This book was written about the history and the evolution of boats and ships. Once upon a time there were no ships. Men did not know the meaning of the word; they did not want them; and, for many, many centuries the sea-gulls had the ocean all to themselves. But boats are of very ancient date. Doubtless the first boats must have been constructed by the first men who dwelt on the earth. They consisted, probably for we are now in the land of conjecture of stumps of fallen trees, or bundles of rushes, seated astride of which the immediate descendants of our first parents ferried themselves over small lakes and across rivers. Various experiments have from time to time been made in the way of building boats and ships with double hulls, the object being to obtain increased stability, and thus reduce to a minimum the rolling and pitching of ordinary vessels. The steamship Castalia was an ambitious attempt in this direction. She was built for the passenger service between England and France. But she did not realise the expectations formed of her.