2s2 



NATURE [April 21, 1 92 1 



Calendar of Scientific Pioneers. 



April 21, 1793. John Michell died.— A fellow of 

 Queens' College, Cambridge, Michell became a clergy- 

 man, and in 1762 was appointed Woodwardian pro- 

 fessor of geology in the University of Cambridge. 

 Magnetism, electricity, and astronomy all engaged his 

 attention, and shortly before his death he devised the 

 apparatus afterwards used by Cavendish to measure 

 the density of the earth. 



April 21, 1825. Johann Friedrich Pfaff died.— The 

 friend of Schiller and the rival of Gauss, Pfaff studied 

 mathematics under Kastner and worked at astronorny 

 with Bode. His original researches were mainly in 

 the domain of the calculus and differential equations. 

 Pfaff was born in 1765. From 1788 to 1810 he was 

 professor of mathematics at Helmstadt, and from 

 1810 onwards held the chair of mathematics at Halle. 



April 23, 1874. John Phillips died. — In his youth 

 the constant companion of his uncle, William Smith, 

 the geologist, Phillips held the chairs of geology at 

 King's College, London, at Dublin, and at Oxford. 

 For his contributions to geology and palaeontology he 

 received the Wollaston medal from the Geological 

 Society, which he served as president during 1859-60. 



April 25, 1840. Simeon Denis Poisson died.— Poisson 

 all his life — first as student, then as professor and 

 e.xaminer — was connected with the Ecole Poly- 

 technique, where he gained the friendship of 

 Lagrange, Laplace, and Legendre. Besides his 

 separate works he published some three hundred 

 memoirs, the chief of which are on the theory of 

 •electricity and magnetism and on celestial mechanics. 

 .Ahvavs working, he replied to one who urged him to 

 rest : "La vie: c'est le travail." 



April 25, 1882. Johann Carl Friedrich Zollner died.— 

 Well know.j for his investigations in photometry, spec- 

 trum analysis, and the constitution of the sun, Zollner 

 from 1872 was professor of physical astronomy at 

 Leipzig. 



April 25, 1914. Eduard Suess died. — Born in London 

 in 183 1, Suess was educated at Prague and at Vienna, 

 where at the age of twenty he entered the Imperial 

 Museum. In 1867 he became professor of geology in 

 Vienna University. His great treatise, " Das Antlitz 

 der Erde," which occupied him twenty-five years, 

 was a comprehensive survey of all that had been 

 accomplished in elucidating the geological structure of 

 the earth. He held various public offices, and servn<^i 

 .as president of the Academy of Sciences of Vienna. 



April 26, 1835. Henry Kater died. — Joining the 

 Army as an ensign in 1794, Kater for a time assisted 

 Lambton on the Trigonometrical Survey of India. 

 Placed on half-pay in 1814, he devoted himself to 

 scientific pursuits, and was especially known for his 

 pendulum experiments, his work on weights and 

 measures, and his invention of the floating collimator. 



April 26, 1920. Srinivasa Ramanujan died. — Distin- 

 guished for his researches in pure mathematics, 

 Ramanujan was the first Indian fellow of the Royal 

 Society. A Brahmin by caste, he was born at Erode 

 in 1887, became a student at Madras University, and 

 was enabled to spend the years 1914-19 in England, 

 where his brilliant work led to his being elected F.R.S. 

 in 1918. He died at Chetput, Madras. 



April 27, 1521. Ferdinand Magellan died. — The con- 

 temporary of Columbus and Vasco da Gama, Magellan 

 — or Magalhaes — came of a noble Portuguese ianiily. 

 Sailing from Portugal in September, 15 19, towards 

 the end of 1520 he discovered the strait that bears 

 'liis name and so reached the Pacific. He met his 

 Kieath in a fight with natives in the Philippines. 



E. C. S. 



NO. 2686, VOL. 107] 



Societies and Academies. 



London. 



Royal Microscopical Society, March 16.— Prof. John 

 Eyre, president, in the chair.- — J. H. Pledge : The 

 use of light-filters in microscopy. The advantages 

 gained are : control of contrast in the stained and the 

 coloured preparations from both the visual and the 

 photographic points of view; aid in resolution of fine 

 structure ; improvement in the definition given bv 

 ordinary achromatic objectives ; modification of the 

 unpleasantness to the eye of artificial-light sources by 

 "equivalent daylight" filters; and the possibility of 

 moderating the intensity of illumination of the micro- 

 scopic field by light-filters of neutral tint of suitable 

 density. Forms of light-filters mostly in use are 

 chiefly dyed gelatine cemented between protecting 

 cover-glasses, but dye solutions in glass-cells are also 

 used. To obtain maximum contrast a light-filter 

 complementary in colour to that of the preparation 

 should be used. 



Faraday Society, March 22»— Prof. A. W. Porter, 

 president, in the chair. — Prof. A. W. Porter : Presi- 

 dential address : Some aspects of the scientific work 

 of the late Lord Rayleigh. The experimental part 

 of Rayleigh 's work could be divided into that requir- 

 ing elaborate apparatus and laborious application, and 

 investigations in which the apparatus was of the 

 simplest kind. The latter was a type of investigation 

 in which Rayleigh specially delighted. His mathe- 

 matical work was always looking forward to its ap- 

 plications. Illustrations were given of the great use 

 he made of the method of dimensions when problems 

 (especially those in hydrodynamics) cannot be yet 

 solved in any other way. His work on intrinsic 

 pressure was outlined and contrasted with more recent 

 work of the Dutch school of physicists. Finally, his 

 mentality was further characterised by references to 

 his excursions into problems dealt with by the Society 

 of Psychical Research. His position was summed up 

 by saying that although Rayleigh founded no school, 

 yet he so advanced knowledge of physics in all its 

 branches as to stand out as one of the leaders in 

 scientific achievement.^ — S. Field : The electrolytic 

 recovery of zinc. Abundant supplies of low-grade and 

 complex ores are available in Great Britain which are 

 not amenable to distillation, but respond readily to 

 electrolytic treatment. Sulphide ores are calcined to 

 oxide and a predetermined proportion of sulphate. 

 The calcine is leached with acid zinc sulphate liquors 

 from the electrolytic cells. Special treatment avoids 

 gel formation, and admits of high extraction and easy 

 filtration. The zinc sulphate solution is too impure 

 for efficient deposition. The methods of purification 

 worked out are given in some detail. Ni and Co 

 constitute two commonly met and insidious impurities. 

 The purified liquors containing not more than 3 to 

 5 parts Co and 02 part Ni per 1,000,000 are acidified 

 and electrolysed between lead anodes and aluminium 

 cathodes. The cells, arranged in cascade, absorb 

 335 volts and give a current efficiency of 90 per cent., 

 representing about 3200 k.w.h. per ton of zinc 

 cathodes. Subsidiary power is amply covered by 

 800 k.w.h. per ton ; 4000 k.w.h, covers all power. 

 At o-33d. per unit, power costs are 5Z. \\s. per ion of 

 cathode zinc. The cathodes are melted and yield 

 ingots assaying at least 99-95 per cent, of zinc. — Prof. 

 A. Findlay and V. H. Wiliiams : Note on the elec- 

 trolytic reduction of glucose. The authors have 

 studied the electrolytic reduction of glucose under 

 varying conditions of temperature, current density, 

 and current concentration, and using both graphite 

 and lead electrodes. No appreciable amount of hexa- 



