JOHANN TOBIAS

MAYER (1723-1762)  , German astronomer, was born at 1\Iarbach, in Wurtemberg, on the 17th of February 1723, and brought up at Esslingen in poor circumstances . A self-taught mathematician, he had already published two original geometrical works when, in 1746, he entered J . B . Homann's cartographic establishment at Nuremberg . Here he introduced many improvements in map-making, and gained a scientific reputation which led (in 1751) to his election to the chair of economy and mathematics in the university of Gottingen . In 1754 he became superintendent of the observatory, where he laboured with great zeal and success until his death, on the loth of February 1762 . His first important astronomical work was a careful investigation of the libration of the moon (Kosmographische Nachrichten, Nuremberg, 1750), and his chart of the full moon (published in 1775) was unsurpassed for half a century . But his fame rests chiefly on his lunar tables, communicated in 1752, with new solar tables, to the Royal Society of Gottingen, and published in their Transactions (vol. ii.) . In 1755 he submitted to the English government an amended body of MS. tables, which James Bradley compared with the Greenwich observations, and found to be sufficiently accurate to determine the moon's place to (A . M .