472 



Table 160 (continued) 

 HORIZONTAL VISIBILITY 



Table 160-C1. — Visual range of point sources of light 

 Function (log. h — log e E) 



1X10 



Threshold illuminance (flux-density) , E, lumens km.- 8 



2X10 3X10 4X10 5X10 6X10 7X10 



8X10 9X10 



Threshold illuminance (flux-density), E, lumens km. -2 



2 3 4 5 6 7 



SMITHSONIAN METEOROLOGICAL TABLES 



