Two men start from the Hut with iron crampons and a full complement of clothes and mitts. Outside they find themselves in a rushing torrent of air, pulsating with mighty gust-waves. Lowered from the estate of upright manhood, they humbly crawl, or make a series of crouching sprints between the gusts. Over the scattered boulders to the east of the Hut, across a patch of polished snow they push to the first low ridge, and there they stop for breath. Up on the side of "Annie Hill," in the local phrase, the tide sweeps by with fiendish strength, and among the jagged rocks the man clutching the puffometer-box has a few desperate falls. At last both clamber slowly to an eminence where a long steel pipe has been erected. To the top of this the puffometer is hauled by means of a pulley and line. At the same time the aluminium sphere is released, and out it floats in the wind tugging at the spring.
The puffometer was left out for an hour at a time, and separate gusts up to one hundred and fifty and one hundred and eighty miles per hour were commonly indicated. I remember the final fate of this invention. While helping to mount it one day, the wind picked me up clear of the ground and dashed myself and the instrument on some rocks several yards away. The latter was badly damaged, but thick clothing saved me from serious injury.
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The wind velocity and wind direction charts for Midwinter's Day, when the steady south-by-east gale was broken after noon by a welcome lull—the wind veering the while all round the compass.
The average velocity for the day 66.9 miles per hour, and the maximum of the average hourly velocities, ninety-six miles.
The steadiness of the temperature was a subject for debate. The stronger the wind blew, the less variation did the thermometer show. Over a period of several days there might be a range of only four or five degrees. Ordinarily, this might be expected of an insular climate, but in our case it depended upon the fact that the wind remained steady from the interior of the vast frigid continent. The air which flowed over the Hut had all passed through the same temperature-cycle. The atmosphere of the interior, where the plateau stood at an elevation of, say, eight thousand feet, might have a temperature -45 degrees F. As the air flowed northwards over Adelie Land to the sea, it would rise slowly in temperature owing to the increased barometric pressure consequent on the descending gradient of the plateau. At sea-level the temperature of the river of air would be, approximately, -20 degrees F.
Such a rise in temperature due to compression is a well-known phenomenon, referred to as the Foehn effect.
The compression of the atmosphere during the gusts affected the air temperature so considerably that, coincident with their passage, the mercury column could often be seen rising and falling through several degrees. The uniform conditions experienced during steady high winds were not only expressed by the slight variation in the temperature, but often in a remarkably even barometric curve. Thus on July 11 the wind-velocity for twenty-four hours was, throughout, seventy miles per hour; the temperature remaining within a few degrees of-21 degrees F., and the barometric curve did not show as much range as one-twentieth of an inch.
In attending to the many instruments and in gathering the voluminous meteorological data, Madigan had his hands very full. Throughout two years he carried on the work capably and thoroughly. It was difficult to keep the instruments free from the penetrating snow and in good running order. The Robinson anemometer was perhaps the greatest source of worry. Repairs and readjustments were unavoidable, as the instrument was constantly working at high pressure. In order that these might be carried out efficiently, the whole apparatus had to be carried down to the Hut. Here, Bickerton and Correll were continually in consultation with the meteorologist on the latest breakdown. Cups were blown off several times, and one was lost and replaced with difficulty. Most aggravating of all was a habit the clocks developed of stopping during the colder spells. The old-fashioned method of boiling them was found of assistance, but it was discovered that the best treatment was to put them through successive baths of benzene and alcohol.
The most chronic sufferer throughout the vicissitudes of temperature was the clock belonging to Bage's tide-gauge. Every sleeper in the Hut who was sensitive to ticking knew and reviled that clock. So often was it subjected to warm, curative treatment in various resting-places that it was hunted from pillar to post. A radical operation by Correll—the insertion of an extra spring—became necessary at last. Correll, when not engaged designing electroscopes, improving sledge-meters and perfecting theodolites, was something of a specialist in clocks. His advice on the subject of refractory time-pieces was freely asked and cheerfully given. By perseverance and unlimited patience, the tide-gauge down on the harbour-ice was induced to supply a good series of unbroken records.