There are many thrilling incidents-all the more attractive because of their truth-in the study, the trials, the disappointments, the obstacles overcome, and the final triumph of the successful inventor. Every great invention, afterward marvelled at, was first derided. Each great inventor, after solving problems in mechanics or chemistry, had to face the jeers of the incredulous.

There are many thrilling incidents--all the more attractive because of their truth--in the study, the trials, the disappointments, the obstacles overcome, and the final triumph of the successful inventor.