MY DEAR FRIEND,

After an absence of four months, we returned here on the 24th instant, and found the Turks in the highest spirits. The Emperor has declared against them: but this was a proceeding they had been prepared for; and, far from his arms having as yet been attended with any decisive success, he tarnished them in the onset, by beginning the war in a pusillanimous style, not at all expected from so powerful an enemy.

We had scarce left this country, before advice was received of a treacherous attempt to take Belgrade; but the slovenly manner in which this enterprise was conducted, gave the Emperor an opportunity of denying his being privy to it. It proved unsuccessful; and, as the Baron De Herbert, the Imperial Minister, had changed his threats into negociations for settling a peace between Turkey and Russia, the Porte, unwilling to provoke the Emperor to hostilities, and in hopes that this failure would discourage him from pursuing his designs against a people who were so much better prepared than he expected, very politically seemed to admit the Internuncio's excuses for this breach of faith.

It seems, that an officer who had passed through Belgrade, reported at Vienna, that the fortifications were in a most ruinous state, and that none of the cannon were fit for service. On this fallacious information, orders were hastily sent to Generals Mitrowski and Alvinzy, to pass the Save, with a detachment of troops, who were to be supported by Generals De Gomingen and Klebeck, and to make an immediate attempt on this important fortress; but the latter Generals not arriving at the appointed time, and the fortifications appearing in a very different state from that in which they had been represented, Mitrowski and Alvinzy were obliged to retreat, and to repass the Save.

Notwithstanding the Internuncio's disavowal of the Emperor's knowledge of this attempt, accounts were soon received, that Generals Mitrowski and De Gomingen were ordered to Vienna, to answer for their failure; and, on the 8th of February, Baron De Herbert delivered a formal declaration of war.

After the journey to Cherson, the unremitting armaments which immediately followed, and, to crown the whole, the treacherous attempt upon Belgrade, the Imperial Manifesto, to the surprise of every body, begins in the following manner.--

Notwithstanding the serious events which this declaration must produce, it was impossible for the Porte to refrain from laughing at the bare-faced manner in which the Emperor attempted to impose on the understandings of the rest of the world.

The declaration of war was read to the Imperial troops in Croatia on the 9th of February, and the same day Dresnick was attacked by them. The garrison consisted of only seventy men; but this little corps made a most gallant defence, and, small as their numbers were, they obliged the enemy to set fire to the place before they could compel them to surrender.

At the same moment a second detachment made an attempt on Sturlich, another inconsiderable post. The Turkish Commandant reserved his fire till the Austrians were near enough for every shot to take place, he then gave them a volley, which destroyed a considerable number of the enemy. The place, however, was afterwards taken; and, it is said, that in revenge for the loss the Imperialists had sustained, they put all the prisoners to the sword. I cannot believe this report, notwithstanding the following account published by authority.

Vienna, Feb. 27th, 1788.

I do not think this account at all extenuates the severity, which it admits to have been exercised; for I never knew that it was the custom to accompany a flag of truce by an armed force; neither was it very military in the German Officer to advance with his whole detachment, even had he imagined the place was going to surrender, before he sent a party to receive the post from the enemy.

The Imperial army now took post with their left flank on the river Korana, near Dresnick, and their right towards the mountains of Plessivicza, so as to have the road to Bihacz open before them.

In the mean while, a considerable corps under Colonel Kesnowick passed the Unna, and attacked Turkish Dubitza, but were repulsed with a heavy loss. The Austrians themselves acknowledge to have had 431 men killed and wounded.

This coup-de-main having failed, Prince Charles Lichtenstein was sent to commence a regular siege. He took the command of the army early in March, and on the 25th of April, a practicable breach being made, the Imperialists advanced to the assault. They met a very unexpected reception, being themselves most furiously charged by the Turks, which threw them into such confusion and dismay, that they were soon repulsed, and the garrison sallying out, without giving them time to form, drove them headlong through their own trenches, burnt their works, and obliged Prince Lichtenstein to cross the Unna that very night, and secure himself on the opposite heights.

A besieged garrison routing a besieging army in so complete a style, is such an extraordinary circumstance, that I was anxious to hear what turn the Imperialists would give it. Their account is so curious a one, that I shall subjoin it for you.

Vienna, May 3d, 1788.

Thus we see, that though the Austrians were victorious, their works were destroyed, the siege was raised, and their army obliged to retreat--to pass a river in the night--and to intrench themselves on the opposite heights, to defend the country of the conquerors, from the incursions of the vanquished. An odd kind of victory this.

In a subsequent account the Austrians mention Generals Klun and Schlaun being wounded, the latter mortally; and they acknowledge to have had five Lieutenant-Colonels, three Captains, four Lieutenants, and 508 rank and file killed and wounded, besides horses. Some few privates they say were missing, and two field pieces, which were advanced to the attack, were taken by the enemy.

These are the latest accounts from the banks of the Unna.

I shall now proceed eastward, and you have only to follow me in this direction along the frontiers, to have a full view of the Imperial armies in the order you will find them on the map.

While Prince Lichtenstein was laying an unsuccessful siege to Dubitza, which ended in a complete overthrow; in consequence of which we have left him on the Austrian side of the Unna, threatened in his new intrenchments, the Grand Imperial Army advanced opposite to Sabacz, on the banks of the Save, about two days march west of Belgrade, where they remained till the Emperor arrived, in order that his taking the field might be marked by a successful enterprise. But, even according to the Vienna account, Sabacz contained but 17 pieces of cannon, and the garrison amounted to only 800 men.

It should seem, however, as if the Austrian Generals, in compliment to their Sovereign, wished to conceal the weakness of the object of their enterprise by the pomp of the attack. A regular siege was commenced, trenches were opened, and the batteries being completed by the 23d of April, began a heavy cannonade, which soon overpowered the fire of the Turks. Nevertheless they kept possession of a few rotten walls, which served by way of outwork, till a column, composed of the riflemen of the regiment of Peterwaradin, of the free corps of Servia, and the regiment Esterhazy, advanced to storm them. On this attack the Turks retreated into the interior part of their works, and finding it in vain, in such a place, to contend any longer against the grand army of the Emperor, and a numerous train of artillery, they surrendered their post.

The Emperor gave the Turks great credit for their defence, and much to his honour, treated the prisoners with attention, sending their wives and children to their own country.

During the few hours the Austrian fire was kept up, their batteries were well served, and the troops ordered to the assault, advanced with great spirit. In short, this enterprise would have done honor to the Emperor's arms, had it been worth the time, labour, and expence he bestowed to achieve it.

His people boast, that among the trophies are twenty pair of colours, but they do not inform us how the number of standards came to be near three times that of the cannon, or why eight hundred men should have forty colours. And the Turks say, that till the Grand Vizir can find him better employment, they have no objection to his Imperial Majesty taking every village on the Save on the same terms he paid for Sabacz.

The number of men the Austrians lost is not exactly known; the accounts from Vienna only mention that Prince Poniatowski, and the Baron de Refroy, a General of Artillery, are among the wounded.

It was supposed that as soon as the Emperor took the command of his Grand Army, that he would have besieged Belgrade, but by the latest accounts he was very quiet in the neighbourhood of Semlin.

The troops employed on the banks of the Danube, between Belgrade and Orsowa, under Generals Wartensleben and Papilla, have had several rencounters with the Turks, with various success; but the only event of any consequence, in this part of the seat of war, was an attempt upon Semendria, in which the Imperialists were repulsed with considerable loss.

General Fabricius, who commands the Austrians in Transylvania, has done nothing decisive, and several of his posts have been carried off by the enemy.

The Prince De Saxe Cobourg, a General I much admire, entered Moldavia early in March, with the most eastern of the Emperor's armies. This province is governed by a Greek Prince, who is appointed by the Porte, but who wishing to give himself up to the Germans, sent them a scheme to get possession of his person, which was executed with such secrecy, that in the night a detachment of the enemy carried him off from the middle of his capital.

It should seem as if the Austrians thought the possession of his person of the greatest consequence, since the moment they got him, they fled with the utmost precipitation, without attempting to destroy the magazines, or to do any other damage.

It does not, however, appear that the defection of this Chief was of any great detriment to the Turkish cause, since the Austrian General only passed through the north-west corner of the province, directing his march by Suczawa and Siret, towards Choczim, the most northern fortress in the possession of the Turks, and their chief frontier towards Poland, distant from Constantinople about five hundred miles.

The grand exertions of the Russians are against Oczakow. The Captain Bashaw sailed for the relief of that fortress on the 20th of May, but it is feared that the enemy are already in possession of both sides of the Liman, by which means their ships, covered by the batteries on shore, may prevent the Turkish fleet from being of any use to the garrison.

The rendezvous of the Ottoman army was first at Adrianople, about 120 miles from the capital, and afterwards at Sophia, near two hundred miles farther on the road to Belgrade. As fast as the troops were assembled, large detachments were sent to all the garrisons on the frontiers, and there are now 80,000 men still left at Sophia; with these, and some other corps, the Grand Vizir will march against the Emperor; and should his Imperial Majesty choose to enter the Ottoman territories, or attempt to besiege Belgrade, a decisive battle must ensue.

It will be some weeks before you hear from me again from this port, since I shall set out to-morrow on a tour to Macedonia; and before I return, I propose visiting Lesbos, Tenedos, Lemnos, and several other of the Greek islands.