262 



KNOWLEDGE. 



[NoVEMliliR, 1001. 



decidedly preferable. If you care to send to the other houses 

 you name for their catalogues, I shall be pleased to give you 

 further advice should you rei|uire it, but you will be quite safe 

 with the Swift instrument. 



,1. G. — The best and most comprehensive treatise you can 

 have on the microscope and its general application?, including 

 botanical matters, is the new edition of " Carpenter on the 

 Microscope," edited by Dr. Dalliuger, published by Churchill. 

 If you require merely instructions in |ireparing botanical 

 specimens, you will get this from " Modern !^Iioroscopy,'' 

 published by Balliere, Tindall it Cos. 



E. J. llant.— l have carefully examined the powder you have 

 sent, but could find very few spicules. Sponge tissue, Xanthidia 

 and organic remains generally, are constantly to be found in 

 flint structure. It cannot be regarded as anything exceptional. 

 With regard to the study of Mycetozoa, there is a small work 

 by Sir Edward Fry and Miss Agnes Fry entitled " Mycetozoa, 

 and some Questions which they Suggest," which you might find 

 useful. It is a reprint of articles which appeared in Knoavleijoe. 

 You will also find the subject treated in a very interesting 

 manner in the new edition of " The Microscope and its 

 Revelations " (Carpenter), edited by Dr. Dalliuger ; in fact, 

 information on nearly every subject of microsco]>ical study is 

 given in a practical manner in this book. 



Communicai/ons and eiiquirien on Microscopical mailers are 

 cordially invited, and should be addressed to M. I. Cross, 

 Knowledge Office, 326, High Holborn, W.C. 



NOTES ON COMETS AND METEORS. 



By W. F. Denning, f.r.a.s. 



Tub G-eeat Comet of 1901. — Elements have been published in 

 Ast. Nach., 3734 and 3739, by H. Thiele, of Bamberg, and C. J. 

 Merfielil, of Sydney. The figures are nearly identical as follows:^ 



T. 



log. q 



Thiele. 



1901, April 24"288i5, 



Mean Time, Berlin. 



o / II 



203 2 1.51 



109 38 .531 



131 4 49-3 



9-38827 



Merfield. 



1901, April i4-2536, 



Mean Time, Green.wich. 



o I II 



203 2 14-8 



109 38 37-5 



131 5 40 



9-388907 



There is a possibility that the comet may be seen during the )ireseut 

 autumn in some of the large telescopes now available to deal witli 

 siu'h faint distant objects. At the beginning of November, 1901, the 

 comet will be nearly stationary in tlie S.E. region of Cancer, and at a 

 distance of about 300 millions of miles from the earth. 



Encke's Comet is now mvisiblc to observers in the noi-thern hemi- 

 sphere, and, no other known comet being in view, there is really very 

 little to observe inthis department. Witli the eicejition of the fine 

 objeet visible in the southern skies in the sjn'ing months, there have 

 been no discoveries effected during tlie present yrar, and this is 

 rather remarkable when we relleet that tlie number of comets i.s 

 very considerable, and that several able observers are engaged in the 

 systematic search for these bodies. Profs. Barnai-d and Swift (the latter 

 a veteran of 81 years) have, we believe, relinipiished comet seeking, 

 but Brooks, Giacobini, Perrine, and others are actively prosecuting 

 the quest, and we may probably, in the ordinary course of events, 

 expect to hear of a discovery very shortly. 



Fireball of September 14, 8n. 44m. — This was an unusuallv 

 brilliant object, and its descent was witnessed over a large area. 

 The sky was clear and moonless, the hour convenient, and the slow 

 motion and dazzling lustre of the fireball attracted many suqirised 

 spectators to watch and record the apparition. In South Wales, 

 and particularly in Pembrokeshire, the object presented a verv 

 striking display, and it is described as suddenly lighting up the sky 

 and landscape with startling vividness. At Llandatf the meteor was 

 estimated to be as bright as the full moon, while at Buabon it was 

 thought to equal the lialf moon. Even as far distant as Chiddingfold, 

 Surrey, Admiral Maclear descrihed it as intensely bright, while Mr. 

 T. H. Astbury, at WallingFord, Berks, says it appeared much brighter 

 than Venus. The meteor parsed over the Bristol Channel, lieginning 

 its luminous career when over a point a few miles off Lyntiin and 

 llfracombe, and travelling to north-west it crossed Pembrokeshire, 

 finally disappearing near St. David's Head. It fell from 66 to 26 

 miles in height along a visihle course extending over 83 miles, which 

 it traversed with a velocity of Mbout 20 miles per second. But the 

 various estimates of the duration of llight are, as usual in such cases, 



very inconsistent. Two of the observers give 2 seconds, while one 

 gives 30 seconds, and another 1 minute ! In deriving the velocity it 

 has therefore been found expedient to adopt the mean of a few of 

 what are obviously the best determinations, and these indicate 

 4 seconds as approximately the duration. A hissing or whirring 

 sound is stated in two cases (St. Clears and Llanwrda) to have 

 accompaided the meteor as it penetrated the atmo»plurr, while 

 at Little Haven, situated near the termiual point of the llight, Mr. 

 J. Phillips rr])oi-ts a distinctly audible booming sound, which came 

 about three uuTiutes after the nucleus had disappeared. Mr. J. Haltou, 

 of Manchester, says the mu-leus seemed to plough its way through 

 the atmosphere as though strongly resisted. Mr. Hilditcb, of New- 

 port (Mon.), remarks that the object was so luminous and apparently so 

 near that he thought it must have fallen to the earth within a few miles 

 to the north-west of Newport. As a matter of fact, however, the 

 meteor was more than 100 nules distant from this town at the time of its 

 disappearance. Had the object been enabled to withstand disruption 

 during a further interval of about three seconds in which it might 

 have traversed the 56 miles separating it from that point of the earth's 

 surface njjon which it was directed, it would have fallen in the St. 

 G-eorge's Channel, a few miles off Wexford, on the south-east coast of 

 Ireland. 



The meteor left a bright train in its wake, but it quickly died away 

 Several of tlie observers were at first impressed with the rocket-like 

 appearance of the object and thought it a brilliant firework, but soon 

 after realised the celestial character of the startling visitor. 



The radiant point of the meteor was at 34.5° -f 1° near /? Piscium , 

 and situated between the constellations of Pegasus and Aquarius. 

 There was a brilliant fireball on 1875, September 14, from a rathaut 

 at 348^ ± 0°, and it appears to have unmistakably belonged to the 

 same system as that which supplied the similar object seen on 

 September 14th last. The shower is a notable one, for its visible 

 activity is prolonged throughout the months of August and September, 

 and it occasionally furnishes fireballs of the largest class. 



THE FACE OF THE SKY FOR NOVEMBER. 



By A. FOVS'LER, F.R.A.S. 



The Sun. — On the 1st the sun rises at (i.-lti, and sets 

 at 4.32 ; on the 30th lie rises at 7.4.5, and sets at 3. .53. 

 There will be an annular eclipse on the lOth-llth, 

 which, however, is invisible at iTreenwich ; the central 

 line passes from the Mediterranean aci'oss Arabia, Ceylon, 

 and Siaiii. 



The Moon. — The moon will enter last quarter on the 

 3rd at 7.24 a.m., will be new on the 11th at 7.34 a.m., 

 will enter first quarter on the IPtli at 8.23 a.m., and will 

 be full on the 2()th at 1.18 a.m. Some of the occultations 

 visible at Greenwich are as follows : — 



The Planets. — Mercury is in inferior conjunction with 

 the sun on the 4th, and will afterwanls be a morning star, 

 at greatest westerly elongation of 19° 42' on the 2lst. 

 The times of his rising from the 16th to the 24th, com- 

 pared with that of the sun, are as follow: — 



