90 



KNO^A^LEDGE• 



[Fer 9. 1883. 



A CDBIOUS RAIXBOW. 



[70C] — Yesterday niornint; (Jan. 21, 1883) I observed a reiin- 

 bow — one fiiniilar to which I do not uvor remerabor seeing before, 

 nt least as rp(;ards ap|ini-ciit conditions and delinition. 



The morninp was line and frosty, and fairly clear, the country 

 round aboat being visible for a tiistance of about ten miles, and 

 there was certainly neither any appearance of rain not yet of snow 

 \isiblo between either horizon. At about half-past nine o'clock I 

 observed a bow in tbo north-western part of tlie sky. The different 

 colours were barely distinguishable, and I at first thought that it 

 was a freak of nature in the shaping of the clouds. 



Now, the sun was shining through a thin layer of clouds (cirrus, 

 I tlunk), which covered the whole sky more or less, and I 8upix)se 

 that the snn shining through those clouds in the east would cause 

 the rainbow to be reflected on the clouds in the west. If this is 

 the case, however, how is it that similar rainbows are not oftcner 

 seen ? If this is an uncommon occurrence, and I have not given 

 the right definition of its cause, I have no doubt you or some of 

 your readers will be able to explain. 



The enclosed rmigh drawing, made of course irrespective of 

 size or distance, will show more clearly what I mean. 



The rainbow lasted for more than an hour and a half. — Yours 

 sincerely, W. H. M. 



MISTLETOE. 



[707] — Mr. Grant Allen, in his moat interesting paper on the 

 " Mistletoe," seems to me to have left out one of the chief ways 

 in which the plant is propagated. Any one who has watched a 

 canary or any small cage bird feeding must have seen the bird, 

 when anything stuck to the outside of its beak, \vipe its beak on 

 the perch. Now, when a bird is eating mistletoe berries, what ij- 

 more likely than that the seeds should get stuck to its beak by the 

 very viscid pulp ? In this case the bird will be almost sure to wipe 

 the seeds off its beak on to a branch of a tree, where the seeds 

 will be left ready to germinate. W. H. Bansall, B.A. 



SLEET AND SNOW. 



[708] — On Wednesday evening, Jan. 2i, between eight and 

 nine o'clock, I happened to be out in the rain, or rather sleet, which 

 was falling, when suddenly the character of the downfall changed, 

 and for about five or six minutes snowflakes of remarkable size fell 

 instead of the sleet ; the flakes, or perhaps accumulation of flakes, 

 were from 1 to 2i inches in length, and f to IJ in breadth ; was 

 it not a rather singular phenomenon ? I could not see if the deli- 

 cate star-forms were plainly visible or not, being unable to examine 

 them in the light. _^ J. Lokd. 



ACOUSTIC EXPERIMENT. 



[709] — The following simple experiment suggested itself to me 

 as an illustration of the way the spectroscope is used to show 

 whether a star is approaching the earth or moving from it. 1 

 soldered a short piece of i-in. brass tube to a brass rod (in 

 order to give it weight), filed up the open end square, and tied 

 the rod to a piece of string about four feet long. 



O 



-O BFAss frao 



Now, when the end of the string was held in the hand and the 

 jiipe swung rapuUy round, like a sling, it emitted a note, which, by 

 a person standmg at a little distance (in the plane in which the ' 

 arrangement was turning), was heard to alternately rise and fall in 

 lutch, bemg higher when the pipe was approaching, and lower 

 when It was receding from the observer. It will be easily seen 

 how this lUuBtrates the use of the spectroscope referred to. 



Andrew Boyd. 



GREAT PYRAMID. 



[710] — Adverting to Mr. Wni. M. FlinderB-Petrie's excavatians at 

 the "Great Pyramid," as detailed in the appendix (B) to Mr. 

 Proctor's recent work, in which Mr. Petrie is represented as saying 

 that the Pyramid " proves to bo several feet smaller than hitherto 

 supposed;" I write to ask whether you can inform j'our readers 

 when the result of " the paper work of the survey," is likely to be 

 submitted to the judgment of those interested in the question, 

 whether viewed from the standpoint taken up by Professor Piazzi 

 Smyth and his following, or that taken by Mr. Proctor. 



If Mr. Petrie's labours substantiate the fact that there is an 

 error of several feet in the hitherto-recorded measures, not only 

 will, as Mr. Proctor remarks, the relations snpposed to connect 

 astronomy with the structure go overboard, but it will be difficult 

 to readjust the pyramid measures of the cubit and inch, so as to 

 make them fit into the " inch for the year " theory of measurement 

 of the passages, and thus inflict a heavy blow and great dis- 

 couragement upon the prophetic teachings and testimony claimed 

 for this wonderful building— claims which have received the sup- 

 port of many, and which have invested it with a halo of sanctity 

 almost amounting to worship. Ax LvqiiBEK after Truth. 



[The greater astronomical relations remain, however, and the 

 Pyramidalists will simply shorten their cubit. — R. P.] 



TRANSIT OF VENUS. 



[The letter from which the following is taken was marked 

 " private," but we feel sure our correspondent will not ebject to 

 our quoting these particulars. — Eo. 



[711] — My telescope is only a small one — 3i in. — by Coi, of 

 Devonport, but with a medium power of 150 both sun and planet 

 were seen very clear indeed, until they set in a bank of clouds 

 very near the horizon. A few light clouds only passed over them 

 occasionally during nearly two hours, through which the disks of 

 both snn and planet were seen well defined without a coloured 

 glass. Before and after the first contact the disks were beauti- 

 fully clear ; and when the planet separated from the sun's disk 

 inside there was no sign of a black drop, or anything to break 



the clearness of both disks, which separated as clearly as I have 

 shown above in No. 1. Very soon after a distinct but very faint 

 pink colour filled up the space between, which got a little brighter 

 when in about the position of No. 2, the brightest colour being 

 planet. It then gradually died away, but there were traces of 

 it, though very faint, when the space was fully equal to the planet's 

 semi-diameter. Thinking at first that my eye might have deceived 

 me, I asked two or three gentlemen to" look carefully at it, and 

 they also saw it clearly. 



There may be nothing unusual in this, but as I have not seen it 

 noticed in any report of the transit, I think you may like to have 

 the account of it.— Yours, &c., B. J. SuirvAN, Admiral. 



[712] — Your article on the "Photographic Eyes of Science" was 

 evidently written last year. Would it not be well to have a state- 

 ment to that effect printed in the next number of the magazine ? 

 Otherwise you may find yourself made responsible for a statement 

 that the transit of Venus is to be repeated iieit December (see 

 top of page 446). The announcement might run thus :— " In com- 

 pliance with a general request, the highly successful performance 

 will be repeated (positively for the last time this centurv) in Decem- 

 ber next. Early application for reserved scats should be made," 

 &c., Ac. This would be as great a windfall to the " science" (?) 

 columns of society papers as the "menacing comet" with which 

 you were credited. It could hardly surprise you next to find your- 

 self possessed of powers like the man in " Uncle Remus," who was 

 " gwine ter fix up der weddcr." yf. 



THE EDELWEISS. 



[713] — A Corkonian will be thankful to any peruser of 

 Knowledge who may happen to be versed in botanical lore to 

 acquaint him with the scientific nomenclature, &c., Ac, of the above- 

 named Alpine plant. 



