16 ANNUAL OF SCIENTIFIC DISCOVERY. 



portion of the spectrum. About 4 or 5 minutes before the 

 end of the charge of 3 tons, the lines begin to disappear in 

 rapid succession, and in the inverted order of their appearance, — 

 first, the bkiish-purple, then the bkie lines, after these the red, 

 etc. When the last green line disappears, the vessel is turned, 

 and the charge completed by the addition of spiegeleisen. The 

 yellow sodium line does not disappear to the end of the oj^eration. 

 Sometimes the vessel is turned, when all lines in the green field 

 with the exception 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 spiegeleisen regu- 

 lated accordingly. The practical results are highly satisfactory, 

 since they make the regularity of the "temper" of Bessemer 

 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. 



It is highly probable that careful trials and observations in this 

 countr}' will prove ver}' similar to those observed with Styrian 

 charcoal iron. By the use of the spectroscope the steel-makers 

 will be able to show to the disbelievers in the uniformity of 

 Bessemer steel that a child may conduct the charge without the 

 least chance of error, just the same as a boy can now work the 

 whole mechanical apparatus of the converters ; the steel-masters 

 will become less dependent upon the skill and attention of their 

 charge-managers and foremen, and the percentage of waste or 

 unsuitable material jDroduced by carelessness, or mistakes, will be 

 lessened m the general run of practice. — Engineering. 



According to the " London Chemical News," of April 3, 1868, 

 Prof. Liellegg was anticipated in regard to the spectrum of the 

 Bessemer flame, by Prof. Roscoe of England, in 1862. 



MANUFACTURE OF STEEL, 



Mr. F. Kohn, at the 1868 meeting of the British Association, 

 read a paper on the recent progress of steel manufacture. Tne 

 process of making steel upon the open hearth of a Siemens' fur- 

 nace, by the mutual reaction of pig and wrought iron upon each 

 other, recently introduced into England, realized the old idea of 

 melting w^rought iron in a bath of liquid pig iron, and thereby 

 converting the whole mass into steel. It was distinguished from 

 previous unsuccessful attempts by the high temperature and the 

 non-oxidizing flame produced by the regenerative gas furnace, and 

 by the method of charging the decarburized iron into the bath of 

 pig iron in measured quantities. He stated that by the process 

 the production of any desired temper of steel could be relied upon 

 with absolute certainty. In the most successful charges the ball 

 was made from a mixture of white Swedish iron and of spiegel- 

 eisen, and a quantity of the latter was added at the end of the 

 operation. Into these charges Cleveland bars entered in the pro- 



