"To conceive, understand, and grasp the whole symmetry of the scientific edifice, including its unfinished portions, is equivalent to tasting that enjoyment only conveyed by the highest forms of beauty…"

"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."

"No law of nature, however general, has been established all at once; its recognition has always been preceded by many presentiments."

"The chemist must descend into the depths within himself, and find the spark of an idea to illuminate the darkness."