Joseph Von Fraunhofer, a German optician, born in Straubing, Bavaria, March 6,1787, died June 7, 1826. The son of a glazier, he exercised in boyhood the trade of his father. In the intervals of labor he studied the laws of optics, made himself familiar with mathematics and astronomy, and in 1806 became technical director of the mathematical institute at Munich. He afterward united with Reichenbach and Utzschneider in founding at Benedict-Beu-ren an establishment for the fabrication of dioptric instruments, which was transferred to Munich in 1819. He manufactured the finest crown glass, much superior to the English, for achromatic telescopes and prisms, and invented a machine for polishing surfaces in parabolic segments, a heliometer, a microscope, and the celebrated parallactic telescope of the observatory of Dorpat. By using fine prisms that were free from veins he discovered about 590 black lines crossing the solar spectrum, and projected the most important of these in a drawing of the spectrum. Similar lines he found in the spectra of the moon and of some of the planets and fixed stars, but none in artificial white lights. (See Spectrum Analysis.)