An Account of the Cause of the Change of the Variation of the Magnetical Needle; With an Hypothesis of the Structure of the Internal Parts of the Earth: As It Was Proposed to the Royal Society in One of Their Late Meetings. By Edm. Halley

Edm. Halley
1686 Philosophical Transactions of the Royal Society of London  
doi:10.1098/rstl.1686.0107 fatcat:44bqua7ycrbs7hkutuuf7nl2ia