《论衡·卷八·艺增篇》
然而耳朵能听到的，眼睛能看见的，不超过十里，即使它在天上鸣叫，人不可能听见。
然则耳目所闻见，不过十里，使参天之鸣，人不能闻也。
However, what the ears can hear and what the eyes can see does not exceed ten li. Even if the crane were crying in the heavens, people would not be able to hear it.