GENERAL A. A. TILLO, Vice-President of the Russian Geographical Society, who died at St. Petersburg on January 11, was the founder of an exact physical geography of Russia, based on correct scientific data. He was born in 1839, and received his education in the Constantine Military School, from which he was promoted officer in 1859. He completed next his education by passing through two military academies, artillery and General Staff, and worked for two years at Pulkova in the Geodetic Department of this last academy. In the years 1879–82, in his capacity as educator of one of the Russian Grand-Dukes, he followed lectures on mathematics in different West European universities, as also a full course of Law at the University of Strasburg. He began geographical work as the head of the surveys of the Orenburg region, by publishing a catalogue of latitudes and longitudes determined in that region, followed by a study of the distribution of magnetical elements, and by a description of the levelling made between the Caspian Sea and Lake Aral. His next works were “On the Byelgorod Magnetic Anomaly,” “On the Present Condition of the Science of Terrestrial Magnetism,” and “On the Yearly Amplitudes of Variations of Level in the Lakes of Russia,” “On the Average Altitudes of the Continents in Both Hemispheres.” Settling some five-and-twenty years ago at St. Petersburg, he began to work out in a most systematic way the different portions of a general physical geography of Russia. The surfaces of different parts of the empire having already been calculated by Strelbitzky, General Tillo measured first, with a very great accuracy, the lengths of the rivers of the Russian Empire, their gradients, and the surfaces of their basins, thus correcting many erroneous statements of his predecessors. Then, he worked for years in collecting all documents relative to the altitudes of European Russia, and finally published in 1889 his most remarkable hypsometric map of European Russia, on a scale of 40 miles to an inch, followed seven years later by the same improved map on a still larger scale (27 miles to an inch), in four sheets. This map, by showing the existence of three great depressions amidst the swelling of Middle Russia, completely altered the hitherto current conceptions as to the orography of European Russia. His next work was a most elaborate atlas of isobars in Russia and Asia altogether, and it was followed by still more elaborate works on the distribution of magnetic elements on the surface of the earth, “Variation séculaire et éphémérides du Magnétisme terrestre,” “Loi de la Distribution du Magnetisme moyen à la Surface du Globe,” “Atlas des Isanomales et des Variations séculaires,” and “Tables fondamentales du Magnetisme terrestre,” which won for Tillo a wide European reputation. His smaller contributions to the publications of the Russian Geographical Society were countless. He was a member of both the St. Petersburg and the Paris Academies of Sciences. His extreme modesty and willingness to undertake any amount of calculations to work out the results of observations made by explorers in Asia, made of him one of the most sympathetic figures in the Russian Geographical Society, in which he presided over the Physical Geography Section. A pamphlet containing an obituary notice of General Tillo, and a full list of his works, has just been published by this Society.