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SCIENCE-GOSSIP. 



the shower ; but some American brethren near the 

 western coast did see numbers of these meteors. 

 There is a special reason this November for keeping 

 a sharp look-out. Next year the moon will be full 

 at 10. 18 a.m. on November 17th, and therefore 

 above the horizon with such brilliance as to drown 

 the light of all the smaller meteors, and so generally 

 to spoil the effect of a great display. This year, on 

 the contrary, the moon will be new just after mid- 

 night on the 14th ; therefore, given a fine night, 

 or, more correctly speaking, morning, observers 

 would have the best conditions for witnessing 

 the " shower." 



There are peculiarities which these Leonids 

 possess. Their flight is very rapid ; for their own 

 real speed has to be added to that of the earth's 

 orbitual motion, because the two paths meet each 

 other. Again, they leave a bright trail behind 

 them, visible for a long time after the meteor has 

 disappeared, and which has a slow motion of its 

 own according to the air currents moving in that 

 high portion of our atmosphere through which the 

 Leonid has passed. 



There is added interest in this meteor shower 

 when it is found that the meteorites are travelling 

 along an orbit apparently identical with that of 

 the faint Comet I. 1866, otherwise known as 

 Tempel's Comet, which Dr. Oppolzer found to 

 have a period of thirty-three years and sixty-five 

 days, and which may be expected to be recovered 

 next spring. 



The shower itself, according to the investigations 

 of Mr. B. V. Marsh, of Philadelphia, U.S.A., is 

 each year divided into three parts — a preceding, 

 central, and following shower. Thus for the 

 present year the preceding shower may be 

 expected from 9.30 p.m., November 13th, to 9.30 

 a.m. on the 14th ; the central shower from 4.15 to 

 8.45 p.m. on the 14th ; and the following shower 

 from 3 a.m. to 4.30 p.m. on the 15th. There is, 

 however, yet much uncertainty as to the exactness 

 of the times of these displays ; therefore a sharp 

 look-out should be kept ; indeed, every available 

 time from November 7th to November 20th should 

 be made use of to pick up Leonids, for during the 

 whole of this period meteors bearing the stamp of 

 this shower are apt to put in an appearance. All 

 who wish to help in observing these bodies should 

 consult Mr. W. F. Denning's valuable brochure on 

 the subject ( 1 ), reprinted from " The Observatory," 

 which gives some useful hints, with quite a fund 

 of information, on this shower, as well as on that 

 known as the Andromedes. This latter shower 

 appears to have a path identical with that of Biela's 

 Comet, and seems to radiate from a point R.A. 25 , 

 Dec. + 43 near y Andromedae. These meteors are 



(1) " The Great Meteoric Shower of November," by W. F. 

 Denning, F.R.A.S., Taylor and Francis, 8J in. x 5J, 52 pp. 

 portrait and four diagrams, is. 



slow in motion, because the earth's speed has to be 

 subtracted from their own orbitual motion. They 

 have a period of about six and a-half years, and 

 the present year is one when a maximum display 

 should be expected on November 23rd, the draw- 

 back being that the moon at that time will be 

 eleven days old. There is one striking difference 

 between these two showers. The Leonids cannot 

 be well observed until after eleven p.m., because 

 the radiant point is below the horizon until near 

 that time. On the other hand, the radiant of the 

 Andromedes is circumpolar in England and there- 

 fore always above the horizon. Observations 

 should be made on the early morning of November 

 23rd after the moon has set, and again during the 

 night and morning of the 23rd and 24th of that 

 month. These meteors usually leave in their wake 

 a train of yellowish sparks. This latter shower 

 may possibly exceed in brilliance that of the 

 Leonids, if it be at all equal to the magnificent 

 displays of 1872 and 1885. 



To make one's observations of use, the paths of 

 the meteors should be carefully determined ; both 

 the place of their appearance and disappearance 

 should be noted as nearly as possible. Some 

 observers at once mark them down on a globe or 

 map, and this is perhaps as accurate a method as 

 can be followed, and one which involves as little 

 loss of time as any. The paths of seventeen Leonids 

 laid down on a special chart are shown in the 

 illustration, for the loan of which I have to thank 

 Mr. Denning. If ordinary star maps are employed, 

 only the shorter paths can be accurately laid 

 down. The times of meteors of special brilliance 

 should be noted, as perhaps others may observe 

 them also, and then comparisons can be made and 

 the real paths of the meteors determined. If 

 possible the duration of the apparition should be 

 estimated, that their rate of motion may be 

 calculated. The comparative brightness of the 

 meteors with known objects may also be recorded, 

 as well as the colours, both of the meteorites 

 and their trains. Another point to be noted is 

 whether they burst, and, if so, if there is any 

 sound heard. Usually after a meteor bursts the 

 path is continued for a short distance, although it 

 is much less brilliant, and often the direction is 

 slightly altered. 



Altogether, given fine weather, there is real in- 

 ducement to all who have any inclination to behold 

 the superb phenomenon to prepare themselves this 

 November to be on the watch. Already the year 

 has proved itself remarkable, both from the number 

 of comets discovered and from the appearance of 

 the new planet within the orbit of Mars. Possibly 

 it may prove exceptional also for its brilliant 

 meteoric displays. Let every observer, therefore, 

 be on the alert. 



60, Lent hall Road, Dalston, N.E. 



