PART FIVE: TECHNOLOGY AND SOCIETY 952 achievement of modern civil engineering in using new materials in an elegant manner to perform on a huge scale one of the basic public services—providing a good water supply. The systematic use of impounding reservoirs to supply water to urban communities in modern times dates from the early nineteenth century, when Robert Thom created in 1827 what was then the largest artificial lake in Britain to supply Greenock on the Clyde estuary in Scotland. It retained this distinction until the Vyrnwy and Thirlmere projects at the end of the century (see below), but by that time extensive water supply projects had been undertaken in many parts of Britain. The first extensive municipal water supply project was that devised by J.F.La Trobe Bateman for Manchester between 1851, when the first part became operational, and 1877, when the works were complete. These consisted of five major reservoirs on the River Etherow in the Longdendale valley in the Pennines to the east of the city, with their associated aqueducts and auxiliary reservoirs. Bateman used earth embankment dams and had great difficulty in making them stable. Techniques of dam construction improved substantially in the second half of the nineteenth century, and pioneering work in Europe on the construction of high-wall masonry dams was adopted in Britain by the end of the century in the Manchester Thirlmere extension in the Lake District (1874–1890), the Liverpool Lake Vyrnwy scheme in north Wales (1881–1892) and the complex of reservoirs to supply Birmingham built in the Elan valley in central Wales (1890–1904). In the Manchester Haweswater project in the Lake District (1923), concrete became an important constructional material. In those places where surface water has not been easily available, thirsty towns and cities have exploited the potential of underground sources. Sometimes natural springs could be directed with little difficulty into water supply systems, but more normally wells have been sunk to reach the water table or to give access to artesian supplies where favourable geological conditions have prevailed. In some dry inland regions such supplies are vital to any permanent settlement. The construction of wells and bore-holes encouraged the use of powerful pumping engines to maintain a continuous flow and thus provided the primary need for the large steam engines which have figured prominently in the history of British water supply. One of the most extensive groups of water works deriving their supply from wells were those built under the direction of Thomas Hawksley to extract water from the New Red Bunter Sandstone for Nottingham, but Hawksley built similar systems for many other British and continental towns. The fine beam pumping engine built at Ryhope in Durham in 1868 under his direction for the Sunderland and South Shields Water Company has been preserved in working order, as has also the elaborately embellished engine and engine-house at Papplewick, north of Nottingham (1884). PUBLIC UTILITIES 953 Treatment Before water can be distributed for public consumption, various processes of treatment are required by modern legislation to ensure that it maintains wholesome standards. The first requirement is filtration to remove the coarser forms of pollution, but chemical treatment of dangerous organisms is also now obligatory in most countries. Filtration was used by Thom in his Greenock scheme in 1827, using mechanical and slow sand filtration processes. Two years later, in 1829, James Simpson brought into use his sand-filtration process at Chelsea waterworks in London. Together with Bateman and Hawksley, Simpson was amongst the leading British water-works engineers of the nineteenth century. His pioneering efforts at Chelsea were partly in response to a loud public outcry against the foul condition of the River Thames from which water was being drawn for public supply at that time. Simpson made a study of methods of filtering water supplies and built an experimental arrangement in 1827 in which water was first allowed to settle and then passed through a downward-flow filter consisting of a four-foot bed of carefully graded sand and gravel. It was this method which he then applied to Chelsea waterworks in 1829. Although successful in giving a vastly improved supply of water, the method took a surprisingly long time to be generally adopted, mainly because of scepticism about its beneficial effects, but also because of the high cost and substantial space required for filter beds. The impact of cholera, however, strengthened the case for filtration, and the principle was made obligatory in Britain by the Metropolis Water Act of 1852. This measure, confirmed by subsequent Royal Commissions and Acts of Parliament, served to give a sound legal basis to the provision of wholesome water in Britain, although chemical purity of water supply was not achieved until the introduction of chlorination to kill off undesirable bacteria. Like filtration, this was accepted with some reluctance by the water authorities, and it only became general practice in Britain after the Second World War. The further addition of chemicals such as fluoride to harden children’s teeth against decay is a matter of continuing controversy about the medication of water supply, but the principle of the responsible authorities being required to provide pure water to every domestic and industrial consumer is no longer in doubt in the developed countries. Distribution The distribution of treated water to its consumers has called on the skills of several generations of civil engineers. In Britain, even the early impounding reservoirs were usually in upland valleys comparatively remote from the towns where the supply was needed, so that extensive culverts and aqueducts were necessary to get it to its destination. The fact that the reservoirs were usually in PART FIVE: TECHNOLOGY AND SOCIETY 954 high land, moreover, meant that the supply could flow largely under the effect of gravitation. As the reservoirs were established farther afield, so the need for siphons, tunnels, and pumping engines increased. For example, the scheme designed by Bateman at Loch Katrine in the Trossachs to supply Glasgow is 48km (30 miles) from that town; Thirlmere is 160km (100 miles) from Manchester; and the Elan valley is 120km (75 miles) from Birmingham. The works by which these distances are covered are rarely obtrusive or easily visible to the casual visitor. In most cases, the level of the reservoirs is such to permit a siphon action to convey the water to the taps of the customers, but in some areas it is necessary to supplement this with water towers, to which the water is pumped in order to allow it to gravitate to its point of use. Powerful steam engines were frequently installed by waterworks in the nineteenth century to perform this function, and several of these have been preserved in various parts of Britain, although the work is now done by more efficient and convenient electrical pumps. Water may be allowed to flow freely in open culverts, but when it is put under pressure by pumping or by passing it through a siphon, or when it is being conveyed underground, it has to be contained in strong piping. The traditional form of water pipes had been those made of elm trunks bored out through the core and fitted end-to-end, but the tremendous expansion of the British iron industry made available new piping materials which were quickly demonstrated to be extremely versatile when used for water pipes. First came cast-iron pipes, flanged and bolted together, providing excellent water mains for laying underneath busy city streets, just as they also provided ideal gas mains. For larger pipes carrying water overground, wrought-iron pipes were constructed by curving plates and riveting them together in a manner similar to that used in the construction of boilers and the hulls of iron ships. Such wrought-iron pipes were well-suited for the aqueducts carrying water across valleys and other obstacles on the routes from reservoirs to its urban consumers. Subsequently, wrought-iron was replaced by mild steel, which remains in widespread use for conveying water although concrete piping is now used for some functions. The use of iron and steel piping has enabled water to be pumped for considerable distances in arid regions of the world where it is not practicable to use open culverts. For instance, inland cities in the USA like Denver, are supplied with most of their water from sources many miles away: in this case, it is collected on the western slopes of the Rocky Mountains and transferred through tunnels across the continental water-shed to the city which is on the arid eastern side of the mountains. Water supply has become increasingly a matter of water conservation as an expanding population with rising expectations presses on the finite fresh-water resources of the world. It has always been a scarce commodity in arid regions. The twentieth century attempts to conserve the water of the River Nile, from the first Aswan Dam completed under the supervision of Sir Benjamin Baker in PUBLIC UTILITIES 955 1902 to the Aswan High Dam finished in 1970, have extended the work of many generations of Egyptian engineers in this respect. In Australia, the driest of all the land masses in the world, most of the areas of human settlement are on the coast, but the development of gold-mining settlements at Coolgardie and Kalgoorlie in the arid deserts of Western Australia was made possible by the opening in 1903 of a 645km (400 mile) pipeline from the Mundaring reservoir near Perth. An even more ambitious project in the south east of Australia, the Snowy Mountain scheme, during the 1950s and 1960s involved converting a large eastwards-flowing river into one flowing westwards into the dry but potentially fertile interior, and providing a large amount of hydro-electric energy in the process. In parts of the world with even scarcer resources of fresh water, the desalination of sea water is the sole means of maintaining essential water supplies. The first large plant of this type was installed in Kuwait in 1949, and despite heavy initial expense on the equipment required to produce the evaporation and condensation of sea water, there is likely to be more use of it in the future as even more-favoured parts of the world begin to find that their available water resources are inadequate to meet expanding needs. Drainage A corollary to a good water supply is a good system of drains. In the first place, drains are required to remove surface water, and secondly to allow the removal of sewage. With the increase in urban building and the paving of streets, natural means of allowing surface water to percolate the sub-soil or to run off in streams are blocked, and it becomes necessary to provide artificial drains for this purpose. As rain rarely falls consistently, the provision of drains has to allow for the periods of maximum rainfall in order to protect settlements from the hazard of serious flooding. In tropical areas this involves ‘monsoon ditches’ alongside main roads to carry off the very heavy rain accompanying frequent thunderstorms, but in more temperate latitudes the service of drains is usually less conspicuous, although some modern cities have found it necessary to undertake storm-water and river-control works in order to guard against exceptional conditions of prolonged rainfall or flash floods. Towns on tidal estuaries have comparable problems when parts of the built-up area are below peak high-tide level. Normally, potential flood conditions can be controlled by extensive river embankments and dykes, as demonstrated in the Netherlands and Belgium around the mouths of the Rhine. In some places, however, the gradual sinking of the land creates a long-term problem and makes the coincidence of exceptional weather conditions with a particularly high tide a dangerous hazard. Parts of the Netherlands and south east England experienced such a combination in 1953, and the construction of the Thames PART FIVE: TECHNOLOGY AND SOCIETY 956 Flood Barrier at Woolwich was undertaken as a defence against a repetition of this event, which could put at risk large parts of London. The Barrier, completed in 1984, consists often rising sector steel gates between hooded piers spanning the 520m (171 0ft) of the river at Woolwich Reach. The gates are normally submerged horizontally, allowing shipping to pass freely, but in an emergency they can be raised in about 30 minutes to stand vertically and hold back any potential tidal surge. The system has not yet been put to a serious test, but it is a considerable comfort to Londoners to know that this public service is now prepared. Sewage disposal Water supply has been an essential factor in the development of successful methods of disposing of large volumes of organic waste. Modern systems of sewage disposal began with the introduction of water-borne techniques inspired by Edwin Chadwick’s public health reforms in Britain in the 1840s, and the insistence of engineers such as Hawksley on providing a continuous rather than an intermittent supply of water wherever it was required. As towns acquired reliable sources of fresh water, so a proportion of this became available to flush water closets and to maintain a continuous flow of sewage waste through a network of well constructed main and tributary sewers. The design and construction of sewers were carefully managed. In the Victorian era good quality brick became the favoured material for the building of the larger sewers, in a pear-shaped cross-section, the narrower end at the bottom to ensure a strong flow of liquid even when the level was low. Such sewers thus had a self-scouring action so long as they remained in use. Most of the early systems of sewers aimed at discharging their effluent into a river downstream from the town being served, but gradually it was recognized that this was not acceptable for inland towns where other settlements depended upon the same river for their water supplies, and even those with access to the sea and tidal estuaries were encouraged to consider the value of recovering minerals from the waste. Thus followed the development of ‘sewage farms’ for securing the partial purification of water to be released back into the rivers and for exploiting those parts of the waste which could be used for agricultural fertilizers and other purposes. The techniques of sewage treatment involved some form of sedimentation process, with the addition of chemicals as appropriate to speed the bacteriological decomposition and to remove unpleasant odours. The most serious problem confronting public health experts and the engineers who served them in the middle of the nineteenth century was that of providing a system of drains and sewers for the metropolis of London. This was achieved between 1855 and 1875 by the Metropolitan Board of Works and its engineer Joseph Bazalgette. The principal feature of Bazalgette’s system PUBLIC UTILITIES 957 was a main drain along the north bank of the Thames, partly to accommodate which the Victoria Embankment was constructed. This cut across older drains and received the discharge from many tributary sewers before finally discharging itself into the tidal waters of the Thames below Blackwall. A similar network provided for the removal of sewage south of the Thames, to discharge at Crossness. On both sides of the river the gradient was such that it was necessary to assist the flow of sewage by the installation of several powerful pumping engines, several of which survive as industrial monuments although no longer active. Bazalgette received a well-deserved knighthood for his work, which did much to remove the curse of cholera and other fever diseases from London. Similar systems were installed in other large cities in Europe and elsewhere. Indeed, from an engineering point of view it is difficult to improve on the system so long as the principle of water-borne sewage disposal is adopted, so that new work has tended to concentrate on improving the quality of sewage treatment; the replacement of old sewers, which have frequently now given over a hundred years of excellent service in many of our big cities, with the minimum of maintenance; and the adoption of concrete and plastics instead of the traditional constructional materials of brick and iron. POWER SUPPLY Gas Coal-gas had been recognized as a by-product of coal before the eighteenth century, but it was William Murdock who, at the end of that century, first discovered how to apply it as a public service (see also p. 208ff.). Murdock was the agent responsible to Boulton and Watt, the Birmingham manufacturers of steam engines, for the erection of their machines in Cornwall. Murdock’s daily work, however, did not prevent him from exercising his inventive and active mind in other directions, and in 1792, while pursuing methods of preparing wood preservatives from materials produced by the distillation of coal, he collected coal gas from his primitive retort and used it to light his house in Redruth. On returning to Birmingham in 1798 he continued his systematic investigation of coal distillation and his coal-gas plant was used to illuminate the Soho Foundry during the celebrations accompanying the Peace of Amiens in 1802. Simultaneously, Phillipe Lebon in France produced elaborate plans for manufacturing coal-gas, incorporating a process to wash it in order to extract useful by-products, and applying it to equipment for lighting and heating, and also for inflating balloons. Lebon was killed in Paris in 1804, and little was done to take advantage of his research, but in the same year Boulton & Watt started seeking orders for Murdock’s gas-making equipment and installed it in several large mills beginning with Phillips and Lee of Salford in 1806. The PART FIVE: TECHNOLOGY AND SOCIETY 958 equipment employed was crude, burning gas in small jets known as cockspurs, generating offensive smoke and smells. Boulton and Watt abandoned the manufacture of gas apparatus in 1814, by which time the quality of their equipment had been overtaken by rivals and particularly by that of Frederic Albert Winsor, an eccentric anglicized German professor who launched the Gas Light and Coke Company in London in 1812, and by Samuel Clegg, who had trained under the chemist Dalton in Manchester and worked with Boulton and Watt before being recruited by the new London company in 1812, just as the demand for gas lighting was increasing rapidly. By the end of 1815, some 26 miles of gas mains had already been laid. Clegg used cast-iron retorts and provided for cooling and washing the gas, and for purifying it in lime. His system was extensively adopted by the gas companies which sprang up in most British towns, often in close competition by the middle of the nineteenth century. Some companies introduced oil-gas to replace coal-gas in the 1820s, using a process based on the distillation of whale oil, but it proved to be an expensive alternative and by the middle of the century most installations had been converted to coal-gas and merged with rival undertakings. Gas was now being very widely used, although suspicion of it had not entirely disappeared and it was excluded from the Great Exhibition in 1851. Gas had been used mainly to illuminate streets and public places, its fumes making the application of gas-lighting in domestic rooms unbearable. But the introduction around 1840 of the atmospheric burner, mixing air with the gas just before combustion, greatly enhanced its utility, and the subsequent applications in the Bunsen burner (1855) and the gas-ring (1867) increased its performance as a heater in boilers and ovens. Gas cooking, however, did not become common until the 1870s and the gas-fire with radiants was introduced in 1880. Dry gas meters also became widespread in this period as a means of registering the amount of fuel supplied to the domestic consumer. A vigorous international market developed for gas equipment, and British engineers were responsible for many installations in Europe, America, and Australasia. As a measure of rationalization was achieved between competing suppliers, coal-gas came to exercise a virtual monopoly in urban illumination (the paraffin lamp developed for use elsewhere), and the industry became complacent about its prospects until the advent of the electric incandescent filament lamp presented a serious challenge from a totally different technology. Thanks to the incandescent gas-mantle patented by the Austrian Carl von Welsbach in 1885, the gas industry continued to provide an efficient system of illumination into the twentieth century, while it transferred its main emphasis to heating functions, both for industrial processes and for domestic heating and cooking. The distillation of coal in retorts underwent little change until the 1960s, although the traditional horizontal retorts operating a batch-production process were gradually replaced, first by inclined and then by vertical retorts which could maintain continuous PUBLIC UTILITIES 959 production. In some smaller gas works however horizontal retorts remained in operation until the end of coal-gas manufacture. The re-introduction of oil- based processes and then natural gas, obtained as a by-product from North Sea oil fields, brought about a spectacular change in the gas industry in Britain in the 1960s and 1970s. Coal-gas retorts disappeared, and even the large bell-tank gas-holders which had long featured on every urban skyline were reduced in number as the gas was processed at a few new units and conveyed around the country in a network of high-pressure mains. Gas has thus managed to remain an efficient and convenient source of heat energy in all developed nations, even though its long-term viability has come to depend on the availability of oil and natural gas and the economics of recovering them from places which tend to become steadily more inaccessible. Electricity The generation of electricity is treated in Chapter 6, but it is appropriate to mention it here as the source of many of the most valuable utilities and services in modern societies. While scientific knowledge of electric power increased rapidly in the nineteenth century, with the discovery of both chemical and mechanical means of producing a continuous current, the electricity supply industry was remarkably slow to take advantage of this accumulating expertise. Not only did the coal-gas industry appear to have established a comfortable monopoly of urban lighting by the second half of the nineteenth century, but the risk capital was not readily available for a source of energy which required heavy installation costs and was then likely to have only spasmodic use. The solution to these problems came in the form of the electric incandescent filament lamp which provided a means of adapting the brilliant light available from arc lamps to a domestic scale; and the development of electric traction in the form of the tramcar and underground train. The filament lamp was developed by Thomas A.Edison in the USA, leading him to the production of a commercially viable electric light bulb in 1881, and by Joseph Swan in Britain. They joined forces to market their invention in Europe. Electric traction began with the adaptation of horse-drawn tramways, which had been established in most major cities of the Western world by the 1880s, for electrically-propelled vehicles. Werner von Siemens opened the first public electric tramcar service in Berlin in 1881, but this was essentially an experimental line and many problems regarding the engines, the power transmission system, and the design of the cars had to be overcome before the electric tramcar could offer a really efficient system of transport. This came in 1888, with the opening of the network in Richmond, Virginia, and in 1891, when the first British system began operations in Leeds. Thereafter electric PART FIVE: TECHNOLOGY AND SOCIETY 960 tramcars became vehicles of mass transport—‘the gondolas of the people’, in the vivid phrase of Richard Hoggart—and were responsible for a rapid suburban expansion of town life. To meet this expanding need for electricity, it became feasible at last to establish power stations generating sufficient electricity to supply a substantial district. Edison pioneered such electricity supply systems as early as 1879, when he demonstrated a complete system of generating plant, distribution network, and lighting apparatus, at his Menlo Park laboratories, and he quickly received contracts from municipal authorities to install such systems in the United States. The first complete installation in Britain was that constructed by Sebastian de Ferranti at Deptford for the London Electric Supply Corporation in 1889 (there had been earlier partial schemes at Brighton in 1881, and in London). Whereas Edison supplied direct current from his power stations, Ferranti and most subsequent electrical engineers adopted alternating current at high voltage, which has substantial advantages over direct current for long-distance transmission. The Deptford plant consisted of six steam engines driving 10,000 and 5,000 volt alternators, and amongst other innovations it employed new types of cable and an electricity meter to measure consumption by the customer. In America, George Westinghouse installed hydro-electric generators at the Niagara Falls in 1893, and like Ferranti’s system these operated on alternating current. As with gas works at the beginning of the nineteenth century, by the end of the century every town in Britain was promoting or seeking to promote its own electric power station, and again like the earlier experience of gas works, many towns found themselves with competing power stations. Enterprises tended to merge, however, as they became larger, and the advent of the steam turbine as a more efficient alternative to the reciprocating steam engine promoted this process by encouraging the construction of increasingly larger installations. By the 1920s these were being combined into national grids, and the process of rationalization continued with fewer but larger power stations producing more and more electricity. Oil-burning furnaces replaced coal- burners to produce steam for the turbines in many power stations, and since the 1950s a significant number of nuclear-fuelled power stations have also come on line. However, a combination of economic and political factors has ensured the retention of coal as an important fuel. The power produced by these large stations is distributed at high voltage over a wide area by overhead wires carried on pylons or by underground cables. It is reduced to lower voltages by local transformers for use by the customers, and the instant availability of electric power has become an assumption on which modern industry and domestic life rely as a matter of course. This universality of electric power has been a powerful factor in increasing the mobility of industry and population. PUBLIC UTILITIES 961 But perhaps the most conspicuous public service of electricity has been in the provision of street lighting. Gas had done much to make urban streets safer and more wholesome at night by reasonably efficient forms of lighting, which eventually came to include automatic control through a clock and a pilot-light, and gas mantles protected from the elements by a glass hood. But for sheer simplicity and ease of maintenance, gas street lighting could not compete with electricity and it was gradually displaced, while electric lighting also became readily available in areas beyond the reach of town gas mains and in new towns which never had cause to use gas lighting. With the introduction of the gas-discharge lamp, moreover, filament bulbs were replaced by neon lights and by mercury and sodium-vapour discharge lamps, which have become generally used in the streets of human settlements all over the world. The sodium lamp, in particular, has become very popular because of its remarkable cheapness and its efficiency in giving a diffused light—despite its unfortunate yellow colour. Electric power, in short, has become the largest single public service in modern societies. Hydraulics and pneumatics Just as the existence of a dependable supply of water made the provision of water-borne systems of sewage-disposal practicable, it served also to promote the use of hydraulic power systems. The possibility of using the pressure in a fluid both to multiply a force in its application and to transmit the force from one part of a machine to another or to another quite different machine had been fulfilled first by the Yorkshire cabinet-maker turned engineer, Joseph Bramah, who took out his patent for an hydraulic press in 1795 (see Chapter 7). Progress was slow for several decades, despite the versatility of Bramah’s machines, and the credit for developing hydraulic power into a popular means of power transmission belongs to William Armstrong, a lawyer in Newcastle- upon-Tyne who became one of the most innovative engineers of his generation. He patented his idea for an hydraulic crane in 1846 and established a large enterprise in Newcastle to manufacture it. Hydraulic power was found to be an ideal medium for operating lock gates in harbours, for raising and swinging movable bridges, and for working elevators in warehouses and public buildings. By the end of the nineteenth century, hydraulic power systems complete with pumping engines and miles of cast-iron mains had been established for public use in several of the largest British cities, and in places further afield including Antwerp, Melbourne, Sydney and Buenos Aires. These remained operational until well into the twentieth century, but they could not compete with electricity for efficiency and convenience, once this alternative was available. Although it has declined as a public service, hydraulic power has undergone important development in the twentieth century, being now used in . Australia, the driest of all the land masses in the world, most of the areas of human settlement are on the coast, but the development of gold-mining settlements at Coolgardie and Kalgoorlie in the. the land creates a long-term problem and makes the coincidence of exceptional weather conditions with a particularly high tide a dangerous hazard. Parts of the Netherlands and south east England experienced. years of excellent service in many of our big cities, with the minimum of maintenance; and the adoption of concrete and plastics instead of the traditional constructional materials of brick and