AERIAL ENGINE

Evening Post, Volume CII, Issue 38, 13 August 1921, Page 5

AERIAL ENGINE

WHY THE WINDS GO ROUND,

Sir Napier Shaw, Professor, of Meteorology, Imperial College of Science and Technology, in the annual Rede lecture at Cambridge, compared the atmosphere to a great steam engine (says The Post's London correspondent). The boiler of the atmosphere was the warm surface of earth and sea, the condenseT some cold surfaces in the Pola<r fegibns and. the great mountains, but principally tho cold regions of the upper air. The fly-wheel was made up partly of the normal winds and partly of the semi-permanent winds of cyclonic depressions. The normal winds grouped themselves into two great circulations—on one hand, a great circumpolar in the upper air in which air* travelled from west to east, and, on the other hand, a comparatively narrow equatorial belt of air continually passing westward. Between the two, over the great oceans, were permanent anticyclonic circulations, huge travelling ■bands of air, a couple of,thousand miles ■long (west to east) amd a thousand miles wide (north to south). They reminded one of tho driving belts of "tanks."- 'As they moved round and round like acogbelt, they carried forward the westward moving air of the equatorial circulation on the south side and the eastward moving air of the polar circulation* on the north side. They were thus the gear that kept the main fly-wheels of the atmosphere in working order. He attributed much imiportftiico to this aspect of the fly-wheel. It was what long-distance travellers in ithe air had chiefly to think of in the ways of the air. By taking advantage of the equatorial portion in the fifteenth ■century Columbus reached 'America, and, similarly, in the: twentieth century, by taking advantage of the cireumpolar part, Mossed the Atlantic in an aexSpi&ns in sixteen hpurv ■