his powers to as many inspectors as he pleased. The duke named Jones to be sole inspector, and persevered in this choice in spite of strong pressure on behalf of a superior officer. Jones's duty was to make periodical inspections of each fortress, to superintend the execution of the approved plans, sanction modifications, and check expenditure. Wellington generally made two inspections of some weeks annually, when he was always attended by Jones alone, and became very intimate with him. On the return to England of the army of occupation, Jones, who became a regimental lieutenant-colonel on 11 Nov. 1816, was appointed to the command of the royal engineers and royal sappers and miners at Woolwich, and to the charge of the powder factories, while still acting as inspector in the Netherlands. In 1823 Jones was sent by Wellington to the Ionian Islands to confer with the high commissioner, Sir Thomas Maitland [q. v.], respecting the defences of Corfu. His plans were approved and gradually carried out. On 27 May 1825 Jones was appointed aide-de-camp to the king, with the rank of colonel in the army. On 19 Aug. 1830 Wellington sent him on a special mission to the Netherlands with a view to any military arrangements advisable on account of the recent revolution in France. At Ghent Jones heard of the rising in Brussels, went to the king of the Netherlands at the Hague, and at the king's request joined the Dutch army and the Prince of Orange at Antwerp. By his advice the prince went to Brussels, where he had a good military position and sufficient force to maintain himself. Two hours after Jones had left Brussels for London to report on his mission the prince retired to the Hague, thus abandoning his advantages and determining the subsequent course of the revolution. On 30 Sept. 1831 Jones was created a baronet for his services in the Netherlands. In congratulating him upon the honour conferred on him, Wellington suggested a castle with the word ‘Netherlands’ as an addition to his armorial bearings. From 1835 to 1838 Jones's health compelled him to live in a southern climate. He was promoted major-general on 10 Jan. 1837, and in 1838 he was made a K.C.B.
In the summer of 1839 Jones was requested by the master-general of the ordnance to revise and digest the projects of defence for our coasts and harbours, and in the spring of 1840 was a member of a commission upon the defences of the colonies. He next undertook at the request of government to lay down a general scheme of defence for Great Britain. In the beginning of October 1840 he was sent to Gibraltar to report on the defences of the fortress. He remained there as major-general on the staff till June 1841, when he returned to England. His proposals for the improvement of the defences of Gibraltar were approved and gradually carried out. He died, after a day's illness, on 25 Feb. 1843, at his residence, Pittville, Cheltenham.
Jones may be ranked among the first military engineers of his day. He possessed talents of the highest order; great mathematical knowledge, coupled with sound judgment and deep reflection. He was present at six sieges, and at five of them acted as brigade-major, and his intimate knowledge of the details of these operations gives great value to his published works on them. His reputation as a military engineer was not confined to his own country. A statue by Mr. Behnes was erected to his memory in the south transept of St. Paul's Cathedral by the officers of the corps of royal engineers.
On 20 April 1816 Jones married, in London, Catherine Maria, daughter of Effingham Lawrence of New York. He had three sons and a daughter. His eldest son, Sir Lawrence, was murdered by robbers on 7 Nov. 1845 when travelling between Macri and Smyrna, and was succeeded in the baronetcy by his brother Willoughby, who died in 1884, and whose eldest son, Lawrence, born in 1857, is the fourth and present baronet.
Jones was the author of a short account of Sir John Stuart's campaign in Sicily, published in 1808; ‘Journal of Sieges carried on by the Army under the Duke of Wellington in Spain between the years 1811 and 1814,’ 8vo, 2 vols., 1814; ‘Account of the War in Spain, Portugal, and the South of France from 1808 to 1814 inclusive,’ 2 vols. 8vo, 1817. He also printed in 1829 for private circulation ‘Memoranda relative to the Lines thrown up to cover Lisbon in 1810;’ these were afterwards published in the ‘Professional Papers of the Corps of Royal Engineers.’ A third edition of the ‘Journal of the Sieges,’ in 3 vols. 8vo, was published in 1843, and edited by his brother, Sir Harry David Jones [q. v.], who added some valuable information, and incorporated in this edition the memoranda on the lines of Torres Vedras.
Jones's ‘Reports relating to the Re-establishment of the Fortresses in the Netherlands from 1814 to 1830’ were also, by permission of the minister for war, edited by Sir Harry Jones, and printed for private circulation among the officers of the corps of royal engineers.[Wellington Despatches; Autobiography (private, in possession of the present baronet); Colburn's United Service Mag. May 1843; Royal Engineers' Corps Papers.]