Old London Bridge and the New River
By the end of the 17th century, Sorocold was working in London, which is the location of perhaps his main achievements in the field of water supply. Certainly, two projects he was associated with there are famous names — the waterworks installed under Old London Bridge
and the New River
water supply system.
All through history, settlements have been established by rivers, streams or springs — people need fresh water in abundance. As settlements grow, water supplies tend to fail to meet demand and additional sources are needed. In London by the mid to late 16th century, water supplies were at a premium. A water carrier industry developed for the conveyance of water to the doors of those willing to pay.
Various schemes for pumping water from the River Thames were tried but were generally small-scale. The first significant scheme was set up by land drainage engineer Peter Morris (or Morice) and completed in 1582. Morris installed a river-driven pumping 'engine' (waterwheel) under the first arch at the northern end of Old London Bridge — followed by another under the second arch. These supplied dwellings and businesses on the north bank. They also contributed to the general obstruction of the tidal flow of the Thames that the bridge itself was causing (see article on Old London Bridge in The Bridges of London
In 1695-6, Sorocold together with John Hadley, a fellow engineer from Worcester who held the patent on the raise-able waterwheel, constructed Marchant's Waterworks on the Thames at Westminster. Little is known of it, although one report suggests that it consisted of three 'engines' working in series. Notable politician Sir Godfrey Copley (1653-1709) met Sorocold and Hadley, commenting, "I do think it the best piece of work I have seen ...". He is generally supposed to have been referring to the Westminster project. Copley was a Fellow of the Royal Society and founder of the Society's Copley Medal, Britain's oldest scientific award.
Although not completely successful as a business, the Morris waterworks under Old London Bridge continued to operate until 1701. Morris' descendants then sold the rights to goldsmith Richard Soame. Soame formed a new company to run it, and decided to develop it further by adding an additional water-raising mechanism under the bridge's fourth arch. The company employed Sorocold to install the new pump, and to rebuild the old ones.
Presumably based on experience in Derby and elsewhere, Sorocold installed a new beam-operated pumping engine. It is described some years later by Henry Beighton in the Royal Society's Philosophical Transactions of 1731 (volume 37) with illustrations. The undershot waterwheel was some 6.1m in diameter and had deep floats, each 4.3m long. The wheel could be raised and lowered as tidal conditions demanded. There were 16 'forcing' pumps provided, each 178mm in diameter, operated by wooden beams and actuated by cast iron cranks turned by the waterwheel.
The pumps could lift 4,000 litres a minute to a head of more than 36m, from where the water was distributed to users via a network of wooden pipes. Sorocold would continue to work on the system, eventually installing similar mechanisms under three of the arches — the third housing two 'engines', making four in all. They drove a total of 52 pumps, raising 8,274 litres a minute. He was widely acclaimed for the success of this scheme.
In a letter written sometime in 1702, Sorocold petitions the Earl of Marlborough (John Churchill [1650-1722], later Duke of Marlborough) for work and summarises his achievements so far. The letter is held in the Melbourne Hall Muniments. At the time, the Earl was Master-General of the Ordnance, responsible for British military engineers, fortifications, etc., and for many large civilian infrastructure projects. Sorocold writes:
"The Right Honble John Earle of Marlborough &c. The humble petition of George Sorocold sheweth That your petitioner for ye space of ten years past hath employed himself in Publick Mechanical works; & with good success watered severall considerable Towns in England. That your Petitioner did about five years since at his own Charge supply ye Garrison & Hospital Barracks at Portsmouth with good fresh water to the greate benefit & Advantage of ye sd Garrison & your Petitioner having lately erected ye new water work at London Bridge & settled himself & his family in London is desirous to serve your Queen Majestie & your Lordship in ye office of Ordnance either as an assistant to yr Surveyor General or in such other employ as yor Lordship shall think fitt. Your Petitioner theirfore humbly prays your Lordship would be gratiously pleased to bestow on him some such employ when any Vacancy shall be. And &c"
In 1704, when Sorocold was still working at Old London Bridge, the owner of the waterworks, Richard Soame, was declared bankrupt and imprisoned. As result, his company stopped paying Sorocold's salary and the rent for the large family residence in Cecil Street (off the Strand, now demolished). The Sorocold family suffered the indignity of ejection from their home. The engineer was also sued for debts incurred by Soame for materials supplied to the bridge works.
He must have overcome these setbacks, for he continued to work elsewhere. There would be further work for him in London too, and a few years later he played a part in another major project to bring water to the people of the metropolis.
The New River
had been supplying London with water from Hertfordshire since 1613. Completed by Sir Hugh Myddleton (1560-1631), the 3m wide open channel is over 32km in length and much of it is still part of London's water distrubution system. In Sorocold's time, the New River terminated at a circular reservoir in Clerkenwell known as the Round Pond. The water was gravity-fed from the pond in wooden pipes to central London.
Life with a canalised water supply was not without its problems. A report dated around 1650 records: "There are many abuses and misdemeanours dailie committed on the river by lewde and ill-disposed people, in cutting the banks and letting out the said water, they cast in dead dogges and filth and letting in sewage and other fowle and unclean water. They also steal branches and cockes from the pipes".
Connection to the system gave householders a single tap, which cost 24 shillings (about £160 today) per year. However, water only appeared on 'water days', when supply was delivered to nominated streets. As London had grown and the distrubtion zone widened, lack of water pressure had became an issue. No suitable power supply had been found to operate pumps.
In about 1707, Sorocold was approached by the New River Company. To provide a power source, he proposed the construction of a windmill at the reservoir at Clerkenwell. It would work pumps that raised water into a second, higher pool that he called the Upper Pond (completed 1709, later Claremont Square Reservoir), some 7.3m above the Round Pond. This arrangement offered additional gravity-fed distribution possibilities, with more pressure available in the mains.
A brick tower windmill with an ogee cap was built, which, unusually for the time, had six sails — a very early example of a six-sailed mill and an early use of the ogee cap in Britain. Perhaps the use of this cap was inspired by the proximity of the dome of St Paul's Cathedral, the shape of which it resembles (see illustration). The base of the structure incorporated a horse-driven mechanism to provide power on days with no wind. However, it was reported that: " ... the mill is a foot too small in circumference to work well with horses, when the wind fails, as it was intended it should".
No details of the mill's dual pumping mechanism have been found and it seems that the horse operation was less than successful. On 20th November 1720, the mill lost its sails in a strong wind, never to be replaced. A separate square-plan horse gin was constructed to drive Sorocold's pumps. One report suggests that seven horses were used at a time, working four pumps — requiring an extraordinary 28 horses to keep the pumps working continuously. The horse mill would be replaced by a steam engine in 1768.
The red brick base of Sorocold's original windmill, now only some 2.6m high and roofed over to create a storeroom, can still be seen near Nautilus Garden, Amwell Street, Islington. Its internal diameter is only 6.8m — not much tread way for horses. The Upper Pond was covered over and turfed in 1855 and is still in use by Thames Water as a reservoir.
main reference BDCE1
image courtesy William Salt Library, Stafford