from particular differences in their shape
and appearance, and sometimes under the general term of comets. In the
Philosophical Transactions, they are called, indiscriminately,
fire-balls, or fiery meteors; and names of similar import have been
applied to them in the different languages of Europe. The most material
circumstances observed of such meteors may be brought under the
following heads: 1. Their general appearance. 2. Their path. 3. Their
shape or figure. 4. Their light and colour. 5. Their height. 6. The
noise with which they are accompanied. 7. Their fire. 8. Duration, 9.
Their velocity. Under these different heads meteors have been
investigated by the scrutinizing of philosophy, and many superstitious
notions, long entertained concerning them, entirely exploded. Meteoric
phenomena, it has been demonstrated, all proceed from one common
cause--irregularity in the density of the atmosphere. When the
atmospheric fluid is homogenous and of equal density, the rays of light
pass without obstruction or alteration in their shape or direction; but
when they enter from a rarer into a denser medium, they are refracted or
bent out of their course; and this with greater or less effect according
to the different degrees of density in the media, or the deviation of
the ray from the perpendicular.
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