Berzelius, not long after arriving in Stockholm’s…

Berzelius, not long after arriving in Stockholm’s Medico-Chirurgiska institute as professor in chemistry and pharmacy, had written a chemistry textbook for his medical students, from which point a long and fruitful career in chemistry began.

While conducting experiments in support of the textbook, he had discovered the law of constant proportions, which showed that inorganic substances are composed of different elements in constant proportions by weight.

Based on this, in 1828 he compiles a table of relative atomic weights, where oxygen is set to 100, and which includes all of the elements known at the time.

This work provides evidence in favor of the atomic hypothesis: that inorganic chemical compounds are composed of atoms combined in whole number amounts.

In discovering that atomic weights are not integer multiples of hydrogen's, Berzelius also disproves Prout's hypothesis that elements are built up from atoms of hydrogen.

In order to aid his experiments, he develops a system of chemical notation in which the elements are given simple written labels—such as O for oxygen, or Fe for iron—with proportions noted by numbers.

This is the same basic system used today, the only difference being that instead of the subscript number used today, Berzelius uses a superscript.