《徐霞客游记·滇游日记三十九》
但是底下无旁洞，来不及转身水就溢满了，也不见水从哪里来，水满达树皮边沿下边一寸五时，就停止不溢。
然底无旁穴，不旋踵即不及转身而水仍满，亦不见所自来，及满至肤边下寸五，辄止不溢。
There is no side hole, and it is too late to turn around when the water is overflowing. It is unknown where the water comes from. When the water fills up to an inch and a half below the edge of the bark, it stops overflowing.