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654 CAMERA OBSCUKA CAMERINO light proceeding from the object at 5, which are caused by refraction to strike the base of the prism, are reflected by its internal surface Fia. 3. to the opposite side of the prism whence they issue, refracted from the perpendicular, and are again reflected by a glass plate to the eye, forming an image which appears as if at c, where the point of a pencil may trace its out- line on paper. CAMERA OBSCURA, an instrument invented in the middle ages, according to some by Roger Bacon, and to others by Battista Porta, in which the image of illuminated objects formed by a convex lens is received upon a screen in a darkened chamber, or in a box. It was for centuries used as an amusement, or as a guide in drawing outlines, but by the invention of Daguerre was suddenly invested with new value as the main instrument in photography. The figure represents a camera obscura intend- ed for use in drawing. It consists of a rectan- gular box made of two parts, one of which slides into the other so that it may be length- ened or shortened, according to the distance Camera Obscura. of the object. The rays of light from the ob- ject pass through a convex lens a, and are re- flected from a mirror m, placed at an angle of 45, upon a horizontal plate of ground glass n, where they form an uninverted image, which may easily be traced with a pencil. < lli:i: Uil I s. I. Joachim, a German scholar, horn at Bamberg, April 12, 1500, died in Leip- s'c, April 17, 1574. His proper name was Liebhard, which he changed into Camerarius, in honor of the office of chamberlain which his ancestors held at the court of the bishop of Bamberg. Educated at Leipsic and Erfurt, his attention was arrested by the writings of Me- lanchthon, and in 1521 he went to Wittenberg to make the acquaintance of that reformer. From this time his life and influence were identified with the reformation. In 1526 he was appointed teacher at Nuremberg, and was afterward sent to the university of Tubingen. Tlie dukes of Saxony, a few years later, em- ployed him to remodel the Leipsic university, of which he afterward became rector. He w* at the diet of Augsburg, and gave important aid in drawing up the Augsburg confession; and when in 1555 the diet assembled there again, Camerarius continued a prominent delegate, and in the year following was at Ratisbon in the same capacity. He was soon after called to Vienna by the emperor Maximilian II. to counsel in the critical affairs of the empire in regard to religion. Camerarius was a scholar of extensive and varied learning. He cultivated medicine, mathematics, and Greek. His works (more than 150 distinct treatises) are mostly on classical and religious subjects. He translated into German many Greek and Latin authors. His biography of Melanchthon (Leipsic, 1592), of which a new edition appeared in Halle in 1777, and his collection of letters of that re- former, are peculiarly interesting to the student of the reformation. II. Joachim, son of the pre- ceding, born at Nuremberg, Nov. 5, 1534, died there Oct. 11, 1598. He was sent successively to Wittenberg and Leipsic, and also studied with Melanchthon, and received a medical diploma at Bologna in 1562. Botany was his favorite study. A genus of plants ( Cameraria) was named after him. III. Rudolph Jakob, a German physician and botanist, born in Tu- bingen, Feb. 17, 1665, died there, Sept. 11, 1721. He was professor of medicine and di- rector of the botanic garden at Tubingen, and was the first to observe the male and female generative organs in plants, and to establish the true sexual theory of plants. His princi- pal work is Epistolw de 'Sexu Plantarum (Tu- bingen, 1694 and 1749). CAMERINO (anc. Camerinum), a town of Ita- ly, capital of a district in the province of Ma- cerata, 40 m. 8. W. of Ancona; pop. about 12,000. The finest public buildings are the episcopal palace, the cathedral, and the church of Omanzia, with pictures by eminent masters. In the principal square is a statue of Pope >Six- tus V. A university was founded here in the early part of the 18th century, and there are many monasteries and a seminary. Silk is the chief article of manufacture. The ancient Um- brian city of Camerinum (originally Camers) was a place of importance during the earlier periods of Roman history. In the middle ages ('.mierino formed part of the duchy of Spoleto. In. the 13th century it was ruled by the Varano family, a member of which became duke of Carnerino in 1520. Ottavio Farnese obtained