Page:Popular Science Monthly Volume 89.djvu/518

 Lost Comets and Their Story

��B\- J. F. Springt'i-

PERHAPS the most mysterious of all the heavenly- bodies are the comets. Some are ne\er seen except with the telescope, or else the\- appear as faint starlike bodies in the sky; others blaze forth, grotesque and fantastic of figure and brilliant in appearance, to excite and appal the ignorant. But always, whether dim or glorious, the appearance lasts but a moderate period at the most, and then the visitor is gone.

Astronomers make obser\ations with instruments of precision and seek to follow the departed heavenly body by prolonging the ascertained path of its movement. And there has. been a good deal of proved success in this work. For astronomers have in the case of some comets found that the orbit was a closed curve — an ellipse — and ha\e thus been able to state in ad\ance the time when and the [jlace where a return would occur.

The most notable instance of a comet which continually returns is that of Halle\'s Comet. This remarkable body rushes through space in an elongated ellipse of such size that three-quarters of a century elapses between \isits.

But there are comets which dazzle the sight

for a period and then disapjjcar ne\cr to

return. Still others begin as regular

visitors and then fail to reappear. Those

comets which dart in from the outer

regions of the solar system for a

tingle glance at the earth and its

inhabitants we are content to let

depart without any especial

concern. But when a comet

makes regular visits and

then disappears irrecov-

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��The comets blaze forth in fantastic glory occa- sionally exciting both curiosity and awe

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