In 1803, John (John Dalton) dollar scientists British atomic theory proposed to use a description of the changes to the message before and after the reaction mass, including the ratio by mass of the elements that make up a compound whose essence is as follows:
-That contains small particles called atoms (Atom) which cannot divide.
-New atom could not be created or lost.
-Atoms of the elements of the same type have the same mass. With the same properties, but differ from atoms of another element-compounds resulting from the atomic number of the chemical between different types of elements, with the ratio to total a simple numeric or a trivial number.
-Two types of atom that may together with different ratios for many types of compounds occurs.