I50 



NA TURE 



\_Dcc. 13, 1883 



blue suns seen in India last September, and they with 

 the great volcanic explosions in Java last August, so 

 destructive of human life ! 



The said green and blue suns were, however, quite a 

 different phenomenon to our red sunsets. For, instead 

 of appearing extra bright and contrasted in colour with 

 clouds near them, like the crescent moon of Decemljer 3 

 just mentioned, they were abnormally faint, and uniformly 

 tinged witli both clouds and fog, and moon and stars at 

 night. Moreover, the spectroscope, in the able hands of 

 Prof. Michie .Smith of Madras College, showed that the 

 intervening medium, through which the sun's light was 

 struggling towards these Indian observers, was e.xtra 

 damp instead of extra dry. And in the west of India 

 since then, as we have just heard from private sources, 

 no less than 140 inches of rain have fallen, and the 

 country was in a temporarily impassable condition from 

 sloppy softness of soil. 



Prof. Michie Smith has indeed enlertaineJ the idea that 

 the particular state of the watery vapour which cut off so 

 largely the red, but passed on the green light of the sun's 

 spectrum in a weakened condition, may have been owing 

 in some degree to particles of pumice dust from the Javan 

 volcanoes. And such dust, once up in the air, may circu- 

 late around the earth, after the manner which Coaimander 

 Maury, U.S.N., was so earnest in teaching with respect 

 to the trade winds and their spiral paths through either 

 hemisphere. 



But how long su:h dust would remain suspended, how 

 high it would rise, and when and where it would fall, are 

 questions that can hardly be answered positively and with 

 exactitude a priori. It did not fall, so far as we have 

 heard, in India, where, if present at all, it must have baen 

 comparatively lo v and dense. .-\nd it wjs not falling 

 here during the recent red sunsets, for the lower air was 

 particularly clear, while the supposed criminating redness 

 was too manifestly due to the extraordinary height, as 

 well set forth by Prof. Helmholtz, of the uppermost cloud 

 stratum, a thin kind of cirrus haze, according to my 

 observation, combined with the discriminating action 

 of the atmosphere on the compound colaured solar 

 light. 



Why that cloudhaze was so high, and whether dust, 

 and if so what dust, had any part in its constitution, 

 are questions which may worthily be discussed, but no 

 very certain answers expected for years to come. But 

 having been myself much struck during a rather long 

 residence on the Peak of TenerifFe in 1856, with the 

 general and apparently normal existence of dust strata in 

 the atmosphere, higher or lower, but often far above the 

 level of ordinary water-vapour clouds, — and as the 

 meteoric researches of Prof. Newton, corroborated by Prof. 

 C. A. Young, in .America, show that not less than 100 tons 

 of meteoric stones (of which the earth encounters nearly 

 3,000,000,000 in the course of a year) must be dissipated 

 in our upper atmosphere on the average e-i'ery day, as 

 impalpable dust, — it seems more probable that Prof. 

 Helmholtz's very high clouds, if they were assisted in 

 putting in an appearance as clouds by dust of any kind, 

 must have derived it from such disintegrated and sublimed 

 meteor-masses coming down day by day in the regular 

 way of nature from above, or outside, rather than from a 

 supposed continued ascent of one particular charge of 

 volcanic dust from Java, full three months after the 

 cessation of all violent disturbance there. 



In fact while it is to be earnestly hoped, as an outcome 

 of the late remarkable sunsets, and the great numbers of 

 the public by whom they have been witnessed,— that our 

 painters will no longer be content to give us so generally 

 mere afternoon pictures slightly yellow ochred and " light 

 red "-ed near the horizon before the sun goes down, as sun- 

 sets, — but will more frequently paint the deep red after- 

 glows at their richest ;— it is equally desirable that our 

 scientists should gauge the ordinary constitution of the 



atmosphere at much greater heights than those to which 

 observatories are usually confined. 



C. PiAzzi Smyth, 

 Astronomer Royal for Scotland 

 15, Royal Terrace, Edinburgh, I-j December 8 



The following summary of atmospheric eftects seen 

 before sunrise and after sunset between November 25 

 and December 11 may be useful for comparison with phe- 

 nomena observed in other parts of the world : — 



November 24. — After sunset, yellowish-green strias in 

 west. 



November 25. — Sunset in amorphous apparent cirro- 

 stratus or cirrus haze. Green light above it, and bright 

 greenish-white arc growing from about ten minutes after 

 sunset ; above the greenish-white, pale red. Lasted about 

 forty-five minutes after sunset. The sky shone with a 

 strange light somewhat as on November g, but much 

 feebler, and there was no sharply marked aggregation of 

 cloudy reflecting material as then. 



November 26.— Fine clear sunset, followed by pheno- 

 mena like yesterday, but much stronger, and lasting 

 nearly an hour bright red. No high clouds seen as light 

 receded from the sky. A few rounded morsels of cumu- 

 lus fringed with green against the red sky. Very strange 

 effect, the greenish-white light in the west, and pink 

 above. 



November 27. — Sunset effect like yesterday, beginning 

 to glow about fifteen minutes after sunset, and growing 

 slowly in apparent brightness. Lasted till about 5.20. 

 Slight, thin cirrus. 



November 28. — Slight cirrus. Clear sunset. About 

 twenty-five minutes after sunset green and pink glow 

 began and grew bright and finely-coloured till about 4.40. 

 Then slowly receded till about 5.10, when it disappeared, 

 and was succeeded by a faint brass-coloured after-glow 

 reaching high above the horizon. Time of sunset, 3.55. 



November 29. — Extraordinary red glow, said to be seen 

 in London from 5.30 to 7.30 a.m. Cloudy evening. At 

 455 a dull faint red glow observed through a small break 

 in the clouds. Time of sunrise, 7 43. 



November 30. — At 6.5 a.m. (and probably a few 

 minutes before) a fine deep red glow in the east and 

 overhead, where small quantities of cirro-cumuli seemed 

 to be touched by the reflected light. At 6.15 a faint, 

 deep red glow had spread from north-north-east to south- 

 east, and up to about 40° above the horizon in the north- 

 east, covering a vast portion of the sky. Then gradually 

 became whiter and less striking. The blood-red band in 

 darkness at 6. 10 mo^t remarkable. The glo* continued 

 (slowly changing in colour and growing in extent), 

 and was evidently independent of ordinary clouds. The 

 bright stars appeared through it. At 6.24 a faint red 

 light extended to the zenith. .At 6.40 the red had gone, 

 and was replaced by a primrose colour, the flocks of 

 cirro-cumuli, however, still remaining tipped with bright 

 red, and retaining that colour till sunrise (7.44)- There 

 was no cirrus visible, and the reflecting haze was invisible 

 both by night and in full daylight. The cirro-cumulus 

 was moving moderately fast from west-north-west. The 

 red bank in the east was not crowned with shafts of rays 

 or prominences as in the sunsets of November 26, 27, 

 and 28, but the intensity of the light diminished con- 

 tinuously upwards from near the horizon. The afternoon 

 being cl'oudv, the only thing observed was a dull greenish 

 light about half an hour after sunset. 



December l. — Sunrise cloudy. Sunset (3.53) in cloudy 

 sky, except near horizon. At 4.25 slight tinge appeared 

 on fringes of clouds overhead. Then densely clouded. 

 At 5 the sky had cleared largely, and a fine amber light 

 could now be seen from near the west horizon to about 

 40°. This gradually sank, following the sun, and grew 

 less bright, finally disappearing about 5.35. Sky clear 

 and starlight, except low strips of cloud near the horizon. 



