102 



NA TURE 



{May 31, 1888 



brown glass the purple of the retina was unchanged. I have 

 never seen any corroboration of these assertions, but they are 

 worthy of further consideration. Stimulated by these observation-, 

 I painted my face brown with water-colour, and spent many 

 hours on the snow of the Corner Grat on the same day that 

 about eighty out of a hundred people who were staying at the 

 Riffel Alp went up to witness the first ascent of the season of 

 Monte Rosa. In the evening everyone except myself and my 

 daughter, who had carefully protected herself with a brown veil, 

 was more or less severely sunburnt, whilst the remaining visitors, 

 who had spent the day on the rocks and mountain-sides in the 

 full sun, were untouched. Connected with this is the fact that 

 visitors to the Engadine in winter become extremely brown, as 

 though coloured by walnut-juice, whilst in summer, unless they 

 go on the snow, this is not so, although of course the heat is 

 greater. I have been there in winter and summer, and have had 

 many opportunities of confirming this observation. Then again 

 the very brown colour of the chalets is only to be seen at high 

 altitudes where snow is, and even those parts of the chdlets 

 which by their position cannot receive rays reflected from snow 

 do not become brown. And over the doors of these brown 

 chalets in which the cows are kept the wood is invariably white 

 and colourless just at that part which would always have, steam- 

 ing up, the warm moist breath of the cows, and by this moisture 

 the reflected rays would be intercepted. I think that all these 

 observations bear upon and are related to the question raised by 

 Prof. Ray Lankester. 



I have made many other experiments and observations, but 

 for brevity's sake I omit them, as I think I have said enough 

 to show that the subject is a large one, and worthy of con- 

 sideration. In a comment on Mr. Abercromby's letter above- 

 mentioned, Petrie says, " We should not look at the surface skin, 

 which is constructed to bear local variations of temperature, &c. , 

 but at the delicate tissues beneath. White skin," he adds, "is 

 translucent, but black stops out solar energy." It is possible 

 that sunlight reflected from snow may have an influence in pro- 

 ducing the improved health of consumptives who remain in the 

 Engadine in winter, and Mr. Abercromby reminds me that the 

 quality of heat which causes snow-burnt is not that which causes 

 sun-stroke. Sun-stroke is very rare (if known at all) on mount- 

 ains. Equatorial countries — Ceylon, Borneo, West Indies, &c. — 

 are not the worst for sun-stroke ; but sub-tropical and semi-tropical 

 dry countries, such as Scinde, North-West Bengal, United States, 

 Italy, &c. 



He also says that photography is much slower in equatorial 

 than in these latter countries. The cause undoubtedly is the 

 absorption of violet and ultra-violet rays by water vapour, which 

 is in excess near the Line. Photography is rapid — except for blue 

 sky — at high altitudes. Robert L. Bowles. 



Folkestone, May 23. 



Mysterious Sky Lights. 



On turning over some back volumes of Nature in search of 

 information concerning the spectrum of the zodiacal light, I 

 have discovered something which appears to be interesting and 

 suggestive, viz. several communications describing what the 

 writers supposed to be abnormal displays of the zodiacal light, 

 displays occurring at the wrong time, i.e. near to the periods of 

 the solstices instead of those of the equinoxes, and displays 

 having the wrong shape, lacking the conical outline, but never- 

 theless nearly in the right place. The most interesting of these 

 letters are from Mr. Maxwell Hall, and dated from Jamaica. 

 He was so much exercised by the heterodoxy of the appearances 

 he observed that he suggested a new theory, and illustrated it by 

 a diagram on p. 204 of vol. vii. 



He fays in this letter that "for several nights lately the 

 zodiacal light has been exceedingly bright and well-defined, and 

 more particularly on the nights of November 24 and' 27 ; on the 

 evening of the 24th I found an explanation of what had often 

 perplexed me before, viz. the existence of a faint, isolated band 

 of light across the zenith, but as soon as it was dark in the 

 evening, the zodiacal light was distinctly seen to stretch across 

 the tvhole sky, forming that faint band of light previously ob- 

 served ; I then began to note its position, but the best observations 

 tvere made on the night of the 2Jth, when it' was most distinct." 



The italics in the above are mine. The dates given, November 

 24 and 27, 1872, are those of the remarkable meteoric shower 

 supposed to be connected with the lost comet, Biela. The 

 grandest display was on the 27th. May not the luminosity 



stretching "across the sky" have been due to sunlight reflected 

 from the meteoric matter lying outside of the earth's atmosphere ? 

 Such a spurious zodiacal light does not demand our actual plung- 

 ing into the meteoric stream producing it, but should be 

 observable whenever such a stream exists between us and the 

 sun, its apparent breadth varying with its actual breadth and its 

 proximity to the earth. 



On p. 85 of the same volume is a diagram of the Biela 



^^rth^_£?^ ( 



meteor-path showing its relation to the earth's orbit and to the sun. 

 From this, reprinted above, it is evident that the meteors should dis- 

 play a spurious zodiacal light at the time named, and on to that of 

 the winter solstice, and later. In vol. xi. of Nature, p. 115, 

 reference is made to a letter from Mr. Hind, dated December 7, 

 1874, in which he points out " that the zodiacal light has been 

 conspicuous for the last few evenings ; and for several years past 

 this phenomenon has been much more marked in December and 

 January than about the vernal equinox." 



The pages of Nature and those of some of the older volumes 

 of the Gentleman' s Magazine contain many records of mysterious 

 streaks and bands and "pillars" of light seen after sunset, 

 variously ascribed to zodiacal light, to aurora borealis, celestial 

 phosphorescence, &c. If I am right in assigning the spurious 

 zodiacal light of the period above named to the Biela meteors, 

 careful observations of such celestial luminosity in relation to 

 other well-known meteor-streams may be very frui ful. 



The Grange, Neasden. . W. Mattieu Williams. 



Curious Apparent Motion of the Moon seen in 

 Australia. 



Can any of your readers explain the phenomenon described in 

 the following extract from a letter received from my daughter 

 residing in Maryborough, Queensland, Australia : — 



" We saw such a curious phenomenon on Sunday night, about 



10.30. Miss C ,-Miss H , and I were sitting in the balcony, 



when we noticed the moon apparently dancing up and dozun. It 

 is on the wane, so looked so extraordinary. The motion was 

 visible only when she was behind a narrow stratum of cloud, 

 and continued at intervals for thirty minutes. I felt quite sea- 

 sick with watching it, and Miss H. was so frightened ; she thought 

 there might be an earthquake coming, so went to bed in her 

 clothes to be ready for an emergency. Our house would soon 

 fall in an earthquake, its walls are thin, and no cellars." 



I presume the phenomenon is connected with the varying, re- 

 frangibility of the atmosphere, perhaps arising from the mixing 

 of hot and cold air ; but should be glad of further information. 



T. Mellard Reade. 



Park Corner, Blundellsands, May 27. 



Another Specimen of Lepidosiren paradoxa. 

 It may interest some of your readers to know that I have 

 lately received another specimen of this rare fish from my friend 

 Dr. J. Barbosa Rodriguez, the energetic Director of the Museu 

 Botanico do Amazonas at Manaos. This is the fifth specimen 

 known. A short notice of the fourth specimen, an adult female of 

 large size, caught in the Igarape do Aterro near Manaos, also pre- 



