Question: When did the military branch Charles Foulkes served in start wearing khaki?

full_context: Document 1: Chemical weapons in World War I: The earliest military uses of chemicals were tear - inducing irritants rather than fatal or disabling poisons. During World War I, the French army was the first to employ gas, using 26 mm grenades filled with tear gas (ethyl bromoacetate) in August 1914. The small quantities of gas delivered, roughly 19 cm3 per cartridge, were not even detected by the Germans. The stocks were rapidly consumed and by November a new order was placed by the French military. As bromine was scarce among the Entente allies, the active ingredient was changed to chloroacetone.
Document 2: Allan Quartermaine: Allan Stephen Quartermaine was born in London on 9 November 1888 and, after attending Highgate School, was awarded a Bachelor of Science degree in engineering at University College London, where he was a Chadwick Scholar and later a Fellow. He served as a commissioned officer in the Royal Engineers during the First World War and was awarded the Military Cross for gallantry as a Temporary Captain. Quartermaine was promoted to Acting Major on 24 May 1919, a rank he relinquished on 15 June 1919. Between the wars he worked for Hertfordshire County Council Surveyor’s Department, Teesside Bridge and Engineering and for Great Western Railway, where he became Assistant Chief Engineer, but he remained liable for recall to the British Army as he was a Captain of the Royal Engineers (Transportation) in the Supplementary Reserve of Officers, being promoted to Major in that unit on 19 November 1924. Quartermaine resigned from the Supplementary Reserve on 1 January 1926, transferring immediately to the Regular Army Reserve of Officers whilst retaining his rank and association with the Royal Engineers. He reached the age limit (50) for recall to the British Army on 9 November 1938 and as of that date ceased to be a member of the British Army reserves. He was Director-General, Aircraft Production Factories in 1940 and Chief Engineer, Great Western Railway and Western Region of British Railways from 1940–51.
Document 3: Ronald Bruce Campbell: Born in Madras, India, on 14 September 1878, Ronald Bruce Campbell was educated at Bedford School and at the University of Edinburgh. He served in the British Army during the Second Boer War, between 1900 and 1901, and during the First World War, between 1914 and 1918, and was promoted to the rank of Colonel in the Gordon Highlanders in 1922. He competed in fencing for Great Britain in the 1920 Summer Olympics, and was Great Britain sabre champion.
Document 4: United States Air Force: The first USAF dress uniform, in 1947, was dubbed and patented "Uxbridge Blue" after "Uxbridge 1683 Blue", developed at the former Bachman-Uxbridge Worsted Company. The current Service Dress Uniform, which was adopted in 1993 and standardized in 1995, consists of a three-button, pocketless coat, similar to that of a men's "sport jacket" (with silver "U.S." pins on the lapels, with a silver ring surrounding on those of enlisted members), matching trousers, and either a service cap or flight cap, all in Shade 1620, "Air Force Blue" (a darker purplish-blue). This is worn with a light blue shirt (Shade 1550) and Shade 1620 herringbone patterned necktie. Enlisted members wear sleeve insignia on both the jacket and shirt, while officers wear metal rank insignia pinned onto the coat, and Air Force Blue slide-on epaulet loops on the shirt. USAF personnel assigned to Base Honor Guard duties wear, for certain occasions, a modified version of the standard service dress uniform, but with silver trim on the sleeves and trousers, with the addition of a ceremonial belt (if necessary), wheel cap with silver trim and Hap Arnold Device, and a silver aiguillette placed on the left shoulder seam and all devices and accoutrement.
Document 5: Charles Foulkes (British Army officer): Major-General Charles Howard Foulkes CB CMG DSO (1 February 1875 – 6 May 1969) was a Royal Engineers officer in the British Army and also a British international field hockey player who competed in the 1908 Summer Olympics in the bronze medal-winning team. He saw service in World War I and, following the first German use of gas on 22 April 1915 at the Second Battle of Ypres, became Britain's chief advisor on gas warfare. He also advised on the use of gas to suppress the uprisings in Afghanistan (1919) and Waziristan (1920), but gas was never actually deployed in these conflicts.
Document 6: Charles Edward Callwell: Major-General Sir Charles Edward Callwell (2 April 1859 – May 1928), was an Anglo-Irish officer of the British Army, who served in the artillery, as an intelligence officer, and as a staff officer and commander during the Second Boer War, and as Director of Operations & Intelligence during World War I. He was also a noted writer of military biography, history, and theory.
Document 7: Rudolph Trower Hogg: Born on 19 January 1877, Rudolph Trower Hogg was educated at Bedford School and at the Royal Military Academy, Woolwich. He received his first commission as a Second Lieutenant in the Royal Artillery in 1896. He transferred to the Central India Horse in 1901 and was promoted to the rank of Captain in 1905. He was appointed Assistant Military Secretary to King George V in 1911 and served during the Delhi Durbar between 1911 and 1912. He served during the First World War, during the Gallipoli Campaign and in France, and was appointed Brigade Commander of the newly-formed Royal Air Force in 1918.
Document 8: Service Dress (British Army): Service Dress was the new style of khaki service dress uniform introduced by the British Army for use in the field from the early 1900s, following the experiences of a number of imperial wars and conflicts, including the Second Boer War. This variant of uniform continues to be worn today, although only in a formal role, as No. 2 Pattern dress.
Document 9: British Army during the Second World War: The pre-war British Army was trained and equipped to be a small, mechanised, professional army. Its main function was to garrison the British Empire. It became evident early in the war that its initial structure and manpower was woefully unprepared and ill - equipped for a war with multiple enemies on multiple fronts. The British Army, an all - volunteer force until 1939, was small in comparison to its enemies at the start of the Second World War in 1939, as it had been in the First World War. By the end of the Second World War, however, over 3.5 million men had served in the British Army.
Document 10: Red coat (military uniform): Red coat or Redcoat is a historical item of military clothing used widely, though not exclusively worn, by most regiments of the British Army from the 17th to the 20th centuries. From the mid-17th century to the 19th century, the uniform of most British soldiers (apart from artillery, rifles and light cavalry) included a madder red coat or coatee. From 1873 onwards, the more vivid shade of scarlet was adopted for all ranks, having previously been worn only by officers, sergeants and all ranks of some cavalry regiments.
Document 11: Uniforms of the United States Navy: The Navy first authorized a khaki uniform in 1913 as a practical garment for early naval aviators; they were given permission to wear Marine Corps khaki uniforms with naval insignia, when flying or working on aircraft. Khakis were authorized aboard submarines in 1931 and as a working uniform on all ships ten years later.
Document 12: Navy blue: Navy blue got its name from the dark blue (contrasted with white) worn by officers in the British Royal Navy since 1748 and subsequently adopted by other navies around the world. When this color name, taken from the usual color of the uniforms of sailors, originally came into use in the early 19th century, it was initially called "marine blue", but the name of the color soon changed to "navy blue".
Document 13: Chemical weapons in World War I: The most frequently used chemicals during World War I were tear - inducing irritants rather than fatal or disabling poisons. During World War I, the French army was the first to employ gas, using 26 mm grenades filled with tear gas (ethyl bromoacetate) in August 1914. The small quantities of gas delivered, roughly 19 cm3 per cartridge, were not even detected by the Germans. The stocks were rapidly consumed and by November a new order was placed by the French military. As bromine was scarce among the Entente allies, the active ingredient was changed to chloroacetone.
Document 14: Eton College: The long-standing claim that the present uniform was first worn as mourning for the death of George III is unfounded. "Eton dress" has undergone significant changes since its standardisation in the 19th century. Originally (along with a top-hat and walking-cane), Etonian dress was reserved for formal occasions, but boys wear it today for classes, which are referred to as "divisions", or "divs". As stated above, King's Scholars wear a black gown over the top of their tailcoats, and occasionally a surplice in Chapel. Members of the teaching staff (known as Beaks) are required to wear a form of school dress when teaching.
Document 15: Charles Spackman: He was 26 years old, and a sergeant in the 1st Battalion, Border Regiment, British Army during the First World War when the following deed took place for which he was awarded the VC.
ground_truth: early 1900s
sub_queries: Charles Foulkes >> military branch Answer: British Army
when did British Army start wearing khaki Answer: early 1900s