《徐霞客游记·浙游日记下》
黑暗中用拐杖探着地走进去几十步，洞更加宽广，只是没有灯火，四顾什么都看不见，这才往回走出来。
从黑暗中以杖探地而入数十步，洞愈宽广，第但是无灯炬，四顾无所见，乃返步而出。
In the darkness, the tour party used their walking sticks to probe the ground as they walked for dozens of steps. The cave became wider, but without any light source, nothing could be seen. So they headed back out.