Page:Popular Science Monthly Volume 40.djvu/273

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HE discovery of the periodic law in the atomic weights of the elements has furnished chemists with a new standard of accuracy and a new guide in research. While it must be regarded as Mendeleef's most conspicuous scientific achievement, the Russian chemist is the author of many other labors of hardly less real importance.

was born at Tobolsk, Siberia, February 7, 1834, the seventeenth and youngest child of Ivan Paulovich Mendeleef, director of the gymnasium there. Soon after his birth the father became blind and had to resign his position, leaving the care of the family upon the mother, a competent and energetic woman. She established and managed a glass-works, and brought up and educated her family upon its profits. Dimitri was sent to the gymnasium at Tobolsk, and, at sixteen years of age, to St. Petersburg, where he was to study chemistry in the university, under Zinin; but was transferred to the Pedagogical Institute in the same building with the university, where he entered the physico-mathematical department, or that of the natural sciences. He studied chemistry, physics, mathematics, botany, zoölogy, mineralogy, and astronomy, under teachers who were most of them also professors in the university. Having concluded his course here, he was appointed to the gymnasium at Simferopol, in the Crimea; then, during the Crimean War, to a gymnasium in Odessa; and in 1856 he became a Privat Docent in the University of St. Petersburg, where he had already received the degree of Master of Chemistry. In 1859, having obtained permission from the Government to travel, he became engaged at Heidelberg in the determination of the physical constants of chemical compounds. In 1863 he was made Professor of Chemistry at the Technological Institute of St. Petersburg, and in 1836 at the university, where he received the degree of Doctor of Chemistry.

Mendeleef had already before his engagement as a Privat Docent entered upon the career of research and publication in which he has so brilliantly distinguished himself. His first paper, on Isomorphism, was prepared while he was still in the Pedagogical Institute. He entered into the discussion of the relations between the specific gravities of substances and their molecular weights, and presented to the physico-mathematical faculty of the university a number of theses or problems relating to specific volumes; and as early as 1856 he accepted Gerhardt's mode of determining the chemical molecule. His researches on specific volumes were continued till 1870, and in them, according