METALS. 



471 



heating this vessel with coke only ; and in 

 that case the lines referred to are very faint, 

 and, it requires some practice or knowledge of 

 the precise spots in the spectrum where these 

 bright lines should be looked for, to discover 

 them. During the first period of the Besse- 

 mer process the spectrum -is very faint. The 

 yellow portion is almost invisible, and even 

 the sodium line is missing ; the blue and pur- 

 ple portions are extremely faint. The absence 

 of the sodium line can be accounted for only 

 by the consideration that there is no real flame 

 formed by incandescent gases escaping from 

 the converter at that early stage, but only a 

 mass of sparks carried by the nitrogen from 

 the blast, the oxygen of which remains in the 

 converter, combining with silicium. As the 

 flame gradually appears in the centre of a vol- 

 ley of sparks, the spectrum widens and shows 

 yellow light, until suddenly the sodium line in 

 the yellow field becomes visible, first only for 

 moments as a flashing bright streak, and after 

 less than one minute as a constant and clearly- 

 defined line. The appearance of the sodium line 

 marks the commencement of the decarburiza- 

 tion, although this line does not belong to the 

 charge of iron at all, but rather to the acciden- 

 tal presence of sodium compounds in very 

 minute quantities. It is therefore only indi- 

 rectly connected with the combustion of car- 

 bon ; i. e., the appearance of the sodium line is 

 a signal of the completion of the continuous 

 spectrum, and this continuous spectrum belongs 

 to the combustion of carbon. As soon as the 

 sodium line has taken a steady and permanent 

 appearance, the characteristic lines of the car- 

 bonic oxide may be looked for in the greenish- 

 yellow, in the green, and in the purple field. 

 In each of these three fields one bright line 

 becomes clearly visible at that time. As the 

 flame increases in size and brilliancy, the spec- 

 trum comes out more and more clearly. Bright 

 lines increase in number in each of the first- 

 named three fields, and ultimately, at the height 

 of the process, some bright lines show them- 

 selves in the red and, occasionally, also in the 

 blue field. The green field in the spectrum, 

 however, is the real point of observation in 

 practice, as in this the lines are most clearly 

 visible, and in it they appear first and disap- 

 pear last. The spectrum, as a whole, is by no 

 means steady or constant, but its fluctuations 

 do not displace any of the bright lines ; they 

 only alter the background or the continuous 

 spectrum upon which they appear. After the 

 "boil," the maximum intensity is reached; 

 and at that stage, and only with very hot 

 charges, a bundle of bright lines appears in the 

 bluish-purple portion of the spectrum. About 

 four or five minutes before the end of the 

 charge of three tons, the lines begin to disap- 

 pear in rapid succession, and in the inverted 

 order of their appearance first, the bluish- 

 purple, then the blue lines, after these the red, 

 etc. "When the last green line disappears, the 

 vessel is turned, and the charge completed by 



the addition of spiegel-eisen. The yellow so- 

 dium line does not disappear to the end of the 

 operation. Sometimes the vessel is turned 

 when all lines in the green field, with the ex- 

 ception of two, have disappeared. This depends 

 upon the special experience of the case, and it 

 is clear that it is of less importance whether 

 the one or the other mark be taken, if it is 

 only regularly adhered to, and the charge of 

 spiegel-eisen regulated accordingly. The prac- 

 tical results are highly satisfactory, since they 

 make the regularity of the " temper " of Besse- 

 mer steel practically independent of the skill 

 and experience of the charge-manager, the 

 changes of the spectrum being made more 

 marked and unmistakable than those of the 

 appearance of the flame itself. The Engineering 

 Magazine, presenting these facts to the British 

 public, adds the remark that no experience 

 with the British haematite irons has been gained, 

 and that the use of the spectroscope in England 

 must be preceded by some careful trials and 

 observations to fix the character of the changes. 

 The Engineering thinks that those changes 

 will prove very similar to, if not absolutely the 

 same as, those observed with Styrian charcoal- 

 iron. 



The EllersJiausen WrougTit-Iron Process. 

 This process, according to the New York Times, 

 consists in the conversion of crude cast iron, as 

 it runs from the smelting-furnace, into wrought 

 iron, by the simple admixture of granulated 

 iron ore. It is conducted at the works of 

 Messrs. Shonberger, of Pittsburg, in the fol- 

 lowing manner : On the casting-floor of the 

 smelting-furnace, a cast-iron turn-table, about 

 18 feet in diameter, is made to revolve on 

 rollers by a small steam-engine. On the put- 

 side edge of the table stands a row of cast-iron 

 partitions, forming boxes, say 20 inches wide 

 and 10 inches high, open at the top. Just 

 above the circle of boxes stands a stationary, 

 wide-mouthed spout, terminating in the tap- 

 hole of the furnace. When the furnace is 

 tapped, the liquid iron runs down this spout 

 and falls out of it in a thin stream into the 

 boxes as they slowly revolve under it, deposit- 

 ing in each a film of iron, say one-eighth of an 

 inch thick. But, before the fall of melted iron 

 reaches the boxes, it is intercepted, or rather 

 crossed, at right angles, by a thin fall of pul- 

 verized iron ore, which also runs out of a wide 

 spout from a reservoir above. These two 

 streams or falls are of about equal volume, say 

 one-quarter of an inch deep and 20 inches 

 wide. A workman, with a bar in the tap- 

 hole, regulates the stream of iron, and the iron 

 spout from which the liquid metal falls into the 

 boxes is removable; other spouts, previously 

 coated with loam and dried, being attached to 

 a common revolving frame, so as. to be ready 

 for use when the loam covering of the first be- 

 comes cracked or removed. 



The thin layers of iron and ore soon chill 

 and solidify, so that, by taking away the outer 

 partition of the boxes (which form the rim of 



