Conlinuity of Metalliferous Bepositories in Depth. 355 



mines, which had reached a depth of between 300 and 400 

 metres, being nearly worn out while the meclianical means 

 employed for draining off the water could not be carried 

 further, it became necessary to provide for future deepening 

 by means of new works. It was proposed to drive a level 

 from the valley of the Elbe, which was greatly to surpass 

 the works of the same kind undertaken in the Hartz or in 

 Hungary, and to carry the mean level of the excavations to 

 600 metres, and even beyond that depth. 



On this occasion, M. de Beust published a great work, in 

 which he shewed that the various systems of veins being 

 cut across in depth, must, according to all the data both of 

 theory and pi*actice, present a vast field for mining. The 

 continuity of the minerals in depth was not doubted ; and 

 M. de Beust's opinion, supported as it was by all mining en- 

 gineers, by the powerful authority of M. de Humboldt, and, 

 finally, it may be affirmed, by the unanimous opinion of prac- 

 tical men and the mining population, was adopted by the 

 Saxon government. This decision was come to with absolute 

 confidence, and the works were begun in accordance with it 

 in 1844, not a single voice being I'aised against this bold ap- 

 plication of the great principles of the art. If an opinion 

 contrary to the continuity of the richness of veins in depth 

 had existed among the practical miners of Saxony, it would 

 assuredly have appeared on this occasion, for nowhere has 

 the richness been more variable. The mines of Himmelfiirst 

 which, in the time of Heron de Villefosse, were in the most 

 productive state, are now in a very indifferent condition; while 

 those of Himmerfahrt, which were but little valued, have 

 become the richest : but these variations have not occasioned 

 doubt as to the future produce, because experience has de- 

 monstrated that, by embracing a large field of operations, 

 the productiveness may be kept up and increased. The only 

 fact which has been discussed was the substitution of the 

 methods of deepening employed in Cornwall, that is to say, 

 the employment of powerful steam-engines instead of a 

 draining level. 



In Cornwall, the mines deepen in a more general and ra- 

 pid manner, by the application of steam-engines on a very 



