At a time when Britain seemed to be eternally at war or under threat, not just from foreign powers but also from influences within, the powder mills at Chilworth played an important part in keeping the guns firing. The mills employed 600 people at their peak but this highly productive industry also brought with it inherent danger which led to frequent fatal accidents.
A Complex Production Facility
The gunpowder mills at Chilworth in Surrey were established in 1626 on the course of The Tilling Bourne, a tributary to the River Wey. Although only a small river, its four principal tributaries, and the fact that it flowed over a steep gradient, ensured a good flow of water that not only powered the gunpowder mills but a good number of other mills too. The river rises close to the summit of Leith Hill (GR: TQ136433) near Forest Green, which at 965 feet (294 metres) is the highest point in South-eastern England.
The Chilworth site was extensive, as the manufacture of gunpowder not only involved a series of difficult processes, but also being a highly volatile procedure required that buildings be widely spaced and separated by protective mounds and trees.
The remains of the mills are a Scheduled Ancient Monument managed by English Heritage covering 11 hectares (27 acres) in a designated Area of High Ecological Value. The natural habitat is a wet woodland predominantly of alder, with the Tilling Bourne running against the northern boundary. A man-made mill race runs along the southern boundary. Above one of the millponds there was a hopfield that produced the hops for beer brewed specially for the workers at the mills, although with hindsight would this have been a very sensible perk given the nature of their work?
Six hundred people were employed at Chilworth at the mills peak, although in reality very few of these were employed directly in the manufacture of the gunpowder. The majority provided services supporting the mills including coopering barrels.
Prior to the mills being established, gunpowder was made by hand. This involved the mixing and crushing together of a mixture of saltpetre (potassium nitrate), charcoal and sulphur (also known as Brimstone) with a pestle and mortar. A very hazardous business for the powdermaker.
Alders grow profusely all along the River Wey, and they made good charcoal for gunpowder. The charcoal was burned in ‘pitsheads’ using traditional methods in the woods where the trees were grown.
The saltpetre was originally imported from India and North Africa where the climate was hot and dry, readily stimulating its formation. However securing this critical ingredient was always a headache, and so the bribery in 1561 of a German Captain, Gerard Honrick, securing the recipe for making saltpetre was a major coup. The method of manufacture involved collecting heapblack earth formed within dovecotes and stables, and to which urine, dung and lime were added. This mixture was turned at intervals over several months until the salts had formed which were extracted in solution. The liquor was then boiled down and cooled so that crystals of saltpetre precipitated.
So critical was ensuring a dependable supply of saltpetre and gunpowder that in 1621 James I appointed Lords of the Admiralty as Commissioners for Saltpetre and Gunpowder. They divided the country into districts for collection, and specialised saltpetre men were appointed and given weekly quotas to meet. They were also awarded powers with the right to enter premises to dig for nitrogenous earth.
Powdermills at Wotton and Abinger on the Tilling Bourne were established by George Evelyn, his son John and one Richard Hill following their appointment as manufacturers by Royal Letters Patent to obtain saltpetre and manufacture gunpowder in 1589. Their grip on supply was considerably strengthened when three year contracts were awarded to them consecutively in 1621 and 1624. The contract provided for two thirds of their output to be delivered to the government’s official stores in the Tower of London, with the balance released to be sold at will to merchant seamen, and others who needed the powder.
Elizabeth I established the system of Crown Appointments imposing a monopoly in which a sole powder maker to the Crown was appointed, and efforts were made to suppress other manufacturers. The importance of Chilworth in the supply of gunpowder was secured when special permissions were granted to the East India Company to manufacture gunpowder for its own use. They established their powder mills at Chilworth in 1626.
The East India Company continued to manufacture their powder here for another ten years until the mills were considerably expanded to supply the government of Charles I, and later made gunpowder for Parliament during the Civil War. Their powder maker stayed on to continue operating the mills.
Powdermaking : an Insecure Occupation
The early manufacture of gunpowder was an insecure and unpredictable occupation. Demand fluctuated considerably and consecutive governments were notoriously bad at paying their bills. Many powdermakers suffered financial hardship. Two of the three sites at Chilworth were out of gunpowder production by 1704, with the upper works closed completely and the lower works converted to paper making. The middle works continued and by the late 19th century had expanded to become a site of national importance again and were at the time the most modern in the country.
Invention of High Explosives
A German company took over the mills in 1885 to manufacture a brand new type of gunpowder that was virtually smokeless and was ideal for the very large guns now in operation. The powder was made using brown charcoal providing the smokeless element, brown charcoal being made from straw rather than the traditional alder wood. Not long later however high explosives were developed using ballistite, a smokeless gunpowder invented by Alfred Noble in 1887, and in 1889 cordite with nitroglycerin as its main ingredient. Both were manufactured at Chilworth with a second cordite factory being built there by the Admiralty in World War I.
Explosions & Tragedies
The manufacture, storage and transportation of gunpowder was a considerably hazardous business. A survey conducted by Sir Jonas Moore in 1677 identified accidents at the three works then at Chilworth: “The Lower Mill, 3 troughs, blown up. The Randills Mill, 3 troughs, blown up.” Many other explosions and tragedies were to follow.
The corn mill at Albury Park blew up in 1727 when gunpowder that was being temporarily stored there ignited. An explosion at the corning house at the Chilworth powdermills in 1760 killed two workers, with many others seriously injured. The corning house is where gunpowder is granulated by forcing it through sieves in a shaking frame, or in later more modernised processes by passing it between toothed gunmetal or zinc rollers. The walls of the mill were split from top to bottom by the force of the explosion, and caused the collapse of St Martha’s Church on the hill over half a mile away. The church was illustrated as ruins in a sketch of 1763, and the church wasn’t rebuilt until 1850. Eighteen years later an explosion, again in the corning house, hurled a wheel and heavy beam a great distance and further damaged the remains of the church. All the windows at the manor house were blown out too.
The occurrence of accidents continued through the 19th century. A massive explosion in 1864, when 30 cwt (1,524 kg) of powder went up, killed two men in the press house and resulted in all work at the mill being suspended for three months whilst repairs and equipment replacements were carried out.
Transporting the powder was no less dangerous. In the same year a powder barge exploded on the Godalming Navigation as it was being hauled from Stonebridge at Shalford to Guildford, instantly killing the two men on board. Over the next fifteen years a further four men died, with the last accident recorded being a particularly extreme one. The press house contained a hydraulic press and a breaking-down machine, both powered by a water turbine. 1,800 lbs (816 kg) of gunpowder ignited in a single shattering explosion instantly killing the two men working inside and hurling their bodies 130 yards (119 metres) into an adjacent field. The press house’s heavy machinery was scattered in all directions and debris was strewn for over 200 yards (183 metres).
Safety Measures Introduced
The mounds and screens constructed for just such an eventuality, assisted by the dense circle of trees specifically retained, protected other buildings on the site. Storage magazines were also buried deep inside large U-shaped mounds, several of which still remain today. It was at the Chilworth mills that a new construction method for protective mounds was developed by which rolls of corrugated iron were filled with earth, these becoming referred to as ‘Chilworth Mounds’ as the idea became adopted all around the world.
The incorporating mills had an added safety feature by way of large drenching pans that were easily overturned to empty their contents over the mill bed to smother any fire hazard. Officials from the Explosives Inspectorate were unable to find fault with the mills’ operating procedures and a cause of accident was unable to be proven. The Explosives Act of 1875 introduced new safety legislation, although it took a period to effectively implement the regulations that were intended to provide further safeguards for powdermill workers.
The 20th century proved that the potential lethality of gunpowder manufacture was not lessened by legislation. The worst explosion ever recorded at Chilworth was triggered by a freak accident. Six men were killed in two consecutive explosions, the first in a powder tram outside the corning house which in turn set off the second in the corning house itself. One of the men had slipped on his hob-nailed boots whilst carrying powder from the tram, the act of slipping creating a spark that ignited the powder on the tram. Tragically two of the men suffered from their horrendous injuries before dying at a private hospital at the works shortly after the explosions. The Inquest was held at the nearby Percy Arms public house which found no fault with the mill’s operating procedures, although the owners were criticised for not having provided additional tracks to allow the tram to be manoeuvred closer to the mill buildings eliminating unnecessary manual handling.
First World War Attack
Additional hazards to mill operations were introduced by the First World War. The factory was provided with anti-aircraft guns by early 1915, and St Martha’s Church was heavily camouflaged with branches to prevent the building being used by enemy pilots as a landmark for navigation. The worst scare of the war was when in 1915 a German Zeppelin dropped 12 bombs in the St Catherine’s area of Guildford not far away whilst the pilot was looking for the gunpowder works. Damage was effected to property but the only casualties were a swan on the river, and 17 chickens.
Industry Rationalisation & Closure
Chilworth powdermills stopped producing explosives in 1920 following a formal rationalisation of the explosives industry, which resulted in the merging of leading companies after the war to provide a centralised consolidation.
Although today there is little left in the way of the original buildings in what was an extensive site, old waterways, half-buried railway tracks, millstones and foundations can still be seen.
The Surrey Wildlife Trust conducted a survey (October 2006) of the area around the Chilworth Gunpowder Works and have discovered that its isolation has encouraged several important rare species to take up residence. The most encouraging was evidence that the endangered common dormouse has taken advantage of eighty years of unhindered growth of vegetation and is breeding amongst the ruins.
The wildlife team were looking for evidence amongst the scrub of hazel, brambles, holly and hawthorn for used hazelnut shells which helps identify the wildlife species that are feeding on them.
Source: Surrey Advertiser 13th October 2006
A public consultation period was instigated by Guildford Borough Council in April 2008 on plans to designate Chilworth with conservation area status. If successful, designation will provide higher legal protection and will give extra protection for the village from development, much of which originated directly or indirectly from the gunpowder industry at the Gunpowder Works.
A family of the endangered species of dormice have taken up residence (July 2009) in a nesting box installed by the Surrey Wildlife Group in the grounds of the Chilworth Gunpowder Mills. MORE HERE
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