292 Mr. J. Tykocinski-Tykociner on the 



following manner (fig. 3). [Mr. John W. Perry was kind 

 enough to draw the figures after the author's rough 

 sketches. — L. S.] 





T 



L_ 



w 



mw~ — + 



ar 



IS 



i 'N'1' l 'i-l-h l -l'l' l 'l-l' l 'l' l -h l 



The circuit II (wave-meter) to be calibrated is placed 

 between the aperiodic buzzer circuit I, the aperiodic indi- 

 cating circuit III, and the harmonic circuit IV with its 

 inductance L 4 and variable capacity 4 , energised by an 

 arc V or valve v. In the buzzer supply circuit the coil W 

 of a telephone is inserted, the diaphragm M of which closes 

 a tube F containing a piston P and rod K sliding over a 

 millimetre scale S. 



After the condenser C 2 of the circuit II is set in a 

 position C 2 ', for which the natural frequency is to be 

 determined, the circuit IV is brought into resonance with 

 it by variation of the condenser C 4 . Then the condenser C 2 . 

 is gradually turned to a position of smaller capacity C2", 

 until the indicator D (hot-wire instrument, heterodyne 

 receiver, or ticker) again shows resonance, corresponding 

 to the first harmonic. Thus a frequency of the circuit II 

 twice greater than that in the position C 2 ' is established. 

 The next step is to close the buzzer circuit and to count 

 the number of maxima while turning gradually the con- 

 denser C 2 from the position C 2 " back to CV. Finally, the 

 piston P is moved, the length of the tube F between 

 the diaphragm M and piston P determined for a certain 

 number of maximum sound intensities heard in the ear- 

 piece H, and the wave-length in air of the sound calculated. 



