Boulder Geomagnetic Observatory
![Image: Boulder Geomagnetic Observatory](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/Boulder02.jpg?itok=v1afKZw4)
Detailed Description
Azimuth mark, Absolutes building and Coil building at Boulder magnetic observatory.
Sources/Usage
Public Domain.
Azimuth mark, Absolutes building and Coil building at Boulder magnetic observatory.
Public Domain.