Sun, the brightest and most important luminary, which imparts light to the world, and the presence of which constitutes the day.

The genial warmth of the sun, conveyed to the earth by its rays, evidently contributes to promote vegetation, while it conduces to the health and comfort of man-land. Its distance from the earth is not accurately ascertained ; as it varies according to the motion of the globe; but, agreeably to the method lately discovered by M. Klimm (professor of mathematics at Meissen, in Saxony), such distance, as well as the size of the sun, may be determined with tolerable accuracy, by calculating the proportion subsisting between the supposed diameter of the sun, and that of the earth. Hence we shall only add, that the axis of the former is, by astronomers, computed to be nearly 883, 210 English miles; and its circumference is about 2, 774, 692 miles.

The sun is placed in the centre of the universe: it revolves round its own axis in 26 days; but its course on the ecliptic is accomplished by the revolution of the earth in 365 days and about six hours. - See Calendar.

Some naturalists have strangely conjectured the sun to be a globe of gold; because that metal endures the action of heat without diminution, for a longer period than any other metallic substance; while others have conceived it to be a mass of ice : but, as a discussion of these opinions, as well as of the spots, which have been observed on its surface, would lead us into abstruse disquisitions, the curious reader will consult the writers mentioned in the conclusion of the article Astronomy.