152 



NA TURE 



\JDec. 13, I J 



it before sunrise, is due to reflection from the first when 

 this is at a proper angle near the liorizjn. The interval 

 between the same stages of the secondary and the primary 

 before sunrise, when conditions are most favourable for 

 accurate observation, is about fifty-on minutes, and the 

 interval between the more conspicuous primary and the 

 actual sunrise about fifty-six- minutes. The first red 

 colour of the primary glow may be caused by the inci- 

 dence of the sun's first rays upon the material. It seems 

 that the reflecting material directly overhead receives the 

 sun's rays about thirty-nine minutes earlier at sunrise, 

 and loses them as much later at sunset, than the surface 

 of the earth. I have not found the colour effects in many 

 cases to be subjective. \ green cloud remains green 

 when cut off from surrounding light. IMay not atmo- 

 spheric sifting produ;e the surviving colour? 



F. A. R. RussKLl. 



The Hon. A. P. Hensman, Attorney-General of West 

 Australia, writes to me as follows, under date of Perth, 

 West Australia, October 27 : — "The captain of a ship 

 lately engaged in a survey of our north-western coast at 

 t)ie time of the eruption in the Straits of Sunda told me 

 that the deck was covered to a depth of an inch or 

 more with a fine dust. We are having, and have had for 

 many weeks, very remarkable sunsets. After the sun has 

 set, a glow commences somewhat high up above the hori- 

 zon, a brilliant rose-colour ; this continues for nearly an 

 hour, gradually descending to the horizon, and becoming 

 deeper in colour. It has never been seen here before, 

 and has given rise to much speculation amongst learned 

 and unlearned, both here and in the other colonies ; some 

 suggesting that it is caused by the presence of volcanic 

 dust in the atmosphere." This extract may be of interest 

 to your readers, as showing that all over Australia similar 

 phenomena have been observed to those discussed in 

 your pages. 



As I am engaged in making a comparative study 

 of the dust which fell at different points during the 

 Krakatoa eruption, I shall feel greatly obliged to any of 

 vour readers who can supply me with samples of such 

 dust, accompanied by a note of the time and place of the 

 fill. John W. Judd 



Science Schools, South Kensington, S.W., Dec. 8 



The uncommon phenomenon witnessed in various parts 

 of India, Ceylon, and the Cape of Good Hope, has made its 

 appearance here. The sun, immediately it sets behind 

 the ridge of Possilipo, throws upwards a group of 

 red rays somewhat irregular in arrangement ; the sky 

 begins then to assume a greenish tmt. These rays soon 

 disappear, and then the whole horizon for iSo' is lit up by 

 a bright orange-red light, which gradually deepens in tint. 

 The height of this light does not usually extend above 25^ 

 or 30''' ;it its centre, and gradually descends to the level of 

 the horizon at its two extremities. So far as I can make 

 out, the centre or most brilliant point of this is quite 20'^ 

 more to the south than the setting sun. All the south- 

 west sides of the houses are suddenly lit up by this 

 peculiar lurid glare, which is best compared to the colour 

 of incandescent iron, and reflected from the surface of the 

 sea makes the gulf look like a veritable lake of molten 

 lava. The effects last at the maximum only an hour 

 after the setting of the sun. On Sunday last the moon, 

 shining through this red glare, had a bluish tinge of the 

 arc electric light colour. The same phenomena precede 

 sunrise. These effects are cjuite independent of clouds, 

 which, when present, have a deep lead colour, and their 

 edges are not illuminated. The weather is cold, the wind 

 variable, chiefly north or north-east. The magnetic 

 instruments at the observatory show no disturbances, 

 which excludes the possibility of an aurora, as also its 

 presence only when the sun is just below the horizon. I 

 send these notes, hoping they may be an addition to the 

 other observations alreaiy published in N,\TURE, to aid 



in an explanation of this remarkable and widespread 

 phenomenon. H. J. Johnston-Lavis 



Naples, December 6 



Sir Adam Bittleston presents his compliments to 

 the Editor of Nature and ventures to send him an ex- 

 tract from a letter written by Sir Adam's son at Umballa 

 (lat. 30'^ N.) on October 30. There seems a long interval 

 of time between the appearances at Ongole (September 

 10) and those noticed at Umballa. 



87, Linden Gardens, Bayswater Road, W., 

 December 10 



Extract from a Letter from Lieut. G. H. Bittleston, 

 R.H.A., dated Umballa, October 30, 1883 



" There has been for sovie time a remarkable appear- 

 ance in the sky every night. The sun goes down as 

 usual and it gets nearly dark, and then a bright red and 

 yellow and green and purple blaze comes in the sky and 

 makes it lighter again. It is most uncanny, and makes 

 one feel as if something out of the common was going to 

 happen." 



The inclosed from the Hawaiian Gazette, October 3 

 may interest students of meteorology. F. J. S. 



" Maui. — With regard to the extraordinary sunsets, a 

 correspondent in Wailuku writes : — ' I do not know what 

 kind of sunsets you are having in Honolulu, but here for 

 some time past they have been most extraordinary. 

 Fiery red, spreading a lurid glare over all the heavens, 

 and producing a most weird effect.' 



" Kauai. — The peculiar sunsets have been noticed and 

 commented on by the Kauai people. No one has 

 ventured on a theory here." 



The line of green suns is carried further west to 

 Panama, where, accor Hng to the Star and Herald, the 

 phenomenon was observed on September 2 and 3, and it 

 is suggested to be in connection with Krakatoa. 



Hyde Clarke 



32, St. George's Square, S.W., December 8 



I send you a bottle of volcanic dust which Capt. 

 Robert Williams of the bark Arabella obtained under the 

 following circumstances. He says : — " On Tuesday morn- 

 ing, August 28, 18S3, it commenced to rain something 

 like sand (some of which I collected from off the decks), 

 which kept on all this day and the next day. Lat. at 

 noon of the 28th, 5° 37' S., long. 88° 58' £., wind light 

 from the west- south-west, and calm at tunes. Java Head 

 bearing east half south, distant about 970 miles." Can 

 this shower be connected with the Java eruption? 



Falmouth, December 6 Howard Fox 



As accuracy of observation is before all things desir- 

 able in the elucidation of natural phenomena, I hope you 

 will allow me to point out an error into which some of 

 our physicists appear to have fallen in connection with 

 the green moon which was visible in the evenings of 

 Tuesday and Wednesday of last week. Mr. Norman 

 Lockyer, in his admirable article in the Times of Satur- 

 day last, refers to " the subjective colouring which cast a 

 green glamour over moon and cloud if one did not take 

 the precaution of preventing the eye being flooded by 

 the rosy pink visible in the zenith long after sunset ; " 

 and a writer on recent solar phenomena in the Daily 

 A'ews says, " This latest phenomenon has caused a 

 greater amount of astonishment than the earlier ones, 

 but, unlike them, admits of very easy explanation, 

 for a moment's reflection will show that on a pink 

 background a w hite moon could scarcely appear anything 

 but green," thus, like Mr. Lockyer, attributing the pheno- 

 menon to the presence of a complementary colour. What 

 I wish to point out is that there is no foundation for this 

 theory. I observed the effect most carefully on both 

 evenings. On the second evening especially I looked 



