as Radiators in Wireless Telegraphy. 



693 



Exp. VII. — Large square coils placed parallel to the 

 earth. Distance 68 feet. Receiver tuned to a frequency o£ 

 162,000 approximately in syntony with the transmitter. The 

 coils were raised to various heights above the ground and 

 the secondory current measured. The transmitter current 

 was kept constant at 5*4 amperes. 



Table VII. 



Height of Coils 



above the ground, 



in feet and 



inches. 



Power taken 

 up in Arc 

 in watts. 



Power factor 

 of Arc. 



Secondary 



Current in 



milliamperes. 



ft. ins. 

 On ground 



2328 



1-0 



45-8 



2 



1424 



0-91 



47-4 



6 



1096 



0-86 



41-2 



1 1 



1104 



0-89 



27-7 



1 7 



1248 



0-92 



22-5 



2 2 



1272 



0-93 



16-0 



4 



1640 



1-00 



5-18 



G 



1856 



0-98 



8-03 



The above observations are reduced to graphic form in fig. 8. 



Fte. 8. 



Weight oj Coil, m/erf 



Phil. Mag. S. 6. Vol. 14. No. 84. Dec. 1907. 



3 A 



