466 



NATURE 



[December 23, 1915 



presence of oxides in the form of pits and films, and 

 in almost all cases in which a test bar failed under 

 a load less than 35,000 lb, per sq. in., the failure was 

 traced to these oxides of tin and zinc. 



At the end of last year the important plumbago 

 mining industry in Ceylon was suffering very severely 

 from the loss of the German and Belgian markets and 

 from other causes connected with the war, and steps 

 were taken by the Imperial Institute to induce users 

 of plumbago in the United Kingdom to buy the whole 

 of their supplies from Ceylon instead of partly from 

 Ceylon and partly from foreign countries as pre- 

 viously. Recent statistics indicate that progress has 

 already been made in this direction, for it is signifi- 

 cant that the percentage of Ceylon plumbago exported 

 to the United Kingdom during the first ten months 

 of the present year is considerably greater than in 

 1913. Moreover, the total exports to this country 

 from January to October this year are more than 

 double those of the corresponding months in 19 14, 

 and, in addition, Russia is a large new purchaser. 

 The most important use of plumbago is in the manu- 

 facture of steel works crucibles, which are required 

 to resist the effects of great variations of temperature ; 

 and it is gratifying to know that a source within the 

 British Empire is available to supply the demands of 

 our munitions works for these articles. 



The Cambridge University Press will publish very 

 shortly a supplementary volume of Scientific Papers by 

 Sir George Darwin. It will be edited by F. J. M. 

 Stratton and J. Jackson, and contain lectures on Hill's 

 lunar theory, a paper on periodic orbits, the inaugural 

 lecture delivered in 1883 on the author's election to 

 the Plumian professorship at Cambridge, and an 

 address to the International Congress of Mathe- 

 maticians in 1912. In addition, the volume will in- 

 clude memoirs of Sir George Darwin by, respectively, 

 Sir Francis Darwin, on his life apart from his scien- 

 tific work, and Prof. E. W. Brown on Dacwin as 

 astronomer, mathematician, and teacher. 



OVR ASTRONOMICAL COLUMN. 



o Ceti. — The maximum of this star is not "due" 

 until January 8, 1916, but strict regularity is not a 

 feature of its light curve, and it has already reached 

 3-0 magnitude (December 16), being only slightly less 

 than a Ceti (2-7 mag.), and is thus a full magnitude 

 brighter than at the last maximum. The present 

 apparition strongly recalls that of December, 1906. 



Comet 19156 (Taylor). — Since this comet was ob- 

 served at Washington many observers have managed 

 to find it. An observation made with the lo-in. re- 

 fractor at the Hill Observatory on Thursday, December 

 16, i3h., gave the following approximate position, 

 R.A. 5h. i6-7m., declination +2° 13', whence it appears 

 that the daily movement is accelerating. As the comet 

 is evidently approaching, increasing in brightness 

 and very favourably placed for observation, it may be 

 expected to become a fairly conspicuous object. 



From observations made on December 6, at Wash- 

 ington, and on December 9 and 12 at Copenhagen, 

 Messrs. Braae and Fischer-Petersen have calculated 

 the following orbit and ephemeris : — 



NO. 2408, VOL. 96] 



The comet's distance from the sun diminishes from 

 172 to 160 million miles between December 13 and 

 January 2, and it comes about ten million miles nearer 

 the earth in the same time. On December 12 it is 

 stated to have been of about the eleventh magnitude. 



Geminid Meteor Shower. — Mr. Denning sends the 

 following notes of observations of this shower : — Mrs. 

 Fiammetta Wilson, observing from Wokingham, on 

 December 11, 6h. 30m., to midnight, saw thirty-seven 

 meteors, of which nearly one-half were Geminids, from 

 a radiant at 109^ + 32°. On December 11 thirty-two 

 meteors were seen before midnight, and a very distinct 

 radiant was found at 117° + 31°. 



Miss A. G. Cook observed the shower from Stow- 

 market on December 11 until interrupted by clouds 

 at 10.30. The radiant was at 109° 4- 33°. 



Mr. T. Hargreaves, at Eton, watched for meteors on 

 the evenings of December 11, 12, and 13, and morning 

 of 14, and recorded forty , of which about eight, seen 

 from i2h. 28m. to i3h. i6m. on December 13, were 

 Geminids with a radiant at 111° 4- 30°. 



Mr. Denning, at Bristol, looked out on December 12, 

 i5h. 30m. to i8h., and in about if hours of that 

 interval saw twenty-five meteors, 18 per cent, of which 

 were from a double radiant at 110° 4- 33° and 118° 4- 32°. 

 Clouds prevented observation on December 13 and 14, 

 but on December 15, i5h. 40m. to i6h. lom., thirteen 

 meteors were counted. Not a single Geminid was 

 seen ; the shower appeared to be over. 



On December 15, 8h. 23m., a fireball was seen from 

 Bristol falling low in due north, path about 207° 4- 53° 

 to 2 10° 4- 47°. It must have been a splendid object 

 from the north of England and south of Scotland. 



Judging from the results of the foregoing and some 

 other observations, it seems certain that the display 

 was not above the normal character. Moonlight, how- 

 ever, partially interfered, and several cloudy nights at 

 the most important period prevented efforts to corro- 

 borate the easterly motion of the radiant. 



Notes on Variable Stars. — A sudden maximum of 

 UV Persei was observed by E. Hartwig (Astronomische 

 Nachrichten, 4815) on September 2, the star reaching 

 II mag., although less than 13-14 mag. on August 28. 

 On September 4 it was again invisible. This fleeting 

 illumination was also observed by Prof. A. A. Nijland 

 (Astronomische Nachrichten, 4818), who reports that 

 the star could not be found on August 31. On Sep- 

 tember 3 it was as bright as the comparison star, but 

 the following night had vanished. The previous maxi- 

 mum occurred on June 19, 1914 — i.e. 434 days earlier. 



Some interest attaches to a new variable star, 4, 19 15 

 Ononis (1900, 4h. 58m. 46s., —4° 20-8'), discovered by 

 Mr. J. Voute, who, seizing a fortuitous opportunity, 

 observed it passing through an extraordinary fluctua- 

 tion of light last September (Astronomische Nachrich- 

 ten, 4821). Estimated magnitudes were: — 



[915 Sept. 12 8-5 mag. 

 Sept. 23 6-4 mag. 



Sept. 28 7-12 mag. 

 Oct. 4 8-3 mag. 



The variability of RU Cassiopeiae and the neigh- 

 bouring star, P.D. 695, was not supported by 

 photographic measures recently published by Dr. 



