It will be necessary, for the purpose of my story, that I shall go back more than once from the point at which it begins, so that I may explain with the least amount of awkwardness the things as they occurred, which led up to the incidents that I am about to tell; and I may as well say that these first four chapters of the book--though they may be thought to be the most interesting of them all by those who look to incidents for their interest in a tale--are in this way only preliminary.