Modern astronomers have long noticed the spots frequently visible on the sun. They are described as having the appearance of vast holes, or fractures, in his outer surface or crust, through which an inner appears to be seen. This, also, seems to favour the doctrine of different spheres. Notwithstanding the sun revolves very slowly on his axis, it is probable that his poles are open to a greater or less extent; but we can never see into them, owing perhaps to the earth, never being very far from the plane of the sun's equator, his being such a vast deal larger than the earth, and the atmosphere surrounding him so extremely luminous. Very little doubt exists in my mind, that the poles of the sun and of Jupiter would appear somewhat like those of Mars or the rings of Saturn, were it not that the two former never present their axes, in any perceptible degree, towards us; neither does our satellite, the moon, ever present either of her poles to us: hence, though this may be in some degree open, (notwithstanding her slow rotation) owing to her axis always being nearly at right angles with a line drawn to the earth, we are not able to see whether they are open or not,――more especially as her atmosphere is so light and rare as not to produce much refraction. The vast round deep caverns observable on the surface of the moon, appear as if they might once have been polar openings; if so, she must frequently have changed her axis. The spots of light which have at different periods been discovered by astronomers, on the surface of the moon, near her poles, when she was on the face of the sun, in an eclipse of that luminary, are perhaps best accounted for by supposing the sun to shine in, either at one of her polar openings or through a cavity on her further side, and appearing to us through one of her annular cavities, on this side, and near her poles: Or the sun being much larger than the moon, and the axis of the moon a little varied from right angles with the earth, (or perhaps the low side of the sphere being next to the earth,) the sun would shine through an annular cavity or open pole, so as to appear to us as a spot of light on the moon's disk.