THE MANUFACTURE OF GUNPOWDER AT DARTFORD
The manufacture of gunpowder and guncotton at Dartford has a long history going back to the first half of the eighteenth century. Dartford was selected as a suitable area for the manufacture of gunpowder because of the proximity of the River Darent. Ample water supplies were needed for the manufacture of black powder and also to provide power to drive the machinery.
In 1732 Messrs. Pike and Edsall took over what is reputed to have been the site of Sir John Spilmans paper mill at Dartford and converted it into gunpowder mills. Unfortunately, by 1778, the Company became bankrupt and the gunpowder mills, sited close to modern-day Powdermill Lane, were sold to Messrs. Pigou and Andrews. Andrews was the son of a Watling Street drysalter.
The manufacture of gunpowder was a dangerous process. There were regular explosions at the Dartford Gunpowder Mills, 1745, the most serious, 1790, 1796 and 1799. At least twenty-seven people were killed in explosions at the Gunpowder Mills between 1750 and 1800. Dartfords parishioners objected to the carrying of gunpowder through the streets of the town, so in 1796 a new road was built to transport the powder to the storage site then known as Robins Hole.
In 1790, there were only four mills at Dartford. Within just twenty years of this date, the powder magazines at Dartford were to become the most extensive in England. A number of special processes were carried out on-site. The gunpowder was milled, dried, granulated, polished and packed. The Dartford mills were surrounded by large earthen embankments to minimise the damaging effects of accidental explosions.
The three main ingredients for making gunpowder were saltpetre, charcoal and sulphur. The saltpetre was mainly mined in Italy and India and imported by ship to the Thames estuary. Sulphur was mostly quarried in Sicily and Italy and again had to be shipped to England. The charcoal required great quantities of wood which was obtained from local woodlands - mostly alder and willow. All three ingredients had to be processed individually on the site. When all three had been prepared they were carefully mixed together in the correct proportions in isolated mixing-houses. Once all the various processes had been completed, the gunpowder in cake form was transported in barrels, either by cart or by barge.