94 



KNOWLEDGE 



[Apbil 1, 1898. 



lance. The other species of viper do not as a rule thrive 

 in captivity, though the cerastes seem to be doing well 

 enough, and there is usually a pufif-adder ( Bids arictanaj 

 on view ; but, as I believe they lost thirteen of these 

 last year, this is probably due to a large number being 

 generally available. At the present moment they have a 

 mamba there, and a true death-adder f^ca«(/«)/i)s ((»«<(?■(■- 

 ticusj, both elapine snakes, which I understand to be the 

 only serpents of these species ever exhibited in this 

 country. 



It may be interesting to those who are inclined to be 

 sceptical to know that the theory as to the derivation of 

 the vipers from the ophistoglyphs has been recently 

 confirmed by researches on the venom-glands of snakes. 

 To attempt to give even an outline of these conclusions 

 would, however, exceed the scope and limits of this article, 

 and it will be sufficient to refer intending students to the 

 paper of M. Phisalix on this subject. 



NOTES ON COMETS AND METEORS. 



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



CoMETARY Discoveries. — The total number of comets 

 observed sufficiently well during the last thirty years 

 (1868-1897) for their orbits to be calculated amounts to 

 one hundred and thirty-five, but of these thirty-seven were 

 returns of periodical comets which had been previously 

 seen. The average rate of apparition of new comets has, 

 therefore, been 3-27 annually, and of new and periodical 

 comets 4-r, annually. In 187.S, 1881, 1892, and 1896, 

 seven comets were discovered ; in 1872 not one was 

 observed ; and in 1875 the only two comets which 

 appeared were known ones. The best months for the 

 discovery of these objects appear to be July and August. 

 Of three hundred and twenty-eight comets discovered 

 between the years 1782 and 1897 inclusive, the following 

 are the numbers found in the various months : — 



These figures include every description of these bodies. 

 During the sixty years from 1782 to 1841 there were 

 eighty-seven comets, averaging 1-45 per year ; but during 

 the fifty-six years from 1842 to 1897 there were two 

 hundred and forty-one comets, averaging 4 -Hi) per year. 



Ponx-Winnerkc's Comet. — -This comet is now too faint 

 for observation, and is, moreover, unfavourably placed in 

 the morning twilight. Its position during the next few 

 months is indicated by Hillebrand in Ast. Ndch., 3480, as 

 follows for Berlin noon : — 



1898. 



April 8 



„ 24 



May 14 



June 3 



„ 23 



R.A. 



Declination. 



22 51 56 -11 51 



5 21 —7 32-5 



1 11 59 -3 21-2 



2 6 82 -fO 1-4 

 2 49 35 +2, 10'9 



Perrine's Comet, 189G, VII.— In Ast. Naeh., 3478, Hans 

 Osten, of Bremen, gives definitive elements for this comet. 

 It was observed from 1896, 8th December, to 1897, 1st 

 March, and was visible, therefore, for twelve weeks. He 

 finds the period 2352-5 days, or 6'441 years, with a probable 

 error of 6-8 days. This result agrees exactly, as regards 

 periodic time, with that given by Ristenpart in Ast. Xach., 



3402, based on observations in 1896, December, and 1897, 

 January. At the time of the comet's next return in 1903, 

 April-May, there is little prospect that it will be observed, 

 as it will pass through its perihelion when the earth is on 

 the other side'of the sun. In 1909, October, however, the 

 conditions will be extremely favourable. 



Fireballs of 1898, February 20ih. — On this night two 

 large meteors were seen, their times of apparition being 

 8h. 54^m. and lOh. 20m. The former was observed by 

 many persons, and some of the details were as follows : — 



Cliidilingfold, Surrey. — Brilliant meteor passed close 

 under Procyon and pursued a straight course through the 

 middle star of Orion's belt to about ten degrees beyond, 

 when it was lost sight of behind the roof of a house. The 

 colour was that of the arc electric light. Nucleus pear- 

 shaped, leaving a trail. When about midway between 

 Procyon and Orion it [blazed up, emitting sparks ; then 

 became much fainter until past Orion, when it blazed 

 again, and then again faded. The meteor seemed to be 

 moving very slowly to the west, and remained in sight 

 about three seconds, during which time it travelled throut;h 

 about fifty degrees of arc. — Rear-Admiral Ma( lear. 



Ealing, Middlese.r. — Meteor of exceptional size and 

 brilliancy appeared in due south at altitude of about 

 twenty to twenty-tive degrees, and travelled to west, at 

 first slightly ascending and then descending. Light 

 greenish, and it left behind a long, broad, livid streak. At 

 middle of flight it threw off numerous small pieces of 

 slightly redder tint. Duration of flight, four seconds. — 

 0. J. Preston. 



Freemantle, Southampton. — Splendid meteor; emitted a 

 brilliant blue light which lit up everything around. Quite 

 stationary for several seconds before it sped away due 

 south, leaving a trail of thousands of sparks behind it. 



Hiirriujati-, Yorks. — Very brilliant meteor low down in 

 south sky. Apparent motion slow, and it was observable 

 for about four seconds. It left a long trail. — J. G. C. 



Edghaston, Iiiniiiniili(im. — Brilliant meteor seen low down 

 in the south (about the height of the middle of the small 

 stars under Sirius). — W. Abthdr Smith. 



Wedtunlniri/. — Magnificent meteor, of an intense orange 

 colour, and leaving a long train of sparks ; travelled a long 

 distance from east to west, and finally disappeared appa- 

 rently just under Sirius. — T. F. Bissell. 



Clifton, Bristol. — Brilliant meteor appeared rather low 

 in the south-eastern sky, and travelled slowly in a westerly 

 direction along a nearly horizontal path. Visible for 

 several seconds, and disappeared nearly in the south. — 

 R. F. Sturge. 



WimbU'dioi. — Walking along a road facing south the 

 meteor came into view in front of me, a little to the right of 

 my course, and about two-thirds up towards the zenith. It 

 travelled quite slowly towards the west. Interior blue 

 with an outer edge of red. It appeared to me a little less 

 than half as large as the full moon. — E. J. R. Radcliffe. 



Westminster. — Meteor brighter than Venus, bluish white, 

 swift. Path, 111° -t-5" to QT-IT.—W. E. Besley. 



Xeiiburi/. — A large and brilliant luminous body travelled 

 across the heavens in a nearly straight line from east to 

 west. Visible for several seconds. It illuminated the entire 

 district. 



Chichexter.^Shot athwart the zenith, crossing the clear 

 open space directly overhead, and leaving a trail of sparks. 

 It moved with slow apparent velocity, and passed north of 

 Pleiades before itdisappearedbehindclouds. — A.Roshridge. 



Without attempting to reconcile these and other accounts 

 it seems that the meteor appeared over the English Channel, 

 and fell from a height of sixty-one to twenty-seven miles. 

 When first seen it was above a point thirty-three miles 



