HISTORY OF PHYSICAL ASTRONOMY.
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The task of providing the instruments for the new establishmentwas confided to M. Struve, the director of the Observatory of Dorpat, socelebrated for his labours on various subjects relating to astronomicalscience, and more especially for liis observations of double stars. Theimperial instructions relative to this object were characterised by un-bounded liberality. The principal instruments of the establishment havebeen constructed by German artists. For meridional observations thereare four instruments, two of which have been supplied by Ertel of Munich ,and two by Eepsold of Hamburgh. The instruments by Ertel are a ver-tical circle 43 inches in diameter, and a transit instrument of 5.85 inchesaperture, and 8 feet 6 inches focal length : those by Eepsold are a meri-dian circle 48 inches in diameter, and a prime vertical telescope of 0.25inches aperture and 91 inches focal length. For extra-meridional obser-vations, the observatory is furnished with a magnificent equatorial tele-scope by Merz and Mahler of Munich, the object glass of which has a freeaperture of 14.93 inches, and a focal length of 22.55 feet. Moreover, itcontains several clocks constructed by the most esteemed artists of Ger-many and England, as well as an ample collection of other instruments,both astronomical and physical, destined for various purposes connectedwith the practice of observation. In short, the Observatory of Pulkowamay be regarded as one of the most complete in existence, of those insti-tutions that have been founded for promoting the advancement of astro-nomical science. The expense attending the erection of the building, andits subsequent equipment, amounted in round numbers to 000,000 roublesof silver*.
The illustrious Struve has been appointed first director of the Obser-vatory of Pulkowa. An ample staff of assistants, several of whom enjoy aEuropean reputation, is allowed him for carrying on effectually the laboursof the establishment. The sum allotted from the imperial treasury for itsannual maintenance is no less than 02,200 roubles f.
M. Struve commenced his labours at the Observatory of Pulkowa in themonth of September, 1839. The main object to which he has proposedto devote the resources of the establishment, is the advancement of side-real astronomy. Eesults of great importance relative to precession,aberration, and other kindred subjects, have already been deduced fromthe observations J.
In the United States of America , practical astronomy has recently beenmaking rapid progress. A central observatory has been established atWashington, which is placed under the direction of Lieut . Maury. Theexpedition to Chili, undertaken with a view to determine the solar paral-lax by means of simultaneous observations of Venus and Mars, bearshonourable testimony to the enlightened views and liberality of theAmerican Government. Besides the national observatory above alludedto, there are similar institutions, upon a smaller'scale, established in severalof the states of the Union. Of these, the most celebrated is the observa-tory of Harvard University, Cambridge, Massachusetts , which boasts of oneof the largest and most perfect refracting telescopes in the world. Thediscovery of the eighth satellite of Saturn, and the establishment of variousfacts of a highly interesting nature, relative to the physical constitution
* £100,000. _ _ + £10,366 13s. id.
J M. Struve has given a complete description of the Observatory of Pulkowa in a mag-nificent work entitled, “ Description de l’Observatoire Astronomique Central de Pul-kowa, par F. G. W. Struve,” 2 vols. fol., St. Petersburg , 1845.