John Dalton

I am of the opinion that the atoms of bodies are not in contact, but are separated from each other by a certain interval, and that the magnitude of this interval is different in different bodies.

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 subsequent reunion. No new creation or destruction of matter is within the reach of chemical agency.

The ultimate particles of all homogeneous bodies are perfectly alike in weight, figure, etc. In other words, every particle of water is like every other particle of water; every particle of hydrogen is like every other particle of hydrogen.

It is one great object of this work to show the importance and advantage of ascertaining the relative weights of the ultimate particles of bodies, and the number of simple elementary particles which constitute one compound particle.

The greatest discoveries of science have been made by the application of common sense to the facts of nature.

I see no reason why we should not be able to determine the relative weights of the ultimate particles of bodies.

Matter, though divisible in an extreme degree, is nevertheless not infinitely divisible. That is, there must be some point beyond which we cannot go in the division of matter.

The cause of the expansion of gases by heat is the increased velocity of their particles.

When two elements combine in more than one proportion, the different weights of one element which combine with a fixed weight of the other element are in the ratio of small whole numbers.

I have been much gratified by the attention paid to my theory, and I trust it will be found to be a solid foundation for the superstructure of chemical science.

The particles of elastic fluids are of different sizes and weights, and that the particles of one kind of fluid are not affected by those of another kind.

I am a poor man, and have always been so; but I have always had enough, and have never been in debt.

I have been much engaged in the investigation of the nature of elastic fluids, and have been led to some conclusions which appear to me to be of considerable importance.

The atomic theory is the only one that can explain the facts of chemical combination.

I have been much struck with the great simplicity of the laws of chemical combination, when viewed in the light of the atomic theory.

The atomic theory is a beautiful and simple theory, and it is capable of explaining all the facts of chemistry.

I have always been fond of experimental inquiry, and have pursued it with great assiduity.

The ultimate particles of all bodies are atoms, and these atoms are indivisible and indestructible.

I have been much interested in the subject of meteorology, and have made many observations on the weather.