112 



THE WORLD'S ADVANCE 



The primary terminals of the transform- 

 er are to be connected with the main 

 switch, as shown in the wiring diagram 

 below, which also shows the connections 

 for the remainder of the apparatus. 

 From the secondary terminals of the 

 transformer pieces of No. 14 rubber- 

 covered wire lead to the terminals of the 

 spark gap. From one terminal of the 

 spark gap a piece of stranded cable, 

 composed of 100 strands of about No. 24 

 insulated magnet wire, runs to one ter- 

 minal of the condenser. From the other 

 terminal of the condenser, a piece of the 

 stranded cable leads to the movable clip 

 on the primary of the oscillation trans- 

 former. The second terminal of the 

 spark gap is connected by cable to the 

 ground connection of the oscillation 

 transformer and this in turn to a series 



passing through the glass is tipped with 

 a connector to which the overhead wires 

 of the plot are secured. 



In the next article, the installation of 

 the overhead wires and the operation of 

 the outfit will be considered. 



THE HIGHEST DAM 



The United States Reclamation Serv- 

 ice is at work on the highest dam in 

 the world, at Arrowrock, Idaho. It will 

 stretch across a narrow canon of the 

 Boise River, 20 miles above the city of 

 Boise, and will be 351 feet high. That 

 is, perhaps, 23 feet higher than the great 

 Shoshone Dam in Wyoming, and 71 feet 

 higher than the Roosevelt Dam in Ari- 

 zona. It will be 1,000 feet long and 25 



TO overr/eotf 



<5porA gc/>^ Condenser Osc/l/otion 



1 j Transformer] 



1 LJiJ 



Transformer 



Wiring Diagram for the Connecting of the Various Pieces of Apparatus to be Used in Electrical 



Plant Culture. 



of wires buried in the ground beneath 

 the plot to be cultivated. 



The high-potential, high-freqency ter- 

 minal of the oscillation transformer con- 

 nects with a piece of light copper rod, 

 which extends upward and out of the 

 side of the building, through a hole cut 

 in the center of a pane of glass. This 

 glass window should be at least 18 inches 

 square and shaded on the outside of the 

 building with a contrivance resembling 

 an awning, in order that the surface of 

 the glass may be kept as nearly dry as 

 possible in wet weather. The copper rod 



feet wide at the top, over which will 

 run a roadway protected by a wall on 

 each side. The dam will hold back suf- 

 ficient water to irrigate 250,000 acres 

 of desert land. 



A German electrician claims to have 

 invented an apparatus by which he can 

 measure the ten millionth part of a sec- 

 ond. While no details of the invention 

 are available as yet, it is very probable 

 that electricity is employed for the pur- 

 pose. 



