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Rh to his meaning. The directness of his thought finds corresponding expression in his words and they carry conviction to the minds of his hearers, while his kindly smile serves to enlist their sympathies and approval.

His greatest work has been in stereochemistry. His work on the atomic transformation, the theory of solutions and other great problems is now classic. His literary activity has covered a wide field and he is the author of more than two hundred original scientific articles or books, nearly all on the subject of chemistry: physical chemistry, biochemistry and stereochemistry. For many years past his contributions to periodical publications such as the Berichte der deutschen chemischen Gesellschaft, Ostwald's Zeitschrift für physicalische Chemie, Lorenz's Zeitschrift für anorganische Chemie, etc., have been of the very highest value to science.

The biographical memoirs he has written of the eminent French chemist Berthelot, whose name is indissolubly associated with the science of thermochemistry, of the great Pasteur and of the celebrated propounder of the periodic law, the renowned Russian chemist Mendeleef, testify eloquently to Walden's intimate knowledge of the life and work of these great leaders of modern science.

Together with Carl Adam Bischoff, Professor Walden published his monumental work, the "Handbuch der Stereochemie," ably treating of this intricate and fascinating department of science. On the twenty-fifth anniversary of the doctorate of Professor Ostwald, whose most brilliant and successful pupil he is, Walden issued his excellent biographical sketch of that great physical chemist and philosopher, and, we may add, enthusiastic Esperantist. Ostwald has said that he owes fifty per cent, of his reputation to Walden's biography. At this time Ostwald was appointed a director of the Polytechnicum, an honor enjoyed only by himself and three others, namely, Aristes, Arrhenius and Teppler.

Besides his original work, Walden has translated into the Russian language Fischer's " Organic Preparations," and also the renowned Lowell lectures by J. H. van't Hoff, delivered in Boston.

Russians are the best hosts in the world. Whereas, in the United States the expenses of the congress were born by the American committee and their friends, in Russia, where the railroads are owned by the government, during the late International Geological Congress the freedom of the railroads was offered to the visiting guests.

St. Petersburg, a magnificent city with its great museums, universities, art galleries and other institutions, will be a splendid meeting place, and the excursions that can be made from it will prove of the greatest interest and value to the visiting guests.