It is apparently a rare design in that the water enters through a circular opening at the top that is surrounded by the stream. The water then cascades down some more smaller rings until it enters a culvert which enters a tunnel under the nearby path before sluicing down to the river a few metres away.
The existing leat which supplied the old corn mill did not provide a sufficient head of water for the new mill, so the level of the water in the mill basiin had to be raised by 2.4 metres. This was achieved by reducing the fall along the leat. Then, as now, the water level was maintained by the circular 'tumbling weir', which discharged the overflow into the river through a short tunnel. Water was conveyed from the mill basin to the 5.5 metre water wheel inside the factory (reported to be capable of producing 30 horsepower) by an overhead aqueduct - the factory launder. A second 3.6 metre overshot wheel powered the corn mill.
The corn mill, according to a notice in the Sherborne Mercury in 1835:
has three pairs of stones, a Bolting Mill, Rubble Machine and Smut Machine, with extensive Lofts; they are driven by a very powerful stream affording a never-failing supply of water and are capable of making at least one hundred sacks a week.
In 1824 the enterprise was converted to the manufacture of silk, and up to 400 female workers were employed. In 1897 the factory was sold to Keetch & Co, brush manufacturers, the first of several subsequent owners.
The corn mill continued to operate until 1937; the factory launder was demolished in 1945.
Today the mill site and the adjoining factory is unoccupied, awaiting re-development. Near the site is the Tumbling Weir Hotel, a converted 17th century thatched house, now a popular hotel and restaurant.