To give an idea of the extent and scope of the work of this department it may be mentioned that its non-magnetic ship _Carnegie_ made in the period 1909-1918 a total run of 189,176 nautical miles, nearly nine times the earth's circumference, with an average day's run of 119 nautical miles. Magnetic observations were made practically every day at a distance of 100 to 150 miles apart. In this nine-year period five cruises were made. On her first cruise the _Carnegie_ sailed from St. John's, Newfoundland, to Falmouth, England, over practically the same course followed by the famous astronomer, Halley, in the _Paramour Pink_ two centuries earlier to determine the variation of the compass. In her fourth voyage the _Carnegie_ circumnavigated the world in sub-antarctic regions in 118 days--a record time. She has traversed all oceans from 80° North to the parallel of 60° South and has crossed and recrossed her own path and the path of her predecessor, the _Galilee_, many times, thus making it possible to determine for the points of intersection the secular changes in the magnetic elements.