German astronomer, b. at Wald, near Mindelheim, in Swabia, 25 July, 1575; d. at Niesse, in Silesia, 18 July, 1650. He entered the Society of Jesus in 1595, and after studying mathematics at Ingoldstadt, became professor in that branch at Dillingen. In 1610 he was recalled to Ingoldstadt, where he taught Hebrew and mathematics with great success and became actively engaged in scientific research. He had already invented his well-known pantograph or copying instrument, and he now constructed a telescope, with which, aided by one of his students, he began to observe the sun. He made use of a helioscope composed of coloured glasses in the beginning, but afterwards conceived the idea of projecting the sun's image on a screen in order to study its surface. Kepler had independently suggested the method, but Scheiner was the first to apply it in practice. It was thus that in March, 1611, he discovered the existence of sun-spots, a phenomenon so contrary to the philosophical notions of the time that his superiors did not wish him to publish it under his own name for fear of ridicule. He therefore communicated the discovery to his friend Welser in Augsburg, who, in 1612, published his letters under an assumed name. In subsequent letters he described the rotation of the spots and the appearance of the faculæ. In the meantime Galileo claimed to have observed the spots before him. This led to further correspondence and a long dispute followed regarding the priority of discovery. It appears, however, that they were first noticed by Fabricius shortly before either, and although Galileo may have observed them before Scheiner, the latter made his discovery quiet independently and also published it before him. Scheiner's special claim, that he was the first to make continuous observations of scientific value, cannot be disputed. Apart from his letters, he continued his systematic study of the sun for nearly sixteen years before beginning the publication of his great work, the "Rosa Ursina" (Bracciani, 1626-30). This is a standard treatise on the subject and besides his numerous observations, contains a detailed account of his methods and apparatus. One of his most valuable results was also his determination of the rotational elements of the sun. In 1616 the Archduke Maximilian of Tyrol, attracted by his growing fame, invited him to Innsbruck, where, besides carrying on his astronomical researches, he made important studies on the eye, showing that the retina is the seat of vision. He likewise devised the optical experiment which bears his name. He became rector of the new college of his order at Neisse in 1623, and later professor of mathematics at Rome. His last years, devoted to study and to the ministry, were spent at Neisse. Scheiner was one of the leading astronomers of his time, and possessed to an uncommon degree the true scientific spirit. Though not endowed with the deep insight into the truths of nature of his great contemporary Galileo, he was nevertheless ingenious in devising methods and a skilled and painstaking observer. He insisted particularly on the need of accurate data as a basis for subsequent theory. He deserves the title of "pioneer" in the study of sun-spots. He wrote "Tres epistulæ de maculis solaribus" (Augsburg, 1612); "De maculis solaribus et stellis circa Jovem errantibus accuratior Disquisitio" (Augsburg, 1612); "Refractiones coelestes" (Ingoldstadt, 1617), in which he first called attention to the elliptical form of the sun when near the horizon and attributed the phenomenon to refraction; "Oculus h. e. Fundamentum opticum" (Innsbruck, 1619); "Pantographice seu ars delineandi" (Rome 1631).

BRAUNMÜHL, Christoph Scheiner als Mathematicer physiker u. Astronom. (Bamberg, 1891); SOMMERVOGEL, Biblioth. de la C. de J., VII (Paris, 1869), 734; WOLF, Gesch. d. l'Astronomie (Munich, 1887), 319; DELAMBRE, Hist. de l'Astronomie Moderne, I (Paris, 1821), 681; SCHREIBER, Natur u. Offenbarung, V, XXXXVIII, 1 sqq.

H. M. BROCK