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known members of the Solar System , we are regretfullyleaving many unnoticed.
To it belong some Comets , whose orbits are so preciselydetermined, that we can calculate their daily places almostas accurately as those of the Planets ; some, whose periodsround the Sun are so short * that they come within the limitsof those of the Minor Planets, while their orbits are not verymuch more oval, or excentric, than those of some of theselast-named little bodies. There are also, as we have pre-viously mentioned, several well-known Comets which, injourneying round the Sun , never go much farther away thanthe orbit of Jupiter ; others whose range is approximatelybounded by that of Saturn , or of Uranus ; others which sweepoutwards a little beyond that of Neptune , amongst which lastis included the great comet of Halley;t while there are others,still under the control of our Sun, which, in their elongatedpaths, rush away to distances far more remote, before they turnback to a nearer proximity again. All these are members ofour Solar System .
And many a swarm of meteorites, mostly minute, butmingled occasionally with some of larger bulk, revolve inregular orbits round the Sun , in which in some cases (if notin most) they lag behind comets to which they have once be-longed, or of the dissipation of which they are the remnants.They are ever falling upon the Sun as fuel; or being explodedinto dust by the furious heat which the friction of our own, orof some other, atmosphere generates as the}- hurry through it;or, by collision with Satellites and Planets, or with one another,losing their individuality and becoming aggregated into somelarger mass. While they thus revolve, they too are membersof our Solar System .
Aud it has its visitors as well—Comets and Meteorites whichrushing onwards from distant regions of space travel once, and
# As, for instance, 3-J years in the case of Encke’s comet, and 51 yearsin the case of Winnecke’s.
t To its return in 1910, in what will probably be a most effectiveposition for observation in our latitudes, those who are now young maylook forward with pleasing anticipations.