Gretna, Hm Factory, Eastriggs Explosives Factory, Nitroglycerine Hill No.5

Canmore ID: 373575

NY26SE 16.05

Centred NY 27345 64655

Only the foundations of one building (NY 27510 64606) remains of the plant that once formed part of this Nitroglycerine Hill, which is situated at the E end of a ridge, the gradient of which eases gently as the topography levels off to the NNE. This is located in gorse 130m NE of Explosive Magazine R57 (NY26NW 46.12). It is rectangular on plan and measures about 9m from NNE to SSW by 6m transversely within very faint traces on the ESE and SSW of a spread blast mound up to 6m in width. However, LiDAR images show a disturbance around the top of the Hill (NY 27306 64523 centred) and also in three locations roughly in a line about 90m to the NNE (NY 27252 64618, NY 27338 64591, NY 27428 64598). In addition, the LiDAR also shows the slight remains of two grass-grown blast mounds immediately to the NNW and NE of Explosives Magazine R64 (NY26NW 46.12). The more westerly (NY 27318 64982) is rectangular on plan and measures 40m from WNW to ESE by 38m transversely over earth banks spread to at least 10m in breadth, while its neighbour (NY 27446 64969), centred 130m to the ESE, is also rectangular on plan and measures 38m from NNE to SSW by 33m over earth banks spread up to 11m in breadth. This visualisation also shows a faint swelling (NY 27393 65034) 90m NNE from the centre of both these earthworks. It is roughly rectangular on plan and measures about 40m from WNW to ESE by about 6m transversely.

The structures associated with Nitroglycerine Hill No.5 are referred to in the report (MMW 1919, 145-163, plans in text) outlining the processes involved in the manufacture of the cordite propellant at H.M. Factory, Gretna (Site 3), which was established by the Ministry of Munitions during the First World War. This section of the factory comprised a complete plant for the manufacture of Nitroglycerine. An undated plan (SUPP 10-39) held in the National Archives at Kew shows the location of the buildings and associated infrastructure, including minor structures such as lavatories and shelters. It indicates that the foundations of the building described above were those of a Wash Water Settling House (NY 27510 64606), while the disturbances mark the location of the Nitrator Separator House (NY 27313 65409) together with its associated buildings, and three Final Wash Houses that were situated to the NNE. It also locates the other buildings that clustered around the Nitrator Separator House. These included a Chemists Hut (NY 27225 64487), a Glycerine Dump (NY 27256 64475), a Soda Solution Dump House (NY 27267 64476), two Acid Storage Tanks (NY 27277 64483), an Acid Dump House (NY 27287 64489), a Charge House (NY 27287 64506), a Brine Store (NY 27307 64471), four Air Storage Tanks (NY 27354 64495), a Pond (NY 27518 64685) associated with westerly Wash Water Settling House, an additional Wash Water Settling House (NY 27178 64642), its Pond (NY 27190 64723) and a Rest Room (NY 27203 64776) that was shared with Hill No. 4 (NY26SE 16.4), a Waste Collecting House (NY 27225 64652) and other minor structures such as shelters and latrines. A description of a blueprint (SUPP 10-21 3956), several blueprints (SUPP 10-24 3075, 3196, number indistinct, 3208, 3211A; SUPP 10-25 3376; SUPP 10-26 3507, 3562; SUPP 10-27 3737, 3798A; SUPP 10-28 3956; SUPP 10-31 4365) and ground-based, contemporary official photographs taken during construction (MUN 5-239; MUN 5-297 pt3, 515-517), held at the National Archives at Kew, illustrate some of the associated infrastructure that once existed here (see Hill No.2, NY26SE 16.02 for the architecture of the buildings that were clustered around the Nitrator Separator House, the Final Wash Houses, the Wash Water Settling Houses and the Ponds). However, it is evident that a decision was taken part way through construction that led to Hill 5 sharing some of the infrastructure of Hill 4; and so although the blast mounds of the two Paste Magazines (NY 27051 65017 and NY 26919 65013) and the offloading platform to their NNE (NY 27393 65034) had probably been at least partly built, work on the Paste Mixing Houses and the Dry Cotton Store was never even begun.

This Nitroglycerine Hill fell into lot 491, which was offered for sale by auction on 22-5 July 1924 (HM Treasury 1924, 89; Carlisle City Archives, DX 170/38), when it was purchased by Greenwood & another of Broomhills, Eastriggs (Carlisle City Archives, DX 2040/3). The remains of all the buildings on top of the Hill (except for the Charge House), the three Final Wash Houses within their blast mounds and the more easterly of the Wash Water Settling Houses within its blast mounds on the ESE and SSW, are visible on an aerial photograph (M124/13 04122) flown on 19 August 1940. None of the blast mounds contained Nissen Huts (see Hills 2-4, NY26SE 16.2-16.4). Another aerial photograph (CAM/031 06211) flown on 13 October 1942 shows that these buildings and their associated blast mounds had been severely damaged and further degradation is visible on an aerial photograph (39/RAF/4701 P0028) flown on the 6 May 1975. Yet another aerial photograph (ASS/62588 0111, flown 13 June 1988) indicates that the remains had all been levelled.

Visited by HES Heritage Recording (MMD and ATW), 7 September 2022.