880 SEC. 19. EDUCATIONAL APPLIANCES. 



4435. Mach's Wave Apparatus, for illustrating the 

 longitudinal and transversal waves. 



4436. Mach's Apparatus for Sound Reflection. 



4437. Mach's Apparatus for Refraction and Reflexion. 



4438. Mach's Apparatus for demonstrating the Law of 

 Refraction by means of fluorescent liquids. 



4439. Mach's Apparatus for demonstrating the Effects of 

 Lenses. 



4440. Model of a Screw, of wood. 



4441. Model of a Screw, of wood. 



4442. Crown Glass Prism. 



4443. Flint Glass Prism. 



4444. Poly Prism. 



4445. Hollow Prism. 



4446. Universal Ealeidophon, for illustrating Lissajou's 

 figures. 



4447. Meyerstein's Heliostat. 



4448. Astronomical Telescope, on a wooden stand with 

 scale. 



4449. Pocket Spectroscope, according to Professor Ems- 

 mann, with only one prism, and contrivance for specially placing 

 the separate colours. 



4450. Another Specimen of the same kind. 



4451. Thermo-electrical Battery, according to Clamond. 



4452. Thermo-electrical Battery, according to Noe. 



4453. Lane's Measure-bottle, fine adjustment, with scale 

 and vernier. 



4454. Separable Leyden Jar. 



4455. Electroscope, after Professor Mach, for demon- 

 strating that electricity lies on the surface of excited bodies. 



4456. Holtz's Electrical Machine. 



Auxiliary apparatus : a. Lightning-tube, b. Lightning-plate. 

 c. Chime of bells, d. Dancing dolls, e. Contrivance for breaking 

 glass plates, f. Henley's discharging rod. g. Discharging rod, 

 with joint. 



4457. Pair of Concave Mirrors, brass, 16 inch diameter, 

 8 inch focal distance, on tripods, with contrivance for adjustment 

 and equipment for heat experiments. 



