Arthur enlisted on 8th September 1915. He was 19 years and 9 months old and a Grocers Assistant by trade. He joined at Aldershot 2 days later and was posted to training camp. On 22nd October, Arthur joined 107th Field Ambulance. He embarked at Southampton on 30th January 1916, then disembarking the next day at Havre he entered the war in France on 31st January 1916. He was the son of James and Emily A Cooper of I Havelock Villas, Coleman Road, Aldershot.