John Dalton

“The ultimate particles of all homogeneous bodies are perfectly alike in weight, figure, etc.”

“I have chosen the word 'atom' to signify these ultimate particles.”

“Matter, though divisible in an extreme degree, is nevertheless not infinitely divisible.”

“We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a particle of hydrogen.”

“Chemical analysis and synthesis go no farther than to the separation of particles one from another, and to their reunion.”

“The cause of rain is now, I think, no longer an object of doubt.”

“I see no sufficient reason why we may not conclude that all elastic fluids under the same pressure expand equally by heat.”

“No new creation or destruction of matter is within the reach of chemical agency.”