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838 Koch—all with the knowledge and consideration of one who had made deep studies of the subjects.

Dr. Siemens's literary efforts were limited, he tells us, chiefly to expositions of his scientific and technical labors and descriptions of his mechanical constructions. He had sometimes occasion to answer attacks upon his firm or upon himself personally. Besides those of which we have already spoken, he mentions as among his principal contributions to scientific literature a paper in Poggendorff's Annals, in 1857, on Electrostatic Induction and the Retardation of the Current in Conducting Wires; a communication made conjointly with his brother Wilhelm to the British Association in 1860 (Sketch of the Principles and of Practical Experience in the Testing of Submarine Telegraph Lines and their Conductivity); his lecture, in 1879, on Electricity in the Service of Life; and his address before the Society of German Naturalists and Physicians, in 1886, on The Scientific Age; papers On the Light of a Flame; On the Admissibility of the Conception of an Electric Sun-potential and its Significance in Explanation of Terrestrial Phenomena (called out by the discussion of his brother Wilhelm's paper. On the Conservation of the Solar Energy); Contributions to the Theory of Electromagnetism; On the Maintenance of Force in the Atmosphere of the Earth, 1881 and 1884; On the Question of Air Currents, 1887; On the General Wind System of the Earth, 1890; and On the Question of the Cause of Atmospheric Currents, 1891.

He elaborated the plans, and saw them adopted by the Prussian Government and Parliament, of the Physical-technical Imperial Institute at Charlottenburg for scientific research, of which Helmholtz is director. In 1874 he was made a member of the Royal Academy of Sciences of Berlin. He received the degree of Doctor of Philosophy, honoris causa, from the University of Berlin; was made a Knight of the Prussian Order for Merit; and received the patent of nobility in 1888. He was also a member of many learned societies.

M. J. Dybowski has transmitted to the French Academy of Sciences specimens of a condiment prepared by the peoples living on the banks of the Oubangui River, one of the affluents of the Congo. It is obtained by the incineration of river plants, and is composed chiefly of chloride and sulphate of potassium, with very little carbonate of potassium and no soda. This confirms former observations of the scarcity of soda in land plants. These usually contain considerable quantities of a very alkaline carbonate of potassium, not suitable as a condiment. The natives choose for incineration certain species containing only slight proportions of the carbonate. Although the salts of potash are considered unwholesome, these natives do not appear to suffer from using them.