MENDELEEFF, Iw.tz'owrro'mi —). chemist, born in '1•oLolsIc. Siberia. Ile graduated from the local gymnasium. and in 15.511 Imlored the Institnte of Pedagogy of Saint l'etorsbitrg„ whore he ap plied himself to the study of natural seionees. In 1556 lie was appointed docent at the Uni versity of Saint Petersburg, and in 1559.61 he worked in Ileidelherg and publislied a monograph on the Capillarity of Gases. Shortly afterwards published his Organic Chemistry. He was made professor of chemistry at the Saint Peters burg Institute of Technology in 1863, and three years later at the university. In 1871-75 he made extensive studies on the of gases, embodied in his On the Elasticity of Oases. In 1876 he was commissioned by the authorities to study the petroleum industry in Pennsylvania and the Caucasus. His work on _Igneous Solu tions (1886) was received by chemists as a notable contribution to experimental chemistry, although his 'theory of solutions,' according to winch solvents invariably form definite or 'in definite' chemical compounds with the substances dissolved in them, has been strongly/criticised by physical chemists of the modern German schools. As member of the Council of Commeree and In dustries, Mendeleelf became the champion of pro tection of home industries, and the policy of Russia in that direction dates practically from the publication of his Tariff Elucidated (1890).
Ile worked out the formula for the pyroeollodial smokeless powder. serviceable for all firearms, when Russia undertook to rearm her forces. In 1893 he was made conservator of weights and measures in the new Chamber of Weights and Measures established in the Department of Finance.
His Elements of Chemistry (1868-70, 5th ed., Saint Petersburg, 1889) is a standard work and has been translated into English, German, and French. In it be first set forth the theory later embodied in La loi pe'riodique des elements chi migues 1879), now known as the periodic law (q.v.), in the following formula: "The properties of the elements. as well as the forms and properties of their compounds, are in periodic dependence on. or form a periodic function of, the atomic weights of the elements." This law en abled Mendebleff to foretell the existence and even the properties of several unknown elements, which have since been actually discovered.
Mendel6eff's scientific contributions, dealing mostly with physical chemistry, and numbering upward of 150. have appeared in several German and French scientific periodicals. Consult T. E. Thorpe, Essays in Historical Chemistry (London, 1894).