Glatz existed as early as the 10th century, and received German settlers about 1250. It was besieged several times during the Thirty Years’ War and during the Seven Years’ War and came into the possession of Prussia in 1742. In 1821 and 1883 great devastation was caused here by floods. The county of Glatz was long contended for by the kingdoms of Poland and of Bohemia. Eventually it became part of the latter country, and in 1534 was sold to the house of Habsburg, from whom it was taken by Frederick the Great during his attack on Silesia.
See Ludwig, Die Grafschaft Glatz in Wort und Bild (Breslau, 1897); Kutzen, Die Grafschaft Glatz (Glogau, 1873); and Geschichtsquellen der Grafschaft Glatz, edited by F. Volkmer and Hohaus (1883-1891).
GLAUBER, JOHANN RUDOLF (1604-1668), German chemist, was born at Karlstadt, Bavaria, in 1604 and died at Amsterdam in 1668. Little more is known of his life than that he resided successively in Vienna, Salzburg, Frankfurt and Cologne before settling in Holland, where he made his living chiefly by the sale of secret chemical and medicinal preparations. Though his writings abound in universal solvents and other devices of the alchemists, he made some real contributions to chemical knowledge. Thus he clearly described the preparation of hydrochloric acid by the action of oil of vitriol on common salt, the manifold virtues of sodium sulphate—sal mirabile, Glauber’s salt—formed in the process being one of the chief themes of his Miraculum mundi; and he noticed that nitric acid was formed when nitre was substituted for the common salt. Further he prepared a large number of substances, including the chlorides and other salts of lead, tin, iron, zinc, copper, antimony and arsenic, and he even noted some of the phenomena of double decomposition. He was always anxious to turn his knowledge to practical account, whether in preparing medicines, or in furthering industrial arts such as dyeing, or in increasing the fertility of the soil by artificial manures. One of his most notable works was his Teutschlands Wohlfarth in which he urged that the natural resources of Germany should be developed for the profit of the country and gave various instances of how this might be done.
His treatises, about 30 in number, were collected and published at Frankfort in 1658-1659, at Amsterdam in 1661, and, in an English translation by Packe, at London in 1689.
GLAUBER’S SALT, decahydrated sodium sulphate, Na2SO4, 10H2O. It is said by J. Kunkel to have been known as an arcanum or secret medicine to the electoral house of Saxony in the middle of the 16th century, but it was first described by J. R. Glauber (De natura salium, 1658), who prepared it by the action of oil of vitriol or sulphuric acid on common salt, and, ascribing to it many medicinal virtues, termed it sal mirabile Glauberi. As the mineral thenardite or mirabilite, which crystallizes in the rhombic system, it occurs in many parts of the world, as in Spain, the western states of North America and the Russian Caucasus; in the last-named region, about 25 m. E. of Tiflis, there is a thick bed of the pure salt about 5 ft. below the surface, and at Balalpashinsk there are lakes or ponds the waters of which are an almost pure solution. The substance is the active principle of many mineral waters, e.g. Frederickshall; it occurs in sea-water and it is a constant constituent of the blood. In combination with calcium sulphate, it constitutes the mineral glauberite or brongniartite, Na2SO4·CaSO4, which assumes forms belonging to the monoclinic system and occurs in Spain and Austria. It has a bitter, saline, but not acrid taste. At ordinary temperatures it crystallizes from aqueous solutions in large colourless monoclinic prisms, which effloresce in dry air, and at 35°C. melt in their water of crystallization. At 100° they lose all their water, and on further heating fuse at 843°. Its maximum solubility in water is at 34°; above that temperature it ceases to exist in the solution as a decahydrate, but changes to the anhydrous salt, the solubility of which decreases with rise of temperature. Glauber’s salt readily forms supersaturated solutions, in which crystallization takes place suddenly when a crystal of the salt is thrown in; the same effect is obtained by exposure to the air or by touching the solution with a glass rod. In medicine it is employed as an aperient, and is one of the safest and most innocuous known. For children it may be mixed with common salt and the two be used with the food without the child being conscious of any difference. Its simulation of the taste of common salt also renders it suitable for administration to insane patients and others who refuse to take any drug. If, however, its presence is recognized sodium phosphate may be substituted.
GLAUCHAU, a town of Germany, in the kingdom of Saxony, on the right bank of the Mulde, 7 m. N. of Zwickau and 17 W. of Chemnitz by rail. Pop. (1875) 21,743; (1905) 24,556. It has important manufactures of woollen and half-woollen goods, in regard to which it occupies a high position in Germany. There are also dye-works, print-works, and manufactories of paper, linen, thread and machinery. Glauchau possesses a high grade school, elementary schools, a weaving school, an orphanage and an infirmary. Some portions of the extensive old castle date from the 12th century, and the Gottesacker church contains interesting antiquarian relics. Glauchau was founded by a colony of Sorbs and Wends, and belonged to the lords of Schönburg as early as the 12th century.
See R. Hofmann, Rückblick über die Geschichte der Stadt Glauchau (1897).