706 ^^ ROBERTSON ON THE IRON MINES OF CARADOGH. 



three hours, or three and a half hours from the commencement, the ore becomes 

 consolidated, but not fused. The blast is then again stopped until that half 

 of the bloom which is next to the slag hearth is turned over with an iron bar 

 (Fig. 10), and pushed on the top of the dam, while the other half is turned round 

 to the centre of the fire. The blast is then immediately recommenced, and the 

 metal of the half bloom in the centre of the fire speedily falls to the bottom. The 

 remaining half of the bloom is then drawn into the centre, and treated in a simi- 

 lar manner, very little charcoal being placed on the top of the fire during this 

 part of the process. When the metal has entirely disappeared by sinking to the 

 bottom of the hearth, the whole semifluid mass is stkred about for a quarter of 

 an hour longer with an iron rod (Fig. 10). The blast being then stopped, the 

 twyere pipe is withdrav/n, and the operator taking his shovel (Fig. 13), pushes 

 the burning charcoal together with the dam into the lower hearth ; the slag im- 

 mediately runs off, and exposes the glowing iron lying in the bottom of the upper 

 hearth ; the metal is then beaten with the back of the shovel into a more solid 

 state, and after being dexterously cut with an iron chisel bar (Fig. 11), from the 

 sides of the hearth, and forced from the bottom, it is removed to the floor of the 

 hut with a large pair of tongs (Fig. 12). The iron is next beaten with large 

 hammers as it lies on the ground, in order to expel the slag and other impurities 

 from its pores ; and after being in this way formed into a rough mass, it is lifted 

 to the anvil, when it is again hammered into a more regular shape. It is next 

 cut into two pieces with large hammers (Fig. 1 4), and is then fit for being drawn 

 into bars of the dimensions required. 



At a single smelting, one hearth generally afibrds about 30 lb. of malleable 

 iron, to produce which there is only required about double that quantity of ore, 

 and three times the weight of charcoal. One smith with his assistants will make 

 about three or four smeltings in one day, or 1 cwt. 



It must strike every one acquainted Avith the iron manufacture, that this 

 t/ield is in a high proportion to the materials used. In England, about four tons 

 of raw ore and eight tons of coal are required to produce one ton of bar-iron ; 

 while, by the process above described, the same quantity of iron, of a much supe- 

 rior quality, is produced in Persia from less than half of these materials. The 

 greater productiveness is no doubt to be attributed in a great measure to the su- 

 perior richness of the Persian ores, and the use of charcoal ; but the simplicity of 

 the process must also have a considerable share in diminishing the waste of ma- 

 terials ; for the roasting, smelting, refining, puddling, shingling, balling, and 

 drawing-out, or something very similar, is all there effected, as it may be said, at 

 one heat, and in a very few hours. 



The rich iron-ores of Cumberland and Lancashire, and many others in Bri- 

 tain, particularly the blackband ironstone of Scotland, which has so recently at- 

 tracted tlie attention of iron-masters, if manufactured in the same manner, would 



