John Dalton

Professional: Meteorology is the poetry of physics.

Last reflection: I die content, having unveiled atoms.

Chemical analysis and synthesis go no farther than to the separation of particles one from another, and to their reunion. No new creation or destruction of matter is within the reach of chemical agency.

All bodies of sensible magnitude, whether solid or liquid, are constituted of a vast number of exceedingly small particles, or atoms of the same kind of matter, which are in contact, or nearly so, with one another.

When two elements unite to form more than one compound, the different weights of one element that combine with a fixed weight of the other are in a simple ratio of whole numbers.

I am nearly fifty years of age; I have been a lecturer in chemistry for twenty years; I have published many papers, and I have made many discoveries.

The relative weights of the ultimate particles of all simple bodies are determined by the most careful experiments.

No two particles of a compound body can be the same, unless they consist of the same number of simple particles, united in the same way.

The greatest difficulty in the investigation of chemical phenomena is to ascertain the number of simple particles which combine together to form a compound particle.

Every atom of a simple body is like every other atom of the same simple body.

The ultimate particles of all simple bodies are indivisible and indestructible.

The force of attraction between the particles of different kinds of matter is different.

The ultimate particles of all elastic fluids are of the same size, and are surrounded by atmospheres of heat, which repel each other.

When two elastic fluids, not acting chemically upon each other, are mixed together, the final pressure of the mixture is the sum of the pressures which each fluid would exert if it occupied the same space alone.

The quantity of any gas absorbed by a given volume of water, at a given temperature, is directly proportional to the pressure of the gas.

I have been much gratified by the attention paid to my atomic theory.

The relative weights of the ultimate particles of all simple bodies are determined by the most careful experiments, and are expressed by numbers.

The number of atoms in a compound particle is always a simple ratio.

It is evident that the ultimate particles of all homogeneous bodies are perfectly alike in weight, figure, etc.

The great object of chemical philosophy is to determine the number and weight of the ultimate particles of all simple and compound bodies.