No. 53 154. 



Wave Machines. 



413 



53149. 1 : 12. 



53152. 1 : 17. 



53153. 1:0. 



5.3,149. Wave Machine after Hillig, Figure, with a .single and a double clamping board s. d. 

 and with two adjustable bell cups fixed on stands 4. 0. 



The apparatus represents an ether stratum and consists of a wood frame 1.5 x 0.5 m upon which 

 a number of lead balls 1 cm in diameter are .strung, being connected with each other and with the 

 frame by means of spiral springs. It is possible to demonstrate with this apparatus (1) the longitu- 

 dinal wave; (2) the transverse wave; (3) the water wave (gravitation wave, in which the frame is placed 

 horizontally); (4) the velocity of propagation (if the centre is plucked both bells ring simultaneously: 

 equal velocity of propagation in the same medium); (5) polarisation; and (6) Huygens's Principle. 

 A description is appended to each apparatus. 



* 53, 150. Apparatus for Demonstrating Wave Motions, after Grimsehl (Ztschr. f. d. phys. u. 

 cliem. U. 19, 1906, p. 271), for demonstrating the Propagation, Eeflection, and Inter- 

 ference of Water Waves 



#5:5,151. Lantern Slide for explaining Wave Motions Each 



5:5,152. Wave Trough after VVeher, Figure, with glass walls 



5:5, 153. Apparatus for the Repulsion and Interference of Wave Motion, F i g u r e (Fr. phys. 

 Techn. I, 2, Figs. 3637 and 3639 [I, Figs. 565 and 566]), comprising an iron plate 

 and dropping vessel for mercury on a movable stand, and two different elliptical 

 vessels 



One vessel is filled with mercury until a smooth surface is formed. If now mercury is allowed 

 to drop out of the dropping vessel in a focus of the ellipse, very visible waves are produced the repulsion 

 and interference of which are rendered visible in a very pretty manner. The phenomena can also be 

 projected by means of the mirror and lens No. 53.154. 



53,154. Adjustable Mirror and Large Bi-convex Lens for above, to enable the phenomenon 

 to be projected by means of the lantern 



3. 15. 

 0. 1. 6 

 2. 4. 



1. 4. 



2. 5. 



# Can be used with the Projection Apparatus. 



5SOO, 338. 



