What scientific measurements did Edmond Halley make aboard the Paramore Pink?

During his command of the war sloop Paramore Pink between 1698 and 1700, Edmond Halley conducted one of the first sea voyages undertaken for purely scientific purposes. His primary objectives were to measure the compass declination—the angle between magnetic north and true north—in the South Atlantic and to determine the accurate latitudes and longitudes of his ports of call.1

These measurements were intended to assist in navigation and explore potential methods for determining longitude at sea. The data collected during this expedition later enabled Halley to publish the first magnetic charts of the Atlantic Ocean and parts of the Pacific Ocean in 1701.1