290 Proceedings of Indiana Academy of Science. 
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Figure l. 
The tuning of the primary coil is by means of a variable condenser in series 
or in multiple with all or a portion of the primary coil. 
The inductance of the coils as wound is secondary, .0185 henry ;.and. pri- 
mary, .0228 henry. The total resistances are, 8.1 ohms and 9 ohms re- 
spectively. The natural wave length of the entire secondary coil as meas- 
ured with a wave meter is 1100 meters, which corresponds to a distributed 
capacity pf .000019 microfarads. The dead end switches break this so that 
the energy absorbed is a minimum. 
As mounted as a slide tuner the length over all is 22 inches. The total 
weight is 15 pounds. An equivalent long wave receiver coil of the single 
layer type would require five times as much wire and would be 25 times 
as long or a length of about 45 feet. 
Thus we have in small dimensions a receiver for any wave length from 
Annapolis 17000 meters to amateur stations 200 meters. European sta- 
tions are received with one bulb using an aerial 125 feet long stretched 
among the trees of the Indiana University campus. 
