; and as suddenly disappear. Thus KRONE "observed
a spot of no inconsiderable dimensions which sprang into existence in
less than a minute of time." DR. WOLLASTON says:--"I once saw with a
two-inch reflector a spot which burst in pieces as I was looking at it."
BIELA also notes that "spots disappear sometimes in a single moment."
SIR WILLIAM HERSCHEL "turned away his eyes from a group of spots he was
observing, and when he looked again the group had vanished."

Of those who attempt to make an estimate of these phenomena by
mathematical formulae, we would ask, What velocities must these sudden
and apparently widespread outbursts represent, if they take place at the
sun?

_Effects of these Wonderful Phenomena._

That this phenomenon is a result of an interruption of the solar current
is rational to suppose. It is indisputable that the interruptions which
produce these manifestations have an important bearing upon terrestrial
phenomena. Winds, storms, vegetation, healthfulness, are manifestly
influenced, and in a measure controlled by these perturbations.

_Mistaken Conceptions._

The claim of many scientists that spot periods may be calculated, and
classified, possesses no element even of probability, much less of fact,
to sustain the supposition. The evanescent character of many of these
spots places them beyond the sphere of statistical calculation.

_May not be Tabulated._

Not even concerted and systematic investigation can insure reliable
conclusions, for persons separated by even inconsiderable distances
would not always observe precisely the same spot manifestations.
Moreover, the spots appear and vanish so quickly that no correct
estimate can be made at any single locality. As well attempt to map and
chart the aurora borealis.

_Unbiassed Estimate of their Character and Location._

SCHEINER was one of the first who ever observed these spots through a
telescope, and was therefore uncontrolled by theories in his estimate of
their character and location. He held it "impossible that they could be
on the sun itself," and imagined some of them to be "as far from the
sun, as the moon, Venus, or Mercury."

CHAPTER XI.

SOUND.

_Essential Character and Medium of Transmission._

Sounds are products of vito-magnetic conditions and changes. They result
from