One customer in particular bought large amounts of ammoniacal liquor from most of the London gas companies. He was active over a period of seven years in the 1820s and early 1830s. If the number of entries in the gas minute books are a measure, he was easily be the biggest customer. Beneke of Deptford bought only ammoniacal liquor.
Deptford Creek is the mouth of the River Ravensbourne flowing into the Thames between Deptford and Greenwich. It has long been an industrial waterway. The mills on its length from Keston to Lewisham processed cutlery, leather, and silk as well as gun barrels for the Napoleonic Wars. Throughout Britain industrial museums give an important place to their local fire brigade equipment, almost always made on Deptford Creek by Merryweather. One major industry there was the manufacture of copperas. In operation since the 14th century, the best known works were at Queenborough and Whitstable in Kent. There were also works at Rotherhithe and Blackwall.
Copperas is 'ferrous sulphate heptahydrate'. made from the oxidation of iron pyrites. Pyrites was known as 'copperas stone' and collected from the Kent and Essex shoreline.4 'Pickers' gathered the stones along the estuary on behalf of landowners. The 17th century account books of Sir John Hayward record the amounts of stone sent to Deptford from the Isle of Sheppey. Copperas was used as a black dye for woollen cloth, inks, marking material and as a 'facing' for green tea. Its real importance can be deduced from its other name "green vitriol"- that is to say 'green' or "raw" sulphuric acid. Before 1800, copperas was a vital raw material for this important commodity.
The Deptford copperas works appears on a plan of 1674. The site was part of the Evelyn estate - although, strangely, John Evelyn never mentions it. The works were owned by a Royalist entrepreneur called Nicholas Crispe. Crispe, and those like him, had many economic interests in the period after the Restoration - Greenwich was full of such men.
Daniel Colwell, a friend of Crispe, described the Deptford works to the Royal Society in 1688. The copperas 'beds' were trenches of about a hundred by fifteen feet and twelve feet deep. The stones were put in these and covered with rain water. After several years the liquid would dissolve a boiled egg in three minutes! The liquid, crystallised, produced 'oil of vitriol', leaving a residue also used as a dye - Venetian red. Crispe's was not the only copperas works in the area. In 1695 another copperas works was owned by a Sir Samuel Thompson at Lamb Lane in Greenwich. For the next hundred years copperas was the basis of chemical manufacture carried out on Deptford Creek. These works passed through a number of owners, including a consortium which owned works throughout the Thamesside area.