A hammer-pond is a pond
formed by a dam
in a stream, to work a mill
that used a hammer
to crush ore
. They appeared in the Industrial Revolution
and are prevalent in the narrow valleys of the Weald
in the south of England.
The dam or "bay" was first made of clay, or later of stone or brick, and sometimes stepped to prevent being undermined by too large a fall of water. Water was led to the mill wheel by oak chutes (or shoots). Because of silting, the bays sometimes had to be increased in height after some use.
Later the same kind of method was used to power blast furnaces.
There is a house in East Grinstead, Sussex, called Hammerpond Park. It was built by Benjamin Latrobe, who was also the architect who completed the US Capitol. There is an H.G. Wells short story from 1894 called The Hammerpond Park Burglary.