380 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 falling 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 it 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' Ency- 

 clopaedia, " Twilight"). I do 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 volcanic 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 tell us. The deposits have been collected at places very wide apart, 

 e.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, etc., 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. Daubree, of Paris, and M. Benard, of Brussels, agreeing with Mac- 

 pherson, Murray, and Diller, as to the analysis and identification of the 

 dust, scepticism becomes less justifiable. The Boyal Society of England 

 has recognized the great importance of the investigation, and specially 



