Annual report of the Board of Regents of the Smithsonian Institution . r the method of quenched sparks, which is based on the factthat if we can quench or stop the spark in the condenser circuit afterthe first few oscillations, the oscillations of the antenna then take place freely and with a single fre-quency (see fig. 11a). The principle which underlies thismethod is the well-known fact, towhich particular attention was calledby Prof. M. Wien, of Danzig, in 1906,that the damping effect of very shortsparks is extremely large. Hence, ifwe form a spark gap consisting of alarge number of very sm
Annual report of the Board of Regents of the Smithsonian Institution . r the method of quenched sparks, which is based on the factthat if we can quench or stop the spark in the condenser circuit afterthe first few oscillations, the oscillations of the antenna then take place freely and with a single fre-quency (see fig. 11a). The principle which underlies thismethod is the well-known fact, towhich particular attention was calledby Prof. M. Wien, of Danzig, in 1906,that the damping effect of very shortsparks is extremely large. Hence, ifwe form a spark gap consisting of alarge number of very small spark gaps inseries, say 10 gaps each of mm., andif we keep the spark surfaces cool,then not only can no arc form be-tween these surfaces but the condenser spark is immediatelyquenched. Moreover, if we supply this spark gap, either from a highfrequency alternator, or from a low resistance transformer, we canproduce as many as 2,000 sparks per second. A form of dischargerfor this purpose has been devised in Germany which consists of aseries of copper disks or. Fig. 11.—Method of utilizing wavesof both frequencies emitted byinductively coupled transmittingantenna. Ordinary Spark copper boxes cooled withwater, the flat surfaces ofwhich are placed in con-tiguity, but separated byvery thin rings of interspace betweenthe boxes is not morethan one one-hundred-and-twenty-fifth of aninch, and ten or twelveof these disks or boxesare placed in series (seefig. 11b). The row ofboxes takes the place ofthe ordinary spark balls,and is connected to thesecondary terminals of atransformer, fed by a highfrequency alternator, and also connected to an oscillatory the transformer is in action it produces a very large number,1,000 or more, of oscillatory discharges of the condenser per second,each of which has a large initial amplitude, but quickly dies out. Theinductively or directly coupled antenna hence receives a very large
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