998 IKON 



mill cinders ,* formerly the bottoms \vero of sand, by which great loss of iron was 

 occasioned, and the metal obtained of interior quality. 



The fine metal obtained by the coke is puddled by a continuous operation, which 

 calls for much skill and care on the part of the workmen. To charge the puddling 

 furnace, pieces of fine inetal are successively introduced with a shovel, and laid one 

 over another on the sides of the hearth, in the form of piles rising to the roof; the 

 middle being left open for puddling the motal, as it is successively fused. Indeed, tho 

 whole arc kept as far separate as possible, to give free circulation to the air round tho 

 piles. The working door of the furnace is now closed, fuel is laid on the grate, and 

 the mouth of the fireplace, as well as the side opening of the grate, are both filled up 

 witli coal, at the same time that the damper is entirely opened. 



The fine metal in about twenty minutes comes to a white-red heafe, and its thin- 

 edged fragments begin to melt and fall in drops on the sole of tho furnace. At this 

 period the workman opens the small hole of the furnace-door, detaches with ;i rako 

 the pieces of fine metal that begin to melt, tries to expose new surfaces to the action 

 of the heat, and in order to prevent the metal from running together as it softens, ho 

 removes it from the vicinity of the fire-bridge. When tho whole of tho fine metal has 

 thus got reduced to a pasty condition, ho must lower the temperature of the furnace 

 to prevent it from becoming more fluid. Ho then works about with his paddle the 

 clotty metal which swells up, exhibiting a kind of fermentation occasioned by the 

 discharge of carbonic oxide, burning with a blue flame as if the bath were on fire. 

 The metal becomes finer by degrees and less fusible, or, in tho language of the work- 

 men, it begins to dry. The disengagement of carbonic oxide diminishes and soon 

 stops. The workman continues meanwhile to puddle the metal till the whole charge 

 is reduced to the state of incoherent sand ; the register is then progressively opened. 

 With the return of heat the particles of metal begin to agglutinate, the charge bo- 

 comes more difficult to raise, or, in the labourer's language, it works heavy. The 

 refining is now finished, and nothing remains but to gather the iron into balls. Tho 

 puddler with his paddle takes now a little lump of metal as a nucleus, and makes it 

 roll about on tho surface of the furnace, so as to collect more metal, and form a ball 

 of about 60 or 70 Ibs. weight. With a kind of rake called in England a dolly, and 

 which he heats beforehand, the workman sets this ball on that side of the furnaco 

 most exposed to the action of the heat in order to unite its different particles, which 

 he then squeezes together to force out the scoriae. When all the balls are fashioned, 

 the small opening of the working door is closed with brick to cause the heat to rise, 

 and to facilitate the welding. Each ball is then lifted out either with tho tongs, 

 if roughing rollers are to be used, as in Wales, or with an iron rod welded to the lump 

 as a handle, if the hammer is to be employed, as in Staffordshire. It is usual to in- 

 troduce a fresh charge when the portion under operation has arrived at the pasty con- 

 dition ; when this is done, the entire process is effected in about 1 - hour. 



The charge for each operation is from 4 cwts. to 4f cwts. of refined metal, and 

 sometimes the cuttings of bar-ends are introduced, which are puddled apart. The loss 

 of iron is hero very variable, according to the degree of skill in the workman, who by 

 negligence may suffer a considerable body of iron to scorify or to flow into tho 

 hearth and raise the bottom. Taking the average of 85 furnaces for 21 years' work- 

 ing, Mr. Truran finds the consumption of refined metal to produce one ton of puddle 

 bars to be 21 cwts. 1 qr. 20 Ibs. The consumption of coal is likewise subject to varia- 

 tion. With coal of good quality, and suitable for reverberatory furnaces, the ton of 

 puddled bars is produced with a consumption of from 12 to 15 cwts. ; but, if the coal 

 be of the anthracitic character, from 18 cwts. to 1 ton will be required. About five 

 puddling furnaces are required for the service of one smelting furnace and one refi- 

 nery. Each furnace, with good workmen, turns out about 23 tons of puddled bars 

 weekly. 



The cast-iron bottom and sides of the puddling furnace are kept cool by currents of 

 air, or, in those portions exposed to the greatest heat, by water. The cinders of the 

 charcoal finery are much esteemed for lining the bottom. When melted into one 

 uniform mass, with the addition of oxide of iron, these scoriae form a bottom offering 

 great resistance to the action of the molted metal. 



Various patents have been taken out within the last four or five years for tho em- 

 ployment of chemical agents to assist in tho purification of iron in the puddling 

 furnace : some of these have already been alluded to. One of tho latest is that of 

 M. Charles Pauvert of Chatcllerault, who proposes to employ a cement composed of 

 the following substances : oxide of iron, 14 parts ; highly aluminous clay, 30 parts ; 

 carbonate of potash, 1 part ; carbonate of soda, 1 part. The iron is to bo placed with 

 the cement in layers, and heated in tho furnace in the ordinary manner. After ce- 

 mentation it is welded, and then drawn into bars ; it is stated to become thus as soft 

 and tenacious as iron made from charcoal. Schafhaeutl's compound, for which a 



