《论衡·卷十一·说日篇》
要是停留在扶桑树上、汤谷水中，那就不符合运行的度数，运行的度数就要发生差错，跟太阳随天转不相应了。
留则失行度，行度差跌，不相应矣。
If it remains on the Fusang tree and in the Tang Valley, then it will not be in accord with the degree of movement, errors will occur in the degree of movement, and it will not correspond to the sun following the sky.