On the 8th of May, 1810, the first battalion marched to Deal Barracks, where every exertion was continued to render it fit for active service. Here the battalion was deprived of the services of Lieut.-Colonel Pack, who was appointed a brigadier in the Portuguese army under Marshal William Carr Beresford, afterwards General the Viscount Beresford. Nothing of moment occurred until the early part of September, when the battalion received orders to hold six companies in readiness for foreign service. They were prepared accordingly by drafting into them, from the companies which were to remain at home, the most effective officers and men, several not having recovered from the Walcheren fever. The following were the companies selected and completed for foreign service, namely:— 1st or Capt. M^cIntyre’s. 2nd ” Hall’s. 3rd ” Adamson’s. 4th ” Walker’s. 6th ” Spottiswoode’s. 10th ” Lewis Grant’s. They consisted of 2 field officers, 6 captains, 15 lieutenants, 7 ensigns, 4 staff, 38 sergeants, 12 drummers, and 603 rank and file. On the 14th of September the above companies embarked in the Downs on board the Melpomene and St. Fiorenzo frigates, three companies with the staff, and Brevet Lieut.-Colonel Nathaniel Levett Peacocke, on board the former; the remaining three companies, under Brevet Lieut.-Colonel Thomas Reynell, afterwards colonel of the regiment, on board the latter. They sailed on the following day for Lisbon, and entered the Tagus on the 25th of September, after a short and pleasant passage. The companies were disembarked on the following day, and quartered in the San Benito and Espirito Santo convents. The greatest exertions were made to complete the companies in field equipment, bât-mules, &c., which being effected, the detachment marched from Lisbon on the 2nd of October to Mafra, where it was shortly afterwards joined by Lieut.-Colonel the Honourable Henry Cadogan, who assumed the command, and Lieut.-Colonel Peacocke returned to the second battalion in North Britain. The detachment being ordered to join the army under Lieut.-General Viscount Wellington, then retreating before Marshal Massena, Prince of Essling, marched from Mafra on the 8th of October, and on the 10th of that month effected the junction at Sobral, where it was brigaded with the Fiftieth and Ninety-second Regiments under Major-General Sir William Erskine, in the first division under Lieut.-General Sir Brent Spencer, K.B.