Singer 221-1 Sewing Machine

My wife, who sews occasionally, uses a Singer 221-1 Portable Electric Sewing Machine. It had belonged to her grandaunt. I am not sure exactly how old it is, but the instruction booklet shows a number of copyright dates beginning in 1915, with 19 updates, the most recent one being in 1952; so it is safe to assume that it is about that old. In other words, about the same age as my wife, who was born in 1953.