The _nature_ of the sun is a subject which has not only excited the most diligent inquiry among men of scientific knowledge, but the opinions concerning it have passed through a variety of vicissitudes. The sun being evidently the source of light and heat, was by the ancients considered to be a globe of fire. But Dr. Herschell’s discoveries, by means of his immensely large telescopes, tend to prove, that what we call the _sun_ is only the _atmosphere_ of that luminary: “that this atmosphere consists of various _elastic fluids_, which are more or less transparent; that as the clouds surrounding our earth are probably decompositions of some of the elastic fluids belonging to the atmosphere itself, so we may suppose that in the vast atmosphere of the sun similar decompositions may take place, but with this difference, that the decompositions of the elastic fluids of the sun are of a _phosphoric_ nature, and are attended by lucid appearances, by giving out light.” The body of the sun this celebrated astronomer considers as hidden generally from us, by means of this luminous atmosphere; that what are called _maculæ_, or _spots_ on the sun, are real openings in this atmosphere, through which the _opaque body_ of the sun becomes visible; that this atmosphere itself is not _fiery_ nor _hot_, but is the instrument which God designed to act on the caloric or latent heat; and that heat is only produced by the solar light acting on and combining with the caloric or matter of fire contained in the air, and other substances which are heated by it.