After many years of effort on the part of the International Geographical Congress, a conference consisting of official delegates from most civilized states met in 1909 to deliberate on the methods to be adopted in the construction of an international map of the world. After much discussion a series of regulations was drawn up to be followed by each country in producing a map of its territories on the scale of 1/1,000,000, or about sixteen miles to the inch. The projection will, of course, be uniform, and altitudes are shown by layers of different tints from sea-level upwards. Actual experience may no doubt demand certain modifications, but it will be a great advantage to have an authoritative map of the world on a strictly uniform plan. As to the progress of geodesy in recent years, in 1899–1902 an arc was measured in the extreme north in Spitsbergen, by Swedish and Russian workers (P. G. Rosen, O. Bäcklund, and others), while Sir David Gill, as director of the Royal Observatory in Cape Town, subsequently initiated the measurement of a great arc in Africa along the meridian of 30° E. These arcs are capable of connection through Asia Minor and Europe, by which means a continuous measured arc of 105° would be obtained. The arc of Quito (Peru) was re-measured in 1901–06 under the direction of the French Academy of Sciences; a great arc in 98° in the United States of America has been undertaken by the Coast and Geodetic Survey, and these again are capable of ultimate connection. Other arcs of special importance have been measured in Europe and India.