Internal evidence suggests that the author of these letters, "W. F. Farrington," who worked for the United States Christian Commission at Sickles Hospital in Alexandria, Virginia, in mid-June 1865, is Methodist minister William F. Farrington (1800-1888).
William F. Farrington was born on September 7, 1800, the son of William Farrington and Hannah Freeman, and became a Methodist minister in 1829. Around 1842, he became pastor of Chestnut Street Methodist Church in Portland, Maine; from 1864-1866, he led the Methodist Episcopal Church in East Bridgewater, Massachusetts. Farrington was married three times; his wives included Mary Ann Bolton and Margaret P. Skillings (m. March 25, 1863). William F. Farrington died on December 26, 1888.