Apkil, 1903.] 



KNOWLEDGE 



93 



The future of microscopy is not dependent on the amateur 

 who only examines ready-pnpared micro slides, but on him who 

 practises known methods and endeavours of his own initiative 

 to find better ones. To such this journal in particular appeals. 



NOTES AND QUERIES. 

 J. H. (rar/iar. — l have not heard of an English edition of 

 Lilljeborg's " Cladocera succiae," and it seems unlikely that 

 such a work will ever be issued. I may mention, however, that 

 at the meeting of the (Juekett Microsco]iical Club on January 

 16th, Mr. Scourfield brought forward the first part of a synopsis 

 of the British species of fresh-water Entomostraca, in which he 

 dealt with the Cladocera, taking Lilljeborg's book as the work 

 of reference, both for descriptions and figures of the large 

 majority of our species. It seems probable, therefore, that the 

 " Cladocera succiae " will become an indispensable book for 

 British students of these interesting animals, and I certainly 

 have no hesitation in recommending it in spite of its being 

 written in Latin and German, and being somewhat expensive. 

 After all, we in this country ought to be thankful that the 

 veteran Upsala professor did not write his great work in 

 Swedish. 



A. W. Cumber (Iiiilia). — It is impossible to advise you as to a 

 course of study which you could pursue on jiarallel lines with 

 your professional work without knowing the direction in which 

 your tastes and inclinations lie. You would find metallurgical 

 work, that is. the study of the composition and surface of 

 metals, exceedingly interesting, and probably the best book on 

 the subject is Hiorn's, entitled '• Metallography." Or perhaps 

 geological and petrological work would prove suitable. You 

 would find a very large and entertaining field in either 

 department. 



Ro<ier. — The fractions of an inch by which objectives are 

 designated express approximately the magnifying power or 

 equivalent focus, and not the distance at which they focus from 

 the object. The equivalent focus of an objective divided into 

 10 gives its magnifying power, thus a 2 inch should magnify .5, 

 a ^ inch 40, ^nd ^ inch, 80 diameters. The troubles you refer 

 to in connecting with your mounting are such as all tyros have 

 to face, practice alone will make you expert. If you cannot 

 obtain guidance from the books you refer to, it would be 

 impossible to give it in a short answer. The assistance of a 

 microscopical friend would probably clear the way. 



J. G. Leii/h. — Probably the book that would suit you would 

 be Wood's " Common Objects of the Microscope," costing Is. ; 

 or Cooke's " One Thousand Objects for the Microscope," i)rice 

 2s. 6d. 



Communications and enquiries on Microscopical matters are 

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

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



NOTES ON COMETS AND METEORS. 



By W. F. Dennino, f.b.a.s. 



Pkrhink's Comet (1902 b). — This object has now passed beyond 



the range of ordinary instrumonts, though it may possibly bo still 



visible in some of the largest telescopes. Mr. F. H. Seiires, of the 



Law's Observatoi'v, Mis80iu"i, has computed the following elements : — 



PP. 1902, November 23-90094, Berlin M.T. 



o) l,?-l i 34-4 

 a 49 20 110 

 i 156 20 5G-1 

 log. q. 9 612596 

 log. e. 9 ■999709. 

 The form of orbit shows a scai-cely perceptible deviation from that 

 of a parabola 



GiACOBiNi's Comet (1902 i>). — This distant and apparently very 

 small comet continues vifible in a good telescope, but its light is 

 gradually declining, and it will soon withdraw from view. At the 

 close of April it will pass near the bright star Castor (a Geminorum), 

 but the comet will be rather a dillicidt object at about this period 

 in telescopes of moderate size, and will have to be swept for very 

 carefully. 



GiACOBiyi's Comet (1903 a). — This comet is considerably brighter 

 than when first discovered on January 15, but its position is too near 

 to the sun for it to be well seen. 



Meteoric phenomena have recently been reported as follows : — 



February 2, 4 a.m. — A large detonating meteor burst over a point 

 about 2 miles south of Anderson, California, and is described in the 

 Daily Telegraph. The roar which accompanied the passage of the 

 fireball startled the townspeople, who ran into the street for safety, 

 thinking that the vibrations were due to an earthquake. Some of 

 the buildings were damaged. 



February 2, 6h. 20m. p.m. — Commander Neate, R.X. , writes from 

 Dover that he observed a meteor brighter than Venus moving from 

 near the Polar Star to J Crsa Majoris. The apparition suggested to 

 his mind "a brilliant jewel at the end of a long chain." Duration 

 l{r seconds. 



February 4, 7h. 7m. a.m. — Large and brilliant meteor seen in the 

 west from Yalding, Kent, by Mr. W. .larvis. 



February 12, 6h. .54m. p.m. — Meteor equal in lustre to Jupiter, 

 seen at Liverpool and moving horizontally at an altitude of about 

 30 degrees in a northerly direction. Alpha Cygni was just below 

 and midway in its course, which occupied about 5 seconds. 



Recently in Cape Colony (date not given), " at 10 p.m. a sudden 

 rumbling and hissing noise was heard, and a tremendous ball of fire 

 was seen falling towards the earth, its velocity being so great that it 

 gave the appearance of a burning gash in the sky. As it reached the 

 ground several explosions took place, and next day a large black stone 

 was extracted from a hole 2 feet deep and 2 feet wide, which the body 

 had made." 



February 17, 9h. 45m. — Brilliant meteor, giving as much light as 

 the moon in her first quarter, seen at Beckley, Sussex, by Mr. R. 

 Forbes Bentley, but trees hid the latter part of the flight. Observed 

 path from 172J° + 20° to 195° + 15°. Duration about 2 seconds. 



February 22. — At Ramsay, Isle of Man. there was a very severe 

 gale during wlueh a huge fiery meteor passed over the town lighting 

 up everything like day. 



February 26, 7h. 45m — A large white meteor observed at Hammer- 

 smith, W., by Mr. E. Delessert. Its course carried it overhead in a 

 direction from S.E. to N.W., and its approximate flight of 100 

 degrees occupied 3 to 4 seconds. 



Apkil Lteids. — This shower should be carefully looked for on 

 April 21 and 22, though it seldom furnishes a rich display. This 

 year there will he very little interference from moonlight, so that 

 with clear skies the meteors ought to be favourably observed. Their 

 radiant pomt, like that of the July-August Perseids, exhibits motion 

 to the eastwards, and as it is essential to obtain more evidence on this 

 point, any earlier and later members of the stream (appearmg on 

 April 17-19 and 23-25 respectively), should they be presented, will 

 deserve special notice, and their apparent paths aTnongst the stars 

 if registered with the gi'eatest possible accuracy will be very valuable. 



Mat Aqparids. — At the end of April and opening of May it will 

 be necessary to watch the eastern quarter of the firmament for the 

 long-pathed, streak-leaving Aquarids first seen by Lieut.-Colonel 

 Tupman in 1870. The radiant point of this shower has never been 

 fully ascertained, and it is hoped that a large amount of new data 

 will be obtained during the ensuing few years. 



THE FACE OF THE SKY FOR APRIL. 



By W. Shackleton, f.r a.s. 



The Sun. — On the 1st the sun rises at 5.41 and sets at 

 ti.2il ; on the 3Uth he rises at 4.39 and sets at 7.17. 



The equation of time is negligible on the I6th, this day 

 therefore is favourable for the checking or adjustment of 

 sun-dials l>y comparison with civil time, since only the 

 correction for longitude need be taken into account. Sun- 

 spots are now oi more freijuent occurrence, and of late two 

 or more spots have been visible at one time. 



The moon is in perigee on the 5th, and in apogee on 

 the 19tli. 



