In the history of human progress we find everywhere exemplified a continuous effort through centuries and centuries of change to obtain an end with the least expenditure of labour. It is one of the most striking characteristics of our nature that we proceed along that road offering the least resistance and requiring the smallest amount of endeavour. Not more true is this assertion to-day than in the ages which have sunk into oblivion, and but for this human instinct, or failing, the progress of the world would have been impossible. The prehistoric man found the action of paddling his dug-out so irksome and wearying that he invented the sail as a means of harnessing the wind to do his work, and, as a result, what does the world not owe to his apparent laziness? How else would new countries have been discovered and peopled, commerce extended to nations beyond the seas, untilled areas made to yield their fruitful produce, and wealth amassed by production and exchange of commodities? It was not until Europe had at last begun to build her big caravels and caracks, and to learn how to handle them with adequate seamanship, that the art of navigation advanced so far as to enable Columbus to sail across the Atlantic, and to lay the foundation of the prosperity of the New World. To have attained such a feat by the means of physical propulsion would have been impossible; it was only by the invention of the sail and the perfection of the sailing ship after many centuries of experimenting that this came about. For man’s endurance is hedged in by stern limits. He can only work for part of the day, and he must eat and sleep. But by yoking the wind to the sail the voyage could be continued without the necessity for plying the oar, and most of the crew could be below at their rest or their meals. But the sailing ship, too, has her limitations. When the wind drops her range of usefulness automatically ends. When the wind becomes contrary, or rises in sufficient fierceness as to become a gale, the sailing ship again loses some of her utility, whilst tides and currents in like manner combine to impede her advance from one port to another. And so, realising all these harassing circumstances, man has ever had a desire to shake himself free from such irritating restrictions, to assert his own independence of winds and seas and tides, and to steer his ships where he liked, and as fast as he liked with the minimum effort.