Hartz , (Ger. Harz, or Harzgebirge), the most northwestern mountain range in Germany, between lat. 51° 30' and 52° N., and Ion. 10° 10' and 11° 30' E. It separates the waters of the Weser from those of the Elbe. This range is divided into two parts, Upper and Lower Hartz, lying W. and E. of the Brocken. Their principal axis, which extends in a direction about W. N. W., E. S. E., is not far from 60 m. in length. The width of this main chain, as from Wernigerode to Hfeld, is about 18 m. The highest summit is the Brocken, a mountain of feldspathic granite, which by its easy decomposition has caused the mountain to assume a rounded graceful form. It rises to the height of 3,737 ft., and overlooks all the surrounding country. The Rosstrappe stands near by in the same group, and is of somewhat inferior elevation to the Brocken, from which it is separated by formations of argillaceous slates and the lower limestones. It is composed of granite in which quartz predominates, giving to the rock a more indestructible character and to the mountain a more rugged aspect than that of the Brocken. The Rammelsberg is a mountain of argillaceous slate and the older sandstones, reaching the height of about 1,200 ft. above the plain near the town of Goslar. The district comprising these mountains is principally made up of granitic rocks, which form the highest summits, and of gneiss, argillaceous slates, and metamorphic limestones and sandstones, which are grouped around, and penetrated by, the granites.
Various rocks of the upper secondary, from the gres bigarre or new red sandstone to the chalk, repose unconformably upon the older formations around their marginal outcrop. The more elevated portions of the district are rough and dreary, with a sterile soil and a cold climate. Numerous streams take their rise in the Hartz mountains. Tributary to the Elbe are the Helme, which flows through the deep and beautiful valley called the Goldene Aue, and the Zorge, on the south; the Eine, Selke, and Bode, on the east; and the Holzemme on the north. The Use, which forms several tine cataracts in its course, the Eeker, Radau, and Ocker, on the north, and the Innerste, Sose, and Sieber, on the west, flow into the Weser. The valleys, being well watered, are very fertile, and produce abundant pasturage, and large herds of cattle are reared here. This district is also well wooded, and timber forms an important article of export. But the mines, chiefly of lead, silver, copper, zinc, and iron, are the principal source of the wealth of this region. The other minerals found here are sulphur, arsenic, granite, marble, and gypsum; and in the east are a number of important salt springs.
For many centuries the mines have been industriously worked, and the business connected with them gives employment to about 30,000 persons. The mines belong chiefly to the province of Hanover (Prussia) and Brunswick; the former possessing those at Clausthal and Andreasberg, in the Upper Hartz, and the latter a portion of those in the Rammelsberg near Goslar. Those of the eastern Hartz are in the territory of Anhalt. The Rammelsberg mines were opened about the year 970, those of the Upper Hartz mostly in the 16th and 17th centuries; and the chief towns upon their sites, as those above named and Altenau, Zellerfeld, Lautenthal, Wildemann, and Grund, were founded in consequence of the discoveries of the mineral resources beneath the surface. These mining towns (Bergstadte) are entitled to special privileges, and no business is conducted in them but what is connected with mining and metallurgy. Clausthal is the headquarters of these operations. The council which has general charge of the mines meets here, and here are a mint and a school of mines, the latter furnished with a fine collection of minerals and models of mining and other machinery.
The mines of the Upper Hartz belong either to the group at Clausthal or that of Andreasberg. In the former the veins follow several lines of fracture in an E. and W. direction. One passes through the town of Zellerfeld, extending from Wildemann to Clausthal, a distance of 3 m. They produce argentiferous galena, copper pyrites, and blende in a quartzose gangue, intermixed with calcareous spar, brown spar, heavy spar, and spathic iron. They are remarkable for spreading out in thin branches through a great breadth of rock, and at Clausthal these strings are profitably explored throughout a width of 300 ft. The famous drainage level of these mines is noticed in the article Adit. The mines and city of Andreasberg are situated upon the steep slope of a mountain of argillaceous and silicious slates. The whole area occupied by the former is hardly a mile square. Rich silver ores are found here in small veins, as the antimonial sulphuret of silver and ruby-red silver of the dark and light varieties. Argentiferous galena is also a product of these mines. At this locality is found the deepest mine in the world.
It is upon an argentiferous vein, which has been followed to the depth of more than 2,500 ft. from the surface, the last 800 ft. since about the year 1820. The richest ores are found in courses which extend only about 100 ft. in length on the vein. The best of these was struck at a depth of about 2,160 ft., and has continued highly productive to the greatest depth named. The Rammelsberg mines produce similar ores to those of the Upper Hartz district. On account of the extreme hardness of some of the veinstones of these mines, it has been the practice, instead of attempting to drill the rock for blasting, to build a large fire against the face of the vein, and leave this to act upon the ingredients, like the arsenic and sulphur, which may be volatilized, and thus cause the mass to be easily attacked and broken down to some extent. Various other ores have been obtained in the Hartz besides those named. Iron mines have been extensively worked; ores of antimony have been produced to some extent, as also those of cobalt and manganese. A small quantity of gold has also been found in Anhalt. The rare metal selenium has been extracted from the seleniuret of lead of the same district.
The Mansfeld bituminous copper slates are singular ores, of so low a percentage that the copper pyrites disseminated through them is not visible, yet they have been long profitably worked in the Lower Hartz. The annual production of the Hartz mines, not including that of the Rammelsberg, which also yields 5 lbs. of gold, is about 40,000 lbs. of silver, 5,000 to 0,000 tons of lead, 150 tons of copper, and 10,-000 tons of iron. - The population of the Upper and Lower Hartz speak different dialects. Besides the Brocken or Blocksberg, which plays an important part in the popular legends and fairy tales of Germany, and which is immortalized in Goethe's "Faust," there are many remarkable localities in the Hartz, as the Stauffen-berg, with the ruins of the castle of Henry the Fowler, the castle of Falkenstein, the Alexis-bad, etc. The Teufelsmuhle, Rosstrappe, and the valley of the Bode are renowned for their fine and peculiar scenery; and two curious caves, Baumannshohle and Bielshohle, are interesting on account of their fossil bones.