THE WORLD'S ADVANCE 



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Detail No. 21 shows the con- 

 tact strips for the switch levers 

 in detail No. 19. 



Detail No. 22 is the switch 

 lever for the primary adjusting 

 switches of the receiving trans- 

 former. The knobs shown are 

 of the regular typewriter type. 

 The best way to attach the lever 

 to the hub of the knob is to turn 

 a shoulder on the hub, force the 

 lever on this shoulder and rivet 

 it over. Soldering is difficult, as 

 these knobs melt very easily. 



Detail No. 23 shows the han- 

 dles and pointers of the adjust- 

 able condensers. The remarks in 

 detail No. 22 apply here also. 



Detail No. 24 is of the levers 

 for the circuit changing switch. 



Detail No. 25 refers to the 

 hard rubber connecting bar for the fore- 

 going-mentioned switches. 



Detail No. 25 refers to the hard rub- 

 ber connecting bar for the foregoing- 

 mentioned switches. 



Detail No. 26 is the rod for the sec- 

 ondary switch on the receiving trans- 

 former. 



The instrument should be carefully 

 made, but does not present any great 

 difficulties. When the fixed tuners are 

 properly calibrated the instrument be- 

 comes a very valuable adjunct to the 

 wireless station and indirectly acts as an 

 indicator of stations picked up at random. 



Considering more in detail the receiv- 

 ing transformer, it should be stated that 

 the primary coil of the same is in this 

 particular instrument wound with 225 

 turns of single cotton-covered magnet 

 wire winding, approximately 40 turns to 

 the inch; there being at the left-hand 

 end ten sections of one turn each, while 

 the remainder of the coil is divided into 

 1 8 sections, the first 15 sections thereof 

 containing ten turns each and the remain- 

 ing sections 25 turns each. 



The arrangement just described, how- 

 ever, need not be adhered to in all cases, 

 such, for instance, where a short aerial is 

 used, in which case it would be desirable 

 to wind the coil with finer wire in order 

 to receive the long- wave stations. 



The secondary of the receiving tuner 

 is wound with single silk-covered magnet 



Wtnno 



Wiring Diagram for the Inductive Tuner. 



wire No. 26 or 28 and divided into n 

 equal sections. 



If, as is quite possible, the circuits 

 should in practice require a loading coil 

 to get perfect tuning, the fixed tuners 

 may be wound with the number of turns 

 required with a loading coil, thus re- 

 placing and thereby adding to the effi- 

 ciency of the combination. 



By providing on the two-way, four- 

 lever switch described a third set of con- 

 tact points, and making proper connec- 

 tions thereto, it is possible to arrange to 

 use, if desired, the receiving tuner in cas- 

 cade with one of the fixed tuners, and 

 thus have a multiple receiving set with its 

 correspondingly greater selectivity. 



It is best that no shellac or varnish be 

 used on the fixed tuner coils, as this in- 

 creases the distributive capacity of the 

 coils. 



A LOG THAT CONTAINS 3,000 FEET 

 OF LUMBER 



The largest log yet found in the North- 

 west was cut down near Ridgefield, 

 Washington. The log was twenty-four 

 feet long and seven feet in diameter at 

 the big end. The log contained about 

 3,000 feet of cedar. It was so large that 

 the shed roof over the saw had to be 

 raised to allow the log to get to the saw. 



