In Hazard Read Online Free PDF Page B

to know of the cat’s anatomy, of the rules which govern its motion—and in addition to that, the cat has been belled.
    By the turn of the century, meteorological science had already advanced a long way. The movements of these storms had been charted and studied over a long period, and their uniformity had been found to be extraordinary. So every seaman was taught what paths West Indian hurricanes usually follow, and where the invisible obstacles lie which tend to deflect those paths towards the north. Thus he could generally avoid running into a hurricane altogether. But if he should find himself on the fringe of a disturbance, there were further rules which enabled him to calculate, by observing the barometer and the wind’s change of direction, where the centre of the vortex lay at the moment; and so, whether he was in a quadrant where he would be sucked in, or buffeted out: in what direction to make his escape.
    For, just as a rapidly-spinning top only creeps across the nursery floor, so, though the velocity of the hurricane wind itself is huge, the shifting of the whole system is not very fast. It seldom averages more than twelve miles an hour, while the storm is intense: and is sometimes only three or four.
    And yet, sometimes ships used still to get caught. Some slow-moving sailing-vessel, or laden steamer: either an eccentricity of the storm’s motion trapped her into a false move, or else she did not discover her danger quickly enough to get away. Now, however, with the advent of wireless, there is little danger even of that. For now, when a hurricane is abroad, all shipping in its neighbourhood keeps tag on it, and telegraphs data regarding it to a shore station. Thus, be its behaviour never so eccentric, the meteorologist on shore is able to watch, as plainly as with his direct eyes, every movement of the hurricane and every variation of its strength: and the least tendency to diverge from the path and the velocity forecast can be immediately observed: and the news, twice a day, can be broadcast back to shipping.
    That is really what I mean by “belling the cat.” You can hear the bell tinkle, twice a day. You can hear the hurricane’s approach before it is anywhere near you.
    It is usually fixed things, such as banana trees, one hears of nowadays as having been damaged by a hurricane: not shipping. Ships (which can run) are safer in those latitudes than government offices (which cannot).
III
    The thing to remember about the atmosphere is its size. A little air is so thin, so fluid; in small amounts it can slip about so rapidly, that the conditions which give rise to a hurricane cannot be reproduced on a small scale. In trying to explain a hurricane, therefore, one must describe the large thing itself, not a model of it. For it is only when one thinks of the hugeness of a parcel of air on the world, the big distance it may have to shift to equalise some atmospheric difference, that one can realise how slow and immobile, regarded on a large scale, the air is.
    It happens like this. The air above a warm patch of sea, somewhere near the Canaries, is warmed: so it will tend to be pushed up and replaced by the colder, weightier air around. In a warm room it would rise in a continuous gentle stream, and be replaced by a gentle draught under the door—no excitement. But on a large scale it cannot: that is what is different. It rises in a single lump, as if it were encased in a gigantic balloon—being actually encased in its own comparative sluggishness. Cold air rushes in underneath not as a gentle draught but as a great wind, owing to the bodily lifting of so great a bulk of air.
    Air moving in from all round towards a central point: and in the middle, air rising: that is the beginning. Then two things happen. The turning of the earth [1] starts the system turning: not fast at first, but in a gentle spiral. And the warm air which has risen, saturated with moisture from the surface of