MECHANICS AND USEFUL ARTS. 23 



" It will be recollected that the process consists in the use of an 

 improved piirilying a^^ent, which appears to exercise a iii:)st im- 

 portant influence in the removal of the sole impurities which have 

 prevented the ores of Cleveland and Northamptonsliire beini^ 

 used in the production of the best quality iron. The Ileaton 

 process lias l)een described by Robert Mallet, F.R.S., as one of 

 those nietallurgic advances which, both with respect to economy 

 of production and utilization of inferior pigf iron, leave their mark 

 indelibly on great national industries. Tne report of Prof. Mil- 

 ler, of King's College, is quite as satisfactory as that of Robert 

 Mallet. It appears that Prof. Miller visited the works in order to 

 be enabled to report upon the process, and certify that the metal 

 analyzed by him was really the result of the process. The *' con- 

 verter" consists of a wrought-iron pot, lined with fire-clay; into 

 the bottom of this a suitable quantity of crude nitrate of soda, 

 combined with silicious sand, is introduced, and the whole cov- 

 ered with a cast-iron perforated plate. The molten pig is now 

 poured in, and in about 2 minutes the reaction commences. At 

 first brown nitrous fumes are evolved, and these are followed by 

 others of a more watery nature. After the lapse of 5 or 6 minutes 

 a violent deflagration occurred, attended with a loud, roaring 

 noise, and a burst from the top of the chimney of brilliant yel- 

 low flame, which, in about a minute and a half, subsided as rapidly 

 as it commenced. When all had become tranquil, the converter 

 was detached from the chimney, and its contents were emptied 

 upon the iron pavement of the foundry. Prof. Miller took sam- 

 ples of the various materials used, and carefully analj'zed the 

 iron, both before and after it had been submitted to the process; 

 and, as the result of his experiments, he states that it was proved 

 that the reaction of the nitrate of soda had removed a large pro- 

 portion of the carbon, silicon, and phosphorus, as well as most of 

 the sulphur; the phosphorus retained was not sufiicient to injure 

 the quality of the steel produced. Steel made by the Ileaton pro- 

 cess has been tested, and the results obtained afl'ord strong evi- 

 dence that uniformity of quality is practically attainable. With 

 regard to the principle of the process. Prof. Miller considers it to 

 be good, and the mode of attaining the result both simple and 

 rapid. The nitric acid in the nitrate, in this operation, imparts 

 ox3'gen to the impurities always present in cast iron, converting 

 them into compounds which combine with the sodium, and these 

 are removed with the sodium in the slag. The action of the so- 

 dium is one of the peculiar features of Heaton's process, and 

 gives it an advantage over former methods." 



MANUFACTURE OF CAST STEEL AND HOMOGENEOUS IRON. 



In treating puddled steel, raw steel, and puddled iron, for the 

 production of cast steel and homogeneous iron, the material to be 

 treated has usually been at great expense balled and shingled to 

 clear it from the cinder, and subsequently generally rolled into 

 bars, cut up in pieces, and remelted. According to an invention 



