Aug. 8, 1872J 



NATURE 



295 



Crovn, R.A. 237', N.P.D. 55°. The same khower has also been 

 recognised by Robert P. Greg, F.R.S., of Manchester, England. 

 This meteor-stream, it is now proposed to show, is prcbab!y de- 

 rived from one much more conspicuous in ancient times. 



In Quetelet's " Physique du Globe," pp. 290-297, we find me- 

 teoric displays of the following dales. In each esse the corre- 

 sponding day for 1S70 is a'so given,* in oider to exhibit the close 

 agreement of the epochs. 



I. A.D. 401, April 9 ; corresponding to April 29, for 1S70 



2- „ 538 „ 6 ,, ,, 25 ,, 



3- » f*39 ,,17 „ May I 



4- „ 9-7 „ 17 ,, April 30 



5- ,. 934 „ 18 „ May i 



6. „ IC09 ., 16 „ April 28 ,, 



The epochs cf 927 and 934'suggest'as probable the short period 

 of seven )ears. It is found accordingly iliat the entire interval cf 

 OoS years — fiom 401 to 1009 — is equal to S9 mean periods cf 

 6'83I5 yiars each. With this approximate value the six dates 

 are all represented as follows : — 



From AD. 401 to A.D. 53S we have 20 periods of 6S5 years 



.. 538 „ 839 ,, 44 ,, 6-84 „ 



839 ,, 927 ,, 13 ,, 677 ,, 



.. 927 „ 934 ., 1 „ TOO „ 



.. 934 >, 1009 „ 11 „ 6-82 „ 



This period corresponds closely to those of several comets 

 whose aphelion distances arc somewhat greater than the mean 

 distance of Jupiter. So long as the cluster occupied but a small 

 arc of the orbit, the displays would evidently be separ.-ited by 

 consider.ible intervals. The t%\o conscrii/k'^ showers in the tcntli 

 centuiy indicate, however, an extensive diffusion of the cluster at 

 that epoch ; so that the preceding part passed the node April 30, 

 927, and the following part, May i, 934; the interval being 

 somewhat more than one complete period. The comparative 

 paucity of meteors in modern times may be partially explained 

 by the fact that the ring has been subject to frequent perturba- 

 tions by Jupiter. 



It is not impossible that this meteor-stream was connected in 

 its origin with the comet which passed its perihelion on April 

 29, B.C. 136. Daniel KiRKvifooD 



SOCTETIES AND ACADEMIES 



London 

 Geologists' Association.- -The excursion to Ludlow and 

 the Longmjnds on July 22 and fi\e following days, the con- 

 cluding and most important field meetirg of the season, was 

 under the direction of Prof. Morris, F.G.S., Mr. R. Lightbody, 

 F.G.S., and the Rev. J. D. La Touche, B.A. After the 

 members had assembled in Ludlow Castle the Upper Ludlow 

 rocks on the right lank of the Teme were examined, and Mr. 

 Lightbody gave his reasons for considering the Aymestry Lime- 

 stone to be represented at a point near the old bridge, although 

 Pciitaincrus Knightii is not found here. The Upper Ludlow con- 

 tains Choiii'tes lata in great abundance, and scarcely a fragment of 

 the rock was picked up without this species being seen on the 

 surface. From the high ground by the river side the valley of 

 the Teme'may be advantrgeously seen. The river here flows 

 through a gorge in the Upper Ludlow rocks, with the castle and 

 town of Ludlow picturesquely situated on the left bank ; while 

 the "Old Red' country extends beyond to the Clee Hills, the 

 igneous summits of which conimandingly rise to the ca^t, sur- 

 rounded by the coal measures. The well-known section in Ludford 

 Lane, showing the "bone-bed," \Aas next visited. This bone- 

 bed, or "gingerbread," as it is sometimes called from its ap- 

 pearance, is in places not more than a quarter of an inch thick, 

 and is found only after careful search. The fragments of the 

 remains of fish, of whrch it is partly made up, were until com- 

 paratively recently the oldest fish remains known. The follow- 

 ing day (Tuesday) was devoted to an examination of sections of 

 the Aymestry Lrmestone, Lower Ludlow, and Wenlock rocks, 

 occurring in the course of a route of about twenty miles. The 

 journey was performed by means of carriages, but abundant occu- 

 pation was given for the hammers of the party at the various 

 exposures of the richly fossiliferous rocks above named. Grapto- 

 Irtes from the Lower Ludlow were obtainid in abundance, and 

 fine specimens of Pliacops lougkmidatiis were found in the Wen- 

 lock, exposed in the bed of the Teme, near Burrington ; while 

 " MaVing proper allowance for rlic precession of the equinoxts. 



rcitlamcnis Kniglitii was seen in great profusion in the Aymestry 

 Limestone of Ruacktree. Near Comus Wood (so called from 

 being the scene of Milton's "Comus") a very extensive view is 

 obtained of the "Old Red" district of Herefordshire, with the 

 Malverns distinctly seen in the distance. In the evening the 

 members were entertained at a soiree given by H. Salvvay, Esq., 

 of "The Cliff," Ludlow. During Wednesday the Upper Lud- 

 low rocks in the valley cf the Tenie were subjected to further 

 examination, and the party proceeded as far as Downton, where 

 the uppermost members of the series are seen at the Tin Mills 

 section. At one point on the rotd to Downton the physiography 

 of the district to the north of Ludlow is well seen, and here Prof. 

 Morris pointed out the principal features of the extensive land- 

 scape, and showed how entirely due they were to their geologi- 

 cal structure, and that tl e coal measures of the Clee Hills had 

 been preserved by the old volcanic outbursts which had formed 

 the central masses of hard " Dhu-stone " composing the sum- 

 mils and caves of these lofty hills. On Thirrsday the party as- 

 cended the Longmynds at their southern extremity, where 

 masses of quaitzose conglomerate of Cambrian age protrude 

 from the surface. The Rev. I Mr. La Touche described the 

 topography and the geology of the district seen from the 

 elevated ground on which his hearers were assembled, and, 

 subsequently, Dr. Hicks explained the order of the suc- 

 cession of the Cambrian and Lower Silurian rocks of St. 

 David's, which he had been re-e.xamining during the previous 

 fortnight, and which he considers to have representatives in some 

 of the beds of the Longmynds. The Llandovery conglomerates 

 lying on the uplifted beds of the Cambrians at an angle of 22" 

 were found to be exposed on the eastern slope of the hil), and tie 

 " Pentamerus limestone," wilh its characteristic Pciitamcnis 

 oMoiigiis, was also seen. The party then proceeded to the 

 quarries of Caradoc sandstone in the Onney valley, at one of 

 which Prof. Morris gave a general description of the Silurian 

 system and the extension in England of its various members. 

 Friday was occupied by a journey in carriages to the mining dis- 

 trict of .Shelve, and by an inspection of the very interesting hill- 

 country between that place and Church Stretton. Quarries in 

 the Cambrian rocks at the- south end of the Longmynds and in 

 Llandovery beds near Norbury occasioned stoppages, and after- 

 wards a visit was paid to Lirdey Hall, the residence of Mr. 

 Jasper Mare, who courteously invited the party to inspect his 

 fine model of the South Shropshire mining districts, the famous 

 pig of lead of Roman age, with the name of ihe Emperor 

 Hadrian upon it, found near .Shelve, and specimens of 

 the mineral products of the locality of extraordinary size 

 and beauty. The members were then entertained at lun- 

 cheon, after which they left Lirrley Hall and traversed a 

 long, narrow, and very beautiful valley in the park, and ter- 

 nrinating at the Stiper Stones. At a little distance from 

 the park enclosure a mass of felspathic ash in Lower Llandeilo 

 rocks is quarried for road metal, and the Llanderlo beds Ihui 

 laid bare were eagerly and rrrost successfully searched for fossils. 

 After a brief visit to the White Grit Mine, the carriages were 

 finally left, and the party commenced the ascent of the Stiper 

 Stone ridge, from the summit of which is seen a fine panorama 

 of the Welsh mountains, with the old volcanic Conidon in the 

 foreground, and Cadir Idris and Plynlirnmon in the extreme 

 distance. The exir-aordinary masses of obtruding hard white 

 quartzile rocks called Ihe Stiper Stones were objects of great 

 interest to the party, some of the members of which were not 

 satisfied with the evidence of their being the equivalents of the 

 Lirgula fi.-rgs. The Longmynds ridge, extending for nearly 

 fifteen miles, bounds the view to the east, and this range h=d 

 now to be crossed. The intervening valley affords sever'al sectiors, 

 at one of which was seen what was considered by Murchison to 

 lie the junction of the Srlurians with the Cambruans. Near the 

 summit of the Longmynds a very fine exposure of Cambran con- 

 glomerates occurs ; and further along the edges of the vertical 

 green and purple shales and s'ates are seen beneath the feet ss 

 the mountain road is traversed. On the eastern side of the range 

 the rocks are well exposed, and the indenting gorges numerous 

 and pictoresqrre. Caer Car-adoc stands boldly out at a little 

 dis'ance to the north-east, w.th the Wenlock and Aymestry lime 

 stone rrdges beyond, and bounding a valley of great beauty ai d 

 exierrt, terminated northwards by the volcano like cone of the 

 Wrekin, nl the foot of which the .Severn flows through a deep 

 gorge. The morning of Ihe concluding day, Saturday, was giviri 

 to an examination of the Upper Ludlow rocks, Ihe "Bone-bed," 

 and the Downton ssndstone in the neisilibourhrod of Morto r 



