\ 



20 



KENNELLY AND KUROKAWA. 



cut in different parts of this slab, with the following diameters; Xo. 1, 

 0.6 cm.; No. 2, 0.95 cm.; Xo. 3, 1.3 cm.; X"o. 4, 1.6 cm., and Xo. 5, 

 full tube aperture (3.1 cm.); i.e., with slab removed. Xo. repre- 

 sents the case of a complete closure of the tube by the unpierced slab. 



RESISTANCE , OHMS 



2W 40 



I 



o 



--60 



z 

 < 



a: -So 



Figure 10. Motional Impedance of Receiver at Constant Impressed 

 Frequencies, attached to Air-Tube of Constant Length (87.8 cm.) with aper- 

 tures of different diameters at far end. 



The origin of the diagram is at K, Figure 10. At the constant fre- 

 quency of 850 f^, the successive motional impedances of the receiver 

 attached to the tube, with successive terminal orifices 0-5 were K-0, 

 K-1 . . . .K-5. The ends of these vectors are connected by the curve 

 AA. Repeating the motional-impedance measurements at the suc- 

 cessive steady frequencies of 901, 921, 949 and 1000 c^, the corre- 

 sponding \-ector loci with different terminal apertures are marked on 

 the curA-es BB, CC, DD, and EE. 



