670 



NATURE 



[July 21, 192 1 



Calendar of Scientific Pioneers. 



July 21, 1575. Francesco Maurolico died. — The first 

 of the mathematicians of the Renaissance to study 

 optics, Maurolico was born at Messina and became 

 Abbot of Sta Maria del Porto, in Sicily. His chief 

 work was one on conic sections. 



July 21, 1888. Henry Carvill Lewis died. — Known 

 for his glacial studies in the United States and Great 

 Britain, Lewis held the chair of geology in Haver- 

 ford College, U.S.A. 



July 21, 1901. Henri de Lacaze-Duthiers died.^The 

 founder and editor of the Archives de Zoologie, 

 Lacaze-Duthiers was the originator of the Marine 

 Zoological Laboratories at Roscoff and Banyuls-sur- 

 Mer, and was known for his important studies of 

 marine invertebrates. 



July 22, 1802. Marie Franpois Xavier Bichat died.— 

 One of the greatest of anatomists and physiologists, 

 Bichat was only thirty years of age when he died. 

 Trained under Desault, he became physician to the 

 Hdtel Dieu, where Napoleon caused a memorial to 

 Desault and Bichat to be placed. Bichat's most im- 

 portant works were his " Recherches Physiologiques 

 sur la vie et la mort " (1800) and "Anatomie 

 G^nerale " (1801). 



July 22, 1826. Giuseppe Piazzi died. — Piazzi was 

 the first director of the Palermo Observatory, where 

 on the first day of the nineteenth century he discovered 

 the first of the minor planets called by him Ceres, in 

 allusion to the titular goddess of Sicily. In 1814 he 

 published an important catalogue of 7646 stars. 



July 23, 1773. George Edwards died. — Edwards 

 made valuable contributions to the ornithology of his 

 day, and In 1750 received the Copley medal for his 

 book entitled "A Natural History of Birds." 



July 23, 1916. Sir William Ramsay died.— Born at 

 Glasgow on October 2, 1852, and educated at Glas- 

 gow and Tubingen, Ramsav from 1881 to 1887 was 

 Principal of LIniversity College, Bristol, and then 

 succeeded Williamson as professor of chemistry in 

 LIniversity College, London. He did important work 

 in many branches of physical chemistry, and became 

 famous the world over for his researches on argon 

 and other rare gases of the atmosphere, the discovery 

 of terrestrial helium, and his investigation of radium 

 emanation. He was knighted In 1902. 



July 25, 1903. Mathieu Prosper Henri died.^ 

 Prosper Henri and his brother Paul (1845-1905) were 

 from 1868 onwards assistant astronomers at the Paris 

 Observatory, where they had an important sh-nre in 

 the development of the great International Photo- 

 graphic Chart of the Heavens inaugurated by Gill and 

 Mouchez. 



July 27, 1759. Pierre Louis Moreau de Maupertuis 

 died. — A native of St. Malo and a member of the 

 Paris Academy of Sciences, Maupertuis, who visited 

 London in 1727, the same year as Voltaire, was the 

 first in France publicly to support the views of 

 Newton. With Clairaut he assisted In the measure- 

 ment of a degree of meridian In Lap'and, and after- 

 wards, on the invitation of Frederick the Great, 

 became president of the Berlin Academy of Sciences. 



Julv z., 1,844. John Dalton died. — Born In Cumber- 

 land In 1766, Dalton from boyhood was engaged in 

 teaching, and for the last fifty years of his life was 

 connected with the Manchester ' Literary and Philo- 

 sophical Society. His meteorological studies and his 

 Investigation of gases and vapours led to his discovery 

 of the law of thermal expansion of gases and to the 

 enunciation of the atomic theory. In 1808 he pub- 

 lished his "System of Chemical" Philosophy." After 

 the death of Davy he was elected one of the eight 

 foreign associates of the Paris Academy of Sciences. 



E. C. S. 

 NO. 2699, "VOL. 107] 



Societies and Academies. 



London. 

 Aristotelian Society, July 4. — Prof. G. Dawes Hicks, 

 vice-president, In the chair. — Dr. F. C. S. Schiller : 

 Arguing in a circle. A scientific system is essentially 

 partial. Being constructed by selections and exclu- 

 sions and relative to a purpose, it contains no war- 

 rant for the postulatlon of any all-embracing system. 

 Objections to a system cannot be met by arguing 

 within it. To meet a challenge it must obtain out- 

 side support. If It is to give satisfaction it must not 

 close itself, but remain open to correction. The 

 sciences are such systems, and so escape the charge 

 of circularity. An all-embracing system is not a valid 

 ideal, because inability to select would reduce it to 

 chaos, while if logically complete it could be rejected 

 as a whole. Also It is self-contradictory, for either 

 It can be enlarged to satisfy objections, and then it is 

 not all-embracing, or it cannot be enlarged, and then 

 it argues in a circle. If it presupposes relativity 

 to purpose, it cannot reach absoluteness. The 

 attempt to base inference on implication within an 

 ideal system is no improvement on formal logic, but 

 merely a half-way house to a complete surrender of 

 the notion of "formal validity." 



Paris. 

 Academy of Sciences, June 27. — M. Georges Lemoine 

 In the chair. — M. Riquier : The complete families of 

 Integral figures of a system of partial differential equa- 

 tions of the first order. — J. Kampe de Feriet : Systems 

 of partial differential equations of the most general 

 hypergeometrical functions.- — M. Hadamard : Systems 

 of partial differentials, comprising as many equations 

 as unknown functions. — T. Varopoulos : A class of 

 transcendental functions. — M. d'Ocagne : Lines of 

 curvature of quadrics.— J. Andrade : The problem of 

 starting (a chronometer), and sustained pendular 

 movements. — A. Thuloup : The equilibrium and 

 stability of elastic apparatus. — F. Quenisset : Photo- 

 graphs of the planet Venus. On February 23, 

 192 1, an observation with the 24-cm. equatorial showed 

 a marked grey spot on the edge of the planet near 

 the centre. Seventeen photographs were immediately 

 taken with varying exposures, and a diagram Is shown 

 giving the appearance of the planet as taken from 

 these negatives.- — M. Juvet : The formulae of Frenet 

 for a Weyl space. — L. de Broglie and A. Dauvillier : 

 The electronic structure of the heavy atoms. A com- 

 parison of the physico-chemical Indications concerning 

 the electronic structure of the elements with those 

 furnished by a study of their X-rav spectra. — G. 

 Ranque : A new mercury pump. A circulating- mer- 

 cury pump, requiring only 400 grams of mercury, 

 worked with an auxiliary water pump. — M. 

 Chevenard : Relation between the anomalous expansion 

 and thermal variation of magnetisation of ferro- 

 magnetic bodies. — R. Dubrisay : The action of boric 

 acid on glycerol and the polyvalent alcohols. The 

 application of a new physico-chemical volumetric 

 method. --»^E. L. Dupuy : The influence of welding on 

 the resistivity of Iron. The presence of ferric oxide in 

 the metal causes an increase In the electrical resist- 

 ance. — MM. Dervin and Olmer : Ammoniacal silver 

 carbonate. This Is formed by the action of atmo- 

 spheric carbon dioxide upon an ammoniacal solution 

 of silver oxide. It forms colourless hexagonal crystals, 

 and has the composition Ag2CO,,4NH,,HoO. — E. 

 Decarrifere : The rdle of the gaseous Impurities in the 

 catalytic oxidation of ammonia. Details of a study of 

 the effects of hydrogen sulphide as impurity In the 

 ammonia.^ — L. Lutaud : General remarks on the 

 tectonics of the pre-RIfiian zone of northern R'arb, 



