Baron Jons Jacob Berzelius (1779-1848), the Swedish chemist. He provided the first major systemization of 19th century chemistry, including the first accurate table of relative atomic masses (for 28 elements in his list of 1828); the reintroduction and use of modern 'initial letter' symbols for elements; concepts including isomerism and catalysis; the division of the subject into organic and inorganic branches; and his theory of dualism, based on his work in electrochemistry. This theory proved first a spur and then an inhibitor to the later division of elements into the electro-positive and electro-negative classes. He discovered selenium, cerium and thorium.