separating the Copp's Hill elevation from
those south of it. A tidal mill was arranged
here, by retaining the water at high tide in
the mill-pond, and letting it dribble out when
the tide had fallen. The average rise and fall
of the tide in Boston is about ten feet, so that
this contrivance gave power enough for grinding corn when there was corn to grind. The
mill-pond was filled up about the period to
which the reminiscences in this book belong.
If this book should stray into the hands of persons who do not know the physical Boston of to-day, or the physical Boston of history, it may be worth while, "for the greater caution," as the lawyers say, to give an outline map of both. In the sketch in the margin the white nucleus represents the Boston which Bradford found, and where we should have been catching lobsters had there been no paternal government or other government, until to-day. The outline of the larger cape, as I have called it, is the outline of Boston now, when what we called the "flats" have been filled in by successive improvements—if improvements they are. Any person, who desires to know my
