462 LECTURE XLVIII. 



knowledge, has discovered a primary planet, and eight secondary ones, 

 unknown before. The astronomers of Sicily and Germany have, however, 

 the honour of the first discovery of the three humbler members of the solar 

 system which have been last introduced to our acquaintance, Ceres by 

 Piazzi, Pallas by Olbers, and Juno by Harding: and the mathemati- 

 cians of France have excelled all their predecessors in the elaborate and 

 refined application of the theory of gravitation, to the investigation of the 

 most minute and intricate details of the celestial motions. 



For the latest improvement that has been made in astronomy we are 

 also indebted to the zeal and ingenuity of Dr. Olbers, who, in pursuit of 

 an opinion which he had formed, respecting the origin of the three small 

 planets from the separation of a larger one into fragments, has been in the 

 habit of examining monthly that part of the heavens in which he supposes 

 the event to have taken place, and through w r hich each of the bodies must 

 necessarily pass. He has had the good fortune to discover, in this manner, 

 a fourth planet [Vesta], which nearly resembles the three others in its 

 appearance, except that it seems to be considerably larger. 



LECT. XLVIII. ADDITIONAL AUTHORITIES. 



Gassendus, Tychonis Brahei Vita, 4to, Hagse Comitum, 1655. Blegny, Le Mes- 

 sager Celeste, 12mo, Paris, 1681. Champollion, Resume de Chronologie, 32rno, 

 Paris, 1730. De L'Isle, Mem. pour servir Histoire de 1'Astr. &c. 4to, St. Petersb. 

 1738. Weidler, Historia Astronomise, 4to, Vitembergse, 1741. Heilbroner, Hist. 

 Math, ab Orbe Condito ad Seculum XV. 4to, Lipsise, 1742. Heathcote, Historia 

 Astronomies, Cantab. 1747. Costard on the Chinese Astr. Ph. Tr. 1747, p. 476. 

 Hist, of Astr. 4to, Lond. 1767. Esteve, Hist, de 1'Ast. 3 vols. 12mo, Paris, 1755. 

 Bernoulli, Lettres Astronomiques, Berlin, 1771. Bailly, Histoire de 1' Astronomic 

 Anc. et Mod. 3 vols. 4to, Paris, 1775-9. Do. Indienne, 4to, 1787 ; Abrege, 1805. 

 Blair's History of Geography, 12mo, 1784. Schaubach, Geschichte der Greichischen 

 Ast. Gott. 1802. Lalande, Bibliographic Astronomique, 4to, 1803. Small's 

 Account of the Discoveries of Kepler, 1803. Ideler, Historische Untersuchungen 

 iiberdie Ast. Beob. der Alten. Berlin, 1806. Voiron, Hist, de 1'Ast. depuis 1781 

 jusqu'a 1811, 4to, 1810. Cassini, Memoires pour servir al'Hist. des Sciences, 4to, 

 Paris, 1810. Gautier, Essai Historique sur le Probleme des trois Corps, 4to, Paris, 

 1817. Delambre, Histoire de 1' Astronomic Ancienne, 2 vols. 4to, Paris, 1817 ; du 

 Moyen Age, 4to, 1819 ; Moderne, 2 vols. 4to, 1821 ; de 18e Siecle, publiee par 

 Mathieu, 4to, 1826. Laplace, Precis de 1'Hist. de 1'Ast. 1821. Rigaud's Memoirs 

 of Bradley, 4to, Oxf. 1832 ; Suppl. 4to, Oxf. 1833. Rothman's History of Astr. 

 (Lib. of Useful Knowledge), 1832. Airy's Report on Astr. Brit. Assoc. 1832. 

 Baily's Account of Flamsteed, 4to, Lond. 1835. 



