390 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



RESTORING BURNED STEEL. 



A simple method of restoring burned steel to a workable 

 condition consists in immersing it in a preparation made by- 

 melting three parts of pure colophony in a crucible, and aft- 

 er it has become perfectly fluid, adding, with continued stir- 

 ring, two parts of boiled linseed oil, care being taken to pre- 

 vent the mixture catching fire, of which there is danger should 

 the temperature be too high. A dark brown mass will ulti- 

 mately be obtained of the consistency of sirup, which has 

 the peculiarity that any piece of cast steel, however much 

 burned, when immersed in it at a red heat, immediately re- 

 covers its original excellence ; and should the operation be 

 repeated several times successively, a quality of steel is ob- 

 tained of a fineness much superior to that of its original con- 

 dition. The tempering is best done at a dark red heat, in 

 rain water. 15 C, 1870, 102. 



THE HEATON AND BESSEMER PROCESSES. 



A careful report by an eminent iron-master in France upon 

 the respective merits of the Heaton and Bessemer processes 

 of refining iron presents the conclusion that" while the former 

 is not likely to replace the latter for the manufacture of steel, 

 yet it is the best hitherto invented for the purification of or- 

 dinary cast iron. It may be remembered that the Heaton 

 process consists essentially in the addition of nitrate of soda 

 to the melted metal, by which all the impurities, s-uch as car- 

 bon, sulphur, phosphorus, etc., become chemically combined 

 with the nitrate, and pass off with a loud deflagration in the 

 form of vapor, leaving the metal in a state of extraordinary 

 purity. 3 A t March 4, 1870, 165. 



SIEMENS's STEEL. 



Among the various methods of preparing steel, that of Sie- 

 mens, so well known in connection with an improvement of 

 the smelting furnaces, is likely, it is said, to attain considera- 

 ble prominence, possessing various advantages, both as to 

 economy and the character of the product, over many others 

 in common use. For its preparation, good haematite ore and 

 spathic ore arc mixed and treated with carbonaceous materi- 

 als, by which their total or partial reduction into metallic 



