OBSERVATORIES, ASTRONOMICAL. We possess only an im perfect knowledge respecting the institutions established in ancient times for the observation of the heavenly bodies. The observatory of Alexandria is alone famous in the history of Greek astronomy. It was there that the observations were first made, upon which astronomy as a science, in the true sense of the term, WAS finally founded. With the revival of science in modern Europe, the establishment of observa tories was soon felt to be indispensable to the progress of astronomy. The observatory of Tycho Brand, erected in the island of If uctia towards the close of the IGth century, under the auspices of Frederick III., king of Denmark, is memorable in the history of astronomy for having supplied the facts which enabled Kepler to destroy the epicy clical mechanism of the planetary movements, and to substitute in its stead the true theory of elliptical 'notion. About the same time NVilliatn, Landgrave of please Cassel, did good service to astronomy by the erection of an observatory, and the prosecution of a series of observations of the heavenly bodies. The lustre shed upon his country by the labours of Tycho Brah6 doubtless acted as a powerful incentive in stimulating the Danish sovereigns to patronise astronomy. We accordingly find that the earliest national observatory of modern Europe wee established in 1)enmark. The observatory of Copenhagen was commenced in 1637, but it was not completed until the year 1656. The first astronomer who was appointed to the direction of its labours was Longomontanus, the celebrated pupil of Tycho Brand.
In the latter part of the 17th century a great impulse was given to practical astronomy by the invention of the micrometer, and the appli cation of telescopic sights to the observation of the heavenly bodies. During this period the observatories of Greenwich and Paris were erected. We proceed to give a brief sketch of the history of the former of these institutions, although as regards priority of establish ment the Paris Observatory has the advantage by a few years.
The Royal Observatory of Greenwich was established in the year 1675. The foundation stone of the building was laid on the 10th of August, and it was finished in leas than twelvemonths afterwards. Flamsteed was appointed Astronomer Royal,with a salary of 1001. a-year. In the warrant of Charles II. for the payment of his salary, he is styled "our Astronomical Observator ;" and he is directed" forthwith to apply himself with the most exact care and diligence to the rectifying the tables of the motions of the heavens, and the places of the fixed stars, so as to find out the so much desired longitude of places for the per fecting the art of navigation." Flamsteed took up his residence at the Observatory on the 10th of July, 1676, and shortly afterwards com menced his duties as an observer. In this capacity he continued to officiate till his death, which occurred towards the close of the year 1719. His observations are collected in an important work, entitled Historia Ccelestis Britannica,' published in three volumes folio ; the third volume contains a catalogue of 2935 stars, reduced to the begin ning of the year 1689.
The second director of the Greenwich Observatory was the cele brated Edmund Halley. His earliest observation is dated October 1, 1721. His labours were chiefly confined to observations of the moon. The results of these observations are inserted at the end of his planetary tables, published in 1749. No other observations made by this astronomer during his directorship of the Greenwich Observa tory have been published. The original records of his labours are deposited in the Royal Observatory in four small quarto volumes. Upon the recommendation of Francis Bally, a copy of these observa tions was taken by order of the Lords Commissioners of the Admiralty, and presented to the Royal Astronomical Society in the year 1832. Halley died on the 14th of January, 1742.