Dimitri Ivanovich Mendeleev
and a draft of his original
Periodic Classification of the Elements
(February 1869)

"Classification is the arrangement together of any series of objects (or of occurrences) which are alike and the separation of those which are unlike, in order to facilitate the operations of the mind in clearly conceiving and retaining in the memory the character of the objects in question"

Huxley

English version Versão Portuguesa


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