Popular impressions respecting the supposed terrestrial effects of the comet of 1811--a fine object in the autumn of that year, long remembered by many--are on record. It was gravely noted, that wasps were very few in number; that flies became blind, and disappeared early; and that twins were born more frequently than usual. The season was remarkable for its bountiful harvest and abundant vintage. Grapes, figs, melons, and other fruits, were not only produced in extraordinary quantity, but of delicious flavor, so that “comet wines” had distinct bins allotted to them in the cellars of merchants, and were sold at high prices. There is, however, no fact better attested, by a comparison of observations, than that comets have no influence whatever in heightening or depressing the temperature of the seasons. The fine fruits and ample harvest of the year in question were, therefore, coincidences merely with the celestial phenomenon, without the slightest physical connection with it. Though the advanced civilization of recent times has led to juster views of cometary apparitions than to regard them as divinely-appointed omens of terrestrial calamity, yet society is apt to be nervous respecting these bodies, as likely to cause some great natural convulsion by collision with our globe. The great comet, which in 1682 received first the name of Halley’s comet, appeared last in 1835, his return having been foretold within three days of its actually taking place. For Halley’s comet is a member of the Solar System, having a yearly journey of seventy-six earthly years. He journeys nearer the sun than Venus, and travels farther away than Neptune. In the years 1858, 1861, and 1862, three more comets appeared, all visible without the help of a telescope. Of these three, Donati’s comet, in 1858, was far superior to the rest. This fine object was first discovered on the 2d of June by Dr. Donati, at Florence. It appeared at first as a faint nebulous patch of light, without any remarkable condensation; and as its motion towards the sun at that time was slow, it was not till the beginning of September that it became visible to the naked eye. A short tail was then seen on the side opposite to the sun. [Illustration: DONATI’S COMET, 1858.] The development was afterwards rapid, and the comet became equally interesting to the professional astronomer and to the unlearned gazer. In the first week of October the tail attained its greatest length, 36°. At this time the tail was sensibly curved, and had the appearance of a large ostrich-feather when waved gently in the hand. At the latter end of October the comet was lost in the evening twilight. Its nearest approach to the earth was about equal to half the distance of the earth from the sun, and the nearest approach to Venus was about one-ninth part of that distance. An elliptical orbit, with a periodic time of more than 2,000 years, has been assigned to our late visitor.