HISTORY OF PHYSICAL ASTRONOMY.

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position wherein he might have been enabled to exercise his talents withstill greater benefit to astronomical science. Upon this point his dis-tinguished countryman, M. Biot, very naturally makes the followingremark:—“ Quel eclat aurait jete Vastronomie observatrice en France ,quelle hauteur aurait-elle pu atteindre, des ce temps-ld meme, si un telhomme avait succede a Picard et a Roemer, dans un observatoire vraimentroyaie, crci avec Vintelligence de la science, disposb pour ses besoins, etpourvu des instruments propres d Vavancer!" *

Tobias Mayer was born on the 17th of February, 1723, at Marbach , atown of Wurtemberg, in Germany . His father having died while he wasyet young, he was thrown upon his own resources at an earlier age thanusual, and -was compelled to support himself by teaching mathematics, aknowledge of which he had acquired solely by the perusal of such booksas he could occasionally procure. He was only twenty-two years old whenho published a treatise on the theory of curve lines. About the same timehe began to apply himself with great ardour to the prosecution of astrono-mical inquiries. In 1750 he communicated to the Cosmographical Societyof Nuremberg , a paper on the libration of the moon, in which he deter-mined the elements of that curious phenomenon with greater precisionthan had been hitherto done by any astronomer. This paper is remarkablefor containing the earliest example of the method of equations of condi-tion, the use of which has contributed so much to the improvement ofmodern astronomy. In 1751 he was appointed to the superintendence ofthe Observatory of Gottingen, having been at the same time nominated toone of the chairs in the University of that city The observatory hadbeen recently furnished by George II. of England with a magnificentmural quadrant of six feet radius, constructed by Bird. Mayer proceededto submit his instrument to a most scrupulous examination, and in theexecution of this task he displayed a combination of sagacity and addresswhich would alone suffice to stamp him as an observer of the highestorder. He now commenced a course of regular observation, with theview of procuring materials to serve as a groundwork for establishing thefundamental points of astronomy. In 1753 he published new solar andlunar tables. The latter will be for ever memorable, from being the firstwhich afforded a practical solution of the problem of the longitude. Theobservations employed in their formation consisted chiefly of eclipses ofthe sun and occultations of the stars. They did not amount to more than200, and yet, with such skill were they discussed by Mayer , that his tablesseldom erred so much as 1|'. In 1755 he transmitted them to England,where they were compared by Bradley with the Greenwich observations,and were deemed by that astronomer to be so accurate that, in so far as thecalculated places of the moon were concerned, they might serve in findingthe longitude at sea within half a degree of the truth, and generally muchnearer!. In 1750 Mayer communicated a paper to the Royal Society ofGottingen , in which he explained the principle of an instrument, sincewell known to astronomers as the repeating circle. He continued to pro-secute his astronomical researches with unremitting assiduity, until atlength his constitution became impaired from incessant application, andhe fell into a languishing illness, of which he expired on the 20th of

* Journal des Savans, 1847, p. 524.

+ This was the chair of political economy. It does not appear that Mayer deliveredany lectures upon that subject.

t Mayer’s Solar and Lunar Tables, p. cxii.