HISTORY OF PHYSICAL ASTRONOMY.

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thousand stars, a partial catalogue only was formed by the author, con-taining the reduced places of 1942 stars*. The remaining mass con-tinued in their original condition, until at length, in 1838, the BritishAssociation, at the suggestion of Mr. Daily, undertook the reduction ofthe whole of the observations according to a uniform system. The com-putations were executed under the superintendence of the late ProfessorHenderson, of Edinburgh . The number of stars is 9700. The epoch isJanuary 1, 1750. The catalogue was printed in 1845, at the expense ofthe Government.

Lacaille’s third catalogue is one of 515 zodiacal stars, which was pub-lished in 1703 as a posthumous work. He contemplated that thiscatalogue should contain the places of 800 stars; but he was preventedby death from realising his design. The observations upon which it isbased were reduced, shortly after his death, by his personal friend Baily ;who does not seem, however, to have executed his task with the scrupulousregard to accuracy which a work of so much importance demanded. Theepoch of this catalogue is the year 1705.

Mayer is the author of a catalogue of 998 zodiacal stars, which appearedin a volume of posthumous works, published at Gottingen , in 1775.Through the influence of Francis Baily , the original observations werebrought from Gottingen to this country, and were published in 1826 atthe expense of the Board of Longitude. The same individual havingcarefully revised the catalogue, by collating it with the original observa-tions, procured its insertion in the fourth volume of the “ Memoirs ofthe Astronomical Society.”

Maskelyne’s fundamental catalogue of 30 stars, published by him,originally in the Greenwich Observations, was by far the most accurateproduction of the kind that had been hitherto given to the world. Thissmall collection long continued to be an indispensable guide to thepractical astronomer.

Observations of circumpolar stars present a peculiar interest, on accountof their utility in researches on refraction and various other subjects ofastronomical science. In 1800 the Rev. Francis Wollaston published asmall catalogue of such stars in a work entitled “ Fasciculus Astronomicus.”

Towards the close of the last century, a vast number of observations ofstars were made at the Ecole Militaire of Paris , by D’Agelet and MichaelLefrantjais Lalande, nephew of the celebrated astronomer of that name.The observations were made in zones. It was contemplated in thismanner to determine the positions of all the stars in the northernhemisphere down to the ninth magnitude. They were published in1801, in a volume entitled “ Histoire Celeste Frai^aise,” but they wereunreduced, and therefore they were, in point of fact, inaccessible to theastronomer. Partial reductions of these observations were shortly after-wards made; but the great mass remained for many years in theiroriginal condition. In 1825, Schumacher published tables for facilitatingthe reduction of the stars contained in the Histoire Celeste, computedaccording to a plan suggested by Bessel. In 1837, the British Associa-tion agreed to defray the expense of the reduction of all the observations,at the suggestion of Francis Baily , who undertook the superintendence ofthe whole operation. The Government, as in the case of Lacaille’sobservations of southern stars, agreed to defray the expense of printing.

* All the observations, including the partial catalogue, were published after Lacaille'sdeath, in a work entitled Caelum Australe Stelliferum 4to., Paris , 1763.