Mar.ii 1, 1901.] 



KNOWLEDGE. 



G3 



jiilo, ;iU wo are tokl of the south pole is that it is iu a 

 certain phiee. and I ilesire an answer to tlie question. Does 

 it remain tliere? A\'.m. S.\npem.\n. 



1-lth January, llH'l. 



[It is rather extraordinary that Mr. Saudenian, after 

 havintr studied tliis sidijeet for so many years, and writing 

 so loutidently upon it, should nevor have applied so simple 

 a test to his theory himself. It is still more extraordinary 

 that he should assume that astronomers who have been 

 oliserviusr aevuratily the places of the southern stars for a 

 eeutury and a half have not yet ascertained whether they 

 showed the effects of prei'essiou or not. However.the answer 

 is simple; the south pole of the heavens moves in exact 

 accordance with the north pole. A pair of stars taken 

 from the nei-jhbourhood of each pole will show this 

 clearly. Nos. ti and 16'.M of Bradley's Cataloi>ne are iu 

 II. A. oh. and 12h., and are distant from the north polo I'S" 

 and 12° respectively. /3 Hydri and y Musca> have similar 

 K.A "s, and are- distant from the south pole 12" and 18° 

 respectively. Now if we compare Lacaille's Catalogue for 

 17o0 with "the Cape Catalogue for 1890; and Bradley's 

 Catalogue reduced to 1 750, with the Eadcliffe Catalogue 

 for 1890, we get the following apjjarent changes in the 

 places of the stars due to the actual motion of the jjoles. 



K.A. 1750. K.A. 1S90. Dili. S.P.D. 17.W. S.P.D. 1800. Diff. 



h. la. 8. h. 111. s. in. s. o • " o ' " / " 



S HrJri II l'.; 120 il 19 KX +7 «■.". 11 20 12 12 7 :U +47 22 



y MusciE 12 17 *)-6 12 25 54-2 +7 59(i 1!) 15 7 18 28 29 —46 38 



E.A. 1750. R.A. 1S90 Difl. N.P.D. 1750 N.P.D. 1S90. Dill. 



h. m. s. b. lu, s. m. s. o . /< o / »< / ,/ 



Briiaie.v6 2 31-3 9 S9-(J +7 2S-3 14 2fi 23 13 .'59 38 —46 45 



Bradley 1634 12 67 12 7 22 +6 55S 10 .i9 37 1148 21 +46 46 



The figures show that the north pole has moved in the 

 14it years about 47' downward tow-ards Bradley 6, whilst 

 the south pole has moved away from |3 Hydri on the 

 same meridian, almost exactly the same distance. — The 

 Reviewer.] 



SUNSET PHENOMENON. 



TO THE EDITORS OF KNOWLEDGE. 



SiR.s, — Before the raihs started here at the beginning of 

 summer a strange phenomenon was occasionally observed 

 at sunset. From a point in the east, exactly opposite 

 where the sun was disappearing below the horizon, rays of 

 light streamed out, extending a considerable distance. It 

 looked just as though the sun had gone down in the wrong 

 place, and when there were rays from both east and 

 west the effect was very striking. Can you give me an 

 explanation in one of the numbers of the paper ? 



P.O. Box 66, R. L. McDonald. 



Bulawavo, Rhodesia, 



fOth January, 1901. 



[The phenomenon is essentially of the same character 

 as the familiar one which children call "the sun drinking," 

 when, in somewhat hazy weather, the shadows of clouds 

 stand out in the moisture-laden air. So, under certain 

 circumstances, about a quarter of an hour after the sun 

 has gone down, we may occasionally see similar shadows 

 apparently radiating from the Sun's place. These are 

 likewi.se the shadows of clouds thrown upon the air full of 

 moisture or of dust. The beams are in reality parallel 

 straight lines, but from the effect of perspective they 

 seem to radiate from the sun's place, and to converge 

 again to a point directly op|iosite to it. It is, however, 

 rare for them to be traced entirely across the sky, and as 

 the air overhead is necessarily freer from the minute 

 particles which make the beam-! evident, they can very 

 seldom be traced across the zenith, even when they are 

 seen near their converging point in the east. — E. Waltkr 

 Maunder.] 



Astronomical. — At the annual meeting of the lioyal 

 Astronomical .^ociety (ui February 8tli, the Gold Medal of 

 the Society was awarded to I'l-oC. K. 0. Pickering, the well- 

 known able and energetic Director of the Observatory of 

 Harvard (.'ollege. In the course of a letter ex[)ressing his 

 appreciation of the honour. Prof Pickering made the 

 interesting announcement that with an instrument of only 

 8 inches aperture, he is now able to photograph the s[>ectra 

 of stars down to the ]'Mh magnitude. 



Professor W. W. Campbell, who is well known for his 

 astrophysical researches, ha.s been appointed Director of 

 the Lick Observafcoiy, in succession to the late Prof. 

 J. E. Kceler. 



The oliservations made by the members of the Variable 

 Star Section of the B. A. A. indicate that the observeil 

 phases of Beta Lyra' fall a little later tlian the (tahnilated 

 phases as published in the C<iitipatd<'ii to the Ohxfrviilury, 

 the difference being perha]is 1'4 days. 



The preliminary reports of the British ollicial ]>artie.s 

 who observed the solar eclipse last May have i-ecently been 

 issued by the Koyai and Koyal Astronomical Societies. They 

 show that although perhaps no striking discoveries were 

 made, a vast number of valuable records of the phenomena 

 were secui-ed. Mr, Newall attaches some importance to 

 the fact that the moon was darker than the sky. thus 

 suggesting that some of the light usually attributed to 

 the sky comes from beyond the moon. Mr. Evershed 

 concludes that the " flash " spectrum is as constant a 

 feature as the Frauuhofer sjiectrum itself. — A. F. 



Entomological. — Some interesting observations on 

 the growth and development of instinct in sjiidi^rs have 

 been recentlv publishi'd bv Miss A. B. Sargent {Proc. Acad. 

 Nat. Sci., FhllaMpia, 1900, pp. ;j9.'')-4dl ). The species 

 studied were a large orb-weaving sjnder Jrfjiope, and the 

 common long-legged tube- weaving spider of North America, 

 Afjelenn nacvia. (Our British A. lahyrinlhicu, is well-known 

 to arachnologists.) Almostall mother sjiiders surroiindtheir 

 eggs with a silken cocoon, iu which the young sjiend the 

 first few weeks of their lives after hatching. Miss Sargent 

 concludes that the main object of this cocoon is to jirevent 

 evaporation of moisture from the young spiders, and that 

 it serves in a less degree as a protection against enemies, 

 such as wasps and ichneumon-flies. The young spiders 

 were kept under observation through the winter, and it 

 was found that they could endure a large amount- of cold 

 and damp, but that warm dry surroundings killed them. 

 When associated together in the cocoon the young Argiope 

 were always found to rest with the ventral surface out- 

 wards, perhaps to facilitate respiration by presenting the 

 breathing holes to the outer air. In the development of 

 the senses, touch si ems to be shown earliest, and light and 

 darkness are distinguished before the form of objects can 

 be made out. The earliest '• psychical " manifestations 

 made by the young spiders were inter]ireted as indicating 

 fear. While still iu their " little n(.'Sts," young spiders 

 seem to live harmoniously together, but the individuals 

 of an Agelena family were eager to eat one another 

 when they had bsgun to make their own way iu the 

 world.— G. H. C. 



