1911 Encyclopædia Britannica/Reichenbach, Georg von

REICHENBACH, GEORG VON (1772-1826), German astronomical instrument maker, was born at Durlach in Baden on the 24th of August 1772. -From 1796 he was occupied with the construction of a dividing engine; in 1804, with Joseph, Liebherr and Joseph Utzschneider, he founded an instrument making business in Munich; and in 1809 he established, with Joseph Fraunhofer and Utzschneider, optical works at Benedictbeuem, which were moved to Munich in 1823. He withdrew from both enterprises in 1814, and founded with T. L. Ertel a new optical business, from which also he retired in 1821, on obtaining an engineering appointment under the Bavarian government. He died at Munich on the 21st of May 1826. Reichenbach's principal merit was that he introduced into observatories the meridian or transit circle, combining the transit instrument and the mural circle into one instrument. This had already been done by O. Romer about 1704, but the idea had not been adopted by any one else, except in the transit circle constructed by Edward Troughton for Stephen Groombridge in 1806. The transit circle in the form given it by Reichenbach had one finely divided circle attached to one end of the horizontal axis and read by four verniers on an " alidade circle, " the unaltered position of which was tested by a spirit level. The instrument came almost at once into universal use on the continent of Europe (the first one was made for F. W. Bessel in 1819), but in England the mural circle and transit instrument were not superseded for many years.