70 Professor Hausmann on Metallurgical Phenomena 



found disseminated in veins, and at the same time, in adjoinirig 

 rocks ; as, for instance, the native silver at Konigsberg in Norway. 



With respect to the relations in which silica is found in the 

 walls of extinguished blast-furnaces, Mr Koch has given an ex- 

 tremely minute account.* Its appearance is in many instances 

 only explicable on the assumption of a penetration in the form 

 of vapour. The above-mentioned fact of the accompaniment 

 of the iron that is found in the interior of the stones of the 

 building, coupled with the mineralogical association with tita- 

 nium and graphite,'hereafter to be referred to, are greatly in fa- 

 vour of this view. Mr Koch has already drawn our attention 

 to the impropriety of doubting that the silica proceeded from 

 silicium, whose reduction from iron-ores rich in that substance, 

 ensued in the highest temperature of the blast-furnace. The 

 silicium was partly combined with the iron ; and this with the 

 crude iron as well as with the refined iron which is sometimes 

 generated, so that it was thus protected against oxidation. But 

 as a vapour too, it penetrated, partly with iron and carbon, also 

 in the form of vapour, into the interior of the mass of the build- 

 ing, and passed here either immediately by means of oxidation 

 into silica, or not until after having again resumed the molten 

 condition : and this is sufficiently proved by the globular and 

 kidney-shaped external forms, by the concentric concretionary 

 layers, and by the arrangement of their fibres. 



The well-known appearance of crystals of titanium in the pro- 

 ducts of the blast-furnace, belongs to the most interesting phe- 

 nomena which these afford. The relations in which cubes of 

 titanium are found in excavations of masses of slag, crude iron, 

 and refined iron, sometimes accompanied by silica, partly in the 

 building, partly even beneath it, are of such a nature as leave 

 no room to doubt of its sublimation. The tendency of the vapours 

 to penetrate downwards, is to be explained by the pressure of the 

 molten mass thaf, exists in the base. 



In the case of the graphite formation also, which accompanies 

 the production of the grey crude iron, the previous existence in 

 the state of vapour may also be fairly assumed ; for the ap- 

 pearance of that crystalline body, which, according to Karsten's 

 researches, wc are authorised to consider as pure carbon, is dis- 

 * Beytrage zur Kenntniss Crystallinischer Ilvitteiiproducte, S. 34-40. 



