. An elementary manual of radiotelegraphy and radiotelephony for students and operators . dthe carbon rod musthave its edge squareand sharp and be keptin slow but very regularrotation. When theseconditions are all ful-filled, the oscillationsin the condenser circuitare powerful and prac-tically undamped orpersistent. In place of coal gas,pure hydrogen gas maybe used, but it is rathermore difficult to main-tain a steady electricarc in an atmosphereof pure hydrogen thanin coal gas or in may also use thevapour of a volatilehydrocarbon liquid suchas pentane, or petrol, oreven alcohol may be
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . dthe carbon rod musthave its edge squareand sharp and be keptin slow but very regularrotation. When theseconditions are all ful-filled, the oscillationsin the condenser circuitare powerful and prac-tically undamped orpersistent. In place of coal gas,pure hydrogen gas maybe used, but it is rathermore difficult to main-tain a steady electricarc in an atmosphereof pure hydrogen thanin coal gas or in may also use thevapour of a volatilehydrocarbon liquid suchas pentane, or petrol, oreven alcohol may beintroduced drop by dropinto the arc chamberand allowed to evapo-rate. This liquid canbe supplied from asight-feed lubricator asshown in Fig. 15, which gives a general view of the Poulsen Arcapparatus. It is found that almost any gas which does notcontain oxygen will exalt the frequency of the oscillationsobtainable from a carbon-copper arc, even an inert gas likenitrogen, but a hydrocarbon gas or vapour is found to give thebest effect. Poulsen proceeded immediately on the discovery of. [Reproduced frem tin Fig. 15. The ElectricianproprieUyri. hy permission of the UNDAMPED ELECTRIC OSCILLATIONS loi these facts to apply them in the practice of radiotele^raphy, butwe shall return to the consideration of this application in alater chapter. r>. Other Researches on the Transformation of ContinuousCurrents into Electric Oscillations.— In uddilioii to the mentioned made on the singing arc, the ellect has beenthe subject of experiments by Siinon and Keich, and researchesby H. Th. Simon, and the last-named investigator has done muchto elucidate the matter as well as to explain the reasons for thediscrepancies between the results of other observers. Simon and Reich in 1903 found that when a high potentialarc was formed between metal balls in vacuo, strong oscillationswere set up in a circuit including a capacity and inductance inseries placed as a shunt across the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
