Dmitri Mendeleev — "I consider it my duty to be useful to my country."

"When we see the order of the elements, we must admit that there is a higher reason."

"The periodic law will not be overthrown, but only further developed."

"The law of periodicity was a result of the accumulation of a large number of facts."

"I saw in a dream a table where all the elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper, only in one place did a correction later seem necessary."

"The greatest value of a scientific discovery is not so much in the discovery itself as in the stimulus it provides for further investigation."