Edmond Halley was already a well-known astronomer, mathematician and natural philosopher when he took command of HMS Paramore. The purpose of Halley's first two voyages was to test his geomagnetical theories; the first voyage ended prematurely, but the second voyage was successful, making a wide sweep through the Atlantic, and resulting in the first published isogonic map. In the third voyage Halley investigated tidal phenomena in a detailed study of the English Channel.