Soon after arriving in Stockholm, Berzelius wrote a chemistry textbook for his medical students, Lärbok i Kemien, which was his first significant scientific publication. He had conducted experimentation, in preparation for writing this textbook, on the compositions of inorganic compounds, which was his earliest work on definite proportions. In 1813–4, he submitted a lengthy essay (published in five separate articles) on the proportions of elements in compounds. The essay commenced with a general description, introduced his new symbolism, and examined all the known elements. The essay ended with a table of the "specific weights" (relative atomic masses) of the elements, where oxygen was set to 100, and a selection of compounds written in his new formalism. This work provided evidence in favour of the atomic theory proposed by John Dalton: that inorganic chemical compounds are composed of atoms of different elements combined in whole number amounts. In discovering that atomic weights are not integer multiples of the atomic weight of hydrogen, Berzelius also disproved Prouts hypothesis that elements are built up from atoms of hydrogen. Berzeliuss last revised version of his atomic weight tables was first published in a German translation of his Textbook of Chemistry in 1826.