《徐霞客游记·楚游日记二》
我揣度若葡旬在水中爬进去，必然口鼻都被沾湿，并且我用火把探了一下，即使贴着缝隙的顶往里爬，火把仍有一半被水浸泡。
计匍匐水中，必口鼻俱濡水，且以炬探之，贴隙顶而入，犹半为水渍。
I estimated that if I crawled in through the water, both my mouth and nose would inevitably get wet, and when I used the torch to probe, even if I crawled along the top of the crack, half of the torch would still be submerged in the water.