20 



KEXXELLY AXD KUROKAWA. 



cut in (litt'erent parts of this slab, -with the following diameters; Xo. 1, 

 0.6 cm.; Xo. 2, 0.9o cm.; Xo. 3, 1.3 cm.; Xo. 4, l.(i cm., and Xo. o, 

 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. 



RES ISTANCE . OHMS 



a -90 



Figure 10. Motional Impedance of Receiver at Constant Impressed 

 Frequencie.'^, attached to Air-Tube of Constant Length f.ST.S cm.) with aper- 

 tures of different diameters at far end. 



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

 quency of S.')0cv3, the successive motional impedances of the receiver 

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

 K-1 . . . K-o. 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 ~. the corre- 

 sponding vector loci with different terminal apertures are marked on 

 the curves BB, CC, DD, and EE. 



