THE U.S. Coast and Geodetic Survey makes magnetic observations at a set of repeat stations every five years, and publishes the results at similar intervals, in the form of tables of secular variation, ...

I BEG to call your attention to the enclosed reprint from the May Pilot Chart of curves of magnetic declination as recorded at the United States Naval Observatory at Washington. This reprint admits of ...

Researchers recently showed that migratory reed warblers depend on an internal geomagnetic map to guide them on their long-distance journeys. But it wasn't clear how the birds were solving the ...