STAHX. 489 STAINED GLASS. christliche Staat (1847), Die Revolntion und die konstitutionelle Monarchie (1848), Die luDierische Kirche und die Union (1859). STAHL, Georg Ernest (1()60-1734). A Ger- man physician and olioniist. born at Ansbach. He was called in 1694 to the chair of medicine, anat- omy, and chemistry in the newly founded uni- versity of Halle, whence he removed to Berlin in 1716, and was appointed physician to the King of Prussia. Stahl was one of the ablest chemists of his time, and destroyed number- less absurd opinions which had found their way into science, and pro|)Ounded the first general theory of chemical transformations (see Chemis- try), which was universally accepted till the time of Lavoisier. His works, according to Hal- )er, number 250, the most important being Theo- ria Medica Vera (1707, and 1831-33), which eon- tains his medical theory, and Expcrimentu, Ob- servationes et Animndversiones Chymico-Phy- sicw (1731), in which his chemical opinions are set forth. An account of his opinions is found in Lemoine, Le vitalisme et I'animisme de Stahl (Paris, 1864). Consult also Lasfegue, De Stahl et sa doctrine medicate (ib., 1846). STAHR, stiir. Adolf (1805-76). A German author, born in Prenzlau, Prussia. After study at the University of Halle he went to the gymnasium at Oldenberg, and in 1836 became professor there. While on a tour through Italy in 1845, which was afterwards described in Ein Yahr in Italien (1847-50), he met the author Fanny Lewald, whom he married in 1855, after separating from his first wife. Perhaps the most noteworthy of his writings are his classical studies, which in- clude translations from Aristotle, Suetonius, and Tacitus, and liilder aus dem Altei^ttum (1863-66). His miscellaneous works, some of which have been translated into English, include: Charakteristik Immermanns (1842); Die Re- puhlikaner in Neapel (1849); Die preussische Revolution (1850); and G. E. Lessing, sein Leben und seine Scliriften (1858). STAIGG, Richard M. (1820-81). An Ameri- can genre and portrait painter. He was born at Leeds, England, and stvidied drawing in an archi- tect's office before coming to America in 1831. He began painting miniatures on ivory, and soon at- tained a high degree of excellence. He was elect- ed member of the National Academy of Design in 1861. In 1867-69 he studied at Paris, and after his return he ceased miniature painting and devoted himself to portraiture and coast scenes. His work is pleasing in color and de- tailed in execution. His genre pictures, character- ized by an unafTected simplicity and grace, in- clude "Learning to Slide" and the "Sailor's Grave." Stuart collection, Lenox Library, New York City, and the "Cat's Cradle." STAINED GLASS The process of coloring glass requires particular care. When it is to be of full color (as commonly for windows of rich decorative effect) it is called 'pot metal;' but, while colored glass of many hues and tints is used in which the whole mass of the glass is equally stained throughout, certain colors are prepared by covering one side of a piece of col- orless glass with pot metal of the color required. Crimson and ruby glass for windows is made in this way, the process being called 'flashing.' Opaline glass, much used for windows in America since 1885, though known and used long before, when very much clouded or stained so as to be nearly opaque, for utilitarian purposes, has some of the opal's power of giving at once the general color and its complementary color; thus glass of smoky blue shows also a spark of orange or of pinkish light. It has been found practicable to give the opaline character to glass of the full color of pot metal; and upon this depends much of the splendor of recent American windows. Glass so colored is often not of the same degree of translucency throughout. Some pieces of opaline and other glass prepared for windows vary much in the same piece with regard to this matter of translucency. The designer, while di- recting the choice of glass for a rich mosaic win- dow, will sometimes be in doubt just where to cut off the sheet, and will experiment with rays of sunlight falling upon the glass to see where it becomes too nearly opaque for his use. Some of these .sheets of glass prepared for rich win- dows have much change of color in their mass, cloudings, and veinings of different hues, the contrasts being enhanced by the varying thick- ness of the parts of the same sheet. . The com- poser of a rich window knows how to utilize these contrasts and gradations. Iridescence, as found on the surface of ancient glass vessels and fragments which have been long buried in the earth, is the result of a curious process of decay, in the course of which the sub- stance of the glass becomes disintegrated, form- ing thin laminte, which are no longer brittle as a thin piece of undecayed glass would be, but have rather the crumbling texture of flakes of mica or the like; that is to say, this part of the glass has lost its vitreous qualities. Modern attempts to produce iridescence are, of course, not in that direction ; the attempt has been to give the changing play of colored light to the surface of perfect glass. They are of different character, according to the greater or less degree of translucency desired. The ancient and partly decayed glass is of course mainly non-transpar- ent, but still allows some light to pass through it. Thus in a phial or plate of that pale green trans- parent glass so common in the Greco-Roman pe- riod, parts will be brilliantly iridescent when the piece is found, and still other parts will have a whitish degenei'acy which is incipient change of mass. These parts will be comparatively opaque, not allowing a small object to be clearly seen through their substances, while other parts of the same vessel will be entirely transparent as soon as the earthy deposits have been removed. The most common iridescent glass of modern manufacture is, however, entirely clear, and an iridescent effect of the surface, like that of the surface of a soap-bubble, is given by some process which is often kept secret. During the last two decades of the nineteenth century a very brilliant glass was made in America by a single establish- ment. In this glass, the uniting of successive layers of the materi.al, one imposed upon another while hot, allows of giving to one or both sur- faces a brilliant iridescence which, when fully developed, makes the whole mass entirely non- translucent. It is full of the play of brilliant color, nearly like a rich piece of mother-of-pearl. This process differs wholly from enameling
