January ii, 19 12] 



NATURE 



359 



August, was 3-72 inches, which iias only been smaller in 

 three previous summers since 184 1. There were during 

 the summer two periods of absolute drought — twenty-three 

 da}s from July i to 23, and seventeen days from August 

 2 to 18. Rain fell on 156 days during the year ; December 

 had twenty-three wet days and November twenty. 



In the Ebbw Vale Sir Alexander Binnie measured 

 29-23 inches of rain from October 18 to December 31, and 

 during the whole of this period there were only nine days 

 without rain. 



The duration of bright sunshine at Greenwich was 1780 

 houis, which is 425 hours in excess of the average of the 

 past thirty years, and is the brightest year on record since 

 188 r ; the next brightest year was 1906, with 1735 hours. 

 July had 335 hours' sunshine, which is the sunniest month 

 since the establishment of sunshine records in 1881. The 

 duration of sunshine was in excess of the average in each 

 month, with the exception of January and March. 



Charles Harding. 



OBSERVATION OF SOLAR HALOS IN 

 AFRICA. 



A N optical phenomenon is reported by a correspondent 

 "^ from Elobey Island, lat. 1° N., long. 9° 30' E., in 

 the Gulf of Guinea. On October 11, 191 1, between i and 

 2 p.m., he observed " a large light, of different colours as 

 the rainbow, encircling the sun, and at times only visible 



on the east side and 

 £ sometimes only on 



the west of the sun, 

 and at 2 p.m., our 

 time, disappeared 

 altogether." During 

 this time the sky 

 was covered with 

 swiftl_v passing small 

 clouds, and shortly 

 after thr- disappear- 

 ance of till' pheno- 

 menon hca\\ rains 

 began to fall. With- 

 out information as to 

 the angular diameter 

 of the ring or the 

 order of the colours 

 it is not possible to 

 say with certainty 

 whether it was a 

 halo or a corona, but 

 i(^ .ippi'iiranci' willi 

 low (loads niaki's it 

 the phenomenon was a corona. The 

 corona sometimes appears round the sun when it 

 shines through thin cloud or mist. It is coloured, red 

 b'-inii outiriiiost, and several successive sets of (dlour'd 

 rin.i4> ai > Li-,iially formed. They are due to the dilhac lion 

 which the light undergoes in parsing among drojjs of wliirli 

 the cloud is composed. 'I h'' radius of the liisi rini; of ihi- 

 corona varies from 1° to 3 ', acct)rding to tlie si/i- of the 

 drops, and radii of the others are successive multiples of 

 that of the first. .As the drops of water in the mist or 



ocr I?:" 



10 30am. 



probable tiiat 



MOON, 



rloud I 



(liiuiniii 



Six ( 



Octob. r 



diagr. 



III 



^^ 



II- lart;rr till" rinj 



(iiisiqui iiiK iinplii's 



after the observaii 



the combination 



Is ohs-TV-fl hv M 



'row --malli' 



Their 



iiii 



■\\ i;iol). \ Mand, on 

 lialo^ shown in the 

 . «.. Oivhardson at 



Kericho, in British i,; 

 probal)ly thi> two ol n 

 of about 22° and 41. 1 

 at th<- time of Ih.' o, , 

 70", and for I !iis all in 

 sun , on \\ liii h uh m 1.: 

 (oucli thi; larj^cr halo ; 



Afi 



iniiiii 111 



lialo. I 

 ui'iinc-. 

 • K . d'hi- allilndi 

 \\a^ piisuinaiih 

 h<iii/ontal I ill 1' 

 ■I- iisiialK found, 

 I'ar to lia\-r iu i, 



,iiui 2 are 

 wilh r.'idii 

 of ihi' sun 

 ahoni lis 

 hidut;h ihi- 

 would jusi 

 iiiri' on ill' 



smaller halo 

 at th>> verli<.'il 

 spiii-ri'. I 

 riiiL; No. 

 the horizon, ii 

 mentioned li\ 

 th'' rircli' was 



111. 



rint^ Udiild hi- produri'd li\ nll-c I ion 

 of iri' rr\sl:ils in ihr hi;;h'r aluio 

 lost lik-.js thai lliis is ihr ori-in of 

 IV. r, 111.- cinli- h.ad ln-i-n paiall. 1 with 

 ol);il)l.- Ihal till- f.icl wuiild ha\. li..-n 

 i-.-rv.-r. Till- \ilh.-r po-siliilil \ i^ thai 

 indar\- halo forin.-d almul ;i moi k --un 



in the same way as the 22° halo is formed about the sun 

 itself. Such secondary haloes are very rare. The position 

 of the mock sun which could produce one in the present 

 case would be at the point where the vertical through the 

 sun met the halo of 22° either at the zenith or half way 

 between the horizon and the zenith. In the former case 

 the secondary halo and the mock sun ring would coincide. 



PRIZES PROPOSED BY THE PARIS ACADEMY 

 OF SCIENCES FOR 1913. 



/'~^ EOMETRY. — The Francoeur prize (1000 francs), for 

 v^ discoveries or works useful to the progress of pure or 

 applied mathematics ; the Bordin prize (3000 francs'), for 

 improving in some important point the arithmetical theory 

 of non-quadratic forms. 



Mechanics. — A Montyon prize (700 francs), for inventing 

 or improving instruments useful in agriculture or the 

 mechanical arts or sciences ; the Poncelet prize (2000 

 francs), for a work on applied mathematics. 



Navigation. — The extraordinary prize of 6000 francs, for 

 a work increasing the efficiency of the French Navy ; the 

 Plumey prize (4000 francs), for improvements in steam 

 engines or any other invention contributing to the progress 

 of steam navigation. 



Astronomy. — The Pierre Guzman prize (100,000 francs), 

 for the discovery of a means of communicating with a 

 star other than the planet Mars ; the Lalande prize (540 

 francs), for the most interesting observation, memoir, or 

 work contributing to the progress of astronomy ; the \'alz 

 prize (460 francs), for the most interesting astronomical 

 observation made during the year ; the G. de Pontecoulant 

 prize (700 francs). 



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

 encouragement of explorers of the lesser known paits of 

 Asia ; the Gay prize (1500 francs), for a siu(l\ of ihe 

 reptiles of warm countries, especially the reptiles of .Mi-\i(0. 



Physics. — The Hubert prize (1000 francs), for ilu- hest 

 treatise or most useful discovery for the practical ai)plira- 

 tion of electricity ; the Hughes prize (2500 francs), for 

 discoveries or works contributing to the progress of physics ; 

 the Gaston Plants prize (3000 francs), for an important 

 discovery or invention in the field of electricity ; the 

 Kastner-Boursault prize (2000 francs), to the author of 

 the best work on the various applications of elicuirity in 

 the arts, industry, and commerce. 



Chemistry. — The Jecker prize (10,000 francs), for works 

 contributing to the progress of org.inic ihiniistry ; the 

 Cahours i)ri/i- (3000 francs), for interestini; n s. ai-ches in 

 chemistry ; a Montyon prize (unhealthy trad. - : ,1 prize of 

 2500 francs and a mention of 1500 francsi, for the dis- 

 covery of a nieans of ameliorating an unln alih\ Ir.ide or 

 occupation ; tb'^ Vaillant prize (4000 fr.uu s), for thr dis- 

 covery of a plioioi^raphic layer wiihoui visihl.- i^rain and 

 as sensitive ;is tin- ;4. latino-bromidi- now {[-^i-il. 



Un)crii/()i^\' in/(/ (.'.-n/.ii,' v. Th.- \ irlor R.iuiin pri/.- (1500 

 franrs), for .-issislin^ lln puhliralion of \\ori<-, n-laling to 

 14. i>log\- and paia>oniology ; the l)el<'ss(> pri/ 

 to the author, French or foreign, of a wor 

 or niineralogical science ; the Josi'ph I,;il 



franc-- 

 evidrnr.' 1 1 

 tectoi .11. -. 

 l-',,,l,,uv. 

 best work 

 .Monia^^m- 

 phyt>iolot;\ 

 Cryptogan 

 on Phanii 

 (',000 frail 



lor 



_;i.al 

 il rich 



- ram 



II- 



( 1^00 francs), 

 on L;iolo-iraI 

 prizi- (looo 

 s putting in 

 onies or pro- 



1 h. n. 



pri/.' 

 drv. 



IIII 



i-d during; 

 Sim franc- 

 ipni. Ill . and 

 )ini \ pri/ 

 L;raiid pri 



di- ( 



pri/i- (iiioo Irani- 

 ihi- \.-ar on ('r\pli 

 , tor works on ill 

 ri|il ion ol 



M, hariro, 

 I 111.- nlu-i. 



-). t< 



th.- Ivsl 

 d.- la 1 



oil Ih.- 



/.■/o.l 



fraiii -I, 



cullni I- 



Id.i/. 



for ih- 



111.- iiu 



h wi-sii-rn 

 -si work o 

 i^-M.-li 



r ihi- iv-o 

 Africa : ll 

 1 the ccllu 

 ,»-,| pri/i- 

 III.- north 

 I lii- 



-1, for the 

 iL;aiiis : the 

 an:itomy, 

 th.- lower 

 or a work 



if 



oiil riluil ill!' lo I 



,/ /. 



.f I-: 



sislai 

 pi a 



S.-ivignv pri/i- (iso" francs), 



liavi-lliiii; nal ur.ilisis, not 



( . . w ho sp.'cialh' w-<-)rI-: on 



id 's\ 1 ia ; till- ( 'uNii-r prize 



NO. 2202, vol.. 88 



