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sun) from what they were before its disappearance. Some,” he 
remarks on the second point, “ like those which appeared in 
1858 and 1861, without altogether disappearing as if swallowed 
up by the sun, after attaining a certain maximum or climax 
of splendour and size, die away, and at the same time move 
southward, and are seen in the southern hemisphere, the faded 
remnants of a brighter and more glorious existence of which we 
here witnessed the grandest display ; and on the other hand we 
here receive as it were many comets from the southern sky, 
whose greatest display the inhabitants of the southern parts of 
the earth only have witnessed. It also very often happens that a 
comet, which before its disappearance in the sun’s rays was but 
a feeble and insignificant object, reappears magnified and 
glorified, throwing out an immense tail, and exhibiting every 
symptom of violent excitement, as if set on fire by a near 
approach to the source of light and heat. Such was the case 
with the great comet of 1680, and that of 1843, both of which, 
as I shall presently take occasion to explain, really did approach 
extremely near to the body of the sun, and must have undergone 
a very violent heat. Other comets, furnished with beautiful and 
conspicuous tails before their immersion in the sun’s rays, at 
their reappearance are seen stripped of that appendage, and 
altogether so very different, that but for a knowledge of their 
courses it would be quite impossible to identify them as the 
same bodies. Some, on the other hand, which have escaped 
notice altogether in their approach to the sun, burst upon us 
at once in the plenitude of their splendour, quite unex- 
pectedly, as did that of the year 1861.” 
It was clear, then, long since, that comets cannot be classified 
either according to their size or their development. But this 
has been even more conclusively shown by the spectroscopic 
analysis of large and small comets. For certain bright bands 
seen in the spectra of the small comets which had been 
examined before the present year, are found also to characterize 
the spectrum of the comet which adorned our northern skies 
last June and July, and to be shown not only by the coma, but 
also by the tail. I do not here enter into any special consi- 
deration of the results of spectroscopic analysis as applied to this 
comet, because to say truth our spectroscopists have not met 
with any noteworthy success ; and we must wait till the spectro- 
scopists of the southern hemisphere have sent in their state- 
ments before we can determine whether any special accession 
has been made to our knowledge. It may, however, be assumed 
from what has been observed here, that the characteristic spec- 
trum of comets, large and small, is that three-band spec- 
trum which was first recognised during the spectroscopic 
investigation of Tempel’s small comet in the year 1866. 
