This drawing, by an artist named Jack Frost, appears in his 1938 book Fancy This: A New England Sketchbook. The drawing is entitled "The Only Rolling Dam in the Country." The text on the page reads as follows:
An industrial center of the early Newton colony in Massachusetts was at Bemis. Here David Bemis built a mill that turned out the first sailcloth in this country. Later the New England cotton sails carried ships of all nations through the seven seas.
Bemis, where the Charles River still tumbles, has supposedly the only "Rolling Dam" in the country, built in 1778. The flood of several springs ago threatened the dam, but it held.
Bemis' mill was also reputedly the first building in the United States to be illuminated by gas, an enterprising innovation in days when mill hands worked fourteen hours a day.
More history of the dam