The numerous investigations now being made with the object of discovering the various combinations of the elements led to many improvements in chemical analyses. When we read Berzelius' accounts of his analyses they seem to have been written only yesterday. He and his contemporaries developed analytical and synthetic methods to almost the efficiency that we see to-day. We also owe to Berzelius a table of the elements showing their electrical qualities, an electrochemical theory, identifying chemical affinity with electric attraction, and a new nomenclature, besides a vast amount of descriptive chemistry. The discovery of the specific heats of various solid elements by Dulong and Petit in 1819, and Mitscherlich's finding of the isomorphic phenomena in 1818, resulted in the publication of a new atomic weight table in 1826 by Berzelius. The experiments made in isomorphism by Mitscherlich led him to discover dimorphism and study crystallography. He used his knowledge of crystal measurement extensively and developed synthetic chemistry and the laws of crystallization. Thompson, Prout, and Wollaston were working on problems in England similar to those examined in Sweden by Berzelius and Mitscherlich. Molecules were discriminated from atoms in 1826 by Jean Baptiste Dumas and Faraday discovered his law of electrochemical action in 1834. Organic chemistry originated in Manchester, England, when Dalton read his paper before the Manchester Philosophic Society in 1803 on the theory of atomic weights. This paper led Gay-Lussac, Thenard, Berthollet, de Saussure and others to study organic analyses as devised by Dalton. Gay-Lussac and Thenard greatly improved Dalton's methods and in 1824, as shown by Chevreul's work on fats and greases, organic analyses had been brought to high perfection. The phenomena of substitution in hydrocarbon compounds like the petroleum oils were studied by Laurent who proposed a theory of basic nuclei. C₁₀H₈ being the nucleus of the naphthalene group and C₂H₄ that of the ethylene group, derived nuclei can be obtained from these by substitution and hydrogen and other elements acting on derived nuclei from numerous hydrocarbon series. The homology of the hydrocarbons was discovered by Gerhardt in 1844 while he was investigating the alcohols. Wurtz's work on the ammonia compounds, Williamson's on the ethers, Hoffmann's on anilines, Graham's and Liebig's on the citrates, and Frankland's, Kolbe's and Kekulé's work on other compounds raised organic chemistry to such a high plane that industrial chemists were able to use their theoretical conclusions and build a great number of important industries upon organic principles.