GIOVANNI BATTISTA

DONATI (1826-1873 )  , ' Italian astronomer, was born at Pisa on the 16th of December 1826 . He entered the observatory of Florence as a student in 1852, became assistant to G . B . Amici in 1854, and was appointed in 1864 to succeed him as director . A new observatory at Arcetri near Florence, built under his supervision, was completed in 1872 . During the ten years 1854-1864 Donati discovered six comets, one of which, first seen on the 2nd of June 1858, bears his name (see COMET) . He observed the total solar eclipse of the 18th of July 186o, at Torreblanca in Spain, and in the same year began experiments in stellar spectroscopy . In 1862 he published a memoir, Intorno alle strie degli spettri stellari, which indicated the feasibility of a physical classification of the stars; and on the 5th of August 1864 discovered the gaseous composition of comets by submitting to prismatic analysis the light of one then visible . An investigation of the great aurora of the 4th of February 1872 led him to refer such phenomena to a distinct branch of science, designated by him " cosmical meteorology "; but he was not destined to prosecute the subject . Attending the International Meteorological Congress of August 1873 at Vienna, he fell ill of cholera, and died a few hours after his arrival at Arcetri, on the loth of September 1873 . See Vierteljahrsschrift der astr . Gesellschaft (Leipzig), ix .

4; . Monthly Notices

Roy . Astr . Society, xxxiv . 153; Memorie degli spettroscopisti italiani. ii . 125 (G . Cacciatore); Nature, viii . 556; &c . (A . M .