Dalton's atomic theory (1808) successfully explained the law of conservation of mass, the law of constant proportion and the law of multiple proportion in terms of atoms combining in fixed whole-number ratios.

However, Gay-Lussac's law of gaseous volumes (gases combining in simple whole-number ratios by volume) could not be explained by Dalton because it would require dividing his "indivisible" atoms. This was later resolved by Avogadro's hypothesis.