3 Aug. 1872, and joined the Staff College in
February 1873, passing the final examinations in December 1874. In April 1875 he was attached to the intelligence branch of the war office, was in Holland on intelligence
duty (10 Jan.-8 Feb. 1876), and became
a deputy assistant quartermaster-general
for intelligence (13 July).
In August 1876 Ardagh began important services in the Near East. He was then sent on special service to Nisch, the headquarters of the Turkish army operating against Servia. In October he was summoned to Constantinople to report on the defence of the city. In fifteen days he prepared sketch-surveys of nearly 150 square miles, and proved himself an expert in strategic geography. These surveys included the position of Buyuk-Chekmedje-Dere, with projects for the defence of the Dardanelles and the Bosphorus, the Bulair lines and Rodosto. The actual works were subsequently constructed by the Turks. Ardagh also reported for the foreign office on the operations in Herzegovina and Montenegro, and in December 1876 went to Tirnovo in Bulgaria to report on the state of the country. After an attack of fever, from which he recuperated in Egypt and Greece, he resumed his duties at the war office in April 1877, when he completed a report and survey begun in the previous year on the sea defences of the Lewes and Laughton levels.
From December 1877 to March 1878 Ardagh was in Italy on special foreign office service, and in the summer attended the congress of Berlin as technical military delegate under General Sir Lintorn Simmons [q. v. Suppl. II]. Ardagh's knowledge of the Turkish provinces proved of value, and in July he was created C.B. (civil). Between September 1878 and September 1879 he was employed on the international commission to delimitate the frontiers of the new principality of Bulgaria. On 30 Nov. 1878 he was gazetted a brevet-major, and was pro- moted regimental major on 22 Sept. 1880. On 14 June 1881, after much negotiation among the great powers, in which he played some part, he became British commissioner for the delimitation of the Turco-Greek frontier. In spite of obstacles the work was completed by the end of October.
In February 1882 Ardagh was appointed instructor in military history, law, and tactics at the School of Military Engineering at Chatham, but on 5 July he was sent suddenly to Egypt, where he was occupied almost continuously for nearly four years. His first duty was to place Alexandria in a state of defence after its bombardment by the British fleet and to take charge of the intelligence department there. Becoming on 21 Aug. deputy assistant adjutant- general, he was subsequently employed in the railway administration at Ismailia, and was present at the actions of Kassassin and Tel-el-Mahuta, and at the battle of Tel-el-Kebir. He was mentioned in Lord Wolseley's despatch at the end of the cam- paign and was promoted brevet lieutenant- colonel (18 Nov. 1882). He also received the British war medal with clasp for Tel-el-Kebir, the Khedive's bronze star, and the fourth class of the order of the Osmanieh.
Ardagh remained in Egypt as deputy assistant adjutant-general to the British army of occupation, and was largely employed in making surveys. In July 1883 he went home on leave, but returned to Egypt almost immediately on an out- break of cholera, and laboured untiringly during the epidemic.
In February 1884 Ardagh, as commanding royal engineer and chief of the intelligence department, accompanied the British force under Sir Gerald Graham [q. v. Suppl. I], which was sent from Cairo to the Eastern Soudan. He was present at the battle of El Teb (29 Feb.), and at the relief of Tokar (1 March) he arranged the removal of 700 Egyptian inhabitants. By 8 March the change of base from Trinkitat to Suakin had been made, and on the 12th Ardagh reconnoitred with the mounted infantry the ground towards the hills. After the battle of Tamai (13 March) the road was open to Berber, and Ardagh shared his general's opinion that an advance should then have been made to Berber to reach out a hand to General Gordon at Khartoum. He afterwards wrote : ' Ber- ber was then in the hands of an Egyptian garrison, and had we gone across, the subsequent operations for the attempted relief of General Gordon at Khartoum would not have been necessary.' Graham's force returned to Cairo in April, leaving a battalion to garrison Suakin. Ardagh was mentioned in despatches and was made C.B. (military).
In May 1884 he went home on leave. In the autumn an expedition to relieve Khartoum was organised. Ardagh favoured the Suakin-Berber route, but Lord Wolseley, who commanded, resolved to ascend the Nile. Ardagh was appointed commandant at the base (Cairo), with the grade of assistant adjutant-general. His energy, devotion, and quiet cheerfulness
