delays ensued; but eventually the stipulated engagements were not only accepted but fulfilled by Persia. In 1841 a new mission under McNeill was cordially received in Teheran; and on 11 Oct. that year a treaty of commerce was concluded between Great Britain and Persia (see Ann. Reg. 1841). On 15 Aug. 1842 McNeill was relieved at Teheran by Colonel (afterwards Sir) Justin Shiel, and returned home. His correspondence during the period of 1836–9 was published as a blue book, entitled 'Foreign Office Correspondence relating to Persia and Afghanistan,' 1839 (cf. Quart. Rev. lx. 162–78).
In 1845 McNeill was appointed chairman of the board of supervision entrusted with the working of the new Scottish Poor Law Act of 1845, a post he occupied for thirty-three years. During the potato famine, which was nearly as disastrous in the Western highlands as in Ireland, he conducted a special inquiry into the condition of the Western highlands and islands, during which he personally inspected twenty-seven of the most distressed parishes. His report to the board of supervision will be found in 'Accounts and Papers,' 1851, xxvi. 829 et seq. (cf. ib. xc. 162 et seq.) At the outbreak of the war with Russia, McNeill published revised editions in French and English of his pamphlet on the 'Progress and Present Position of Russia in the East,' with supplementary chapters dealing with the progress of events since 1836, and insisting on the importance to England and to Christendom of the autonomy of Turkey and Persia. At the beginning of 1855, when the Crimean disasters had roused public indignation, McNeill and Colonel (afterwards Sir) Alexander Murray Tulloch, an officer of great administrative experience at the war office, were sent to the Crimea with instructions to report on the whole arrangements and management of the commissariat department and the method of keeping accounts, and also the causes of the delays in unshipping and distributing clothing and other stores sent to Balaklava.
The commissioners started at once for the seat of war. They took no shorthand writer with them, as the remuneration sanctioned by the treasury was insufficient to secure a qualified person (McNeill in Tulloch's Crimean Commission, ed. 1880, p. 72). In the face of many difficulties they collected much valuable information; they pointed out impartially that the delays in the distribution of stores at Balaklava were due to the want of a road from the base to the camp, but that no labour could be spared for the construction of such a road; and they prepared statistical tables illustrative of the sickness and mortality in the army. Their final report was signed in London in January 1856, and at once laid before parliament. It forms vol. xx., with appendices, of 'Accounts and Papers,' 1856. Some of the remarks in the report were resented in military quarters, and a board of general officers was directed to assemble at Chelsea, as Lord Panmure stated, 'to allow the officers adverted to in the report to have an opportunity of defending themselves.' The board exonerated the Crimean general and departmental staff from blame [see under Airby, Richard, Lord Airby], and the verdict was accepted by the public as a just one. McNeill kept entirely aloof from the inquiry. In a vigorously written preface to the posthumous edition of Sir A. M. Tulloch's 'Crimean Commission,' written a quarter of a century later, and shortly before his own death, McNeill explained some of the difficulties with which he and his colleague had to contend, and administered a not unmerited rebuke to the 'levity,' which long after, 'in the face of the appalling statistics of disease and mortality annexed to that honest and able review, and the indisputable facts it set forth,' would refer 'the fatal privations so heroically endured by the troops to so ludicrously inadequate a cause as a deficiency of pressed hay from England' (McNeill, Preface to Tulloch; cf. Kinglake, 6th ed. vol. vii. chap, v.) The Chelsea report was sent in in the summer of 1856; in the spring of 1857 the Crimean commissioners were still unrewarded. When Questioned on the subject in parliament on 2 March 1857 Palmerston replied that 'the crown had done all that it could properly be advised to do,' but the house forthwith passed a resolution praying the throne to confer some special honours on McNeill and Tulloch. Shortly afterwards McNeill was made a privy councillor and Tulloch a K.C.B. The university of Oxford created McNeill a D.C.L., and the university of Edinburgh chose him as honorary chairman of the amalgamated societies of the university the same year. His inaugural address to the latter, on some evils of secrecy in competitive examinations for public appointments, was afterwards published in pamphlet form (Edinburgh, 1861).
McNeill retained the chairmanship of the board of supervision until 1868. He was a F.R.S.Edinburgh, and was the last survivor of the original members of the Royal Asiatic Society, with which he was associated for over sixty years. He died at Cannes, 17 May 1883, at the age of eighty-eight. McNeill married, first, in 1814, Innes, fourth daughter of George Robinson of Clermiston, Midlothian—she died in 1816; secondly, in 1823, Eliza, third