Gretna Hm Factory Eastriggs Factory, Acids Section, Final Acid Mixing House

Canmore ID: 374956

NY26SW 38.17

NY 24926 64928

The remains of this building are situated in dense deciduous scrub woodland about 7.5m NNE of the Acid Storage Tanks (NY26SW 33.33) and 30m WNW of the Denitration Plant (NY26SW 38.28). The main building is rectangular on plan and measures 22.5m from WNW to ESE by 10m transversely overall. It is outlined by small concrete footings for timber uprights enclosing a concrete floor. Attached to the SSW is a narrower concrete apron beyond which is a rectangular, rubble-filled basin measuring about 12m from WNW to ESE by 2m transversely within brick walls 0.5m in thickness and 0.8m in height.

The building is identified as housing Acid Mixers on the plan of, and in text referring to, the works the works (MMW 1919, 83-94, plan) given in the report by the Ministry of Munitions of War outlining the processes involved in the manufacture of the cordite propellant during the First World War at H.M. Factory, Gretna (Site 3). It was here in the Final Acid Mixing House that Nitroglycerine acid and Nitro-cotton acid from the Preliminary Acid Mixers (NY26SW 38.36, NY26SW 38.37) were blended. The building is also denoted elsewhere as the Final Acid Mixing plant (MMDES, 1920, 20). A blueprint held by the National Archives at Kew (Devil’s Porridge Muse-um, blueprint no. 3693; MUN 5-297 pt2, 3505), along with ground-based, contemporary official photographs (MUN5-297 pt1 251A; MUN 5-297 pt2 301; MUN 5-297 pt3 453; MUN 5-297 pt4 631; MUN 5-297 pt5 717) taken during and after construction also held at Kew, show that the building was a tall single storey, wood- framed, weather-boarded, Belfast roofed building capped by a vent running its full length. There were five windows below the eaves in the NNE and SSW elevations and three in the ESE and WNW elevations. The building was open at the base and there were dwarf walls running its full length which supported three large, steel mixing tanks. A weather-boarded outshot with a sloping roof was attached on the SSW and this contained four pumps. There was a doorway on the ESE of the outshot adjacent to a window with another window on the WNW. The brick-built basin to the SSE contained two long blow casks, one for Nitroglycerine acid and one for Nitro-cotton acid, which were open to the elements. These were provided in case the pumps broke down.

The building fell into lot 507, which was offered for sale by auction on 22-5 July 1924 (HM Treasury 1924, 101), when the lot was bought by Messrs James Jackson & Co Ltd, St Vincent Street, Glasgow (Carlisle City Archives, DX 2040/3). After its removal from the site, only the foundations were left in place and these together with the whole course of the main flue and the two branches on the S, are readily visible on an aerial photograph (M124/13 04117) flown on 19 August 1940.

Visited by HES Heritage Recording (MMD and ATW), 10 May 2022.