1909] 



on Researches in Radiotelegraphy . 



667 



series of copper discs or copper boxes cooled with water, the flat sur- 

 faces of which are placed in contiguity, but separated by very thin 

 rings of mica. The interspace between the boxes is not more than 

 -i4-3^th part of an inch, and 10 or 12 of these discs or boxes are placed 

 in series (see Fig. 11b). The row of boxes takes the place of the 

 ordinary spark balls, and is connected to the secondary terminals of 

 a transformer, fed by a high frequency alternator, and also connected 

 to an oscillatory circuit. When the transformer is in action it pro- 

 duces a very large number, 1000 or more, oscillatory discharges of 



^ Mica Ring 



_ Copper 

 \ Flanged Plate 



Plan of Copper Flanged Plate 

 Fig. 11b. — Plan and Section showing Poetion of Discharger. 



the condenser per second, each of which has a large initial ampHtude, 

 but quickly dies out. The inductively or directly coupled antenna 

 hence receives a very large number of impulses per second, each of 

 which sets up in it free electrical oscillations of one definite period. 



A discharger composed of a single pair of metal plates with inter- 

 posed separating paper ring has been devised and employed by Yon 

 Lepel. In this case the plates are connected to the terminals of a 

 high-voltage direct-current dynamo, and are shunted by a circuit 

 having inductance and capacity, one of the plates being also connected 

 to an antenna and the other to a balancing capacity. 



