838 THE POPULAR SCIENCE MONTHLY. 



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 Poggen- 

 dorfFs Annals, in 1857, on Electrostatic Induction and the Retar- 

 dation of the Current in Conducting Wires ; a communication 

 made conjointly with his brother Wilhelm to the British Associa- 

 tion in 1860 (Sketch of the Principles and of Practical Experi- 

 ence in the Testing of Submarine Telegraph Lines and their Con- 

 ductivity) ; 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 Ter- 

 restrial 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 Main- 

 tenance 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 Prus- 

 sian Government and Parliament, of the Physical-technical Im- 

 perial 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 speci- 

 mens 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 observa- 

 tions 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 propor- 

 tions of the carbonate. Although the salts of potash are considered unwholesome, 

 these natives do not appear to suffer from using them. 



