Flying a lone mission over the very top of the world, a four-engined aircraft and its 12-man crew have just completed the final 2,000,000-square-mile section of a Canadian geomagnetic investigation that stretches across the Pacific to Japan and the Atlantic to Europe. Part of the varied work of the Dominion Observatories, this globe-straddling scientific survey was made possible by Canada's unique airborne magnetometer, designed, tested and developed by observatory staff. Operating during the long hours of arctic darkness, constantly fixing their position by the crystal-sharp, circum-polar stars, the scientists and crew members flew 40,000 miles of lines 100 miles apart across the frozen wastes of the Arctic Ocean and islands. The resulting magnetic maps will increase the safety of sea and air travellers, add a large Canadian contribution to international scientific knowledge.