GEORG VON

REICHENBACH (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 Benedictbeuern, 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 tae 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 18o6 . 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Bessel in 1819), but in England the mural circle and transit instrument were not superseded for many years .