RADIATION CHARACTERISTICS OF AN ANTENNA. 247 



allies computed on the assumption that the osciUator is a Hertzian 

 oublet. This latter assumption gives 



R= 100 



X2 



It is seen that the departure of the present theory from the 

 doublet theory is very large for the straight vertical antenna, as 

 should be expected. 



It should be noted that the first value in the column of resistances 

 computed by the present theory agrees with the xnhw for this case 

 computed by Abraham in the work cited in the introduction. This 

 one value is the only value arri\ed at by Abraham for the fundamental 

 oscillation, and is the case of a straight vertical antenna oscillating 

 with its natural freciuency. Al)raham's other computed values are 

 for the harmonic vibrations with more than one loop of potential 

 always without loading the antenna by inductance, and without any 

 flat-top extension of the antenna. 



24. Comparison of Computations on the Present Theory 

 with Dr. Austin's Values for the Battleship " Maine." — Figure 

 16 gives the Radiation Resistance of the Antenna of tiie Battleship 

 "Maine" as computed by the present Theory in comparison with 

 Dr. Austin's measured values of the total resistance of this antenna, 

 and in comparison with values computed on the doublet theory of 

 Hertz. The black dots of Figure l(j are Dr. Austin's observed values. 

 The heavy line was obtained by computation by the present theory, 

 and the weaker line, by computation regarding the antenna as a 

 doublet of half-length equal to the vertical height of the antenna. 



It is seen that the departure between the present theory and the 

 doublet theory is not so great as in the case of the straight vertical 

 antenna, for the reason that the doublet theory becomes more nearly 

 correct as the half-length of the oscillator becomes small in comparison 

 with the wavelength. 



Neither of the theories gives a rising value of the resistance with 

 increase of wavelength, and, as Dr. Austin has pointed out, his rising 

 values for long waves are probably not due to radiation from the 

 antenna but possibly to dielectric hysteresis in the ground beneath 

 the flat-top. 



I do not give more extended comparisons with experimental values 

 at the present time, because I am now making some experiments to 



