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POPULAR SCIENCE REVIEW. 
As to the distance to which this meteoric corona, so to call 
it, extends, we need entertain no doubt that in reality it is 
coextensive with the solar system itself. The zodiacal light 
probably indicates its more condensed portion ; but, inasmuch as 
our earth encounters meteors which come from beyond the 
orbits of Uranus and Neptune, we can entertain no question 
that the real limits of the meteoric matter lie far outside the 
apparent extension of the zodiacal light. How far the existence 
of light-reflecting matter can be recognised during eclipse is a 
totally different question. Nor is it one to which any definite 
reply can be given — for the apparent extension of the corona 
depends upon the condition of our atmosphere, the height of 
the station, the visual powers of the observer, and other 
circumstances of the sort. It may be mentioned, however, that 
during the late eclipse Captain Tupman recognised radial 
polarisation in the coronal light at a distance of from forty to 
fifty minutes from the moon’s limb, showing that there was 
light-reflecting matter at a distance of more than a million 
miles from the sun’s surface. 
I cannot better close this paper than by quoting the words 
with which Janssen concluded his first letter to the President of 
the Paris Academy of Sciences : “ The question whether the 
corona is due to the terrestrial atmosphere is disposed of 
( tranchee ), and we have before us the prospect of the study of 
the extra-solar regions, which will be very interesting and 
fruitful.” A pity only that this study should have been put 
back for two years through the enunciation of an erroneous 
theory, and that now, when the real significance of the corona 
has at last been recognised by all, there should be no prospect 
of effective eclipse observations for years to come. 
