143 



IRON. 



into pieces by means of large hammers, for the 

 purpose of undergoing another process called pud- 

 dling. 



A side view of the puddling furnace is annexed ; 

 as will be immediately seen 011 inspecting the figure. 



It is of the reverberatory kind, and formed of bricks. 

 A is the ash pit, over which the grate is laid on 

 which the fuel is placed. B is a aoor in the side, 

 through which the workman introduces the rod with 

 which he puddles the metal. C is the hearth on 

 which the lumps of metal from the refinery are placed; 

 these are piled on the sides up nearly to the vault, 

 the centre being left open for the flame and smoke to 

 pass out by the chimney D. The chimney is furnished 

 with a damper, in order that the draught may be 

 increased or diminished as may be required. The 

 furnace being heated, the metal begins to melt and 

 flow down to the hearth, the temperature is then 

 lowered, and the workman introduces his long iron 

 rod, and stirs the melted mass, during which it swells 

 and emits carbon, combined with oxygen, which burns 

 with a bluish flame. The metals become thicker as 

 the process advances until it assumes a sandy appear- 

 ance, at which period the temperature of the furnace 

 is raised, and the particles cohere, when the charge 

 is said to work heavy. The workman now forms it 

 while hot into five or six balls, each of from 70 to 80 

 pounds weight. The balls are removed and sub- 

 jected to several blows of a heavy hammer, and 

 formed into what are called blooms. The blooms are 

 passed through successive pairs of rollers until they 

 acquire the proper shape of long bars. The loss of 

 weight by this process is generally about 10 per 

 cent. 



Five or six of these bars, cut to one length, are now 

 piled together, and placed in a furnace similar to 

 the puddling furnace, and brought to a welding heat, 

 and then taken out and passed through successive 

 pairs of rollers, until the bar is brought to the proper 

 dimensions when the process is finished. The loss 

 of weight is by this last process about 10 per cent. 



It may be useful to bring under the reader's eye 

 the actual weight of material employed in the manu- 

 facture of one ton of iron. 



Raw mine.. ......3 tons = 2. 4 tons of roasted ore. 



Coal for furnace 31 tons = 2. 5 of coke. 

 Do. for kiln, &c.\ , tn 

 Kn g ines.........J lton - 



Flux .............. 1 



81 tons of materials for 1 ton pig iron. 



... 

 Kaw mine .......................... 4.12 



Limestone ......................... 1.37 



Add n fi,; I Coal* used in refinery .. 

 thl8 Do. in the puddling, &C.1. 



81 



1.90 



12.02 



2.51 



Total, 14.53 tons csed in 

 the production of one ton of finished bar. 



Manufacture of Iron in Great Britain. Iron mines 

 have been wrought in this country from a very early 

 period. Those of the Forest of Dean, in Gloucester- 



shire, are known to have existed in the year 1066. 

 In consequence of the great consumption of timber 

 which they occasioned, they were restrained by 

 act of parliament in 1581. Soon after this, Edward 

 Lord Dudley invented the process of smelting iron 

 ore with pit coal instead of wood fuel ; ana it is 

 impossible, perhaps, to point out an instance of 

 another invention that has proved more advantageous. 

 The patent which his lordship had obtained in 1619, 

 was exempted from the operation of the act of 1623 

 (21 Jac. I. c. 23.), setting aside monopolies ; but 

 though in its consequences it has proved of immense 

 value to the country, the works of the inventor were 

 destroyed by an ignorant rabble, and he was well 

 nigh ruined by his efforts to introduce and perfect 

 his process; nor was it till about a century after, that it 

 was brought into general use. In the early part of 

 last century, well-founded complaints were repeatedly 

 made of the waste and destruction of woods caused 

 by the smelting of iron ; and the dearth and scarcity 

 of fuel that was thus occasioned, led, about 1740, to 

 the general adoption of lord Dudley's process for 

 using pit-coal, which was found to be in every 

 respect superior to that previously in use. (Report 

 of Committee of the House of Commons on Patents, 

 p. 168, &c. From this period, the progress of the 

 manufacture has exceeded the most sanguine expecta- 

 tions. In 1740, the quantity of pig iron manufac- 

 tured in England and Wales amounted to about 

 17,000 tons, produced by fifty-nine furnaces. The 

 quantities manufactured at the undermentioned 

 epochs, in Great Britain, have been as follows : 



1750 

 1788 

 1796 

 1S06 

 18SO 



22,000 tons. 



68,000 produced by 85 furnaces 

 125.000 121 



250,000 162 



400,000 unknown. 



The extraordinary increase that has taken place 

 in the production of iron since 1823, is principally to 

 be ascribed to the high prices of 1824, 1825, and 

 1826, when pig iron met with a ready sale at from 

 9 to 12 and 13 a ton. But, in consequence 

 partly of the failure or postponement of most of the 

 projects as to rail-roads, &c., that were then on foot, 

 and partly of the vast additional supplies which the 

 extension of the manufacture threw on the marketT 

 the price fell in 1828, to from 5 to 7 a ton ; and 

 continued gradually to decline, till in 1832 it was 

 only worth 4 15s. So heavy a fall had the effect 

 of introducing the severest economy into every 

 department of the manufacture. In despite, how- 

 ever, of all the saving that could be effected in this 

 way, many of the manufacturers were involved in 

 much distress, and the production of iron is believed 

 to have been considerably diminished. This, coupled 

 with the increasing demand for iron, naturally led to 

 a reaction. Prices began to rise early in 1833 ; and 

 the advance had been such, that in the beginning of 

 1834, pig iron brought 6 a ton, and the manufac- 

 ture continues in a state of great activity. The price 

 of iron at present, (Jannary, 1836), varies according 

 to quality from 5 15s. to 7, and seems to be likely 

 to advance in price. This may at first sight appear 

 strange, when the saving to the manufacturer by the 

 employment of the hot blast, and the recent introduc- 

 tion of that rich and productive vein of iron stone 

 called black band, are taken into account. But the 

 truth is, the increased demand for cast iron, in conse- 

 quence of railway speculations and other causes, far 

 exceeds the increased supply. 



The following statement as to the number of 

 furnaces, and the quantity of iron produced in the 

 different districts where the manufacture is carried 

 on, in 1828, and 1830, appeared originally in the 

 Birmingham Journal.- We have been assured that 

 their accuracy may be depended upon. 



