Volume 14 Australasia - dana ward's homepage

M-VEIXE CUBEEXTS. 23of the conflicting winds at times gives rise to tremendous hurricunes, especially atthe change of the monsoons and during the summer heats. These disturbiiucesare most disastrous in the neighbourhood of the Mascarenhas, although theyalso occasionally spread havoc over the waters of the Gulf of Aden and the Bay ofBengal.On their outer borders in the direction of the poles the region of the tradewinds is skirted by zones of variable currents, the mean result of which generallytakes the direction from west to east. Being enclosed towards the north, theIndian Ocean has naturally one only of these zones comprised mainly between 28°and 60° south latitude. But the Pacific, as well as the Atlantic, has its twosystems of variable winds, one in the northern the other in the southern hemisphere,the latter merging westwards in that of the Indian Ocean, eastwards inthat of the Atlantic, and thus completing the circuit of the globe. The discoveryof these oceanic regions dominated b}- the western currents, that is by the countertrade winds, has been of paramount importance in the history of maritime research.Guided by his knowledge of the Atlantic winds, Urdaneta was thus enabled todirect vessels across the Pacific towards the shores of the Jfew World, while by followingthe corresponding zone of variable winds in the southern hemisphere Cooksuccessfully accomplished the circumnavigation of the planet in the contrarydirection to that followed by Magellan.Marine Currents.The movement ofthe marine corresponds to that of the aerial currents in thegreat oceanic basin, but the former, belonging to a more stable element, arenaturally of a more constant character than the latter. They represent, so to say,the fly-wheel of the great terrestrial mechanism. Hence the rythmical displacementsof the waters across the boundless oceanic spaces have been of even greatermoment than those of the atmosphere in the history of human progress. If thetrades and coimter-trades have enabled European navigators the more easily totraverse the ocean between the Old and the Xew TTorld, and thus hastened thework of exploration amongst the oceanic islands and austral lands, to the marinecurrents was largely due the dispersion of mankind and gradual peopling of halfthe globe.The prominent feature in the vast system of oceanic movements is the greatstream which in the equatorial seas sets in the same direction as the apparentcourse of the sun between the shores ofthe New World and those of New Guineaand the Philippines. The liquid volume which thus trends from east to west hasa mean breadth of probably over 3,000 mUes, for it is occasionally observedranging from 26^ south to 2-1° north latitude, but with a reflux or a zone of calmwaters in its central parts. The whole body of equatorial seas moves with avelocity varying from 20 to 40 miles a day according to the seasons and thesurroundings, and to a depth which certainly exceeds 750 fathoms in the axis ofthe stream. And this prodigious moving mass traverses nearly one-half of the