August of the same year, and Cathcart purchased a cornetcy in the 7th dragoons in June 1777, and then obtained leave to serve in America with the 16th light dragoons. He was appointed an extra aide-de-camp to Major-general Sir Thomas Spencer Wilson, bart., commanding at Boston, and so distinguished himself at the storming of Forts Clinton and Montgomery on 6 Oct. 1777 that he was promoted first lieutenant and then captain in the 17th light dragoons in the November and December of that year. In January 1778 he surprised a large body of the enemy on the Schuykhill, which had heedlessly advanced too far from the encampment at Valley Forge. He again distinguished himself at the battle of Monmouth Court House, and towards the close of 1778 he was appointed major-commandant of a body of loyalist Scotchmen in the States, enrolled as the Caledonian volunteers. Cathcart added to it a company of volunteer cavalry, and as the British legion it did good service at the outposts. On 10 April 1779 he married Elizabeth, second daughter of Andrew Elliot of Greenwells, co. Roxburgh, the lieutenant-governor of the state of New York, and uncle of Sir Gilbert Elliot, first earl of Minto. On 13 April 1779 he was promoted major into the 38th regiment, and shortly after was made a local lieutenant-colonel, and appointed to act as quartermaster-general to the forces in America until the arrival of General Dalrymple. He then reverted to the command of the British legion, and sailed with it to Savannah in December 1779, and commanded it at the siege of Charleston. His health, however, broke down, and he returned to New York in April 1780, when he was ordered to choose between his regimental and his local command. He preferred the former, and after resigning the British legion to Colonel Banastre Tarleton, afterwards M.P. for Liverpool, joined the 38th in Long Island. He commanded it with marked ability in the actions at Springfield and Elizabeth Town in June 1780; but in October 1780, as his health had entirely broken down, he resolved to return to England.
He received a most cordial welcome from the king, and in February 1781 was promoted to a captaincy and lieutenant-colonelcy in the Coldstream guards. On 10 Jan. 1788 he was elected a representative peer for Scotland, and in October 1789 he exchanged his company in the Coldstreams with Lord Henry Fitzgerald for the lieutenant-colonelcy of the 29th regiment, of which his friend and comrade in the American war, the Earl of Harrington, had just been appointed colonel. That regiment was then stationed at Windsor, and the king took the keenest interest in the improvements which the new commanding officers introduced into its discipline. In November 1790 Cathcart was promoted colonel by brevet, and in December 1792, when the Earl of Harrington was promoted to the colonelcy of the 2nd life guards, his lieutenant-colonel received the colonelcy of the 29th. In 1790, when he had only sat in the House of Lords for two years, he was elected chairman of committees in that house. In November 1793 he was made a brigadier-general, and appointed to command a brigade in the army which was assembling under the command of the Earl of Moira at Portsmouth. After the failure of the Quiberon expedition Lord Moira's army was at last ordered to reinforce the Duke of York in the Netherlands; and when Moira returned to England Cathcart, who had been promoted major-general on 3 Oct. 1794, remained with the army in command of the first brigade of the division of General David Dundas, consisting of the 14th, 27th, and 28th regiments. At the head of his brigade he distinguished himself at the battle of Bommel, and throughout the winter retreat. At the battle of Buren, on 8 Jan. 1795, Cathcart established his reputation by suddenly turning upon the advancing enemy, and utterly defeating them with his single brigade, taking one gun and several prisoners. When the remnant of the British infantry embarked at Bremen in May 1795 Cathcart remained in command of a few squadrons of English and Hanoverian cavalry, which finally left Germany in December 1795. He was received with the greatest favour by the king. He was made vice-admiral of Scotland in 1795, appointed colonel of the 2nd life guards, and gold stick in the place of Lord Amherst in August 1797, sworn of the privy council on 28 Sept. 1798, and promoted lieutenant-general on 1 Jan. 1801, and Lady Cathcart was made a lady in waiting to the queen.
He received the command of the home district in 1802, and from 1803 to 1805 acted as commander-in-chief in Ireland; but in the latter year was recalled by Pitt, acting on the strong advice of Castlereagh, made lord-lieutenant of the county of Clackmannan and a knight of the Thistle, and nominated ambassador at St. Petersburg. The news then arrived that Napoleon had broken up the camp at Boulogne, and was marching across Germany. Pitt at once equipped a powerful army, and sent it across to Hanover under his command to make a diversion in favour of Austria. But Cathcart made no attempt to attack the flank of the French; he established his headquarters at Bremen, fought
