On his return to England Bolton was transferred to the 12th Regiment of Foot and promoted as captain on 21 September 1860. He was for several years engaged with Captain Philip Howard Colomb R.N. in developing a system of visual signalling, applicable to naval and military operations, which was adopted by the authorities. He also invented and developed an application of the oxy-calcium light for night signalling. The Army and Navy Signal Book was compiled by Bolton and Colomb, assisted by an officer of Royal Engineers, and was used during the British Expedition to Abyssinia of 1867/8.
