260 MINES 



waters of several mines of Cornwall are pumped put by means of steam-engines, whose 

 force is equivalent, in some instances, to the simultaneous action of many hundred 

 horses. 



GENEBAL SUMMABY OF MINES. 



Mines may be divided, generally, into three great classes : 1. Mines in unstratified 

 rocks and the geological formations anterior to the coal strata. 2. Mines in the car- 

 boniferous and secondary formations. 3. Mines in alluvial districts. 



The first are opened, for the most part, upon veins, masses, and metalliferous beds. 



The second, on strata of combustibles, as coal ; and metalliferous or saliferous 

 beds. 



The last, on deposits of metallic ores, disseminated in clays, sands, and other allu- 

 vial matters, geologically superior to the chalk and tertiaries, and of far more recent 

 formation. 



The mines of these three classes, placed for the most part in very different physical 

 localities, differ no less relatively to the mode of working them, and their mechanical 

 treatment, than in a geological point of view. 



The progress of geological science, however, shows that these divisions cannot be so 

 definitely made as was formerly supposed, and that same of the rocks which were con- 

 sidered to be very ancient, are, in fact, among the more modern of the secondary 

 strata. Thus, most of the metalliferous formations of the Andes, and of Hungary, 

 ought, in strictness, to be classed with the upper secondary, or even the tertiary strata, 

 although they have often been so metamorphosed as to present an appearance very 

 similar to the older rocks. 



The following' groupiag, it will be understood, refers the mines to physical and not 

 to political boundaries : 



MINES OF THE HABTZ. 



The name Hartz is given generally to the country of Forests, which extends a 

 great many miles round the Bracken, a mountain situated about 55 miles W.S.W. 

 of Magdeburg, and which rises above all the mountains of North Germany, being 

 at its summit 1,226 yards above the level of the sea. The Hartz is about 43 miles 

 in length from SS.E. to NN.W., 18 miles in breadth, and contains about 450 square 

 miles of surface. It is generally hilly, and covered two-thirds over with forests 

 of oaks, beeches, and firs. This rugged and picturesque district corresponds to a 

 portion of the SUva Hercynia of Tacitus. As agriculture furnishes few resources 

 there, the exploration of mines is almost the only means of subsistence 'to its in- 

 habitants, who amount to about 50,000. The principal towns, Andreasberg, Claus- 

 thal, Zellerfeld, Altenau, Lautenthal, Wildemann, Grund, and Goslar, bear the title 

 of mine-cities, and enjoy peculiar privileges ; the people deriving their subsistence 

 from working in the mines of lead, silver, and copper, over which their houses are 

 built. 



The most common rock in the Hartz is greywacko. It incloses the principal veins, 

 is associated with clay-slate, Lydian stone, or siliceous slate, and greenstones ; and is 

 succeeded in geological order by a limestone referable, with a large proportion of 

 the slaty bods, to the Devonian system. The granite of which the Brocken is formed 

 supports all this system of rocks, forming, as it were, their nucleus. 



The veins of lead, silver, and copper, which constitute the principal wealth of the 

 Hartz, do not pervade its whole extent. They occur chiefly near the towns of An- 

 dreasberg, Clausthal, Zellerfeld, and Lautenthal ; are generally directed from E. to 

 W., and dip to the N.E. in the Andreasberg, and to the S. in the Clausthal district, 

 at an angle of about 80 with the horizon. 



The richest silver mines are those of the environs of Andreasberg, among which 

 may bo distinguished the Samson and Neufang mines, worked to a depth of 2,740 

 English feet or 456 fathoms. In the first of them there is the greatest step exploir 

 tation to bo met with in any mine. It is composed of 80 underhand slopes, and is 

 more than 650 yards long. These mines were discovered in 1520, and the city was 

 built in 1521. They produce argentiferous galena, with silver ores properly so called, 

 such as red silver ore, and ores of cobalt. 



The district which yields most argentiferous load is that of Clausthal. It compre- 

 hends a great many mines, several of which are worked to a depth of above 300 

 fathoms. Such of the mines as aro at the present day most productive, have been 

 explored since the first years of the 18th century. Two of the most remarkable ones 

 are the mine of Dorothea, and the mine of Carolina, which alono furnish a largo 

 proportion of the whole net product. The grant of the Dorothea mine extends 

 over a length of 257 yards, in the direction of the vein, and through a moderate 



