RADTOTELEGRAPHY MARCONI. 



119 



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 numerous examples of this fact, 

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

 experiment. 



Other illustrations of this principle may be given; e. g., if we have 

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

 impulses, the latter must be timed to the period of the pendulum, as 

 otherwise its oscillations would not acquire any appreciable amplitude. 



In 1900 I first adopted the arrangement which is now in general 

 use, and which consists (as shown in fig. 3) of the inductive associa- 

 tion of the elevated radiating wire with a condenser circuit which may 

 be used to store up a considerable amount of electrical energy and 

 impart it at a slow rate to the radiating 

 wire. 



As is now well known, the oscillations 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 antennae 

 these oscillations are radiated into space 

 in the form of a series of waves, which 

 through their cumulative effect are emi- 

 nently 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 con- 

 ductor, and by the employment of the right value of capacity or 

 inductance required 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 con- 

 ductor or aerial connected to earth or capacity through an oscil- 

 lating transformer. The latter also contains the condenser and 

 detector, 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 

 upon my syntonic system of 1900, to which have been added numerous 

 improvements. 



Fig. 3. 



