Industrial Archaeology The Royal Gunpowder Mills site is an important industrial monument containing one of the most extensive ranges of industrial archaeology in the country. Gunpowder The saltpetre melting and the ingredient mixing houses adjacent to the exhibition centre date from the time of Government purchase in 1787 and mark the beginning of the application of scientific method to gunpowder manufacture. Production followed the route of the Millhead Stream, which provided power. The production process involved nine different operations with each set of buildings served by a central water wheel. The Millhead complex was one of the first factory systems in Britain. The steam powered gunpowder incorporating mills to the east of the Millhead are an impressive expression of the growing power of the nation in the Victorian period and the underfloor drive train reflects the weight and bulk which charactensed Victorian engineering. Chemical Explosives The end of the dominance of gunpowder coincided with the end of the Victorian era in the last years of the 19th century. The 20th century ushered in the era of organic chemistry applied on an industrial scale to explosives and a wide range of other products. The north of the site containing the chemical explosive production area is an evocative industrial landscape with grass covered blast mounds, prominent features such as the nitrating hill and deserted process buildings such as the mixing houses where a large part of the cordite requirements of the British Forces literally passed through the hands of a handful of skilled workers engaged in the dangerous task of mixing the ingredients. Hydraulic Power The gunpowder and explosives industry was a significant user of hydraulic power. The 1856 water powered hydraulic press is unique. The era of steam produced hydraulic power is represented by the Group E Mill central production point with its tall accumulator tower and the other accumulator towers. Various hydraulic powered process buildings survive. Waterways The waterways of the Mills are a unique two level industrial canal system, originally extending to five miles, with two locks between the levels and a cut to the Lee Navigation to enable the transportation of finished product by sailing barge to magazines on the Thames. Smooth shock free water was preferable to road for transport of materials between the process buildings. Industrial Railways When the first steam powered incorporating mills were built in 1857 a hand pushed tramway was introduced linking the mixing house and the mill. The gauge was changed to l8 inches in the late 1890s. This system was gradually extended and further extended when in 1917 paraffin - petrol locomotive working and later battery electric traction was introduced. An industrial railway with authentic rolling stock is being re-created on the site. Rocketry One of the main activities of the post WWII research era was investigation of rocket propulsion materials. Test firing was carried out in the buildings of a disused nitroglycerine factory in the New Hill area. The photo to the right shows Rocket Propellant Testing at No. 2 Firing Point, New Hill. The Archive Reflecting the industrial archeology of the site, the Mills Archive has an extensive holding of historical maps dating from 1590 and building drawings from the 1850s. In addition, around 5000 documents and 80,000 images are held, covering the history of gunpowder and explosives manufacture with particular reference to Waltham Abbey.