For maximum strength, 8-inch diagonal pipe re- 

 inforcing was welded to the 16-inch diameter 

 cylindrical legs during tower fabrication in Wil- 

 mington, California. Railway tracks were welded 

 to three sides, and a beam was welded across the 

 bottom for anchoring guide cables. The central 

 part was left free of crossbeams in order to allow 

 instruments to be lowered through the center of 

 the structure. The open pipe at the bottom of the 

 legs will hold steel anchoring pins. On comple- 

 tion, the structure was treated with preservative 

 paint. 



The partially assembled tower was floated 

 to San Diego and lowered into place by 

 giant crane. Orientation of the sides was 

 made exactly N-S and E-W. The center point 

 rests at 32° 46' 21. "330 N, 1 17° 16' 03."939 

 W. Thirteen by fifteen-foot instrument house 

 sits on barge (left). 



110 



