Mason was born in New York City on May 8, 1848. He entered the U.S. Naval Academy in 1864 and passed the examination for lieutenant on April 2, 1872. On September 1, 1872, he sailed from Philadelphia in the U.S.S. Omaha on a cruise to the Pacific. In Valparaiso, Chile, on February 14, 1873, he transferred to the U.S.S. Pensacola, a surveying vessel. In that ship, he visited other South American ports and arrived in Hawaii on February 13, 1875. After seven months in Hawaiian waters, he returned to the United States.

The journal gives a day-by-day account of Mason's cruise onboard the Omaha and Pensacola, prefaced by an outline of his previous career.