IX. EDUCATIONAL. 427 



IX. -EDUCATIONAL. 



1876. Sphere, moved by clockwork, of Just Burgh (1580). 



Conservatoire des Arts et Metiers. 



1877. Sphere, moved by clockwork, of Jean Reinhold (-1588). 



Conservatoire des Arts et Metiers* 



1884. Planetarium or Orrery, designed by Ch. Huygens, 

 constructed by J. Van Ceulen, set in motion by clockwork. 



Prof. Dr. P. L. Rijke, Leyden. 



1887. Model devised by the Rev. James Bradley, Savilian 

 Professor of Astronomy, &c., and used by him for illustrating his 

 discovery of Aberration. R: B. Clifton. 



For a description of this model, see Phil. Mag., Dec. 1846, vol. 29, p. 429. 



1879. Apparatus for demonstrating the Retrogression of 

 the Superior and Inferior Planets, also the Synodic Revo- 

 lutions, the Transits of Venus and Mercury, &c. 



J. J. Oppel. 



The long wire represents the line of vision, the small shield at one end 

 the apparent position of the planet, the fixed ball at the other end the earth, 

 and the movable ball the planet. The latter is fixed on the pivot of the 

 smaller or larger turn-table, according as it is wished to demonstrate the 1 

 retrogression of an inferior or superior planet. The twelve signs of the zodiac 

 are hung up on the walls of the lecture room ; the handle must be turned 

 from left to right ; the angular movement of the line of vision from left to 

 right demonstrates the retrogression. 



1880. Cosmographical Apparatus, to explain various natu- 

 ral phenomena, made by M. Robert, of Paris, and purchased for 

 the South Kensington Museum in the Paris Exhibition of 1867. 



1. The seasons. 



2. The seasons. 



3. Phases of the moon. 

 4. Eclipses. 



5. Librations of the moon. 



6. Real and apparent motion of the planets. 



7. Fall of bodies. 



8. Inequality of the seasons. 



9. Precession of the equinoxes, physical. 



10. Precession of the equinoxes, geometrical. 



11. Precession of the equinoxes, mechanical. 



12. Star to indicate a point in space. 



1881. Nutoscope. Apparatus showing the laws of preces- 

 sion and nutation, and the conservation of the plane of rotation. 

 With diagrams, constructed by the aid of the apparatus. 



Prof. Carl Wenzel Zenger, Prague. 



