And the reason of this must be particularly set forth. When the planets are struck by the rays of the sun, in the situation which I have described, _i. e._ in their quadrature, they are prevented from holding on their straight forward course, and are raised on high by the force of the fire[231]. This cannot be immediately perceived by the eye, and therefore they seem to be stationary, and hence the term station is derived. Afterwards the violence of the rays increases, and the vapour being beaten back forces them to recede. This exists in a greater degree in their evening risings, the sun being then turned entirely from them, when they are drawn into the highest apsides; and they are then the least visible, since they are at their greatest altitude and are carried along with the least motion, as much less indeed as this takes place in the highest signs of the apsides. At the time of the evening rising the latitude decreases and becomes less as the motion is diminished, and it does not increase again until they arrive at the second station, when the altitude is also diminished; the sun’s rays then coming from the other side, the same force now therefore propels them towards the earth which before raised them into the heavens, from their former triangular aspect[232]. So different is the effect whether the rays strike the planets from below or come to them from above. And all these circumstances produce much more effect when they occur in the evening setting. This is the doctrine of the superior planets; that of the others is more difficult, and has never been laid down by any one before me[233]. CHAP. 14. (17.)—WHY THE SAME STARS HAVE DIFFERENT MOTIONS.