How did Dalton advance the atomic philosophy proposed by Democritus?

Dalton was a polymath, a natural philosopher, and a true scientist. His extensive experiments led him to propose an early theory of the atom, for which we would have to search hard today to find exceptions:

Dalton suggested that,

Atoms are the smallest units of matter that make up elements. They are massless and identical to one another, but different elements have different masses and sizes in relation to one another. Atoms cannot be created, divided, or destroyed; instead, they combine in simple whole-number ratios to form chemical compounds. Atoms can also be combined, separated, or rearranged in chemical reactions.

His work could be replicated by other researchers, and new findings could be integrated into this atomic theory. All of these proposals were based on extensive experimentation.

Dalton advanced the atomic philosophy proposed by Democritus by providing experimental evidence for the existence of atoms and by introducing the concept of atomic masses and their ratios in chemical reactions. He also proposed the law of multiple proportions, which states that when two elements form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element can be expressed in small whole numbers.