NIL G3 135. 



Goldstein's Tubes. 



1023 



63 126. 1:5. 63 127. 1 : 5 



63 128. 



63 129. 



63 132. 



63 133. 



63 134. 



1131. 1:4. 



63,130. Canal Ray Tube after Goldstein, new, simpler pattern; with polished wood base, 

 Figure 



63.131. -- idem, after Wien, with polished wood base, Figure 



This tube permits of showing the positive and negative charges of the cathode and canal rays. 

 The perforated plate is earthed, the aluminium wire being the anode. If, then, the first electrode disc 

 is connected with the negative terminal of a well-insulated induction coil, the cathode rays pass through 

 the perforated plate, strike on the other disc and give a current of negative electricity if this latter disc 

 is connected with a sensitive electrometer. If, now, the negative terminal of the induction coil is con- 

 nected with the perforated plate (the earth connection remaining) instead of with the disc, a current 

 of positive electricity is obtained from the cathode rays which are then emitted. 



63.132. Goldstein Tube, Figure, filled with powdered sodium chloride, potassium chloride, 

 potassium iodide, or potassium bromide. The substances mentioned change colour under 

 the action of the cathode rays (Annalen der Physik und Chemie, Vol. 60, 1897, p. 491) 



The lead (a quite flexible stranded conductor) from a small induction coil (of not more than 

 3 cm spark-length) is slung fast to the platinum eyes. The thinner portion of the tube is clamped 

 in a wood retort-holder or the like and while the current is passing through, the powder is approriately 

 shaken up. In a few seconds this powder has assumed the characteristic colouring under the influence 

 of the cathode rays, and this colour only disappears after a fairly considerable lapse of time. If only 

 a large induction coil is available a 2 3 centimetre spark-gap must be put in parallel with the tube. 



63.133. Goldstein Tube with powders phosphorescing in different colours; for tilting over, 

 Figure 



Cathode Ray Tubes after Braun: see p. 899. 



63.134. Vacuum Tube after Thomson, Figure, for studying the deflectivity of the cathode 

 rays by static electricity and by magnets, with osmose regeneration to enable the vacuum 

 to be maintained uniform 



63,135. Wood Stand for above 



s. d. 



0. 15. 



1. 4. 



0. 6.0 



0. 12. 



2. 5.0 

 0. 6.0 



Cl. 2949, 2950, 6507, 6505, 3560, 



6508, 

 (5502,6503,3572. 



