Answer is: John Dalton proposed that matter is made of tiny particles.
Proust's law or law of constant composition said that a given chemical compound always contains its component elements in fixed ratio and does not depend on method of preparation.
Water (H₂O) is made of two hydrogen atoms and one oxygen atom:
m(H) : m(O) = 2·1 : 16 = 1: 8.
Dalton said that matter is composed of atoms and atoms of different elements can join to form chemical compound.
