On land the most active spheres of operation were in winter naturally in the tropical or sub-tropical regions. The East African campaign still hung fire owing to various causes, principally perhaps because of doubts and possibly disputes whether it belonged primarily to the sphere of purely British, Indian, or South African activity, and could best be fought with the different kinds of troops those various Governments had at their disposal. The earlier operations had been undertaken mainly by troops from India, and for a year longer there was little but border fighting until in March 1916 General Smuts arrived with South African forces to begin the serious work of conquest. The principal work of the winter was the reduction of the Cameroons. Considerable progress had been made by June in overrunning this vast territory, half as large again as the German Empire in Europe: the French had occupied Lome from the south, while the British, after some checks on the Nigerian frontier, had advanced to Ngaundere. The rainy season then set in, and operations were suspended until October. The Germans had transferred their capital to Yaunde, which was made the objective of converging attacks by British, French, and Belgian columns from north, east, and south. The British reached it on 1 January 1916, but the movements had been admirably timed, and the French came three days later. Only isolated posts in distant localities remained, and the last of them fell on 18 February. Mesopotamia From Egypt the Turks had been diverted, since their defeat in February 1915, by the attack on the Dardanelles; but the German advance in the Balkans had synchronized with attempts to disturb us on the western borders of Egypt by German and Turkish intrigues with the Senussi federation of Moslem tribes, and in Tripoli, which the Italians had never succeeded in completely subjugating. Trouble began to threaten in November 1915, and the frontier post at Sollum was withdrawn to Mersa Matruh, the terminus of a railway line from Alexandria. The Arab attacks began on 13 December and increased in strength until the middle of January 1916; but with their inferior equipment and means of communication they had little chance of success and were easily beaten off with considerable losses, which led to dissension among the Arab forces and then to their dissipation. They were finally defeated at Agagia on 26 February, and Sollum was regained on 14 March. There was no further trouble on the western frontier of Egypt, and a repercussion of the Senussi discontent far south in Darfur was satisfactorily suppressed by a detachment of the Egyptian Army which occupied El Fasher on 22 May. East of the Suez Canal there were only raids in which we were generally successful, except for the loss of Katia on 23 April; in retaliation El Arish was destroyed by bombardment from British monitors on 18 May.