1058 



Voltaic Electricity. Section 11: Telephony and Microphony. 



No. 63 390 



63 395, 50 892, 63 386, 63 388, 63 389. 1 : 8. 



Complete Apparatus for Experiments with the Speaking Arc Lamp after Weinhold (W. D., <i 



Fig. 601), consisting of: 



Arc Light Hand Regulator and Resistance: see Nos. 50,892, 63,386 and 63,387, p. 1057. 



63.390. Induction Coil, Figure 3. 4. 



63.391. Microphone with Switch and Regulating Resistance, and 1 Fuse with simple current 

 indicator for same 3. 0. 



Additional Apparatus for above so as to be able to demonstrate the automatically singing 

 (whistling) arc lamp also, consisting of: 



63.392. Small Induction Coil (W. D., Fig. 604), with aluminium ring for Thomson's Experiment 0. 16. 

 61,122. Switch 0. :5. (i 



63.393. Paper Condenser in wimple wood box, approx. 8 mfd 2. o. o 



63.394. Staged Paper Condenser, with four steps, for use instead of No. 63,393; this permits 

 of obtaining a simple melody with the arc (electric piano) since the pitch varies with 



the capacity cut in 6. 0. 



Apparatus for Demonstrating Photophony, Figures, consisting of: 



50,892. Arc Light Hand Regulator (I). C. of at least 80 volts and 10 amps, is necessary) . 2. 2.0 



63,3S(i. Series Resistance for Arc Lamp, for 110 volts, Figure 0.18.0 



63.387. Series Resistance for Arc Lamp, for 220 volts 2. 0. 



63.388. Self-induction Coil, Figure 2.10.0 



Cl. 3087. 



