313 THE SCIENTIFIC PAPERS OF 



specific action in neutralizing the effect of sulphur, and no chemi- 

 cal explanation, that he was aware of, had ever been even given of 

 that fact. On the other hand, he (Dr. Siemens) did not think 

 that the deoxidising action of the manganese was the essential 

 effect of that substance in the process with which his name had 

 been connected, because they could regulate the oxidising action 

 on the bath to such a degree, that the absorption of oxygen by the 

 bath had not commenced before the spiegel was added, and yet 

 the addition of spiegel was necessary. If the operation of decar- 

 burisation was carried on to the point at which oxygen was 

 absorbed from the atmosphere, that is, until the carbon was 

 reduced to below 1 per cent., it was very difficult to get rid of the 

 oxygen. After spiegeleisen had been added, and the bath had 

 become perfectly quiescent, they would find the steel, when poured 

 into the moulds, set up a violent ebullition. Now, that ebullition 

 proved that oxygen existed in the fluid metal and probably in 

 combination with carbon, which was liberated suddenly after the 

 steel had been lowered in temperature to near the point of solidifi- 

 cation, but which the manganese had not been capable of removing. 

 He was aware that, in the Bessemer process, when spiegeleisen 

 was added, a powerful ebullition was set up ; but that was not 

 the case in his process, in which ore was used as the decar- 

 burising agent, and the steel when poured into the ingot moulds, 

 or moulds for casting purposes, showed no sign of ebullition, if 

 carefully prepared ; on the contrary, the steel contracted, or what 

 was technically called piped, but if the operation had been carried 

 too far, it seemed to acquire an extraordinary affinity for oxygen, 

 and that oxygen at very high temperatures did not seem to go out 

 again, notwithstanding the addition of manganese, but remained 

 associated with the metal until it had cooled down near to the 

 point of solidification. He would like to have that important 

 point cleared up in this discussion. 



