Such a comet as Halley's (fig. 3) for instance, though one of comparatively limited range in space, yet travels so far from the sun that, from the extreme part of its path, it sees the stars displaced nearly twenty times as much (owing to its own change of position) as they are from the earth on opposite sides of her comparatively narrow orbit. And the length of this comet's year, if it indicated the length of the lives of all creatures travelling along with it, would suggest a power of patiently watching the progress of changes lasting not a few of our years only, but for centuries. Seventy-five or seventy-six years elapse between each return of this comet to the sun's neighbourhood, and one who should have lived during sixty or seventy circuits of this body around its mighty orbit would have been able to watch the rush of stars, with their velocities of many miles per second, until visible displacements had taken place in their positions. [Illustration: Fig. 3.--Halley's Comet of 1835.] This, however, is as nothing compared with the mighty range in space and the enormous period of the orbit of the great comet of the year 1811 (fig. 4). This comet is, on the whole, the most remarkable ever known. It was visible for nearly seventeen months, and though it did not approach the sun within 100,000,000 miles, and was therefore not subject to that violence of action which has caused enormous tails to be thrown out from comets which have come within a few million miles of him, or even within less than a quarter of his own diameter, it flourished forth a tail 120,000,000 of miles in length. Its orbit has, according to the calculations of the astronomer Argelander, a space exceeding the earth's distance from the sun 211 times, and thus surpassing even the mighty distance of Neptune fully seven times. It occupies in circuiting this mighty path no less than 3065 of our years (with a possible error either way of about forty-three years). So that, according to Bible chronology, this comet's last appearance probably occurred during the rule of the judge Tola, son of Puah, son of Dodo, over the children of Israel, though it may have occurred during the rule of his predecessor Abimelech, or during that of his successor Jair.[1] During one half of the enormous interval between that time and 1811 the comet was rushing outwards into space, reaching the remotest part of its path somewhere about the year 278 (A.D.), and from that time to 1811 it was on its return journey. It is strange to think, however, that though the remotest part of its path lay 211 times farther from the sun than the earth's orbit, yet even this mighty path, requiring more than 3000 years for a single circuit, cannot be said to have carried the comet into the star-depths. If the earth were to shift its position by the same enormous amount the nearest fixed star would have its apparent position changed only by about an eighth part of the apparent diameter of the sun