358 



NATURE 



[January ii, 19 12 



OVR ASTRONOMICAL COLUMN. 



Obskrvatioss ok Comets 1911c, iqiie, iqii/, am> 1911^'. 

 In No. ^544 of thi- Astronomische Sachrichten Dr. 

 Henip<ira<! tli!.(uss«'s at Iriifjeh the photometric ohsfrvations 

 of HriM»ks's romct (iqiir), inndf at the Catania Obs«r\a- 

 ttiry <lurin>i the p«Tiod August 14 to Novonib«T 28, 191 1. 

 I hr greatest apparent brightness was recorded on 

 October 33, when the comet was about as bright as a 

 ;-5 magnitude star. On a chart accompanying the paper 

 III- plots the curves i = fc/r'A' and i = fe'r*A* with the curve 

 <it observed magnitudes, and this shows that the comet 

 lnoam»> brighter even than the value given by the latter 

 lormula. .\ fourth curve, on which the intensities reduced 

 111 A=i are shown, indicates that the rise of intensity near 

 P'-rihelion was very steep, the magnitude rising from 9-5 



1) October 13 to 48 at perihelion. 



As an abstract from Hemel en Dampkring (October, 

 iciii), Prof. Nijiand sends us an account of the Utrecht 

 observations of comets it)uc, 1911/, and igiifi- A draw- 

 ing of Beljawsky's comet (1911^), made on Octob<'r i, 

 M)ii, shows the head quite near to 1 Leonis, with the tail 

 • \tending nearly to ij Leonis, while an enlarged drawing 

 ■of the head shows two dense streamers flowing as a para- 

 bolic envelope from the head. 



The .Algiers observations, made by MM. Rambaud and 

 \illatte, of Borrelly's comet (1911c) are reported in No. 

 4544 of the Astronomische Nachrichten. On October 27, 

 i<»ii, the comet was observed as a round nebulosity 45' in 

 diameter, with a brilliant nucleus of magnitude 10-5. 



A HRiLLiANr .Meteor. — .\ meteor of extraordinary 

 hriiliancy was observed at South Kensington by Mr. W. 

 Mosv ,ii 5I,, loin, on December -•■, ini. .Starting from a 

 |iuiiu lu.u t rcisei, the object nin\<(l \. ry quickly, passing 

 above .Mars and .Saturn to a point = 35°, 6= + 12°. The 

 latter part of the path was distinctly wavv, and the meteor 

 was at least as bright as Mars, and left a slight trail. 



Nickel-on-Glass Reflectors. — As is well known to any- 

 one who has done any photographic work in the ultra- 

 violet, silver reflects scarcely any light in the neighbour- 

 liood of A 3i(K), therefore, for this special region, a silver- 

 n-glass mirror is practically useless as a reflector. To 

 'vercome this difliculty, primarily in his experiments on 

 the uitr.i-viMl, t photography of "the moon. Prof. R. W. 

 Wood <aiii.il Dut some trials, during his last summer 

 vacation, in which he endeavoured to replace the silver film 

 on a figured glass disc by some other metal capable of 

 reflecting light throughout the whole range of the spec- 

 trum; the production of large mirrors of speculum is too 

 diflTicult for ordinary work. 



Consulting Rubens 's tables, he found that nickel was 

 probably the most .suitable metal, and after numerous 

 •experiments he succeeded in depositing, electrolyticallv, a 

 film of nickel on a previously silvered, figured disc. The 

 method of doing this and the results obtained are described 

 in an interesting paper which Prof. Wood publishes in 

 No. 5, vol. xxxiv., of The Astrophysical Journal. To 

 illustrate the various reflecting powers of glass, silver, 

 nickel, and speculum, he photographed, through a quartz 

 lens, a mirror partly covered by Ag, partly by Ni, and partly 

 left bare, alongside a piece of polished speculum. With 

 blue and violet rays passing through the lens the order 

 <mcreasing) of reflecting power was glass, Ni, .\g, 

 speculum, but when the quartz lens was heavilv coated 

 with silver, thus allowing only the ultra-violet ravs to pass 

 through it, the silver was found to reflect as little as the 

 bare glass, and came out nearly black, while the nickel 

 surface was almost as bright as the speculum surface on 

 the resulting photograph. Incidentallv. Prof. Wood points 

 out that such ultra-violet photographv as that which ho 

 has applied to the moon may prove exceedingly useful in 

 other branches of science. For example, some white sub- 

 stances come out quite black (e.g. zinc oxide), and white 

 flowers show very different reflecting powers ; common 

 phlox comes out quite black, while white geraniums are 

 much lighter. 



Almanacs for 19 12. —From the Observatory of Madrid 



we have received a copy of the oflicial Anuario (525 pages) 



for 1012, which, in addition to the usual astronomical and 



meteorological tables, contains special articles dealing with 



NO. 2202, VOL. 88] 



the obtervations of comets, the solar eclipse of April 17, 

 the spectroheliofiraph of the Madrid Obiiervatory« and the 

 solar and meteorological observations made in 1910. From 

 the discussion of the various data, the writer of the article 

 on the .April eclipw suggests that possibly a totality of 

 three or four seconds will <x:cur in Spain and Portugal, 

 and mentions three favourable stations, viz. Cacabelos, 

 liarco de Valdeorras, and Verin. 



The Annuaire Astronomiquc for 1913, published by M. 

 Flammarion, is of the usual form, and, being published 

 later than usual (December, 191 1), contains in the annual 

 revue of astronomy some very interesting notes and com- 

 ments on recent solar, planetary, and cometary obsen'a- 

 tions. 



The " (,'ompanion to the Observatory " is too well known 

 to need any description here, and should, of course, be in 

 the observatory of every British astronomer. This year's 

 issue resembles that of other years, and may be obtained 

 from Messrs. Taylor and Francis at the price of is. 6d. 



The Pahsa-Wolf Star Charts. — The fifth series of the 

 star charts prepared by Drs. Palisa and Wolf is now ready, 

 and until .April 1 a set may be obtained for 30 marks ; 

 after that date the price will be 40 marks. 



WEATHER IN 191 1. 

 pRO.M a meteorological point of view, the year which 

 has just closed was of considerable interest. The 

 feature which stands out beyond all others is the abnormal 

 summer, during which both the temperature and sunshine 

 have established a record, whilst the rainfall was also 

 exceptional. Afrer the heat and brilliancy of the summer, 

 the exceptionally heavy rains of the late autumn and earlv 

 winter are probably of next importance, although in many 

 parts of England rain was sorely needed. 



Taking the country as a whole, the mean temperature 

 for the year was everywhere in excess of the average, and 

 in England, where the excess was greatest, the difference 

 amounted to fully 2°. The rainfall was deficient over the 

 entire kingdom, except in the south-east of England and 

 the Channel Islands, the deficiency in the English Mid- 

 lands, where the summer drought was keenly felt, amount- 

 ing to 4-20 inches, the aggregate rainfall being onlv 84 per 

 cent, of the average. The duration of bright sunshine was 

 everywhere largely in excess of the average, the excess 

 amounting to 336 hours in the south-east of England, and 

 the duration was 121 per cent, of the normal. 



The Greenwich observations, which may fairly be taken 

 to represent England, show that the mean temperature for 

 the year was 52°, which is 2° above the average. The 

 warmest month was August, with the mean temperature 

 69 , which is 6° above the average, and was the warmest 

 August since 1841. The temperature was in excess of the 

 average every day throughout the month, and on August 9 

 the sheltered thermometer registered 100°, which is the 

 highest reading as yet recorded in anv part of the British 

 Isles. ^ The mean temperature in July was 68°, which 

 IS 45° above the average, and there have only been two 

 Julys warmer in the last seventy years. The first twelve 

 days of September were also the' warmest on record. The 

 mean temperature was in excess of the average in every 

 month, with the exception of January and April. The 

 thermometer was continuously above the average for sixty 

 days from July 11 to September 13, and there were in ail 

 224 warm days during the year. The lowest temperature 

 was 22°, in February, and frost occurred on thirfrv-three 

 days. Two of the coldest days on record for .April occurred 

 on April ? and 6, and on May 22 the radiation temperature 

 fell to 25°. ■ 



The aggregate rainfall for the year was 2367 inches, 

 which is 0-46 inch less than the average. The rainfall was 

 above the normal in six months and below in six months. 

 The wettest month was December, with 399 inches, which 

 is 2- 16 inches more than the average, and in both October 

 and November the rainfall exceeded 3 inches. The total 

 for the three closing months of the year was 10-71 inches, 

 which IS 45 per cent, of the fall for" the vear. The driest 

 month was July, when the total measurement was 0-26 

 inch, and rain only fell on three davs during the month. 

 The aggregate summer rainfall, for June, Julv, and 



