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![Signal lamps theb1639.jpg Signal lamps](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_theb1639.jpg?itok=9QMgGA5R)
Description
Signal lamps (Image credit: NOAA National Geodetic Survey)
Credit
NOAA National Geodetic Survey
Collection
Historic Coast & Geodetic Survey
Geodesy
Triangulation
Heliotropes & Signal Lamps
Keywords
Geodesy
Triangulation
Lights
Electric