May 5, 1921J 



NATURE 



317 



Calendar of Scientific Pioneers. 



May 5, 1859. Peter Gustav Lejeune Dirichlet died. 



— The successor of Gauss at Gottingen, Dirichlet did 

 original work on the theory of numbers and Fourier's 

 theorem, and wrote on the discoveries of Gauss and 

 Jacobi. 



May 5, 1892. August Wiihelm von Hofmann died. — 

 A great leader in the chemical world, Hofmann in 

 1845, at the age of twenty-seven, through Liebig, 

 became head of the Royal College of Chemistry, 

 London, where many prominent chemists were 

 trained. His work related to many problems in 

 organic chemistry, and especially to the coal-tar in- 

 dustry. Returning to Germany in 1864, the following 

 year he succeeded Mitscherlich in the University ot 

 Berlin. 



May 6, 1859. Friedrich Heinrich Alexander, Baron 

 von Humboldt died. — Possessing a passion for travel 

 and science, Humboldt during 1799-1804 made a 

 memorable journey with Bonpland in South America. 

 His great scientific work, "Cosmos," was published 

 during 1845-58. 



May 6, 1904. Alexander William Williamson died. — 

 Williamson in 1855 succeeded Graham in the chair of 

 chemistry in University College, London. For his 

 work on etherification he was awarded one of the 

 Royal medals of the Royal Society. 



May 8, 1794. Antoine Laurent Lavoisier died. — The 

 founder of modern chemistry and one of the most 

 distinguished victims of the French Revolution, 

 Lavoisier perished beneath the guillotine at the age of 

 fiftv. In prison he refused poison, saying, " I set no 

 more value on life than you do; and why seek death 

 before its time? It will have no shame for us. Our 

 true judges are neither the tribunal that will condemn 

 us nor the populace that will insult us. We are 

 stricken down bv the plague that is ravaging France." 

 One hundred and six years after his death Paris, as 

 the result of an international subscription, erected the 

 monument to Lavoisier which stands behind the Made- 

 leine Church, close to where he once lived. 



May 8, 1892. ' James Thomson died. — The elder 

 brother of Lord Kelvin, Thomson was a distinguished 

 physicist and engineer, and in 1873 succeeded Ran- 

 kine in the chair of engineering at Glasgow. 



May 9, 1850. Joseph Louis Gay-Lussac died. — A 

 professor of chemistry at the Ecole Polytechnique, 

 Gay-Lussac was known principally for his researches 

 into the chemical and physical properties of gases 

 and vapours. In 1815 he isolated cyanogen. 



May 10, 1568. Lebnhard Fuchs died. — Fuchs is 

 regarded as one of the founders of German botany. 

 His name is perpetuated by the word "fuchsia," first 

 applied to the plant in 1703 by Plumier. 



May 10, 1829. Thomas Young died. — A pioneer in 

 physiological optics, the advocate of the undulatory 

 theory, the first to use the term "energy" for the 

 product of mass into the square of velocity, and the 

 introducer of "Young's modulus," Young has been 

 referred to as the most clear-thinking and far-seeing 

 natural philosopher of his age. 



May lOj 1910. Stanislao Cannizzaro died.— The 

 greatest of Italian chemists, Cannizzaro held posts at 

 Pisa. Alessandria, Genoa, and Palermo, took part in 

 the liberation of Sicily, and from 1871 was professor 

 of chemistry at Rome. His greatest work was the ex- 

 tension and application of the hvpothesis of Avogadro. 



May 12, 1871. Sir John Frederick William Herschel 

 died. — By his work in physics and astronomy and bv 

 his writings Herschel exerted a great influence on his 

 fellows. His fanie was largely enhanced by his astro- 

 nornical work at the Cape' "of Good -flooe during 

 1S34-38. f" "E..e. S. '■■. 



NO. 2688, VOL. IO7I 



Societies and Academies. 



London. 

 Royal Society, April 21. — Prof. C. S. Sherrington, 

 president, in the chair. — Prof. J. Joly : A quantum 

 theory of colour vision. In accordance with the 

 physiological law of nerve impulses, known as the 

 " all-or-none " law, the cone is connected with the 

 optic nerve through a plurality of nerve-fibres, the 

 rod being connected through one fibre only. This is 

 supported by histological evidence. The fundamental 

 colour-sensations may be taken as corresponding to 

 frequencies in the ratio 2:3:4, and this is the ratio 

 of the energies of the corresponding quanta and of 

 the kinetic energies of the electrons liberated. It is 

 supposed that this is also the ratio of the numbers 

 ! of fibres activated in the cone. In the case of the 

 rod, quanta can activate but one fibre; hence its 

 achromatic functions. In the case of the cone the 

 activation of two, three, or four fibres evokes the 

 fundamental sensations. White sensation arises when 

 all nine fibres are activated. Colour-sensation curves,- 

 colour blindness, and the energy relations of colour 

 sensation and luminous sensation are discussed. — Prof. 

 A. V. Hill : The energy involved in the electric change 

 in muscle and nerve. An expression is given for the 

 heating effect in a muscle or nerve of the currents 

 produced by the electric response accompanying the 

 propagated impulse. In a muscle the heat produced 

 is not more than one-hundred-thousandth part of the 

 energy liberated in a twitch ; in- a nerve it is of the 

 order of size of 3-5x10-'° calorie. It is concluded 

 from the smallness of these quantities that no- 

 app?eciable provision of energy is required in the 

 propagation of the electric response, and that the 

 physico-chemical change producing the response is 

 tTie only factor involved in the propagated nervous 

 impulse. -^H. M. Kyle : Asymmetry, metamorphosis, 

 and origin of flat-fishes. The flat-fishes owe their 

 change of form in the beginning to an inherent asym- 

 metry of the abdominal organs, the coil of the gut ; 

 other organs develop asymmetrically according to the 

 balance, and persistent flexures convey the asymmetry 

 to the skull. Many normal teleosts focpi a coil and 

 display the same initial disturbances, but their balance 

 is less defective and the skull escapes deformity ia 

 various wavs. The metamorphosis of flat-fishes takes 

 place during the pelagic stages ; the fish swims and 

 lies on one side because that side becomes the heavier. 

 After the demersal habitat has been attained, changes 

 in fundamental structure are improbable, so essential 

 differences indicate separate origins. The flat-fishes 

 have appeared in phylogeny — that is, the skull became 

 affected by the asymmetry of the body when the coil 

 of the gut was forming and when the caudal region 

 came to occupy more than half the total length. Con- 

 firmation of this view is found in the affinity of each 

 group to separate types of normal teleosts ranging" 

 from the Macrurids to the Percoids. — T. L. Prankerd : 

 Studies in the cytology of the statolith apparatus in 

 plants, viewed in relation to their habit and biological 

 requirements, (i) The reaction to external stimuli of 

 some liverv^-orts. The degree of geotropic irritabilitv 

 corresponds in general with the biological require- 

 ments of the plant. The statolith apparatus is usually 

 absent in vegetative thalli where position is of no- 

 importance, while it is most ' strikingly developed vn 

 the strongly geotropic gametophores and soorogonia. 

 (2) The movements executed by fern-frond^; in 

 response to internal and external stimuli. In fifteen- 

 species representative of the Filicales geotropic 

 irritability was always present, though both latent 

 and reaction times are greater than the corresoondtng^ 

 periods fdr ' " Aiigiosperms, implying physiological 



