In the interval between the 16th and 20th of May, the 114th regiment and the lst of the Vistula, set out from Fraga and Torriente for the purpose of investing Mequinenza : general Musnier was appointed to command the forces and to direct the siege.

The elevated plateau that supports the Monnegro, and which is traversed by the route that leads from Saragossa to Fraga, by Bujaralos, Penalva, and Candasnos, terminates at the Cinca and the Ebro; it sinks very rapidly as it approaches the banks of those rivers, but an elevated counter-ridge extends not only to the point where they form a junction, but for 600 feet farther down the bank of the combined streams. The little town of Mequinenza, which is shut in between the rocky foot of this ridge and the bank of the river, forms a kind of port on the Ebro, which is no longer navigable at Saragossa or above that town, and only begins to be so when joined by the Segre and the Cinca. Thus Mequinenza, without being in any of the lines of land communication, forms the key of the Ebro as far as Tortosa and the sea. This important position, which is mentioned by Caesar under the name of Octogesa, and which has figured in almost all the Spanish wars was, when besieged, in a respectable state of defence. At the extremity of the counter-ridge already alluded to, stands an old castle surrounded by a terraced inclosure, which follows all the bends and turns of the rock on. which it is situated. The rock, which is very precipitous on three sides, extends towards the west to the breadth of about l50 toises. This is the only point that admits of a regular attack; it is defended in front by bastions faced with stone, and has a ditch cut in the solid rock, and a very good covered way, palisadoed. Some old walls built in the times of the Moors, which extend from the fort to the bank of the river, except in those parts where the rock is perpendicular, connect the defences on the heights with those below, and thus cover the town, the two ferries, and the roads that lead to them. Intrenchments and out-works had been formed and batteries added, chiefly on the Fraga road, which is the only one by which guns can be transported. The part to be attacked was soon determined on, for it was impossible to force the approaches unless on the side of the plateau. The principal difficulty was to bring up the artillery. It was necessary to construct a road from Fraga to within gun-shot of the works, and our four reconnoissances had not enabled us to discover the means of effecting it. In the month of November preceding, colonel Haxo, taking advantage of the movement of a detachment of our troops between Fraga and Candasnos, had advanced very near to Mequinenza, and had examined the ground in its neighbourhood He accompanied general Musnier, when the latter went over it at the head of the troops, and by his directions the road was traced out, which after all, it was necessary to open from Torriente. For about two leagues the troops had merely to follow the plateau, which served, with a very few repairs, for their purpose. When they had advanced about 1,200 toises the difficulties began to increase. The peasantry were employed as labourers, and it was found necessary to cut out a path in the steep declivity, and to blast the rock in a number of places, in order to reach the lower plateau: this work continued until about the 1st of June..

So early as the 20th May, whilst these preliminaries were in progress, general Musnier had driven in a number of the enemy's advanced posts, and established his camps. A part of the 121st appearing sufficient for the left bank of the Segre, the remainder crossed to the right bank, and thus formed the left of our line; they took up their position behind a small hillock within gun-shot of the Fraga road. The 114th and the 2nd of the Vistula, with the artillery and sappers, occupied the plateau by which the attack was to be made, while several companies of voltigeurs were as far in advance as the banks of the Ebro, to which the want of water compelled our soldiers to have constant recourse, although the road was long and difficult, and very much exposed, at least in the beginning of the siege, at which period general Montmarie, who had orders to march from Aicaniz, in order to complete the investment of the place, had not yet arrived. On the 28th May he took up a position on the heights on the right bank, and the Spaniards, who had dragged a cannon thither, threw it into the river and retired. The 2nd of the Vistula, which was destined for the attack on the town, was stationed on the brink of the stream at the foot of the slope of the left bank and an embranchment was added to the road, in order to facilitate the communications between the river and the camps. The park of artillery remained on the height where the new road had been cut; it consisted of eighteen pieces of cannon, six of which, twenty-four pounders, were provided with every thing necessary for 800 discharges each. On the day of the 30th May the general of engineers arrived from France. He brought with him a brigade of officers of the same corps two companies of sappers and one of engineers. Of nine companies of miners or sappers that had been collected in Arragon the previous year, only three now remained with the 3rd corps. The reinforcement brought by general Rogniat was extremely useful in the sieges to which this division of the army was successively directed. General Rogniat's fame, which had been acquired at Dantzig and at Saragossa, had preceded his arrival, he crowned it afterwards by the sieges he directed while with the army of Arragon in the east of the Peninsula.

This same 30th May our main guard, by favour of a cover, pushed forward to within 300 toises of the outer wall. The enemy commenced a brisk cannonade next day, and even attempted a sortie with great appearance of resolution; 300 voltigeurs, however, who firmly awaited the attack of the 800 Spaniards that composed it, soon checked their advance by a close and well directed discharge of musketry, our advanced post in con sequence maintained the position it had taken up. The enemy had still an outer post on a hillock about l00 toises in advance of the castle; on the night of the 2nd June they were driven from it by the voltigeurs of the 114th. Advantage was immediately taken of this to open a parallel, and 500 men were employed under general Haxo in effecting that purpose. The ground was difficult, and the sound of the pickaxes on the rock having directed the attention of the enemy to the spot, they kept a smart and uninterrupted fire of grape shot on the labours during the whole of the night. As they were very close to the place and crowded together, they suffered a good deal before they succeeded in covering themselves. Fifty men were killed and wounded on the occasion, and the chef-de-bataillon, Seve, was also hurt; the parallel was finished notwithstanding, as well as a communication to the rear on the right side.

During the night of the 2nd an attempt was made against the town, as it was considered most important to close up and isolate the garrison as much as possible, in order to cut off the chances of escape by water. To effect this object, a battalion of the Vistula attacked and carried a Spanish fortified post, about eighty toises from the wall of the town, and a trench was immediately cut at that distance in the narrow slip of land that stretches from the hill to the river. At the same time general Montmarie established on the right bank some strong posts of infantry. They occupied a position close to the river in trenches, so constructed as to protect them from the fire of the castle; but before these dispositions could be completed or could produce any effect, eleven vessels suddenly left the town for the purpose of sailing down the Ebro. In spite of every effort of our soldiers, who were very disadvantageously situated for pursuing them, only two of them were captured. They were found to be laden with inhabitants of the town, who were endeavouring to escape from the inconveniences of the siege, and who were carrying away all their effects along with them. This trifling event served to convince us still more of the necessity of getting speedy possession of the town.

During the night of the 3rd the attack on the fort was continued; the parallel was completed and was prolonged for a score of toises towards the left. The artillery began immediately to construct their batteries upon the very stubborn piece of ground where the breaches had first been opened. We succeeded in forming some battlements, by means of bags filled with earth, for the purpose of cannonading the embrasures of the enemy, and we forced him in consequence to keep them closed the whole of the day with bags of wool; our pioneers were no longer disturbed in their operations. On the town side we advanced forty toises, but it was found difficult to cover ourselves from the fire of the castle, and still more from that of a small intrenched post, which was within fifty toises of the fort and took in flank the whole of our works all the way along the stream. It was found impossible to get a position for erecting a battery against the town, on one hand, because of the narrowness of the slip of ground between the hill and the river, and on the other, because of the fire of a piece placed on a square tower, which terminated 'the outer wall of the town on the side next the water: the musketry of general Montmarie was directed against this fort.

On the evening of the 4th the engineers pushed forward on the right of the parallel by a zigzag of thirty toises long, and the branches and communications were completed. The miners, meanwhile, continued to blast the rocks, which they could not contrive to get round; Mary, lieutenant of the engineers, was wounded. General Rogniat, perceiving that the fire of our light troops from the right bank of the Ebro had compelled a portion of the defenders of the square tower to abandon it, and to retreat to the castle, and imagining that he perceived some hesitation in those who remained, immediately ordered forward a company of the sappers, under the command of captain Foucauld, and a company of the grenadiers of the Vistula, led on by the chef de bataillon, Chiusowitz, supported at some distance by the whole battalion. Our men rushed forward to the tower, scaled the walls, and the adjacent intrenchments which were only eight feet in height, and by nine o'clock in the evening succeeded in establishing themselves in the tower, and in the houses adjoining to it. The enemy instantly retired to the fort, abandoning the town to us at discretion, with eight pieces of cannon, four hundred muskets, and some ammunition. The sappers as soon as the town had surrendered, busied themselves in securing by epaulements, our communication between the streets and squares that were commanded by the castle, while the battalion of the Vistula took up its station in the town, in order to ensure possession of it, and began to loop-hole the walls of the houses that looked towards the ramps of the fort, in order to prevent the enemy from debouching by those points. It was, however, difficult to imagine that they would attempt a coup-de-main by a way which was both steep and narrow, and up which, if driven back, their retreat must be so full of danger. In fact, they contented themselves with throwing shells, and rolling down stones, from the effects of which the townspeople suffered more than we did. Our artillery constructed three batteries, the first of which consisted of four mortars, and which was placed in the rear of the parallel, about two hundred toises from the place it was intended to bombard—the turret of the castle. The second was erected on the right of the parallel, within one hundred and twenty toises of the covered way; it consisted of two twenty-four pounders, and two six inch howitzers and was intended to batter the right face of the bastion on the left of the horn-work, and also to throw howitzer shells into the continuation of the faces of that work. The battery No. 3 contained four twenty-four pounders, and two sixteens; it was placed in the parallel towards the left and was within one hundred and ten toises of the covered way; it was destined to batter the curtain and the left face of the bastion on the right. These different works which were began on the 4th, were finished during the night of the 5th of June. In the mean time the engineers pushed forward the zigzag on the right, which they had begun the evening before, and under favour of a hollow way, advanced to within thirty toises of the wall, and began to form there a place of arms. In the night of the 6th forty grenadiers of the 114th, were commanded to carry the small intrenchment, called the horse shoe, which the Spaniards still kept as an outwork, and whence they very much incommoded our attack from below. They carried it like thorough-bred soldiers, with vigour and rapidity, and maintained themselves there, notwithstanding a keen fire from the fort.

The commander-in-chief, who had been called to Saragossa by the affairs of Arragon, arrived in the camp on the 7th in the morning, and immediately proceeded to visit the trenches, the whole of which, as well as the town, he narrowly examined. Sixteen guns were at that time in battery, and of these he confided the command to the artillery chef-d'escadron, Raffron, an officer of the highest courage; the fire was opened, by his direction, on the 8th of June, at four in the morning. Our superiority was for some time disputed, and three pieces of the battery No. 3 , were dismounted by the enemy, but such were the skill and intrepidity of our gunners, that this accident but redoubled their efforts, and the advantage was speedily seen to be on our side. About nine o'clock two large masses of the parapet had tumbled in, four embrasures were rendered useless, and the fire of the fort was nearly silenced. The enemy endeavoured, by keeping up a very sharp fire of musketry, to conceal the check sustained by his artillery, and at the same time he endeavoured to re-mount his guns ; but our shells, which occasioned yet more terrible effects on the turret than our bullets did on the ramparts, speedily threw the whole garrison into disorder and alarm.

At ten o'clock the governor ordered a parley to be beaten and terms of capitulation were immediately entered on; the commander-in-chief authorized general Musnier to sign the articles, by which the garrison became prisoners of war. It was, when the fort surrendered, 1400 strong, besides seventy-eight officers. We found within the castle forty-five pieces of ordnance, 400,000 cartridges, 30,000 weight of powder, an immense quantity of cast-iron, and provisions for three months.

The fall of Mequinenza completed our possession of all the fortified places in Arragon. By its conquest we took away from the enemy the last depot for stores, the last retreat for his troops, when defeated, on the left bank of the Ebro; and lower Catalonia lost in it an advanced post, of which it could at any time make use to disturb the peace of Arragon, by pouring into it its bands and armed corps, whenever a favourable opportunity presented itself. The capture would have been attended with still more valuable consequences to our arms, had the forts of Cardona, Berga, and Sen d'Urgel been in their turn occupied by our army in Catalonia, for in that case we might have completed the entire submission of the mountain-valleys between the Ebro and the Pyrenees. It was not so ordered, however, and the result was that, during the whole of the war, the mountains, either of Arragon or of Catalonia, were continually receiving instructions, arms, and ammunition, for the purpose of harassing or attacking our troops..

At all events, it was most important to take advantage of the moment when the enemy was discouraged, and therefore the commander-in-chief, only two hours after the surrender of Mequinenza, gave orders to general Montmarie to assemble his brigade, to penetrate into the kingdom of Valencia, and take possession of Morella. This movement was executed with great celerity, for on the 13th of June our troops entered the castle of Morella, in which they found but eight pieces of cannon, and these in an indifferent condition, and without ammunition; the enemy had neglected that post, though an advantageous one, and capable of being well defended. The commander-in-chief resolved to put it in a respectable state, on account of its possessing the two-fold advantage, that with it he could cover Arragon and threaten Valencia; the Spaniards felt, when it was too late, the importance of occupying this fort. General O'Donohu, at the head of a body of troops belonging to Valencia, advanced upon the fort at the end of June, and began to take up a position as if he meant to surround the French troops, and to cut off their supplies. General Montmarie, with his brave 14th regiment and 3rd of the Vistula, did not, however, allow him to complete that manoeuvre ; on the contrary, he marched boldly out against him, routed him, and put him to flight. Our possession of Morella was not disputed after this; the army of Arragon established a garrison there in the first instance, which a good while afterwards received some reinforcements; and, with this assistance, our soldiers maintained their position there until the complete evacuation of the kingdom of Valencia. Following the example of the Moors, who long waged war in the same quarter, we took possession of all the rising grounds in the neighbourhood, and fortified them, in order to place our stores, both of provisions, and ammunition, in security, but more especially for the purpose of enabling us to exercise an influence over the population, which, even in those places where it had been subdued, frequently exhibited symptoms of hostility or of discontent. They were, indeed, ever disposed to deny altogether, or at least to undervalue any advantages we might obtain in fighting on plain ground, but the capture of a station, or of a fort, was a positive and indisputable result, the traces of which were not to be erased, and which consequently beat down opinionativeness however obstinate and silenced incredulity however sceptical.