Norwich bulletin., 1920-01-24
THE AUDIoN, THE AMPLFiER OF SOUND

Q 7 r. i Generally speaking, the audion isl to the sense of hearing what the mi croscope is to sight, but specifically, nifies and 4 translates into sensation electric energies the very existence of which, as, well as form and frequency, would remain entirely unknown but for that instrument. Concering it Professor Lee De Forest says:
 "The first commercial audion as it originally appeared in 190S,. was no accident ,or sudden inspiration. For, failing to find in the incandescent gas mantel the, genuine effect of response to electrical vibration which I had first searched for in 1900. next explored the Bunsens burner flarne, using two platinum electrodes held close togeth- CT in the flame, with an outside cir cult containing a battery and a tele- phone receiver. From that successful flames detector' was evolved the evacuated. vessel containing first two, then three electrodes, one at least of which was incandescent. Considering the actual genesis of the audion, it will be seen that it was never, strictly speaking, rectifying device.
 @In surveying the wide field. of cleo tric communication today one cannot look back at the first grid- electrede of the audionr without a sense of won der at the enormous changes. which it has wrought. It has made possible commercial transoceanH radio teleg- raphy. It has. realized ,transcontinental telephony It has made reception of wireless signals halfway around the globe as an everyday occurrence.
 "The uncanny accuracy of millions of shells from the; Allies guns, the clocklike precision of advancing bar rages, would have been impossible save for effectiveness of their trench and airplane radio service, in which the -audion. was, the essential heart. Today this little grid controls and modulates an ever r=increasing Xii i lowattage of radio telephone energy
 which as early. as 1915 conveyed the spoken voice from Arlington to Hone Brunswick to the transport George Washington, in the harbor. of Brest, Il has already placed ten simultaneous telephone messages upon a single pail of wires.
 "A few ounces of grid wires makes possible the saving of hundreds of tons
 of copper in long distance, telephone conductors. It has given to the .phy-
 sicist a tool for, the exploration of un- probed fields of research and to tht electrical engineer a generator withou moving parts of alternating current. of any desired frequency, from 1,000,- 900 to 1O,O0e,00e periods per. second a machine absolutely constant and re liable in it's silent work.
 Tt was in the summer of 1912, whel at work on the problem of audion am plifiers in cascade arrangements lfo telephone repeaters, that I first dis
 covered that if the input or grid cir
 cult was inductance, the audion be
 came a generator of, continuous al
 ternating currents, originally mad evident by a shrill tone in the tele' phone receiver.
 A few months after the audion wal
 first. used for the. production of al ternating current of audible 1 frequency I first demonstrated tht
 fact that weak high-fre- quency currents :. could be equally well be generated, simply by sub- 1 stituting radio-frequency coils for tn
 original iron-cored coils and small va
 riable air condensers for the larg | telephone condensers of my origina experiment of 1912.
 "The uniform generation of electric 1 al oscillation in circuit by mean
 of an audion is one of the most strik | ing and fascinating of it's applications | There seems to be, in fact, no limi | to the number of applications to whicl | this. three electrode vacuum tube cal 1 be applied as a tool in the hands o
 the experimental physicist.
 i Probably the most promising fielt ] of all is the arrangement of audi
 ons in cascade as amplihers, of pull