The water-lifting machines

The two five-metre-deep, oak-lined shafts discovered in an otherwise undeveloped area of Roman Londinium posed a mystery for the archaeologists at Gresham Street. It was solved when the well-preserved remains of two Roman water-lifting machines were found at the bottom of the shafts.

Londinium had at least two public baths and a population of more than 10,000 when the first of the two machines was made, but no known aqueduct or other obvious means of supplying the water that the city would have needed. The shafts, it turned out, had been dug as wells to provide a reliable water supply, which could then be raised by means of these sophisticated machines, which are the first to be discovered in Britain.

The earlier shaft was dated (using dendrochronology, or tree-ring dating) to 63 AD. It formed part of the large-scale reconstruction of the city following its destruction in the revolt led by Boudicca in 61-62 AD. It appears to have been used for fewer than ten years before being abandoned.

At the bottom of the shaft was a perfectly preserved Roman half-barrel, with even its hoops still in place. The waterlogged conditions meant that the wood was almost as fresh as the day it was cut; the trader's mark was still clearly visible on the barrel. In deposits that had accumulated over the barrel, a series of 12 oak containers, each capable of holding two litres of water, were discovered. Museum of London experts worked out that the containers would have been linked together to form a continuous chain. Water could then have been raised to the surface by means of a treadmill, operated either by animals or human slaves.

The second shaft is thought to date from the early second century. This yielded a complete copper cauldron and another water-lifting machine. This was a more advanced device, consisting of a series of huge wrought iron cranked links, which lifted as many as 20 six-litre water buckets. Again, the machine would have been powered by a treadmill.