I used to wonder at the ease with which a cockroach can climb a perfectly smooth wall and run across the
ceiling. I know now that to do this is the easiest thing in the world-if you have the proper incentive behind
you. When a skunk, tail poised to spray, entered my tent, I certainly had the proper incentive. I went up one
wall of the tent and had crossed over and was in the act of coming down the other side when the skunk
wandered back out the tent door.
What is the tone of this passage?
friendliness
longing
humor
fear