Our next neighbour, Venus, between us and the sun, (though her being between us and the sun prevents us from having so favourable an opportunity of examining her poles, as those of Mars, who is our next neighbour on the side opposite the sun) presents appearances at certain times, which seem to lead to the conclusion, that she also is constituted of concentric spheres. At times, when this planet is nearly a crescent, we are able to discover a deficient space near the tip of one of her horns. Admitting Venus to be constituted of concentric spheres with open poles; and supposing one of the vacant spaces, between two of her spheres about the polar openings, to traverse her horn or cusp, at the place where the dark space occurs,――it would present to us exactly such an appearance as does actually occur. At other times, one of the horns or cusps of Venus is seen to wind inward as it were into the body of the planets, extending about fifteen degrees further than the other horn. This is an appearance which would also be presented, if Venus is formed according to Symmes's theory. And again, supposing one of her horns to terminate around the verge of a polar opening, in such way as to follow the curve of the verge for some distance, (which is of course more curved than the periphery of the planet) and the same appearances, I think, would occur. The axis of the planet not being at right angles with the polar openings, in its revolutions one side of the verge would be thrown much nearer to us than the other; and the different spheres revolving on their axes with different velocities would at different times exhibit to our view the verge of a different sphere.[5]