THE TECHNOLOGIST. [June 1, 1865. 



514 MINERAL SUBSTANCES FOR WRITING ON. 



entered upon in order to reach the chief slate quarries of " Lotliar 

 Heil," two miles distant from the manufactory, possesses a picturesque 

 character of its own. On one side stands the gloomy forest, while on 

 the other naked masses of greenstone-rock rear their heads aloft in a 

 threatening manner over the road which they seem to block up, other 

 detached masses having fallen into the narrow bed of the stream, which 

 dashes in foam over them. Alexander von Humboldt, who was em- 

 ployed as mining officer in the mining district of Steben in the year 

 1807, in writing about these valleys, of which there are so many in the 

 forest of Franconia, in one of his later works especially mentions the 

 so-called " Hollengrund " (Hell-gulf) as one of the finest valleys of 

 Europe. After passing through the finest part of the valley of Diirren- 

 waid the road begins to ascend, until on attaining its highest point the 

 slate-quarry with its mine buildings come3 in sight, surrounded by 

 magnificent beeches, pines, and firs. 



The open works first attract attention, for here the bed of slate 

 manifests itself in great richness and on account of its freedom from 

 pyrites and other impurities. This slate not only affords an excellent 

 material for roofing, but also for the manufacture of furniture, 

 tables, &c, and objects of luxury which are turned out by the Slate 

 Manufactory of A. W. Faber. 



But the subterranean works are the most interesting. At a depth 

 of 120 ft. below the open works the adit's dark mouth is seen. Here 

 the underground world is entered upon with its impenetrable gloom, 

 while the miner's candle throws its dim light upon the wet rock, and 

 the close walls seem ready to crush you with their vast rocky masses. 

 Proceeding thus along the dark passage with its death-like stillness, you 

 suddenly perceive little sparks of light glittering from various points. 

 In a straight line you have penetrated to a distance of 400 ft. and 

 reached the underground works. Towards the west and north vast 

 halls open out, in which the work is proceeding busily. Monotonously 

 do the hammer strokes assail the ear while workmen are continually 

 ascending and descending, carrying loads of the material won to the 

 opening of the adit, where they are rapidly forwarded on an iron tramway. 

 Immense surfaces of slate meet the eye, which have been opened up to 

 the great height of 40 ft. and stand ready to be worked. 



You breathe more freely on quitting these subterranean recesses and 

 on reaching the open air soon find your way back to the manufactory, 

 in whose spacious and pleasant premises, the erection of which was the 

 work of years, a great activity is displayed. 



On entering the workshops novel and peculiar machines attract your 

 attention. The institution of the manufacture offered many difficulties ; 

 many things had to be invented expressly, while experience yielded no 

 data on which to proceed, nor showed how this or that difficulty was to 

 be overcome, or how the whole process might be arranged so as to be 

 in every respect the most practical when in action. A steam-engine sets 



