At the conclusion of the war the numbers were 17,711 officers and 322,739 other ranks. This enormous increase was not merely a multiplication of existing organizations, but the creation of a vast number of new branches of the Engineers' arm, of a nature previously unforeseen, to suit the advance of science applied to war. Besides the field and fortress and railway companies, with signaling units and field squadrons and bridging trains which had formerly been employed, there were electrical and mechanical companies, tunnelling companies for mining, water supply units, field survey battalions, and sound ranging and observation companies. There were units for land drainage and for inundations. there were sections for field and anti-aircraft searchlights. There were others for forestry, camouflage, meteorology, chemical warfare, and a large number of units for transportation by land and water, such as road and railway companies of many kinds and inland water transport. The raising and organizing of all these units,with their varying requirements and their special officers, was a gigantic task. General Curtis had to work, day after day, in a dark and ill-ventilated room at the war office, and his strength, already weakened by years of valuable service in Africa, was strained beyond recovery. But the units he raised were a notable contribution to the success of the operations . . . In 1917, he was appointed to command the Cromarty naval base defences, before taking charge of administration at Aldershot. He retired in 1920, when he was promoted to Major-General and received a knighthood. Curtis married the Hon. Hilda Margaret, daughter of Viscount Barrington in 1894, and they had three daughters.