MAKING A CHART.

Press, Volume LX, Issue 18237, 22 November 1924, Page 16

MAKING A CHART.

HOW NAVIGATION IS POSSIBLE. DEBT TO BRITISH AYORK ON BARRIER REEF. (rEOU OL".". OTS- COEHESTOXDE.VT.' SYDNEY, November 12. The British are masters of the seas, but is it generally realised how liberally they have shared frith* the rest of the world the fruits of patient toil of ecntaries not in the art of shipbuilding alone, but in the stupendous knowledge of the seas that make 3 world navigation in safety possible? The wonderful charts' tell stories of infinite details to practised eyes that read them, and it is because these charts, compiled by the Naval authorities of the British Empire, have freely been made available to the world that all the nations are able to traverse the seas in their ships with full knowledge of the great ocean highways. Such ideas as these are brought into grand relief by the remarks of Mr Charles Hediey. F.L.S., scientific director of the Great Barrier Reef committee of Queensland, who is accompanying H.iLA.S. Geranium on its expedition for the survey and charting of the reef —a work "which will occupy a considerable number of years. After describing the work, with the aid of a seaplane, amongst the beautiful coral mazes of the reef Mr Hediey savs:—

"Who i 3 the cleverest guide in the world? Some can find a path across a. waterless desert, or across the dense, untrodden jungle, but there are better. Some can safely lead across snowfields and glaciers where a false step might pitch a wayfarer to death down a crevasse in the ice, but there are better. Those there arc who, after sailing across the ocean for days or without sight of land, or marks or milestones, can announce: 'Tomorrow at noon we shall see land, and there will be palm trees growing on the shore.' The traveller who sees palm trees appear punctually as foretold will grant that it is the master mariner who is the best guide in the world. But the navigator who performs this miracle of guidance must have tools for his work, his compass, his sextant, and especially his chart. A chart, or sea map, is something about which everybody has read, but which few landsmen ever see' or "would comprehend if they did see it. So complex, so interesting is a chart that the writer claims that no other single sheet of paper contains so much and so varied information as an Admiralty chart. The chart shows the navigator in which direction to point hi 3 ship that lie may reach her destination. Then the lighthouses are described, how each may be known from the oJ'hers, and how* far the light shines, so that a vessel may travel as safely and as fast by night as by day. The chart tells not only how deep the sea is, but what there is at the bottom, mud, sand, or rock.' Sometimes local magnetic currents affect the compass, so that it points falsely to the north; the chart invariably warns the mariner of this. If you should happen to be shipwrecked 011 a desert island, the chart might even mention if the people of the neighbourhood were savages, and direct you where to find -wood and water. The chart tells all about tho tides and the currents, and, indeed, about almost everything in and out of the soa.

"Though all nations use charts, it is the chart of the Royal Navy that is found in the captain's room, whether the ship be Dutch or Japanese, Freneli, German, or Scandinavian. Most of the seven seas are now fully charted. But in Australian 'waters, especially along the Great Barrier Reef, there are dangerous places, where charts are not. safe guides. At various places along the coast of Queensland it is written that ships pass at their peril, 'because the surveys are incomplete. The Australian Government has wisely decided that the whole of the Great Barrier Beef is now to be thoroughly surveyed. The work on a particular section between Cairns and Townsville is now entrusted to H.M.A.S. Geranium, under Commander H. T. Bennett. It wa3 the .guest of this officer and as a scientific representative of the Great Barrier Eeef Committee that I enjoyed the privilege of seeing a chart in the making. In this section the landscape is dominated by a lofty range, the highest in Queensland, which, towering over 5000 ft. reaches its culminating point at Ht. Bellenden Ker. In front of this extend a row of mountain island draped in the splendour of tropical vegetation. To the north lies Fitzroy Island, then the Franklin Islands, followed by the Barnard Islands, where there is a lighthouse. Lastly there is beautiful Dunk Island, famous as the home of Banfield, the Beachcomber. Eastwards of these islands lis a broad channel where the ships go up and down in safety. Here but little coral grows, the reason being that the water is too muddy for them to thrive. Numerous small rivers that enter the sea hereabouts keep up a good supply of muddy water, which is swept up and down the channel by tides and currents. Further seawards the water is pure and so clear that when a plate a foot in diameter was lowered from the ship it could be seen far more than a hundred feet below the surface. In this zone beyond the ship channel the banks are overgrown "with luxuriant coral.''