THE RECENT RED SUNSETS.

Thames Star, Volume XV, Issue 4678, 4 January 1884, Page 3

THE RECENT RED SUNSETS.

Mr Thomas Robertson writes to the Sydney Morning Herald at great length, on the subject of the recent sunsets, and thus concludes:—l think I have, with due deference to the high authorities referred to, said sufficient to show that there are very grave, if not insuperable, difficulties to the acceptance of either the volcanic dust or moisture theories, and I now ..venture, to suggest that the foreign substance which has caused the abnormal reflection of the red rays may be hydrogen gas. Under ordinary circumstances hydrogen gas is not found in nature in a free state, but Bunsen has recorded that be found it in a mixture .of gases collected by him in 1846 from the volcanic district of Nyrnafjoll, in Iceland, and that it existed in tho proportion of 45 per cent. Now this ahows that hydrgen gas is a product of volcanic action, and it is, more* over, the lightest known form of matter. It is 14.4 lighter than air, and 11,000 times lighter than water, and consequently it is the very substance which, if thrown up in large volumes by volcanic eruption in Java, would have at* tamed a sufficient altitude to have caught the rays of the setting sun long after it had sunk down below our horizon ; and, moreover, hydrogen gas has the highest reflecting power of all gases. Compared with air it is as 6614 to 1000, and I think that every one will concede that the recent red glow in the evening sky was at least six times as deep a red as the ordinary tints of the morning or evening sky, and it will.be readily conceded that gas would be most likely to diffuse itself over the very wide expanse through which this red glow has been risible during the last few months than any amount of volcanic or meteoric dust. That it is owing to the passage of light through our atmosphere that all its rays become absorbed, except the red rays, is proved not only by the reflection from the clouds and mountain tops at sunrise and sunset, but also by the coppery red appearance of the moon's face just before it enters, and just after it emerges from the earth's shadow during a lunar eclispe. Assuming, therefore, that it is to the recent volcanic eruption that the phenomenon that is attracting so much attention is to be attributed, I think" I have demonstrated that it is more probable that it is owing to the presence of hydro* gen gas than to either dust or moisture."