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of Dartford, Kent
1732 A gunpowder factory was founded at Dartford by Pyke and Edsall.
1778 Following the bankruptcy of Edsall the factoruy was sold to Frederick Pigou and M. P. Andrews
Early 19th century the Dartford factory was being run by Pigou and Wilks.
The firm amalgamated with Charles Laurence and Son of Battle becoming Pigou, Wilks and Laurence.
From 1890 gunpowder manufacture was supplemented by production of gun-cotton and (for a short time) nitrocellulose flake.
1898 Curtis's and Harvey was incorporated to take over the businesses of certain firms and companies manufacturing black and smokeless military and blasting powders, including Curtis's and Harvey, John Hall and Son, Pigou, Wilks and Laurence. 
Shortly afterwards black powder operations were closed down, with only gun-cotton surviving.
From the 1920s the Dartford site was merely a ballistics and research station
1934 All activities ceased. The works was then sold.