Dec. 



1883.] 



♦ KNOWLEDGE . 



341 



r 



^\ 



MA0Z1NE OF^NCE 



I FLAINlYVf ORDED -EXACTlf DESCRIBED . 



LONDON FlilDAY, DEC. 7, 1883. 



Contents op No. 110. 



FAGB 



The Estroardinary Sunsets, By 



A. C. Eanyard 311 



The Chemistry of Cookery. XXIV. 



By W. Mattieu Williams 342 



The Senses in Infants. II 343 



Submarine Cables. By \\ . Slingo . 345 

 Neglected Insects. By E. A. 

 Butler, B.A.. B.Sc 



The Lancelot Fish (Tlliia.) 348 Oar Chess Coli 



Editorial Goss 

 The Face of the" Sky. By P.E.A.8. 350 

 Correspondence : Is the Sun Green ? 

 — Strange Coincidences — Tri- 

 cycles — Severe Weather of the 



13th— 16th, &c 351 



Whist Coll 



, 354 



THE EXTRAORDINARY SUNSETS. 



By a. C. Ranyard. 



THE last number of Knowledge contains an extract 

 from a letter received from a resident at Graaff 

 Reinet, in South Africa, mentioning that a brilliant glow 

 in tho sky after sunset had for a month past attracted the 

 attention of the inhabitants. Similar letters have been 

 received from places in the northern hemisphere as distant 

 as Ceylon on the one hand and Trinidad on the other ; and 

 within the last month sunset and sunrise tints of more 

 than usual splendour have been observed in England and 

 over the continent of Europe. 



Professor Piazzi Smyth has endeavoured to account for 

 the sunset and sunrise phenomena observed in India, by 

 supposing that there must have been an unusual amount of 

 aqueous vapour in the higher atmosphere, due to excep- 

 • tional meteorological conditions such as precede a great fall 

 of rain. But similar meteorological conditions .seldom exist 

 over so wide an area as that embraced between the Cape, 

 India, and the West Indian Islands, and exceptional meteoro- 

 logical conditions seldom remain with comparatively little 

 change for more than two months. I am rather inclined to 

 attribute to a cosmical origin the glorious phenomena which 

 have been observed over a whole hemisphere, and possibly 

 all round the globe. Before explaining my theory, I will 

 give a short resume of the phenonema observed, with some 

 of the observations I have collected on tho subject. 



Dr. J. Arnold, writing to the Times of October 9, 

 makes the following quotation from the letter of a friend 

 in the Island of Trinidad : — " Last Sunday (September 2), 

 about five o'clock, the sun looked like a blue globe 

 .... and after dark wc thought that there was a fire in 

 the town, from the bright redness of the heavens." Mr. 

 Arnold adds, "AH my correspondents agree as to the blue 

 colour of the sun." Three days afterwards a cyclone swept 

 over Martinique. 



In Nature, of Oct. 11a letter is printed from ]\lr. W. R. 

 Manley, dated Ongole, India, Sept. It, in which he says : — 

 "My attention was first called to the matter on Sept. 10. 

 On looking out I saw that tlie sun, which was somewhat 

 dimmed by a haze, had a decidedly greenish-blue tinge. The 

 same thing was observed on tho 11th and 12th, both morn- 

 ing and evening ; but my observations were confined to the 



evenings. About four o'clock (at least I did not notice it 

 earlier) an indistinct bluish tinge appeared in the light 

 This gradually passed into a greenish colour, and this in 

 turn became tinged with yellow as the sun approached the 

 horizon. After the sun was down, light yellow orange 

 and red appeared in the west, a very deep red remaining 

 for more than an hour after sunset ; whereas under 

 ordinary conditions, all traces of colour leave the 

 sky in this latitude within half-anhour after the 

 sun disappears. On the evening of the 13th the sun 

 appeared to be perfectly clear, but after it was below the 

 horizon the western sky became brilliantly illuminated with 

 yellow orange and red in the order I have mentioned. 

 These sank one after the other, leaving at last an arc of 

 brilliant red along the west, the inner portion of the seg- 

 ment contained by the arc being composed of orange. I'his 

 disappeared in turn, and the whole western sky became 

 yellow again without any distinct outlines, and this 

 gradually deepened into red, which remained for an hour 

 or more after sunset. The latter phenomenon was not 

 unlike an ordinary sunset, except in brightness and dura- 

 tion .... there was apparently nothing unusual in the 

 state of the weather at the time." 



Since the beginning of September, numerous communica- 

 tions have been received from all parts of India giving 

 accounts of the remarkable sunset tints, and for the last 

 two months similar sunsets have been observed in Europe.* 

 A friend, writing to me from Nice on Nov. 15, says: — 

 " We have had extraordinarily beautiful sunsets for the 

 last month, with a coloured twilight lasting much longer 

 than usual." The prolonged afterglow has been noticed 

 in England. Captain Noble, in the last number of 

 Knowledge, says that on Nov. 8 " the whole of the 

 western sky was ablaze with the most vivid crimson glow; 

 albeit, the sun had set for an hour and a half ; " and Mr. 

 W. T. Lynn, formerly of the Greenwich Observatory, 

 informs me that there is a very striking increase in the 

 duration of the morning as well of the evening twilight. 

 It is therefore evident that there must be finely-divided 

 particles of matter suspended at a considerably greater 

 height than usual in the atmosphere ; and the question 

 arises. Is this matter condensed aqueous vapour ? Is it 

 volcanic dust from the great eruption of Krakatoa in the 

 Malay Archipelago, which occurred at the end of August ' 

 Or does the dust come from outer space % 



As to the first hypothesis. The meteorological con- 

 ditions at the earth's surface have not been strikingly 

 uniform over the area within which the remarkable sun- 

 sets have been observed ; and there has been no wide- 

 spread and exceptionally great downpour of rain such as 

 might have been expected if the amount of aqueous 

 vapour in the atmosphere over a whole hemisphere of the 

 earth had been much larger than usual. 



The date of the great eruption of Krakatoa, as compared 

 with the date of the earliest observations of the green sun 

 in India, would seem at first sight to favour the hypothesis 

 that the colours must be due to light dispersed by volcanic 

 ashes or volcanic dust borne away by the trade winds. 



Those who have watched an eruption of Etna or 

 Vesuvius know how the volcanic vapours are carried to a 

 certain altitude above the crater, where they spread out in 

 a horizontal cloud, which, under ordinary circumstances, 

 does not attain a very great altitude. It is possible to 

 conceive that such a cloud laden with dust might, in the 



• I have searched a filo of American newspapers, and tho pages 

 of Science, a. periodical published at Bo.«ton, but have not succeeded 

 in finding any referenco to red snnsets in America. I should be 

 glad to know whether they have been seen in the United States and 

 China. 



