This class of furnace is usually known as an open fire or hearth, and is represented in a more advanced stage of development by the Catalan, German and Walloon forges formerly used in the production of malleable iron.
But as the collection of authentic decretals does not begin till Siricius (385), the pseudo-Isidore first forges thirty letters, which he attributes to the popes from Silvester to Damasus; after this he includes the authentic decretals, with the intermixture of thirty-five apocryphal ones, generally given under the name of those popes who were not represented in the authentic collection, but sometimes also under the names of the others, for example, Damasus, St Leo, Vigilius and St Gregory; with one or two exceptions he does not interpolate genuine decretals.
At the time of the Domesday Survey there were between 400 and 500 mills in Lincolnshire; 2111 fisheries producing large quantities of eels; 361 salt-works; and iron forges at Stow, St Mary and at Bytham.
Bilston contains numerous furnaces, forges, rolling and slitting mills for the preparation of iron, and a great variety of factories for japanned and painted goods, brass-work and heavy iron goods.
From Bayonne, there are large metallurgical works, the Forges de l'Adour, and chemical works.