this was a gunpowder mill, established in 1811 by john children and william burton of tonbridge. william was the brother of decimus burton. the powder mills cost £30,000 to set up. humphry davy was also involved at the start, but he soon withdrew. the children family sold out to the burton at the end of 1812. william ford burton managing the mills. in the early 1820s the burton family bought the land, which had been leased initially. the site was known as the tunbridge gunpowder works. in 1834, thomas wells of powder mills died and was buried at penshurst. three explosions were recorded in the years 1832-35, the last killing two people. in 1837, there were four mills, each taking water from the same pond. the available head of water was some , and the waterwheels were breastshot. another explosion occurred in 1845, without loss of life. william burton died in 1859, and the mills were put up for sale. they were bought by charles and thomas curtis for £10,000. an explosion on 6 july 1864 killed four people. the firm was called curtis's and harvey by 1874. in this year, the transport of gunpowder along the river medway ceased owing to the inhabitants of maidstone fearing for their safety from the passage of the barges along the river. in 1878, there was an explosion that killed a man. steam power having been added by this date. the mills were reworked in 1885 when another explosion killed a man. cordite was being produced by this time and the manufacture of gunpowder ceased by 1897. curtis's and harvey became a public company in 1898. there was a tramway system around the site, probably introduced in 1885. the gauge was some . no locomotives were worked, all propulsion being by manual labour. an explosion in 1917 was caused by a lightning strike. after world war i, production was cut back, and curtis's and harveys had become part of explosives trade ltd, which became nobel industries ltd in 1920. nobel industries became part of imperial chemical industries. another explosion in 1927 killed several people. production ceased in 1934, with the manufacturing of explosives being transferred to ardeer in scotland. many of the buildings were burnt down. in 1942, the site was bought by t g east and son, and developed as a small pharmaceutical works. in 1952, the site came into the ownership of smith kline and french, which later became smith kline beecham and then glaxo smith kline. the site is now used for pharmaceutical research and is still known as powder mills to this day.