FAVERSHAM TR 06 SW HAM ROAD 659/6/10017 West Crystallising House (Building 18) 14-DEC-01 at former Marsh Gunpowder Works, Work shop Area GV II Crystallising house at saltpetre refinery, part of gunpowder works, now store.1800-10. Timber framed, clad with weatherboard, the SE and SW walls filled with brick nogging, with slate hipped roof. PLAN: Rectangular single-cell plan. EXTERIOR: Single storey, with double doors in SW end and NW side, 3 tall 5/5-pane casements each side and 1 in the end. INTERIOR: 3 king post trusses, the outer ones with ties to end walls, and stone flagged floor. HISTORY: The Marsh works were part of the Royal Gunpowder Factory which was established outside Faversham in 1786 after an explosion in the town, to remove some of the more dangerous processes. They played an important part in the improvement of the British gunpowder leading up to and during the Napoleonic Wars, under William Congreve. The saltpetre refinery was built in 1789 as part of Congreve's successful drive to improve the ingredients of British powder. It was privatised after the war, and closed in the 1920s. The crystallising house was where saltpetre was crystallised out of the solution which had been treated in the nearby refining house (qv), by placing it in racks of vats to cool, hence the open structure. This is one of two original refinery buildings on this site, and is a particularly impressive through the close relationship between the structure and the process, and is little altered. It forms part of a discrete, coherent group of late C18-early C19 industrial buildings for refining saltpetre, the best preserved of this type in the country comparable with French and Swedish examples. (Wayne Cocroft, Dangerous Energy. The archaeology of gunpowder and military explosives manufacture. Swindon (English Heritage), 2000, pp. 54-67)