KENT ARCHAEOLOGICAL SOCIETY
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Dr.Robert Spain,

Bob Spain is a mechanical engineer by discipline, who took early retirement from the City a
few years ago following a lengthy career in Energy Management. His life-long interest has been
ancient technology, particularly water-power and his doctoral dissertation (Imperial College
1992) concerned Roman water-power. He has continued to research ancient water-power and is
currently preparing for publication the hydro-mechanical analysis of several Roman water-mills
including recently discovered Romano-British specimens. He was involved in the design and
full-scale reconstruction of the Roman water-lifting machine discovered in London in 2001 and
has taken part in Time Team programmes. He is a long-standing member of Council of the
Kent Archaeological Society.

Title: A POSSIBLE ROMAN TIDE MILL
Abstract: During the years from 1988 to 1992 a massive building development within London gave archaeologists the opportunity to explore the lower valley of the River Fleet. They found two hitherto unknown islands on the east side of the Fleet estuary that during the early Roman period were developed and used for industrial purposes. The archaeologists have proposed that a tide-mill existed on the northern island. No tide-mills have ever been found in the Roman world dated before 600 A.D.
An examination of the archaeological archives has facilitated a detailed analysis of the Roman structures and artificial channels and concludes that a possible tide-mill operated on the north island. A theoretical tidal profile has been generated that has been used to determine realistic diurnal and lunar mill power-generation cycles. This has provided enlightenment on the impact of tidal regression in the second century A.D. supporting the theory of abandonment of tidal power in the Fleet estuary. On the east bank of the estuary a major Roman landscape feature, the purpose of which was not determined, has been re-examined and identified as an aqueduct, probably built to provide water-power for grain milling close to Londinium. Its interaction with the tide-mill has been explored.
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