unnecessary. The whole force of thirty thousand men had been without refreshment of any kind, except, perhaps, a little water, for forty-eight hours; and, after having put their opponents to flight, they found it absolutely necessary to come to a rest themselves, not far from the scene of the principal conflict.

It was not till noon of the following day, that Urquiza reached Palermo, and established his head-quarters there. Here the deputation first met him, and readily secured the interposition of his authority in the point of mercy craved. Notwithstanding this, early the same morning—that immediately succeeding the battle—before any thing had been heard from the deputation, the sack of the city in one quarter was reported to have commenced; and, in confirmation of the rumor, the alarm-bell of the Cabildo, or town hall, sent forth an incessant peal. It appeared that a large number of the routed cavalry of Rosas, finding the pursuit by the victors given over, remained in the outskirts of the town during the night; and at the dawn of the next day, commenced breaking open the shops and houses in the more remote parts, and stripping them of their contents, bore off the plunder; alleging the authority of Mancilla himself, the governor of the city, for the outrage. The dress of the troops of both armies is the same; red flannel shirts, caps, and cheripas or swaddling cloths. Those of Urquiza, that they might be distinguished by each other in battle, had chosen for a badge a square piece of white cotton cloth, placed on the shoulders by thrusting the head through a hole in the centre, in the manner of a poncho. This badge these marauders assumed that they might be mistaken for the invading soldiery. Emboldened by success in the outskirts, they began to penetrate the central parts of the place. The terrified inhabitants believing them to be the invaders, submitted unresistingly to rapine and spoliation, lest they should lose their lives; and consternation spread every where with the increasing violence and robbery. Many of the largest and most valuable plate and jewelry shops had already been sacked; and the spirit of plunder grew in proportion to the success.

At this juncture, while a party of twenty or thirty of these mounted pillagers was engaged in bursting off the door-locks of a rich jeweller’s shop with powder, a company of American marines and sailors, in charge of Midshipman Walker, accompanied by Mr. Graham, the American Consul, on their way to the chief scene of pillage—turned into the street near them. The robbers at once fired upon them, happily without injury to any one. Our fellows, under the authority of their officers, were not slow in returning the salute; bringing to the ground, by one volley, four of the leading brigands. Two were killed outright, and two mortally wounded. The rest wheeled instantly in flight, and were seen no more. This first example of the manner by which to check the pillage, led at once to a rally by the citizens. They immediately commenced arming themselves, and a stay was put to the progress of what, in a short time, would have become a general sack of the town.

Mr. Glover arrived the same moment, at the consulate near which the above scene took place, to report the success of the mission on which he had accompanied Mr. Pendleton. He had passed a sleepless night, and been in the saddle many hours; but, as there was reason to fear that the check which had been put by our marines upon the pillage, would be but temporary, and that the marauders would soon return in augmented numbers to avenge the death of their comrades, as well as to load themselves with fresh booty, he was requested by Commodore McKeever to return immediately to Palermo, and solicit from Urquiza a force sufficient to control the disorder and robbery existing. The Chief of Police, at the same time made his appearance, to urge the same measure. Accompanied by this functionary, Mr. Glover, therefore, again hastened as an express to the Quinta. He was admitted immediately to the chieftain, though his companion, the Chief of Police, was forbidden his presence. The object of his visit was accorded, by an instant order for the entrance to the city of a body of troops sufficient for its protection. Informed of the result of the rencontre with the American marines and sailors, he gave full sanction to the interference, and authorized its continuance. The report of this interview was quickly spread through the city; and the patrol of the foreign marines and armed sailors, and the speedy arrival of the forces promised by Urquiza, allayed the panic of the inhabitants.

The troops of Urquiza brought with them orders to shoot down all persons implicated in the robbery and disorder. This was reiterated by the Provisional Government appointed by him upon receiving, as soon as he had taken up his quarters at Palermo, the deputation from the city, empowered to surrender it to his mercy. Under the orders thus issued, three or four hundred persons, both men and women, were summarily put to death, within twenty-four hours; and a scene of such frightful carnage was taking place, with the liberty of its continuance for eight days, that the humanity of Mr. Pendleton led him, accompanied by Mr. Glover, to hasten once more to head-quarters, to beseech that an immediate stop might be put to a slaughter in which it was so apparent that the innocent, through false accusations of robbery, might become the victims of their political and even private enemies. The good sense of Urquiza led him at once to appreciate the justice of this appeal to his humanity, and to countermand the order first issued. The alarm was thus quieted, and a general feeling of safety restored.

It is quite a matter of congratulation with us, that the marines and sailors of the Congress and Jamestown, should have been so eminently the means, by their prompt and gallant conduct, of staying a frightful evil; and, that the prestige of the American name, through the frank and philanthropic agency of Mr. Pendleton and Mr. Glover, should have had such ready and such important influence with the victor, now invested by right of conquest with all power here.

These particulars I learned before leaving Montevideo, from my friend Lieut. Turner. This officer was despatched to Buenos Ayres by Captain Pearson, immediately after the report made by Mr. Schenck of the overthrow of the Dictator. He went in charge of the American propeller, “Manuelita de Rosas,” which the emergency of affairs and the absence of every suitable tender of the kind in the squadron, led Commodore McKeever to charter for the time being. He arrived in the midst of the excitement and consternation of the second day after the battle, when the pillage was at its height, and the summary execution of the perpetrators by the troops of Urquiza was begun. Being a fellow Virginian and a friend of Mr. Pendleton, he was invited to a seat in a carriage with him and Mr. Glover, on their last mission of humanity to Palermo; and thus was a spectator in the city and its environs, and at the Quinta itself, of a succession of scenes of alarm and confusion, of bloodshed and affecting tragedy in various forms, which it is not often the lot even of a naval officer to witness. The city, containing more than a hundred thousand inhabitants, was under pillage and in panic; the wide suburbs were thronged with ten thousand savage troops, dashing to and fro in various directions; the bodies of dead men were scattered about, after having been shot down, or having their throats cut, not in the conflict of battle, but in wanton pursuit, or by order of a drum-head court-martial; women in common life were rushing here and there in terror, and ladies of wealth and rank hastening in their carriages through these scenes, in agitation and affright, to the centre of power, to throw themselves at the feet of the conqueror, in supplication for the lives and fortunes of those dearest to them.