Before the seventies almost every old building was filthy with soot from heating fuels and cars. It's amazing what a little steam cleaning will do...the Ames Hotel and Adams Courthouse are two other examples.
"Electrically operated clock with four dials twenty-two and on-half feet diameter and three hundred and thirty-five feet about the sidewalk. The tower and clock are visible for many miles and is one of the first landmarks to be seen from vessels entering the Port of Boston.