1044 



Voltaic Electricity. Section 10: Electrical Oscillations. 



No. 63 288 - 



63 288. 1 : 6. 



63289. 1:8. 



63 291. 1 : 15. 



63,288. Lecher Tube for Apparatus Nos. 63,28663,287 



63.289. Apparatus after Walter Biegon von Czudnochowsky, for demonstrating stationary 

 Electric Waves on Wires, Figure; simple pattern (Ztschr. f. d. phys. u. chem. II. 16, 

 1903, p. 345); without tube or spark coil 



Two foot terminals No. 60,172 ( 0. 6. each) and a helium tube No. 63,295 are necessary for 



the experiments with this apparatus. 



t 



63.290. Exciter for stationary Wire Waves, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 21, 

 1908, p. 9; Physik. Ztschr. 8, 1907, p. 485) 



Supplied with the apparatus are: 2 copper wires, wire holder with terminals. 3 bridges and a 

 small helium tube. 



63.291. Aron's Tube, Figure, for demonstrating electrical Oscillations (Wied. Ann., 45, 

 p. 553, 1892,) without exciter or induction coil 



One of the experimental arrangements similar to Lecher's is used. From the secondary zinc 

 plates opposite the exciter plates, at a mutual distance of 30 mm, two 2 mm thick aluminium wires 

 are conducted parallely 3.5 m through the air and 2.5 m through the 60 mm diameter Aron tube, the 

 wire in the tube being of the same length as that outside. The glass tube is connected by a length 

 of tubing with the water air pump and evacuated to a pressure of 10 20 mm mercury column. 

 With this arrangement the tube is usually .seen to light up over its entire length in the darkened 

 room. If, however, the free portion of the leads is bridged over, the light is generally extinguished. 

 By sliding the bridge, however, it is possible to generate stationary electric waves so that the tube 

 shows one more or non-luminous nodal points. 



63.292. Apparatus after Ooolidge-Blondlot, for demonstrating electric Waves, F i g u r e 

 (Wied. Ann. 67, 1899, p. 578^, consisting of a modified Blondlot Exciter with ebonite 

 protecting jacket, on stand with glass pillar, a Tension Device on stand, 2 Copper 

 Wires cadi 0,2 mm thick and 5.5 m long, and 6 Bridges of different size 



In this apparatus use is made either of a Lecher Tube at bridge or wires lighting up in vaeuo 

 are employed, but the waves are visible by the luminesence of the wires in free air. 



In order to obtain as strong oscillations in the secondary circuit of the exciter as is po>-il>]e. 

 the exciter is of the same size as the primary oscillating circuit and is brought as near to it as possible. 

 With a view to attaining this the two circuits are separated simply by mica plates of a total thickness 

 of '2 mm and are contained in an oil bath, thus preventing any sparking over in the secondary. The 

 primary circuit is constructed in two parts, the distance apart being regu'ated by insulating screws 

 fitted on the ebonite cover of the appara.ni- 



The following are necessary for working the apparatus: 1 Induction Coil of l.">o 2(Hi mm spark- 

 length; 1 spark Micrometer No. 63,208 or 63,209; 1 High-tension Transformer \o. (i:>.^10 and 1 Leyden 

 Jar No. (ii>..VS-_>. 



Directions for use sent on application. 



>(>. 



Leyden Jar, height 26 cm, with terminals 



63,293. Wavemeter after Drude, with air condenser for determining the period of oscillation 

 and, consequently, the wave-length in the oscillation circuits for wireless telegraphy 



(I)rudes Annalen, 9, 1902, p. 615), Figure. Without vacuum tube 



The apparatus consists of a small air condenser with two 1 mm thick parallely stretched copper 

 wires connected to it, these wires being fixed to a wood baseplate -1 m long. An electrodeless vacuum 

 tube is used as indicator. \Vuve-lengths from \~2 to .">< in can be determined with ease. 



Cl. 3581.3031. 



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s. d. 

 0. 4.0 



2. 0.0 



4. 0. 



1. 16. 



4. 0. d 



1 . 0. 



5. 0. 



