Dmitry Ivanovich Mendeleev (27.01.1834 - 20.01.1907) - a great Russian scientist, encyclopedist, chemist, physicist, technologist, geologist and even meteorologist. Mendeleev possessed an amazingly clear chemical thinking, he always clearly represented the ultimate goals of his creative work: foresight and benefit. He wrote: "The closest subject of chemistry is the study of homogeneous substances, from the composition of which all the bodies of the world are composed, transforming them into each other and the phenomena accompanying such transformations."He was born in 1834 in Tobolsk and was the last, seventeenth child in the family of the director of the Tobolsk gymnasium Ivan Pavlovich Mendeleyev and his wife Maria Dmitrievna. By the time of his birth, two brothers and five sisters were living in the Mendeleev family of children. Nine children died in infancy, and three of them parents did not even have time to give names.In the autumn of 1841, Dmitry Mendeleev and his older brother entered the Tobolsk gymnasium. He was accepted into the first class on the condition that he would stay there for 2 years, before the age of eight.In the spring of 1849, Mendeleev graduated from the gymnasium and went with his mother to Moscow to enter the Kazan University. He was refused admission.At the Pedagogical Institute of St. Petersburg, students were enrolled every two years, and in the autumn of 1850 there was no reception. Mendeleyev's mother filed a petition with the ministry to make an exception for her son. Mendeleyev was accepted. He was enrolled in the Faculty of Physics and Mathematics.The study of Dmitry Mendeleyev in St. Petersburg in the Pedagogical Institute at first was not easy. He had to catch up with his fellow students and independently study the material that his colleagues had in the first year. A huge mental strain adversely affected his health. Long stay in the hospital and constant ill health prevented Mendeleev from catching up with his fellow students. In the first year he managed to get unsatisfactory marks in all subjects, except mathematics. He had to repeat the first two years of training. But on the senior courses the matter went differently - the average annual score of Mendeleev was four and a half (out of five possible). Soon the teachers noted his exceptional abilities. In his student years, Mendeleev began to write short reviews of the successes of science, for which he received small fees - his only income.My favorite leisure activity at Mendeleev for many years was the production of suitcases and frames for portraits. Supplies for these works he bought in the Gostiny Dvor. One day, choosing the right product, Mendeleev heard behind him the question of one of the buyers:"Who is this venerable lord?""You need to know such people," said the clerk with respect in his voice. "This is a master of suit cases of Mendeleev."In 1895, Mendeleyev became blind, but continued to lead the Chamber of Weights and Measures. Business papers were read out to him aloud, he dictated the orders to the secretary, and at home, blindly, he continued to gloss suitcases. Professor IV Kostenich removed cataract for two operations, and soon vision returned ...