January 12, 1911] 



NATURE 



349 



VlilZE SLBJECTS PROPOSED BY THE PARIS 

 ACADEMY OF SCIENCES FOR 1912. 



/^^EOMETRV.— Grand prize of the mathematical, 



^ sciences (3000 francs). The subject proposed for 



12 is the improvement of the thewy of algebraic difler- 



ial equations of the second or third order the general 



• gral of which is uniform. No memoirs having been 



ived on the question proposed for 1910, this will also 



awarded in 1912. Francoeur prize (looo francs), for 



:k useful to the progress of pure or applied mathe- 



tics ; Poncelet prize (2000 francs), for a work on pure 



iihematics. 



'lechanics. — Montyon prize (700 francs), for inventions 



improvement of instruments useful to the progress of 



iculture, or the mechanical arts or sciences; Fourneyron 



ve (1000 francs), for a memoir on the theory and 



)eriment of air resistance, applicable to aviation. The 



stion set for 1910 is also postponed to 1912. Boileau 



ie (1300 francs), for researches on the motion of fluids 



tributing to the progress of hydraulics. As an 



-rnatwe, the funds may be applied to the assistance of 



scientific man without means. 



Xavigation. — The extraordinary prize of 6000 francs, for 

 work tending to increase the efficiency of the French naval 

 forces ; Plumey prize (4000 francs), for an improvement in 

 steam engines or any other inventicMi contributing to the 

 progress of steam navigation. 



Astronomy. — Lalande prize (540 francs), for a memoir 

 work useful to the progress of astronomy ; Valz prize 



francs), for the author of the most interesting observa- 



1 made during the current year ; Janssen prize, a gold 

 dal awarded for a discovery or work representing an 

 portant progress in ph3sical astronomy. 



Geography. — Tchihatchef prize (3000 francs), for the 

 encouragement of exploration in the lesser known portions 

 of Asia ; Binoux prize (2000 francs), for original geo- 

 graphical work ; Delalande-Guerineau prize (1000 francs) ; 

 Gay prize (1500 francs). The question proposed for 1912 

 is the study of the tides of the earth's crust. 



Physics. — Hubert prize (1000 francs), for a treatise or 

 discovery concerning the practical employment of elec- 

 tricity ; Hughes prize, for a discovery or work contributing 

 to the progress of physics ; L. La Caze prize (io,ooo 

 francs), for works or memoirs contributing to the progress 

 of physics. 



Chemistry. — ^Jecker prize (10,000 francs), for works con- 

 tributing to the progress of organic chemistry ; Cahours 

 prize (3000 francs), for the encouragement of young 

 chemists ; Montyon prize (unhealthy trades) (prize of 2500 

 francs and a mention of 1500 francs), for a means of 

 rendering a trade or calling less unhealthy ; L. La Caze 

 prize (10,000 francs), for the best work on chemistry. 



Mineralogy and Geology. — Victor RauHn prize (1500 

 francs), for facilitating the publication of works relating 

 to mineralogy and petrography. 



Botany. — Desmazieres prize (1600 francs), for the best 

 work published during the year on cryptogams ; Montagne 

 prize (1500 francs), for memoirs on the anatomy, physio- 

 logy, development, or description of the lower cr}.'ptogams ; 

 de Coincy prize (qoo francs), for a work on phanerogams. 



Anatomy and Zoology. — Savigny prize (1500 francs), for 

 the assistance of young travelling zoologists, not receiving 

 Government support, concerning themselves specially with 

 the invertebrates of Egypt and Syria ; Da Gama Machado 

 prize (1200 francs), for memoirs on the coloured parts of 

 the tegumentary system of animals ; Thore prize (200 

 francs), for the best work on the habits and anatomy of 



-'" species of European insects. 



Medicine and Surgery. — Montyon prize (2500 francs, and 

 mentions of 1500 francs), for works or discoveries useful 

 in the art of healing ; Barbier prize (2000 francs), for a 

 discovery useful in surgical, medical, or pharmaceutical 

 science, or in botany in relation to medicine ; Breant prize 

 (100,000 francs), for the discovery of a specific cure for 

 cholera, or, as an alternative, for the discover}' of the 

 causes of this disease, leading to its eradication ; Godard 

 prize (1000 francs), for the best memoir on the anatomy, 

 physiology, and pathology of the genito-urinary organs ; 

 Baron Larrey prize (750 francs), for a work dealing with 

 the subject of military medicine, surgery, or hygiene ; 



NO. 2150, VOL. 85] 



Bellion prize (1400 francs), for works or discoveries useful 

 in medicine; M^ge prize (10,000 francs); Argut prize (1200 

 francs), for the discovery of a remedy for a disease at 

 present incurable. 



Physiology. — Montyon prize (750 francs), for experi- 

 mental physiolc^y ; Philipeaux prize (900 francs), for ex- 

 perimental physiology ; Lallemand prize (1800 francs), for 

 researches relating to the nervous system ; L. La Caze 

 prize (10,000 francs), for the best work on physiology ; 

 Martin-Damourette prize (1400 francs), for a work on 

 therapeutical physiology ; Pourat prize (looo francs), for 

 new data on the utilisation and assimilation of albumenoids- 

 in food. 



Statistics. — Montyon prize (1000 francs, and two men- 

 tions of 500 francs), for the best memoir on questions re- 

 lating to statistics. 



History of Sciences. — Binoux prize (2000 francs). 



General Prises. — Arago medal, Lavoisier medal, Berthe- 

 lot medal, Henri Becquerel prize (3000 francs), Gegner 

 prize (3800 francs), Lannelongue prize (2000 francs), ■ 

 Tremont prize (iioo francs), Wilde prize (one of 4000 

 francs and two of 2000 francs), for work in the fields of 

 astronomy, physics, chemistry, mineralogy, geology, or 

 experimental mechanics ; Longchampt prize (4000 francs),- 

 Saintour prize (3000 francs), for work in the physical 

 sciences; Victor Raulin prize (1500 francs), for work in 

 mineralog}' and petrography ; Bordin prize (3000 francs), 

 for researches on determining sex in living beings ; 

 HouUevigue prize (5000 francs) ; Cam^r^ prize (4000 

 francs) ; Jerome Ponti prize (3500 francs) ; prize founded 

 by Mme. la Marquise de Laplace ; Felix Rivot prize (2500 

 francs). 



H ALLEY'S COMET. 

 A LTHOUGH our British skies were so unfavourable 

 •^^ for observations of Halley's comet, the almost 

 constant flow of published results shows that those 

 astronomers more fortunately situated in clearer atmo- 

 spheres and lower latitudes reaped a rich harvest ; some ot 

 the most striking results are briefly referred to below. 



Among ■ the favourably situated observatories, that at 

 Johannesburg, the Transvaal Government Observatory^ 

 was one. of the most favoured, and appears to have used 

 its opjx>rtuhities to the fullest possible extent. Brief notes 

 have appeared in Nature from time to time, but in 

 Circular No. 4 the results to the end of June are described 

 in full, and illustrated by some forty reproductions of 

 photographs and numerous drawings of the nucleus and 

 head on various dates. 



The photogi-aphs are described by Mr. H. E. Wood, 

 who, at the request of Mr. Innes, the director, employed 

 the lo-inch Cooke lens, of 446 inches focal length, to 

 photograph the comet on every possible occasion. This 

 instrument is the one presented to the observatory by Mr. 

 Franklin-Adams, and has two finders, one of which is 

 mounted on swivels, allowing it to be moved in two 

 directions ; this device proved exceedingly useful for getting 

 the whole of the comet on the plate when the length of 

 the tail exceeded 8°. 



On the original photographs the scale is i"' = 20 mm., 

 but in reproducing them this has been slightly reduced, 

 and varies, on the nine plates, between 19-2 and 14-2 mm. 

 per degree. 



Between April 11 and June 3 the weather conditions 

 were very favourable, except for the occasional intrusion 

 of the moon, and photographs were secured on forty-four 

 dates. Their general excellence is emphasised by two 

 unmounted, direct prints which accompany the circular, 

 thus affording a comparison between original and repro- 

 duction. Seven of the photographs were taken by Mr. 

 Mitchell, the others by Mr. and Mrs. Wood, and Mr> 

 Wood describes each in detail. 



The maximum lengths of the tail shown on the photo- 

 graphs are 17° on May 6 (60 minutes' exposure), 17° 15*^ 

 on May 14 (38 minutes), and 18° on May 30 (120 minutes), 

 but in each case the image of the tail evidently extended 

 beyond the edge of the plate. On June 3, however, 120 

 minutes' exposure failed to record more than 4° 30' of 

 tail. 



The majority of the photographs show a composite tail 



