Complex sentence: During the Spanish-American War, Bartlett was recalled to active duty, from May to October, 1898, and placed in charge of the Office of Naval Intelligence, the US Coast Signal Service and the US Auxiliary Naval Force.
Split into simpler sentences: During the Spanish-American War, Bartlett was recalled to active duty, from May to October, 1898. He was placed in charge of the Office of Naval Intelligence, the US Coast Signal Service and the US Auxiliary Naval Force.