An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

wcc c0 thlt erroneously rlpresentecl in orreries and diagrams,
1)ut are sparsely scattered at illlcnense distances friom each
other.:'They are like insects flying in the expanse of ]eaven.
If a comet's tail lay Awith its axis int t~he plane of the cclip.
tic whellcn it was nIear the sun, we can imnagine that the tail
inight sweep over tie earth; but the tail may be situated at
any anglCe with the ecliptic as wcll as in tlle same plane with
it, andl tihe chances that it will not be in the same 1)lanle are
llmost infinlite. It is also cxtremely imp)robablc tthat a comet
will cross the lallne of thle clipjtic precisely at thlc earth's })ath
ill that plane, since it may as )roblably cross it at any other
point nearer or more reml' ote fr'oml the sun. Still, some comets
have occasiolnally apll)roached near to the earth. Titls 13Bila's
comet, in returning to tlhe sunll in:1832, crosse'd the celiptic very
near to the eartf's tr'ack, and haadtlhe earth been tlhen at tlhat
point of its orbit, it migllt haveo passed through a portion of
thle nebulous atmtosphere, of thie comect. Thell earth was withtil
a mnonlth of reaclthing tlhat point..lis miglt at; first viewr seen
to involve some tazard; yet wo must consi(der tthat a month
short implied a distan6e of nearly 50,000,000 miles. Laplace
has assignled the consequences lthlat would ensue inl case of a direct collision between the carth and a comet "; but terrible as
hle has rlcprcesented them onl the slupl)ositioln that the nucle11us of
thel conmet is a solid body, yet considering a comet (as most of
them (loubtless ar1c) as a mass of exceedingly light lnebulouts
matter, it is lnot p)robable, even were the earth to make its way
directly through a comet, thalt a particle of the colmet w\ould
reach tthe earth.'IThe portions encounterecd by the earth, would
be arrlsted by the tatmospllerl,' and probably inflamecd; and
they would perhaps exhibit, oni a morel0 magnificent scale than
fwaks ever before observcd, thle plhenomena of fihooting stars orl
mlleteoric showers.
MFIrTEORIU 1 [OW'IRS,
406. The remarlkable exhibitions of shooting stars which
have occurred withint a few years past, have excited great interest among astronomers, and led to solme new views respecting the construction of the solar system. IThe.cir attention was....................................
* i Syst. (itt monde, 1, iv., o. 4,