1. Whenever _Venus_ is in conjunction with the Sun, that is, when she is in the same direction from the Earth, or towards the same part of the Heavens the Sun is in; she either appears with a bright and round face, like a Full Moon, or else disappears: Or, if she is visible, she appears horned, like a new Moon; which phænomena could never happen if ♀ did not turn round the Sun, and was not betwixt him and the Earth: For since all the Planets borrow their light from the Sun, it is necessary that ♀’s lucid face should be towards the Sun; and when she appears fully illuminated, she shews the same face to the Sun and Earth; and at that time she must be above or beyond the Sun; for in no other position could her illuminated face be seen from the Earth. Farther, when she disappears, or if visible, appears horned; that face of her’s which is towards the Sun is either wholly turned from the Earth, or only a small part of it can be seen by the Earth; and in this case she must of necessity be betwixt us and the Sun. Let S be the _Sun_, T the _Earth_, and V _Venus_, having the same face presented both towards the _Sun_ and _Earth_; here it is plain that the Sun is betwixt us and _Venus_ and therefore we must either place _Venus_ in an Orbit round the Sun, and likewise betwixt him and us, as in _Fig. 1._ or else we must make the Sun to move round the Earth in an Orbit within that of _Venus_, as in _Fig. 2._ Again, after _Venus_ disappears, or becomes horned, at her[3] ☌ with the ☉, she then must be betwixt us and the Sun, and must move either in an Orbit round the Sun and betwixt us and him, as in _Fig. 1._ or else round the Earth, and betwixt us and the Sun, as in _Fig. 2._ But _Venus_ cannot move sometimes within the Sun’s Orbit, and sometimes without it, as we must suppose if she moves round the Earth; therefore it is plain that her motion is round the Sun. [Sidenote: Why _Venus_ is always either our Morning or Evening Star.]