Chapter 151 Summary

This very short chapter follows Christopher for several days at school. He explains that some things are mysteries that are not really mysteries. Lightning, for example, was a mystery until someone discovered electricity, and then it became science. He relates the tale of an uncle who saw a ghost in a shop where the people say they see this particular ghost all of the time and that the ghost is not to be feared. Christopher, of course, does not believe in the supernatural, so he reasons that science will some day find an explanation for ghosts, just as science found an explanation for lightning. Christopher also outlines a rather complex formula for determining the population densities of species. The formula proves that some things in nature are simply too complex to predict, and he concludes that sometimes species become extinct for no reason...