Dmitri Mendeleev — "To tell the truth, I never thought of myself as a genius; I just worked hard."

"The capital fact to note is that petroleum was born in the depths of the earth, and it is only there that we must seek its origin."

"I have always been convinced that the universe is governed by laws that are discoverable through observation and experiment."

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

"There are no limits to the perfectibility of human knowledge, and it is in this spirit that the periodic system was conceived."

"It is the function of the scientist to do 3 things: to observe, to generalize, and to predict."