Coal of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath), although in fact easily accessible surface coal from what became the Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron-working in the city during the Roman period has been found. In Eschweiler, Rhineland, deposits of bituminous coal were used by the Romans for the smelting of iron ore. No evidence exists of the product being of great importance in Britain before about AD 1000, the High Middle Ages. Mineral coal came to be referred to
Escadrille SPA.31 use of a Roman archer as the "escadrille" insignia. In October, "Escadrille N 31" shifted to support "II Armee". The following month, the unit was incorporated into "Groupe de Combat II". "Escadrille 31" began receiving SPADs on 7 January 1917. However, it would not totally rearm with SPADs until 17 September, when it was renamed "Escadrille SPA 31". The "escadrille" would serve as part of "GC II" through the remainder of the war. When the armistice came, it had been credited with 42 aircraft and four observation balloons destroyed, and have earned two citations from Army Corps. Escadrille SPA.31 Escadrille