John Dalton presents in 1803, in lectures in Manchester, his atomic theory: each element is composed of atoms identical to each other but distinct from those of other elements, and compounds form by combining atoms in simple, fixed numerical proportions. Dalton developed the idea to explain analytical data from Cavendish and Lavoisier on the composition of nitric acid. He published the full version in 1808 in "A New System of Chemical Philosophy", a work that also introduced a symbolic notation for the elements and an early table of relative atomic weights. Dalton's theory established for the first time a quantitative basis for chemistry, although for half a century incompatible atomic-weight systems coexisted between different countries, a problem not resolved until the 1860 Karlsruhe Congress.