88 



KNOWLEDGE. 



[Apkil 1, 1901. 



the last six chapters the intimate structure and the class! ficati in 

 of plants are dealt with. One of the most remarkable features 

 of the book is the abundance and excellence of the illustrations, 

 many of which are quite unique in a work of this character. It 

 may iierhaps be considered that the volume is over-illustr-ated. 

 Copious representations of Nature in a school-book of B itany 

 are not unlikely to supplant field observations, and thus prove 

 themselves a snare rather than a blessing. We trust that this 

 work is destined to become well known in this country, and 

 therefore the more regret that its u'jef ulness is impaired by the 

 use of popular (American) names of plants which are quite 

 unintelligible to the British reader. The botanical names in 

 brackets would have been of great assistance both to teachers 

 and scholars. These and a few other minor defects do not 

 seriously detract from the excellence of Prof. Bailey's work, 

 which we have read with great pleasure, and can heartily 

 recommend to those who seek a first-class school-book of 

 Botany. .-.-■ 



BOOKS RECEIVED. 



Practical Organic Chemijifri/ for Advanced Studenis. By .Julius 

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Eepnrt on the Census of Porto Pico, 1S99. (Washington : Govern- 

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The A B C of Di/namo Desii/n. Bv .Vlfred IT. .\vciT. (Dawbarn 

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Model Boiler Making. By E. L. Pearce. (Dawbarn & Ward.) 

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S'lrtor Pesartiis. Heroes and Hero-Worshiji. Past and Present. 

 By Thomas CarUle. (Wa-d,Lock.) 2s. 



Researches on the Past and Present Mistorg of the Earth's 

 Afmos here. By Dr. Thomas Lamb Pliipson. (Griffin & Co., 

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The Child: Mi^ Nature and Nurture. By W. B Drummond, 

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First Aid to the Injured and Imlulance DHll. By H. Drinkwater, 

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The Complete Works of John Keats. Vol. IV. Edited by H. 

 Button Forman. (Gowans & Gray.i Is. net. 



Whist Dialogues. t!y Major Jack Teuace. (Bruxelles: Imprimerie 

 E Waj-nians.) 



An Enquirg concerning the Principles of Morals. By David 

 Hume. Keg>in Paul » Is. 61. 



The Value of Scientific Training. By Prof. J. Logan Lobley, 



F.G.S., r.R.G.S. (CuMTfll.) 



The Structure and Inher-ent Motions of the Universe. By Edward 

 Meyer. (Adelaide : A. & E. I ewis.) 



The Phuto-Miniature, Januarg, 1901. (Dawbarn & Wai'd.) 

 Monthly. • d. 



J'uper Work. Bjr Eev. F. C. Lambert. M.*.. and Charles Godfrey 

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Sfventeenth Annual Report of the Bureiu of American Ethnology 

 to the Secretari/ of the Smithsonian fustitutton, 1S95~G. Part II. 

 (Wa-hiuiton : Government Printing Office.) 



Catalogue of Chemical Apparatus, t^'c. (London : Gallentamp 

 & Co., lid.) 2s. 



Thornton-Vickard Photographic Specialities. (Thornton-Pickard 

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The Norwegian North, Po'ar Expedition, 1893-1806 — Scientific 

 Besulis. Edited by Fridtjof Nansen. Vol. 11. (Longmans.) 30s.net. 



Urttcrs. 



[The Editors do not hold themselves responsible for the opinions 

 or statements of correspondents.] 



SUNSET PHENOMENON. 



TO THE EDITORS OF KNOWLEDGE. 



SiR.s, — T think Mr. E. W Maunder, in liis note .Tppeurled 

 to Mr. McDonald's letter on ihe above subject, treats the 

 matter possibly a little too cursorily, in stating that the 

 rays are rarely traced right across tl\e sky. In the dry 

 uplands of South Africa, in the brilliant dry weather one 

 gets in winter. I have uight after night observed these 

 lovely pink streamers stretching rii;ht across the sky, and 

 meeting at a point, opposite the sun's position ; and 1 have 

 often speculated as to their origin. They would never be 

 i|uite the same two evenings running; sometimes there 



would be several of these rays, well defined, all a beautiful 

 pink, contrasting exquisitely with the pale blue of the 

 twilight sky. Next evening there might perhaps be one 

 huge tan-like one stretching laterally over many degrees 

 of the sky, with one or two narrow ones. I quite admit 

 that they are exactly analogous to the rays of the sun 

 piercing an aperture in clouds, which cut off his direct 

 light from the space surrounding the cylinder of atmosphere 

 illuminated directly. Rut the difficulty always occurred 

 to me. where were the clouds that produced the streamers 

 or rays, because we knew for certain (in the Transvaal 

 where I was then stationed) that in the winter season the 

 whole sky, over an enormous tract of country, was abso- 

 lutely free from cloud. Those who have lived in the 

 country referred to will, I think, appreciate this question. 



I have dwelt on this topic before, in the columns of the 

 English Mechanic, and observed I should like to see the 

 subject treated seientifically. Query : At what distance 

 should, clouds be situated from the observer to produce 

 the effect of these pink streamers shortly after sunset ? 

 Of course the exact time would have to be given, in order 

 to ascertain the depression of the sun, at that time, below 

 the horizon. Also, is it not possible that the rays might 

 be caused by the sun's light passing over rautres of broken 

 hills aud mountains which abound in South Africa? The 

 valleys between mountains might admit the tangential 

 rays of the sun, while the mountains would cut them off. 

 I have hv me a water-colour sketch of the Magaliesburg 

 Range taken from a spot a few miles distant from Pretoria. 

 The horizon goes up and down, as peak and valley are 

 define 1 in the clear blue distance, and the gorge where 

 the Crocodile i^iver cuts through the range is sharply 

 marked. Might not such irregularities in districts some- 

 what beyond the terrestrial horizon be the, cause of the 

 pink streamers ? 



In some cases this phonoraenon is no doubt due to 

 clouds, for I find that when at sea, in the year 1885, I 

 noticed a curious effect one evening just after sunset ; the 

 left hand part of the sky (looking westwards) was ru Idy, 

 while the right was a beautiful turquoise hue. This was 

 umloubtedly only a form, or sp^-cial case of the pink 

 streamers, but in this case mountains could nut be brought 

 in as the cause, as we were at the time far from land; and 

 clouds must have been the cause. In England one does 

 not often see the streamers stretching across the sky, and 

 meeting at the point opposite the sun. I seem to recollect 

 only one occasion. 



They usually take the fonu of a fan, and are so repre- 

 sented in landscapes ; sometimes radiating upwards and 

 sometimes downward, the sun being generally supposed to 

 be above the horizon at the time. 



This phenomenon is quite distinct from the " pink 

 glows," when the uhole of the western sky is illuminated 

 with a pink glow, verging through orange to cojipery red 

 near the horizon.. This is due to either aqueous vapour or 

 fine dust ilisseminated in the upper regions of the atmo- 

 sphere under peculiar conditions. 



E. E. Markwick (Col.). 



Devonport, 10th March, 1901. 



" MRS. QUICKLY'S TABLE OF GREEN FIELDS." 



TO THE EDITORS OF KNOWLEDGE. 



Sirs, — Surely a " table of green fields " is the correct 

 reading. Dame Quickly, whose mind could not soar 

 above the most homely ideas, was thinking (or, rather, 

 Shakespeare was thinking for her) of a map of a country 

 parish, on which the size and positions of its several 

 fields are marked — the map is called a " Terrier " from 

 terra — and she meant that Falstaflt's nose was so 

 wrinkled and indented with lines as for it to be com- 



