430 SEC. 11. ASTRONOMY. 



a. The apparatus, placed on a common centrifugal machine and turned 

 slowly from right to left, shows the maintenance of the plane of oscillation 

 of the pendulum with respect to the spectator and its apparent revolution 

 relatively to the apparatus, a revolution which the ball of the pendulum 

 (painted half black half red) does not itself accomplish. 6. With a movable 

 tangent cone the instrument demonstrates, by means of some large diagrams, 

 that the fact and the reason of the apparent angular velocity of revolution of 

 the pendulum being proportional to the sine of the geographical latitude. 



1896. Apparatus for demonstrating the alteration 

 of the date in journeys round the world, from west to east. 

 Property of His Highness Prince Pless, Fiirstenstein. 



The Breslau Committee. 



This instrument dates from the first quarter of the 18th century. 



1897. Sidereal Atwood's Machine, with a ball, which 

 represents either tHe moon or a planet. Chr. Trunk, Eisenach. 



The peculiarity of the apparatus and its object are explained in the descrip- 

 tion which accompanies the model. 



By its means a sphere, placed on a free vibration axis, is caused to oscillate 

 with changeable velocity round a focus in an elliptic orbit, as the satellites 

 round the planets, and the planets round the sun. 



The apparatus shows the libration of the satellites and of the planets, 

 causing the precession of the equinoxes. 



1898. Ring Sphere. Dr, H. Lockermann, Hamburg. 



This armillary sphere, of which a more detailed explanation accompanies 

 the instrument, is to be used for instruction in mathematical geography. It 

 is to serve for object lessons, and makes therefore no pretence to scientific 

 accuracy. The instrument demonstrates the apparent motion of the sun and 

 moon, and of the more important constellations (49 constellations with 359 

 stars of from first to fifth magnitude) at any given place and at any given 

 time. 



1899. Projection Apparatus. J. and A. Molteni, Paris. 



1900. Descrivani's Orrery, by M. Pierret. 



Conservatoire des Arts et Metiers, Paris. 



1901. Wall Maps (11) for teaching Cosmography : 



1. The Ptolemaic system. 3:It 



2. Tycho Brahe s system. ^^ 



3. The Copernican system. 



l*nf. rComparative sizes of the sun and earth. 



o.< Comparative sizes of the planets (with map of Mars). 



6. The seasons. 



7. The phases of the moon. 



8. Eclipses. 



9. Parallax. 



10. Comets. 



11. Nebulae. Ernest JRecordon, Geneva. 



1902. Three Astronomical Diagrams and Two Rules, 



with scales, for the solution of problems in spherical trigonometry. 



Michael Elbe, Ellwangen. 



