4. In every new phase of this 19th century movement German scholars have taken the leadership. The deep philosophical longing of the German soul had created the unique move ment which led from Kant to Hegel, but when the opposite tendency of the newer time de manded the patient work of the specialist, it was the world-known German thoroughness which won the laurels for the German laboratory ex periment and naturalistic research and historical investigation.
Of course this specializing work had not waited for the downfall of philosophy; it took its rise in the work which we traced through the period of enlightenment in the 18th century. And further, the emphasis on specialization does not mean that the scientific life of Ger many lacks in the 19th century great central figures, scholars with broad synthetic energy: the geographer Alexander von Humboldt, the physicist Helmholtz, the pathologist Virchow, the historians Ranke and Mommsen, are cer tainly not specialists in the narrow sense of the word. A short survey of the different fields indicates the abundance of brilliant thinkers who were grouped about such leaders. We may begin with mathematics and the inorganic natural sciences, then turn to the organic sciences and medicine, then to the historical and philological, economical and juristic fields, finally to the theological and philosophical.
For mathematics the first place belongs to Gauss (1777-1855) and after him the chief ad vance came through Jacobi, Dirichlet, Riemann, Kronecker, Weierstrass and others; yet the mathematical achievements were always blend ing with the works of physicists and astron omers — as not a small part of the mathemati cal progress belongs to naturalists like Kirch off, Helmholtz, Enck, Clausius, etc.
Gauss gave the strongest theoretical impulse also to astronomy, while Bessel (1784-1846) may be considered the founder of the practical astronomy of the century. Most influential for the theory were Hansen and Encke and their followers, Bruhns, Argelander, Briinnow, Auwers, etc. Here belongs also as a special triumph of German thought, the discovery of spectral analysis by Kirchoff and Bunsen, ap plied by Winer and others.
In physics the turning point of the century lies at its middle when Helmholtz (1821-94) and independently R. Mayer (1841-78) formu lated the law of the conservation of energy. In the first half of the century the best work in physics was done outside of Germany; among the Germans Ohm excelled (1787-1854) with his fundamental theories of galvanism; the brothers Weber, Poggendorff, Lenz, belong to the same period. The influence of Helmholtz
is felt not only in the theory of energy, but in the whole field of mechanics, optics, and acous tics, besides physiology and psychology. The next and last climax is reached by Hertz through his study of the propagation of electric waves. Important too are the of Clausius, the electrolytic work of and most recently the discoveries of Röntgen concerning cathode rays.
In chemistry the decisive step was the foundation of a chemical university laboratory in Giessen by Justus Liebig (1803-73), the greatest chemist of his time, who revolution ized organic chemistry and whose researches became invaluable for agriculture, pharmacy, the preparation of food, etc. Out of his school came influential chemists of all nationalities; in Germany itself especially, Kekule, Hofmann, Fehling, Kopp, Bayer, V. Meyer. Other centres of chemical ideas were the laboratories of Wohler in Gottingen, of Bunsen in Heidelberg of Mitscherlich and Rose in Berlin. The theory of atomistic combination was furthered by the antagonists Kekule and Kolbe, stereochemistry by Wislicenus and von Meyer, inorganic analy sis by Wohler, Winkler, Kirchoff, Bunsen, whose epoch-making spectral analysis has been mentioned before. The first organic synthesis is the famous work of Wohler in 1829. It opened in long series of synthetic successes of which not a few became technically important, as those of Fettig, Grabe, Hofmann, Fischer. Practical gain also to pharmacy came directly from German chemistry; chlorohydrate and chloroform, salicyl and antipyrin, etc., are prod ucts of German laboratories. The incomparable position of German chemical industry is the immediate outcome of the wonderful develop ment of chemical science in German universities and technological institutes.
The independent growth of physical chemis try prepared by Kopp, Bunsen, Wiedemann, be came most significant in recent times through Ostwald, Van t Hoff, Nernst, etc. Mineralogy and crystallography connects its development in Germany in first line with the name of C. S. Weiss in Berlin, Neumann in Konigsberg, Hessel in Marburg, Rose in Berlin, von Rath in Bonn, Zirkel in Leipzig, etc.