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A RETROSPECT OF WIRELESS COMMUNICATION. 559 
modulation on which signals and voice depend, are determined by the grid, which 
carves the otherwise continuous traffic into an intermittent stream, in accordance 
with the fluctuating potential of the grid. So that, although the grid is supplied with 
very small power, its influence in regulating the traffic is considerable ; and the power 
derived from the valve is thereby regulated in accordance with the received wave, 
but has a power depending only on the local battery. It acts, in fact, as a relay, 
putting fresh energy into the disturbance, but not otherwise interfering with it. The 
electrons are so docile that they follow every fluctuation with precision, so that every 
feature or tone of the voice is accurately reproduced, however much it be magnified. 
That is the beauty of the three-electrode valve: it magnifies without appreciable 
distortion. There is no distortion in the Ether of Space, and accordingly the feeble 
fluctuations imposed on the wave by the voice at the sending station can travel any 
distance across space without injury, except that they become weaker; and then 
these residual fluctuations can be magnified up in amount, still retaining their features, 
until they are capable of actuating a loud-speaker and being heard all over a hall. 
Tf the magnification is being pressed to extremes, a little distortion does enter in, not 
because the ether has any deleterious effect, but because a certain amount of matter 
is introduced into the cireuit, which has the usual imperfections associated with 
matter; and thus, though the magnification that could be used is very great, ib is 
not infinite. 
Next it was found that the valve could also be used for generating continuous 
waves, at the same time enhancing their power enormously ; so that a talker at the 
microphone could have the modulations of his speech magnified till they were repre- 
sented by great electrical energy, which then emerged as-ether waves from the aerial, 
and travelled to a distance, where some trace of them was picked up by another 
aerial, again magnified, rectified, and transmitted to the ear. In that way it became 
feasible to transmit speech or music to great distances. This was in 1913. 
Four years later the remarkable property of quartz was utilised. A crystal of 
quartz, if squeezed, becomes positive at one end and negative at the other, this being 
the kind of electrification produced by pressure applied to the peculiar structure of 
the crystal. This effect is reversible, so that when it is electrified it constricts as if 
squeezed. Quartz thus furnished an intermediary between mechanical and electrical 
vibrations. The pressure applied to quartz was mechanical; the electric effect 
resulting was ethereal. The two being reversible, there was a possibility of transmuting 
an ether wave into a sound wave, or vice versa. Quartz could be used either for 
sending or transmitting. A thin plate of quartz would have a high rate of mechanical 
vibration in the longitudinal direction. An electrical vibration of the same frequency 
applied to it would call out this very high frequency sound vibration. It could not 
be heard, it would be supersonic, but it could produce various effects. These effects 
have been studied of late years by R. W. Wood of Baltimore and other people. The 
facts are astonishing, and have introduced a fresh department into science called 
Supersonics. 
Eccles, however, proceeded to use the vibrations of quartz as a transmitter for 
electrical waves of steady frequency. He regulated the frequency by a tuning-fork, 
adjusted once for all to the frequency desired. He then caused the fork to operate 
on a piece of quartz so as to generate electrical vibrations of the same frequency. 
These could then be magnified up, transmitted to the aerials of the Rugby station, 
and so send out waves of enormous power all over the earth, with a precision of tuning 
hitherto unequalled, so that an operator at a distant receiving station with an 
accurately tuned receiver could do anything he liked with them. 
Broadcasting on a large scale now became possible. In 1920 it was initiated in 
the United States, and in October 1922 the British Broadcasting Company started 
its career in this country. Later it became a Government institution, the British 
Broadcasting Corporation, and under the management of Sir John Reith throughout 
made itself responsible for transmitting speech and music from a number of stations 
on different wave-lengths to all the houses in the British Isles (and far outside them) 
who would pay for a licence. 
(Published in Nature, Oct, 3, 1931; cf. Lodge, Past Years, Hodder & Stoughton, 
1931.) 
