《论衡·卷二十·须颂篇》
所以，如果过于广阔，长宽就很难计算；非常深，深浅就很难测量。
故夫广大从横难数，极深，揭历难测。
Therefore, if something is too wide, it is difficult to calculate its length and width; if something is too deep, its depth is difficult to measure.