-S7A' WILLIAM .S7AM//;.V\, I-.R.S. 213 



been clearly demonstrated. It is certain that only traces of 

 metallic manganese are ever found in cast-steel, and that the bulk 

 of the manganese added is found combined with oxygen, silica, 

 and alumina, in the form of slag ; yet it follows, from experiments 

 which I have had occasion to make, that on adding manganese to 

 a bath of liquid steel in an open reverberatory furnace, its beneficial 

 action ceases if the metal is retained in the furnace, exposed to the 

 flame for any length of time, say more than half an hour. This is 

 the case quite independently of any sensible reduction in the pro- 

 portion of carbon in the steel, and indicates that the effect of 

 manganese is not due to the removal of sulphur or other substances 

 with which it may enter into combination, but it is inseparable 

 from the presence of metallic manganese in the steel, in however 

 small a quantity. A further confirmation of the view, that the 

 addition of manganese removes no impurity from the steel, is 

 supplied by the fact, that if cast-steel from English iron which 

 has been rendered perfectly malleable at a red-heat, by the ad- 

 dition of manganese, is re-melted ivitlwut adding manganese, it 

 becomes as red-short as ever. According to Parry, the presence of 

 manganese in sensible quantity in steel tends to render it brittle 

 when cold. 



SILICON. Silicon in small quantity seems to increase the hard- 

 ness of steel without taking away from its malleability or tough- 

 ness when cold, and the presence of a trace of silicon appears to 

 have the singular effect of preventing that violent evolution of 

 gas from fluid steel at the moment of solidification, which renders 

 the ingot so frequently unsound. Steel containing above 0'5 per 

 cent, of silicon breaks up under the hammer if heated above low 

 redness. 



TITANIUM, &c. The effect of titanium, tin, arsenic, silver, and 

 other metals upon steel, is stated to produce increased Itardmss, 

 but I have not myself made any experiments upon this subject, 

 nor been able to find very reliable observations of others. 



TUNGSTEN has a very remarkable effect upon steel, first ob- 

 served by Dr. Werner Siemens, in 1853, in increasing its power of 

 retaining magnetism when hardened. Being specially interested 

 in this question, I have determined, by careful experiments, the 

 extent of the increase ; and the practical result is, that whereas 

 a horse-shoe magnet of ordinary steel, weighing 2 Ibs., is con- 



