No. 63389. 



Telephony. Telephonograph. Speaking Arc Lamp. 



1057 



63 384 A. 



63 384 B. 



63.383. Telephonograph after Poulsen, for permanently fixing and conveniently repeating a s. d. 

 telephonic conversation, Figure (cf. E. T. Z., 1901, p. 57, 181; Drudes Annalen d. 

 Physik, 3, 1900, p. 754), with microphone for transmitting, two telephones for receiving, 



and the necessary cells, also two steel discs and demagnetizing device 11. 0. 



The fluctuations in a current produced by a microphone are carried through a magnetizing coil, 

 which is guided over a hardened steel plate in a spiral line, in a similar manner as employed in gramophones. 

 The fluctuations in magnetization of the steel plate which are permanently recorded, suffice to induce 

 currents in the coil of the magnet when the latter is again guided over the steel plate, these currents 

 giving in the telephone an accurate and surprisingly plain reproduction which can be repeated at 

 will of the sounds originally conducted into the microphone. 



63.384. Demonstration Apparatus for Wireless Telegraphy with electric Waves, consisting of 

 a Transmitting Station, Fig. A, and a Receiving Station, Fig. B, for single direction 

 working 27. 10. 



Direct Current at 220 volts is necessary for working. Complete description sent on application. 



63.385. - - idem, consisting of two stations which can both transmit and receive, for reci- 

 procal working 37. 10. 



Complete Apparatus for Experiments with the Speaking Arc Lamp, Figure on p. 1058, 

 consisting of: 



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



63.386. Series Resistance for the Arc Lamp, for connecting to 110 120 Volts 0. 18. 



Or: 



63.387. Series Resistance for the Arc Lamp for connecting to 220 volts 2. 0. 



63.388. Self-induction Coil 2. 10. 



63.389. Microphone with Switch and Eegulating Eesistance 2. 0. 



Cl. 81AF, 81BP. 



67 



