academy made for convenience and efficiency are all now embraced in the two classes already named. The king died in 1840. At that time the income of the academy from all sources was a little more than $15,000. It had not increased materially since 1809, and yet out of this small income some money had been saved and invested as capital. The king had preserved the independence of its members save in regard to the censorship exercised over their private writings, and had entrusted its care to wise advisers. During this reign, advance in knowledge, especially in scientific directions, had been very great. The academy had done some excellent work in all the departments of knowledge which it represented. In mathematics, worthy of mention are Dirrichlet, Steiner, Weierstrass, Jacobi and Kummer. When only twelve years, Dirrichlet spent his money for books on mathematics. From the Cologne gymnasium he went to Paris to hear La Place, Legendre, Forier and Poisson. He not only could understand Gauss's 'arithmetical disquisitions,' but he could make their meaning clear to others. He married Rebecca Mendelssohn Bartholdy in 1832, and after that time till his death his house was an intellectual and social center in Berlin. In the estimation of those who know it best his work was as important as that of Descartes in the use of analysis in geometry. Astronomy made good progress under Encke. His study of the occultation of Venus in 1796 enabled him to determine more accurately than had ever been done the parallax of the sun. In physics many names have become famous. Paul Ermann and Seebeck were in the academy before Frederick William III. occupied the throne; Dove, who laid the foundation of the science of modern physics; Poggendorf and Magnus came in prior to 1840. Ermann was in the academy from 1806 to 1851, was one of its secretaries from 1810 to 1841 and did as much as any one to help forward its development. DuBois Reymond was accustomed to speak of him as one of the best physicists of his era and as preparing the way for physicists like Magnus, and physiologists like Johannes Müller. Magnus was trained in chemistry by Berzelius and Gay Lussac, and in his turn trained many of the best modern chemists of Germany. Seebeck, after laboring thirteen years in the academy, withdrew to Jena, living upon his private means and devoting himself wholly to scientific studies. Mitscherlich, the discoverer of isomorphism, and Heinrich Rose, the discoverer of niobium, were trained by Berzelius and as analytical chemists have been ranked with their teacher. J. B. Karster, Weiss and G. Rose were eminent as mineralogists, and Leopold von Buch is credited with having laid the foundation for the study of geology and paleontology in Germany. His geological map in twenty-five leaves, published in 1821, had in 1843 run through five editions. For many years Link was the keeper of the botanic garden in Berlin, and with his own money founded its present magnificent herbarium. Harkell and Kunth were associated
