1911] 



on RadiotdegrnpJiy. 



195 



•^ 



after only a few oscillations, and, consequently, anything approaching 

 good tuning between the transmitter and receiver was found to be 

 unobtainable in practice. 



Many mechanical analogies could be quoted which show that in 

 order to obtain syntony the operating energy must be supplied in the 

 form of a sufficient number of small oscillations or impulses properly 

 timed. Acoustics furnish us with niuuerous examples of this fact — 

 such as the resonance produced by the well-known tuning fork experi- 

 ment. 



Other illustrations of this principle may ])e given, e.g. if we have 

 to set a heavy pendulum in motion by means of small thrusts or im- 

 pulses, the latter must be timed to tlie 

 period of the pendulum, as otherwise its 

 oscillations would not acquire any appre- 

 ciable amplitude. 



In 1900 I first adopted the arrange- 

 ment which is now in general use, and 

 which consists (as shown in Fig. ?>) of 

 the inductive association of the elevated 

 radiating wire with a condenser circuit 

 which may be used to store up a consider- 

 able amount of electrical energy and 

 impart it at a slow rate to the radiating 

 wire. 



As is now well known, the oscilla- 

 tions in a condenser circuit can be made 

 to persist for what is electrically a long 

 period of time, and it can be arranged 

 moreover that by means of suitable 

 aerials or antenna3 these oscillations are 



radiated into space in the form of a series of waves, which through 

 their cumulative effect are eminently suitable for enabling good tuning 

 and syntony to be obtained between the transmitter and receiver. 



The circuits, consisting of the condenser circuit and the elevated 

 aerial or radiating circuit, were more or less closely coupled to each 

 other. By adjusting the inductance in the elevated conductor, and 

 by the employment of the right value of capacity or inductance re- 

 quired in the condenser circuit, the two circuits were brought into 

 electrical resonance, a condition which I first pointed out as being 

 essential in order to obtain efficient radiation and good tuning. 



The receiver (as shown in Fig. 4) also consists of an elevated 

 conductor or aerial, connected to earth or capacity through an oscil- 

 lating transformer. The latter also contains the condenser and de- 

 tector, the circuits being made to have approximately the same 

 electrical time period as that of the transmitter circuits. 



At the long distance station situated at Clifden in Ireland, the 

 arrangement which has given the best results is based substantially 



2 



