miles. The whole had the
appearance of being supported on pillars of fire, these seeming
pillars being in reality hydrogen jets brighter and more active
than the substance of the cloud. At half-past twelve, when
Professor Young chanced to be called away from his observatory,
there were no indications of any approaching change, except that
one of the connecting stems of the southern extremity of the cloud
had grown considerably brighter and more curiously bent to one
side; and near the base of another, at the northern end, a little
brilliant lump had developed itself, shaped much like a summer
thunderhead.

[Illustration: Fig. 34.--Solar Prominences of Flaming Hydrogen.]

But when Professor Young returned, about half an hour later, he
found that a very wonderful change had taken place, and that a
very remarkable process was actually in progress. "The whole thing
had been literally blown to shreds," he says, "by some inconceivable
uprush from beneath. In place of the quiet cloud I had [Page 87]
left, the air--if I may use the expression--was filled with the
flying _debris_, a mass of detached vertical fusi-form fragments,
each from ten to thirty seconds (_i. e._, from four thousand five
hundred to thirteen thousand five hundred miles) long, by two or
three seconds (nine hundred to thirteen hundred and fifty miles)
wide--brighter, and closer together where the pillars had formerly
stood, and rapidly ascending. When I looked, some of them had
already reached a height of nearly four minutes (100,000 miles); and
while I watched them they arose with a motion almost perceptible to
the eye, until, in ten minutes, the uppermost were more than 200,000
miles above the solar surface. This was ascertained by careful
measurements, the mean of three closely accordant determinations
giving 210,000 miles as the extreme altitude attained. I am
particular in the statement, because, so far as I know,
chromatospheric matter (red hydrogen in this case) has never before
been observed at any altitude exceeding five minutes, or 135,000
miles. The velocity of ascent, also--one hundred and sixty-seven
miles per second--is considerably greater than anything hitherto
recorded. * * * As the filaments arose, they gradually faded away
like a dissolving cloud, and at a quarter past one only a few filmy
wisps, with some brighter streamers low down near the
chromatosphere, remained to mark the place. But in the mean while
the little 'thunder