How many of us, re-reading the fairy stories of our childhood have for a moment believed that many of these tales might be based upon scientific truths? Of course it is probable that most of these stories have _no_ basis of fact behind them, but that they are merely the product of the story-teller's imagination--just as similar stories today are produced in this manner. But, on the other hand, it is quite conceivable that many of the seemingly fabulous accounts are in truth based upon realities; and that genuine occurrences may have happened, giving birth to these tales. We all know the general character of many of the legends. I may mention, as typical of the marvellous things done: becoming visible and invisible, as did "Jack the Giant Killer"; the existence of giants and dwarfs, as in _Little Tom Thumb_; incredibly rapid growth of vegetation, as in _Jack and the Beanstalk_; being suddenly transported without effort through immense distances and seeing at the other end of such a journey scenes and events actually transpiring at the time--as occurred in many of the _Arabian Nights_ stories; cases in which plates and dishes washed themselves, and many other household feats were performed, as in _Prince Hildebrand and Princess Ida_; cases of long sleep, such as the _Sleeping Beauty_; cases in which human beings have been transformed into animals, and vice versa, as in _Beauty and the Beast_; cases in which palaces have sprung up over night, existing on the desert plain, only to vanish the next night and leave it as barren as before--as so often happened in the _Arabian Nights_.