NAT URL 



[December 26, 19 18 



OUR ASTRONOMICAL COLUMN. 

 The Planei Mercury. This planet will be favour- 

 visible as a morning star a1 the end of the 

 present year and the first week oi January. Orl 

 December .;i it will rise at 6h. 18m. a.m., or ih. 50m. 



i the sun, and this interval will undergo little 



change on the few following mornings: The greatest 

 elongation will occur on the morning of January 8 



i ;' \V.). The planet will be situated in 

 Ophiuchus, and at the period from December 26 to zg 

 will be placed about 4J south of the star q Ophiuchl 

 (mag. zi)'. With a clear sky in the region of the 

 S.E. horizon it will be possible to observe Mercury 

 with the naked eye on the mornings from about 

 Christmas Day to 'January 10. The planet's stellar 

 magnitude on January 1 will be I 0-2, and on January <> 

 ±00, according to the Nautical Almanac. 



The Jam aki Mr. i ions- This display will probably 

 furnish a rather striking event on January 3, when 

 there will be no moonlight to interfere with observa- 

 tion. Last year the meteors were unusually abundant, 

 and presented a curious feature, the centre of radia- 

 tion being about 7° north of the position determined in 

 previous years. Formerly this was at 23I°+S2?, but 

 on January 3, 1918, the point was at 234 +5o.i°, which 

 nearly corresponds with the place of the star 1 Draconis. 

 The meteors move rather slowly, and they often 

 traverse long flights, the radiant being low in altitude, 

 and only 14 above the horizon in due north at 

 8.40 p.m. if the- point is in N. deck 52 . The shower 

 will probably be presented to the best effect in the 

 morning hours of January 3, but observations should 

 .iUi. be conducted in the early evening hours of 

 January 2. It will be important to determine the 

 place of radiation as accurately as possible. 



Opposition of Vesta. — Vesta will be in opposition 

 On January H>, magnitude 69. The following 

 ephemeris is from the Berlin Rechen-Institut : 



Distribution ok Luminosity in Star Clusters. 



An interesting summary of some recent work by Prof. 

 E. Hertzsprung on the distribution of luminosity in 

 globular clusters is given in the Observatory for 

 December. In view of the immense distances of 

 thesi objects, it is probable that a multitude of faint 

 stars belonging to them leave no impression on the 

 photographs, although they must contribute ap- 

 preciably to the general luminosity of the cluster. In 

 of M3, by giving a long exposure with the 

 stars somewhat out of focus, Prof. Hertzsprung ob- 

 tained an image with a continuous distribution of 

 photographic density, which permitted measurements 

 of tin total amount of light given by different parts of 

 the cluster. The luminosity due to the stars which 

 appear in the ordinary photographs was then sub- 

 tracted, and tin remainder represented the light of 

 the faint star-. The distribution of these faint stars 

 was thus found to follow closely that of the bright 

 ones. The total photographic light of the cluster was 

 equivalent to mag. 7 17, and half of this was from 

 the space within a radius of 50". If the distance 

 of the cluster be 10,000 parsers, half the stars lie 

 within a radius of 2^ parsers, indicating a remarkable 

 concentration towards the centre. The light-iritehsity 

 in unit volume would, in fact, be to 5 times higher than 

 that in the neighbourhood of the sun. 

 NO. 2565, VOL. I02] 



l'RIZE AWARDS Oi- THE PARIS 

 ACADEMY OF SCIENCES FOR 1918. 

 Mathematics. — Grand prize of the mathematical 



sciences to (.aston Julia, Samuel Lattes receives a 

 very honourable mention; the Poncelet prize to Sir 

 Joseph Larmor, for the whole of his mathematical 

 work; the Franavur prize to Paul Montel. 



Mechanics. — The Montyon prize to Ch. Boileau, for 

 his studies on petrel motors; the Boileau prize to 

 MM. C. Carhichel, I). Eydoux, and M. Gariel, 

 their experiments and calculations on hammering in 

 water-mains; Henri de Parville prize to Smile Belot, 

 for his scientific and industrial work. No memoii 

 was received on the subject proposed for the Fout- 

 nevron pi ize. 



Astronomy.— The l.alande prize to Aristarch Belo- 

 polsky, for his work on spectrum analysis applied to 



astronomy; the Valz prize to FredeVic Sy, for his 

 astronomical work as a whole; the Jansscn prize to 

 P. Stanislas Chevalier, for his astronomical work in 

 China. The Damoiseau and Pierre Guzman prizes 

 are not awarded. 



Geography. — The Tchihatchef prize to Filippo de 

 Filippi, for his contributions to the geography of the 

 Kara-Korum range and of Central Asia. The Dela- 

 lande-Guerineau, Gay, and Binoux prizes are not 

 awarded. 



Navigation. — The prize of 6000 francs between 

 Finest Berger and Erilile Guilbert (3000 francs) and 

 Georges VValser and Andre Broca (3000 francs), for 

 work which cannot at present be disclosed; the 

 Plumey prize divided equally between Maurice de 

 Broglie and C. J. Tossizza, for work bearing on the 

 national defence. 



Physics. — The L. La Caze prize to Ainu- Cotton, for 

 his researches in magneto-optics; the Hubert prize to 

 P. Boucherot, for his work in electricity; the Hughes 

 prize to Anatole Leduc, for the whole of his work; 

 the Danton foundation to Louis Dunover, for his 

 works on radiant phenomena; the Clement Felix 

 prize to Paul Langevin, for his work on electrical 

 resonance. 



Chemistry. — A Montyon prize (unhealthy tradt-) t. 

 Henri Guillemard and Andre Labat (2500 francs), for 

 their work relating to collective protection against 

 asphyxiating gases; an honourable mention (1500 

 francs) to Felix Leprince-Ringuet, for his researches 

 on the inflammability of methane, and to Louis 

 Nomblot (1000 francs), for a method of preparation 

 of a dangerous product utilised by artillery; the 

 Jecker prize to Robert Lespieau, for his work as a 

 whole; L. La Caze prize to Paul Lebeau, for his 

 chemical researches, mainly in inorganic chemistry; 

 the Cahours foundation divided between Mme. Pauline 

 Ramart-Ljucas (2000 francs) and Etienne Boismenu 

 (1000 francs); the Houzeau prize to Marcel Guichard, 

 for his researches on iodine and molybdenum com- 

 pounds. 



Mineralogy and Geology. — The Cuvier prize to 

 Arthur Smith Woodward, for his work on fossil 

 vn tebrates. 



Botany. — The Desmazieres prize to Camille 

 Sauvageau, for his researches on the biology of the 

 Alga?; tin' Montagne prize to Joseph Capus, for his 

 researches in plant pathology, with an honourable 

 mention to Amedeo Laronde for his contributions to 

 cryptogamic geography: the de Coincy prize to Jules 

 Laurent, for his work on the flora and botanical 

 gebgraphy of the neighbourhood of Reims. 



Anatomy ami Zoology. The Thore prize to Pierre 

 Chretii in, for his researches on the Lepidoptera. The 

 da Gama Machado and Savigny prizes are not 

 awarded. 



