Southwest corner of Beacon and Tappan.

From the 1887 photo series taken just before the widening of Beacon St., most likely by Augustine H. Folsom, a Boston photographer. This photo likely contains the mystery man. He closely resembles the man standing in the driveway talking to the worker and was otherwise posed in a number of the 1887 photos.
incl. Streets

[Courtesy of the Digital Commonwealth (CC BY-NC-ND). From the Brookline Photograph Collection published by the Public Library of Brookline]