Having, I trust, allayed all tremors by these preliminary remarks, let me go on to say that while all sane civilized persons believe this earth of ours to be more or less globular in shape, it probably occurs to but few that the shortest distance from point to point on a globe is along a curve. But in order to get any substantial gain out of this knowledge in the direction of shortening a ship’s passage, it is necessary first of all to have a considerable stretch of sea whereon to draw your curve, which is after all a straight line, since it is the shortest distance between two points. Even the fine open ocean between England and America is hardly sufficient to induce navigators to make use of Great Circle Sailing on outward or homeward passages, the gain being so small. When, however, the captain of an outward bound ship has wriggled through the baffling belt of hesitating winds that have hindered his progress southward from the equator to Cape, and begins to look for the coming of the brave westerly gales that shall send him flying before them to Australia or New Zealand, an opportunity occurs as in no other part of the world for putting the pretty Great Circle theory into practice.
It may be necessary to remind the reader that Great Circles are those which divide a globe into two equal parts, such as the equator and the meridians. If, then, the navigator at Cape in South America draws a thread tightly on a terrestrial globe between that point and, say, the south-east cape of Tasmania, the line it describes will be the arc of a Great Circle, and consequently the shortest distance between the two places. But when he comes to lay down the track which that thread has described upon his Mercator chart he finds that, instead of steering almost a straight course between the two places, he must describe a huge curve, with its vertex or highest southerly point well within the Antarctic circle. Now, no sane seaman would dream of seeking such a latitude upon any voyage but one of exploration, since it is well known what kind of weather awaits the unfortunate mariner there. But, without saying that Captain Jellico was a lunatic, it is necessary to remark that he was no ordinary shipmaster, and those who knew him best often prophesied that one day his persistent pursuit of hobbies and fads would involve him and all his unfortunate crew in some extraordinary disaster.