The process of casting iron was as follows. The moulds were made of a sandy substance, composed of a mixture of brick dust, loam, plaster, and charcoal. A bed of this sand was made, and into it was pressed a wooden or metal pattern. When this was removed, the imprint remained in the sand. Liquid metal was run into the mould so formed, and would cool into the desired shape. As with a plaster cast, it was necessary to employ two such beds, the sand being firmly held in boxes, if the object was to be rounded, and then the two halves thus made were put together. Flat objects, such as fire-backs, could be run into a single mould. Bartholomew, in his book "On the Properties of Things," makes certain statements about iron which are interesting: "Though iron cometh of the earth, yet it is most hard and sad, and therefore with beating and smiting it suppresseth and dilateth all other metal, and maketh it stretch on length and on breadth." This is the key-note to the work of a blacksmith: it is what he has done from the first, and is still doing. In Spain there have been iron mines ever since the days when Pliny wrote and alluded to them, but there are few samples in that country to lead us to regard it as aesthetic in its purpose until the fifteenth century. For tempering iron instruments, there are recipes given by the monk Theophilus, but they are unfortunately quite unquotable, being treated with mediaeval frankness of expression. St. Dunstan was the patron of goldsmiths and blacksmiths. He was born in 925, and lived in Glastonbury, where he became a monk rather early in life. He not only worked in metal, but was a good musician and a great scholar, in fact a genuine rounded man of culture. He built an organ, no doubt something like the one which Theophilus describes, which, Bede tells us, being fitted with "brass pipes, filled with air from the bellows, uttered a grand and most sweet melody." Dunstan was a favourite at court, in the reign of King Edmund. Enemies were plentiful, however, and they spread the report that Dunstan evoked demoniac aid in his almost magical work in its many departments. It was said that occasionally the evil spirits were too aggravating, and that in such cases Dunstan would stand no nonsense. There is an old verse: "St. Dunstan, so the story goes, Once pulled the devil by the nose, With red hot tongs, which made him roar That he was heard three miles or more!"