Born: February 17, 1855, Ware, Massachusetts.
Died: October 8, 1930, Somerville, Massachusetts.
Buried: Wyoming Cemetery, Melrose, Massachusetts.
Blackmer married twice, to Jennie M. Baker (1881) and Dora Josephine Roby (1906).
A member of the Adventist Church, he attended the Wilbraham Academy. When it came to music, though, he was largely self taught.
He wrote his first song at age 16, and over 300 more during his life.
He lived mostly in Somerville, Massachusetts, and had a pianoforte business.
He directed the choir at the Advent Christian Church in Somerville, and was a song leader at the Alton Bay camp meetings in Lake Winnipesaukee, New Hampshire (1914–30).
If you know where to get a good photo of Blackmer (head & shoulders, at least 200×300 pixels),