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HISTORY OF PHYSICAL ASTRONOMY.

February, 1762-'=. An improved set of lunar tables, which he leftbehind him at his death, were transmitted to England by his widow,in consideration of which she obtained from the British Governmenta grant of money amounting to £3000 j. In 1770, his Theory of theMoon |, which served as the basis of his tables, was published at Lon-don. It is substantially the same as Euler ’s, but the values of the co-efficients were determined by the aid of his own observations. In thesame year there was published, also at London , Iris improved solar andlunar tables §. There is appended to them, a short dissertation entitledMethodm Lonyitudminn Promota, in which he recommends the method oflunar distances for finding the longitude at sea, and suggests for thispurpose the use of a reflecting circle, with the repeating principle appliedto it. This work also contains his formula for refraction, embodying theresult of his researches on that important subject ||. The two worksabove mentioned were published at the expense of this country, under thesuperintendence of the Board of Longitude, the task of editing thembeing executed by Dr. Maskelyne . In 1775 the first volume of Slayer’s“ Posthumous Works ” was published at Gottingen , which, among othersubjects, contained a catalogue of 998 zodiacal stars. The remaining por-tion still exists in manuscript, with the exception of the observations fromwhich the catalogue was formed, which were printed at London , in 1820.

Mayer lias earned for himself an imperishable reputation by his lunartables. Some astronomers may have achieved results of greater brilliancy,but few have been privileged to contribute so directly by their labours tothe well-being of their fellow-men. Even independently of the improve-ment which he effected in this instance, Mayer possesses claims to beranked with the greatest astronomers of ancient or modern times; but, asin the case of either of his illustrious contemporaries, Bradley orLacaille, his labours are not of a nature to be generally appreciated,and therefore his reputation is less widely diffused than that of many anindividual whose contributions to science, though more showy, are infinitelyless substantial.

Bradley was succeeded at the Boyal Observatory of Greenwich by Dr.Bliss, Savilian Professor of Geometry in the University of Oxford . Thisastronomer adopted the same plan of observation as that pursued by hispredecessor, but his death in 1705 prevented his labours from acquiringany degree of importance in the annals of the observatory.

Neville Maskelyne, the fifth Astronomer Koyal of Greenwich , was bornin London in the year 1732. He completed his education at TrinityCollege, Cambridge, and subsequently qualified himself for entering thechurch. It is said that his attention was first drawn to the science of

* It is somewhat singular (hat Bradley, Lacaille, and Mayer, the three greatest astrono-mers of the eighteenth century (supposing Halley to have been of the seventeenth), diedwithin a few months of each other.

t A copy of the resolution of the Board of Longitude, recommending Parliament togrant Mayer’s widow the sum of £5000, will be found at page cxxiii. of the Solar andLunar Tables of that astronomer. It appears from Maskelyne ’s preface to these Tablesthat the sum actually awarded by Parliament amounted to £3000.

t Theoriae Lunae juxta Systema Newtonianum, &e., 4to., Lond., 1767. Although thetitle-page of this work bears the date of 1767, it was only published in 1770, as appearsfrom Maskelyne ’s preface to Mayer’s Solar and Lunar Tables, published in the last-men-tioned year.

§ “ Tabulae Motuum Solis et Lunae, novae et correct®,” &c., 4to., Lond., 1770.

|| See page 117 of the work referred to in the text.