May 19, 192 1 J 



NATURE 



3«i 



Calendar of Scientific Pioneers. 



l/ay 19, 1786. Carl Wilhelm Scheele died.— Pre- 

 eminent as an exjjerimental investigator and chemical 

 discoverer, Scheele \rorked as an apothecary in various 

 towns in Sweden, devoting his leisure to chemistry. 

 Included among the many substances he discovered 

 are chlorine, ammonia, oxygen,, and several acids. 



May 20, 1793. Charles Bonnet died.— A well-known 

 naturalist of Geneva, Bonnet made researches on 

 parthenogenesis, the respiration of insects, and the 

 use of leaves. He also published works on psychology. 



May 20, 1880. William Hallowes Miller died.— A 

 fellow of St. John's College, Miller from 1832 to 1870 

 was professor of mineralogy at the University of Cam- 

 bridge. He developed a system of crystallography 

 adapted to mathematical calculation. 



May 21, 1894. August Adolf Eduard Eberhard 

 Kundt died. — A student under Magnus, Kundt in 1888 

 succeeded Helmholtz as professor of experimental 

 physics and director of the Berlin Physical Institute. 

 His most successful work related to sound, light, and 

 magneto-optics. 



May 22, 1666. Caspar Schott died.— To Schott, 

 Guericke, and Johann Sturm belongs the credit of 

 reviving the study of the physical sciences in Germany 

 after the Thirty Vears' War. Schott was educated in 

 Italy as a Jesuit, but afterwards taught at Wurzburg. 

 His. " Mechanica — hydraulica — pneumatica " (1657) 

 contains the first description of the air pump. 



May 22, 1868. Julius Pliicker died.— A mathe- 

 matician and physicist of Bonn, Pliicker extended 

 analvtical geometry, and was known for his discoverv 

 of magneto-crystailic action, and for his researches 

 on spectroscopy and the electric discharge in rarefied 

 gases. 



May 23, 1857. Auguste Louis Cauchy died.— Cover- 

 ing the whole field of mathematics and mathematical 

 physics, the work of Cauchy is noteworthy for the 

 rigorous methods he introduced. He was a professor 

 at the Ecole Polytechnique. 



May 23, 1894. George John Romanes died.- After 

 early work on the nervous and motor svstems of the 

 Echinodermata Romanes turned his attention to such 

 questions as mental evolution in animals. He was an 

 intimate friend of Darwin, and did much to popularise 

 his views. 



May 23, 1895. Franz Ernst Neumann died.— 

 Neumann was born in 1798, and from 1829 to 1876 

 was professor of mineralogy and physics in the Uni- 

 versity of Konigsberg. He did important work on 

 the dy/iamical theory of light and on the mathematical 

 theory of electrodynamics. 



May 24, 1543. Nicolas Copernicus died. — Born at 

 Thorn^ in 1473, Copernicus, or Koppernigk. was the 

 fourth child of a merchant. After studying at Cracow, 

 Bologna. Padua, and Ferrara, Nicolas, through his 

 uncle the Bishop of Ermland, became a canon of 

 Frauenburg Cathedral. Later on he was administrator 

 of the diocese. Among his great contemporaries, 

 Luther. Erasmus, Leonardo da Vinci, and Paracelsus, 

 Copernicus is the representative of the reformers of 

 astronomy. All his leisure wr • given to observation; 

 his "De Revolutionibus " i- he result. The first 

 printed copy of this work •.. s placed in the hands of 

 Copernicus when he was dying. Dedicated to Pope 

 Paul III., many years afterwards it was placed upon 

 the Index. 



May 24, 1837. Karl Ernst Adolf von Hoff died.— The 

 friend of Werner and Goethe, Hoff is known to 

 geologists for his " History of the Changes on the 

 Surface of the Earth " (1822-41). E. C. S. 



NO. 2690, VOL. 107] 



Societies and Academies. 



London. 

 Linnean Society, April 21. — Dr. A. Smith Woodward, 

 president, in the chair. — Prof. R. JSewstead : Some 

 observations on the natural history of the Upper Shiri 

 River, Nyasaland. The common types of the flora 

 and fauna were discussed. The flora was dealt with 

 under three sections : — (i) The river and its banks, 

 (2) the open "dambo" or savannah, and (3) the forest. 

 Dealing with the insects, special reference was made 

 to a highly protective species of Mantis {Taracodes 

 perloides) and the common tsetse-fly of the country 

 {Glossina morsitans)^ the latter being the chief factor 

 in the dissemination of sleeping sickness in man. 

 Seventy-eight species of birds were collected ; among 

 these a new species of flycatcher {Erithrocerus nyasae) ; 

 and large flocks of the rare lorikeet {Agapornis 

 Ullianae) were observed. 



Faraday Society, May 9. — Prof. A. W. Porter, presi- 

 dent, in the chair. — E. K. Rideal and U. R. Evans: 

 The problem of the fuel-cell. Fuel-cells niay be 

 classified as : — (i) Direct fuel-cells burning solid fuel. 

 These suffer from current polarisation due to the low 

 velocity with which carbon enters into electrodic re- 

 actions. (2) Semi-direct fuel-cells burning gaseous 

 fuel. These suffer usually from current polarisation 

 due to the difficulty of keeping the electrode material 

 saturated with gas. Mond and Langer overcame this„ 

 but in doing so used so much platinum that their cell 

 became far too expensive for practical use. An at- 

 tempt to use nickel instead of platinum as the sub- 

 stratum of a gas-electrode was unsuccessful. (3) In- 

 direct cells of (a) oxidation-reduction type. These sufler 

 from not only (i) current polarisation, dependent on, 

 the electrode area, but also (ii) tune polarisation, de- 

 pendent on the cell volume. This second kind of 

 polarisation is economically most important, but has. 

 been overlooked by some workers. Some fresh cells 

 of this type were tested, but proved unsuitable. 

 (b) Metal anode type. Zinc appears unsuited, but pre- 

 liminary experiment with different cells (both hot and 

 cold) in which tin was the active element gave results 

 which seemed promising. — L. F. Knapp : The solu- 

 bility of small particles and the stability of colloids. 

 A theoretical paper in which Ostwald's relation 

 between the solubility and size of particles is modified 

 for the case where the particles are electrically 

 charged. An attempt is made to explain the connec- 

 tion between the stability of colloids and the charge 

 carried by their particles. 



Edinburgh. 



Royal Society, May 2. — Prof. F. O. Bower, presi- 

 dent, in the chair. — Dr. Dawson Turner and Mr. 

 D. M. R. Crombie : Behaviour of an electrified pith 

 ball in an ionised atmosphere. This communication 

 concerns a delicate method of demonstrating the 

 ionised atmosphere surrounding flames and hot bodies 

 by means of a pith ball suspended from the knob of 

 a charged Leyden jar. The effectiveness of various 

 sources of ionisation was demonst^ted, and the direc- 

 tive influence of the charged Leyden jar shown. The 

 conclusions arrived at were : — (i) A charged pith 

 ball can serve as a very delicate indication of the 

 electrical condition of its surroundings. (2) The ions 

 are concentrated along the straight line joining the 

 centre rod of the charged jar and the source of 

 ionisation. (3) The ions tend to be carried upwards 

 by convection currents. (4) The ionisation of the 

 atmosphere does not depend upon the luminous or 

 actinic intensity of the flame, but is associated with 

 a radiation of longer wave-length. (5) The effect 



