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POPULAR SCIENCE REVIEW. 
opened to liim in the path of discovery by diligent observation 
of the solar spots alone, remembering 
No earnest work 
Of any honest worker, howbeit weak, 
Imperfect, ill-adapted, fails so much 
That ’tis not gathered like a gram of sand . 
To enlarge the sum of human action used 
For carrying out God’s end.” 
Strange to say, it is when the sun is entirely hidden from view 
(as during the darkness of a solar eclipse) that we become best 
acquainted with its clouds, its atmosphere, and the general 
phenomena of its surface. Look at those two illustrations 
representing the appearance of the sun, or rather the light sur- 
rounding it, and the moon at the last two solar eclipses of 1858 
and 1860. What strange forms are beheld in the halo or glory 
about the moon ! What are those crimson flames ? Are they 
our old friends the bright streaks of lio-ht — the faculae? Is it 
this corona or glory which is the suspected outer atmosphere 
of the sun, and which causes that dimness of the sun’s light 
towards the margins which has been already mentioned? Does 
it buoy up and float those cloudy protuberances for some forty 
or fifty thousand miles above — not the real surface, but the 
outer photosphere of the sun ? These are questions which, not- 
withstanding that they have been critically observed during the 
solar eclipses of 1842, 1851, 1858, and 1860, still remain unde- 
cided. Some scivans hold that they are purely optical, caused 
by the sunlight striking the edges of the moon — the effects of 
that phenomenon in optics known by the name of interference, 
i. e. when light passes by any rough edge, and produces certain 
coloured fringes to the ray which is received on a screen. Are 
those ruddy prominences produced in this manner ? In the 
first place, they are too sharply defined to have their origin in 
this way ; in the second, they have been seen to increase in 
length as the moon passed away from them, and to decrease in 
dimensions as the moon passed towards them. This circum- 
stance, which was confirmed by many observers, would seem 
to be conclusive of their being’ part of the real body of the sun, 
that the red flames are the faculae, that the corona is the lumi- 
nous atmosphere of the sun. But how are these strang’e rays 
of light produced in the corona? How are we to explain that 
they appeared on the left when total darkness commenced, 
and to the right when the moon was leaving the disc of the 
sun ? The Astronomer Royal is of opinion that the atmosphere 
of the earth extends all the way to the moon, and that the light 
is reflected by this atmosphere. There are methods even of 
detecting whether such is the case, and in the present instance 
