272 



NATURE 



[January 18, 1900 



The Bi'e/t'd meteors numbered only about ^th, and the Taurids 

 about |th, of the number of ordinary, or woM-^/V/?rf shooting- 

 stars ; and of the latter divers-centred meteors, the above seven 

 greater and ten lesser ordinary showers supplied together about 

 fths of the whole meteor number. At the rale of 

 frequency of shooting-stars on ordinary November nights, of 

 about six or seven per hour, it is evident that on such 

 nights, watches would ordinarily have to be continued for six or 

 eight hours to obtain a sufficiently copious path-register of six 

 or seven Bielid or Taurid shooting-stars, for determining their 

 radiant-points' positions with exactness ; and for the less 

 productive showers of which the six stronger and nine weaker 

 ones of the above lists furnished on an average only four and 

 two per cent, of the sundry-centred meteors, watches to record 

 the same numbers of their flights would in general have to be 

 maintained for 25 or 50 hours on successive clear November 

 nights. But as the Bielid shower betrays, no weight sufficient 

 to deter observers from attentive watches for them should be 

 attached to most of these showers' low average productivenesses, 

 because they usually appear in sudden rushes of more or less 

 abundant profusion, on no very fixed dates of apparition. Such 

 a marked example of sudden change of strength, seen actually 

 in a single night, appears to have presented itself this year in 

 the Taurid meteor-stream, during the preliminary watches 

 kept in the beginning of Nove mber for possible forerunners 

 of a coming shower of Leonids. No later vestiges at all of the 

 brief shower of seven bright t\ Taurids seen in his watch by Mr. 

 Besley between 11 h. and I3h. on November 8th, ^ were notice- 

 able here in my 2 hrs. watch after 13 h. 40 m. on that night. 

 Only one meteor's path seen here, an exactly true | Taurid, but 

 4*" distant in its direction from the point nearr; Tauri, among the 

 eighteen meteors mapped in clear sky during those two hours, 

 proceeded backwards from any focal region nearer than io°-i5° to 

 7) Taurt ; and no signs of even diffuse radiation from a consider- 

 able space round the shower's radiant-point near rj Tauri, were 

 shown among the 46 meteor-paths recorded here in my earlier 

 and later watches of 2^-3 hrs. each, on the nights of November 

 6th and loth ; so that this shower of remarkably bright meteors 

 must certainly, it appears, have been a pretty conspicuous one 

 of very brief duration. 



Nor must it be expected that the same showers will be visible 

 every year, in the same strengths, or in the same relative 

 strengths to one another. Such changeful phases of appearance 

 and non-appearance of showers in different years, were well 

 exemplified in the present shooting-star survey, by a fact of 

 great value and help to the collection, that nearly half of its 

 meteor-tracks (100 paths) were observed in a single fortnight of 

 November, 1897, under the clear sky of the Riviera Coast of 

 Italy, by my nephew, Mr. J. A. Hardcastle, who also reduced 

 his own observations and sorted them under their several 

 radiant-points. It thus happens that the radiants marked in 

 the above two lists, of main showers, and of less prominent 

 addenda, as only, or chiefly seen in 1897, were not distinguished 

 by more than one meteor, at most, among the earlier set of 

 English observations (the y Orionids, (, ri and k Perseids, a 

 Arietids, a Cetids, and ir Androniedes) ; and that on the other 

 hand the c Camelopardids, k Lyttcids and f Hydrids were 

 scarcely seen at all in November, 1897; while the remaining 

 radiant-points, 7 Andromedae, e Tauri, S Geininorum, i Aurigae, 

 e Arietis &x\d o Tauri, y Pegasi and Pises, presented them- 

 selves about equally in both the lists. 



To correspond with the, « Taurids, so plentifully visible on 

 these Bielid nights, only a branch shower, apparently, of this 

 main Taurid sXxe2,m, at 68°, + 17", was noted here, this year, 

 in the beginning of November ; and only one (doubly observed) 

 meteor then was recognised as belonging to the active co-Bielid 

 meteor-centre near i Aurigae. Similarly a well-focused flight 

 of ten Taurids among 64 ordinary meteors of the earlier 

 watch, produced among about thrice as many ordinary ro-^?'(?//a? 

 meteors, only three meteors from the same radiant -point ; 

 and these few distinctions rather than likenesses between the 

 two periods' showers, were the only examples which occurred 

 of either identity or general resemblance in the two periods' 

 stream-directions. But since they all, or nearly all, formed part 

 of a well established contemporary shower list for the middle of 

 November, frequently renewed, well sorted observations would 



_ 1 Referred to in the 'iiote on p. 271, as apparently a very important observa- 

 tion of a tmcteor-shower, from the brightness and very perfect radiation of 

 the meteors, and from the clearness and accuracy of their paths' descrip- 

 tions. 



no doubt disclose many distinct continuities of the same ordi- 

 nary showers from one meteor-period in November to the other, 

 just as the radiant-points extracted for the Bielid period from 

 a long series of years were found to agree distinctly in a 

 considerable number of cases, with those recorded in a single 

 year. 



Twenty-one Bielid shooting-stars were among the lOO 

 meteors mapped at Alassio in November, 1897 ; and in a pro- 

 jection of his observations which was then made by Mr. Hard- 

 castle on one of Prof. Lorenzoni's gnomonic polar nets, these 

 are shown in the adjoining map, diverging from near t, i; and 

 7 Androtnedae. Of the two maxima of frequency or of hourly 

 rate of appearance, shown at the foot of the map, which they seem 

 to have presented on November 23rd and 26th, the first agrees 

 closely with the date of the shower's last bright return on 

 November 24th, 1892 ; while the second seems to be a still- 

 lingering remnant of the older date of the stream's returns, on 

 November 27th, in 1872 and 1885, before the meteor-cluster's 

 node was shifted backwards 4°, as Dr. Bredichin has proved, by 



Paths of 21 Bielid Meteors observed at Alassio, Italy, No'c'e)iiher 

 lC)tli-i'jth, 1897, by J. A. Hardcastle. 



Dates, 1897, November ... 

 Duration of Watch, in clear sky 

 Numbers of Bielids mapped 

 Numbers of Bielids per hour ... 



0-5 



NO. 1577, VOL. 61] 



strong attractions of the planet Jupiter on the meteor-swarm in 

 the year 1890. No large action of Jupiter on the swarm, it has 

 been shown by the late Dr. Abelmann,' would afterwards occur 

 again until the year 1901, when another near approach of the 

 cluster to the giant planet will shift the node backwards 6°, and 

 make the date of the shower's next expected great return 

 November 17th, 1894 or 1895. On the two occasions of the 

 earth's passage through the node on November 23rd or 24th, in 

 1898 or 1899, Mr. Denning has conjectured that the earth 

 would first pass in front of and then behind the cluster, thus 

 escaping a very central passage, which might, in that case, how- 

 ever, be expected to occur, with the comet's periodic time of 

 revolution of 6| years, with near enough exactness for a great 

 display, on November 17th, 1905. But as watches for the Bielid 

 star-shower, at the present nodal passage will now no doubt 

 have been kept attentively at many stations well favoured, if 

 not very generally in the British Isles, by clear sky and fair 

 weather for observing both the Bielid shooting-stars and other 

 meteors, these recent meteor-notes may perhaps usefully suggest 



1 Astronoitiische Nachriclitcn, No. 3516, September ; and The Observ 

 aiory, October 1898. 



