880 Transactions.— Miscellaneous. 
similarly tinged. According to the size of the particles suspended in the 
air, would be their effect by refraction upon the rays of light fallmg on 
them. Gravitation would naturally bring the heavier particles down first, 
and so it is conceivable that for some months perhaps the air was filled with 
strata of dust, whereof the lower were composed of heavier, and the upper 
of lighter particles. Hence, as it seems to us, the change in the colour of 
the sun as if mounted in the heavens, and again in reverse order as it 
descended, was just what it was natural to expect. But if you ask me why 
the abnormal colours of the sun were not seen daily like the sun-glows, I 
can only suggest that the dust varied in density and character from day to 
day according to winds, or that for the most part some counteracting influ- 
ence, moisture e.g., was at work, so that the coloured sun and moon were 
rare phenomena. Even the after-glow is a result which dust in the air 
might be expected to produce; for this species of second twilight is not by 
any means unusual in the Nubian Desert, and Sir T. Herschell referred it 
to a second reflection of solar light in the atmosphere (Chambers’ Eney- 
clopedia, ** Twilight"). Ido not know that this circumstance has hitherto 
attracted any notice in this discussion, but it seems to me that it deserves 
to do so. 
6. Chemists and microscopists have been busy in many different places 
in collecting from rain- and snow-water the dust brought down from the 
atmosphere, and have, generally speaking, from the analysis subsequently 
made, come to the conclusion that the matter so collected is voleanic in its 
origin ; further, that it corresponds to the dust ejected from Krakatoa. 
M. W. Beyerinck, of Wageningen, says that this is beyond doubt. That rain- 
and snow-water have for some time back left considerable deposits in the 
rain-gauge and otherwise seems pretty certain. Whether such sediment 
has been collected and examined here in Nelson, our local microscopists 
can tellus. The deposits have been collected at places very wide apart, 
¢.g- Queenstown (Cape Colony), Launceston (Tasmania), Harrow (England), 
Sandhurst (Victoria), Unaluska (Alaska), and in parts of Norway. But as 
there is always more or less dust in the atmosphere, and as in some places 
from local causes, such as iron and other manufactories, dust storms, strong 
desert winds, ete., it occasionally becomes abnormally charged with addi- 
tional matter, accurate and careful analysis alone will help us here. 
Such analysis would need to be made by most skilful experts, or it would 
not be trustworthy as the basis of argument. But when we find such men 
as M. Daubrée, of Paris, and M. Renard, of Brussels, agreeing with Mac- 
pherson, Murray, and Diller, as to the analysis and identification of the 
dust, scepticism becomes less justifiable. The Royal Society of England 
has recognized the great importance of the investigation, and specially 
