This ancestor was a mystery indeed. Some background on him. There isn't much known on him before his marriage. In this photo he is acting in his occupation which according the 1900 Census is Engineer Stationery or Stationary Engineer. According to the International Union of Operating Engineers, the following is said: "The work of stationary engineers is varied and complex. We are responsible for the operation, maintenance, renovation, and repair of boiler systems and all other mechanical systems in a facility." I think it's very cool to have a picture of an ancestor doing their occupation. Now on to the story of the mystery of this ancestor.
Before this mystery was solved the earliest record we had of him wasa marriage record recorded as William Hanlon Baker married to Mary Alice Baker. The marriage took place 12 February 1871 in Manhattan, New York. From the censuses we know he was born January 1845 in Maine and from his death certificate found later he died 15 April 1906 in Manhattan and his parents were listed as Noah and Susan Webb. Naturally, that tells his father's name Noah Baker when listed like that. It's unknown who told the information to the physician who filed the death certificate.
I have to say this mystery was a lot of fun to find. Because of this find, I was able to extend my line three generations from this ancestor. Genealogy is like a mystery novel. You put together clues to find out the mystery, the only difference is, the answer isn't given to you at the end of the story. Sometimes you have to work backwards.