Page:Popular Science Monthly Volume 21.djvu/296

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296
THE POPULAR SCIENCE MONTHLY.

anxious to get away from them. The Fuegians in Paris are described as accustomed to squat for hours, without moving, around a fire on the lawn, perfectly indifferent to everything, and listlessly looking at the crowd who peer at them through the bars of the fence as if they were some extraordinary animals, and as occasionally exchanging with each other the guttural duckings which serve them for a language. Only one thing will excite liveliness in them—the desire for food.

 

Forms of Aurora Borealis.—Lieutenant Weyprecht, in his recent work on the observation of the aurora borealis, distinguishes between seven forms in which the light appears in the polar regions. The first form is that of almost regular arches rising or sinking from the magnetic south or north to or away from the zenith, and generally extending to both sides of the horizon. Second, are streamers of irregular form and varied appearance, appearing like bands much longer than broad, moving in the atmosphere, and nearly always bent in folds and twists; they consist either of masses of light unequally distributed along the length of the band, or of single beams of the breadth of the band closely arranged together in a direction toward the magnetic zenith, and having their intervals filled with light-masses. This form is cut away on every side, or at most touches the horizon on only one side. Of the third form are threads, extremely fine beams of light of various lengths, some of them reaching from near the magnetic zenith to near the horizon, and grouped in such a manner as to resemble a fan covering a part of the firmament. The beams are not united, but are separated by dark spaces of greater or less width. Generally, they are prolongations of a streamer, which in such case answers to the continuous lower border of the fan. Fourth, is the corona, in which the beams or light-masses are joined in a common center near the magnetic zenith, and a constant movement is maintained toward or around the same. Fifth, haze dim, unformed accumulations of light-masses illy defined, at some point in the firmament. Sixth, the dark segment, a darker appearance, forming a segment of a circle, in the magnetic north or south, bounded by a fixed and low seated bow of light. Seventh, the polar shine, an illumination of the polar sky, the form in which the light generally appears in middle latitudes, but which is not observed in its home. Its characteristic feature is that the rays diverge from the horizon up, while the divergence in all the other forms, if their rays can be distinguished, is in the reverse direction. The movements of the mass consist either of a rising and sinking of the rays and arches with reference to the horizon, a lengthening, and shortening, and sidewise motion of the threads, or a general change of place. The mass has also motions within itself, which may consist of undulations or flashes of the light. The undulations are waves, streamers, or partial arches, which pass along generally from the magnetic east or west, toward the opposite end of the phenomenon, and then appear to spring out from it. The flashes are the shooting of short, broad beams, with the velocity of lightning, from the streamers toward or from the zenith. They are the forerunners or accompaniments of intensive coronas, and originate in particular when a stream of rays merges into the corona.

 

Wyville Thomson.—The death of Sir Charles Wyville Thomson, in the fifty-fourth year of his age, is announced. He was born in Linlithgow, Scotland; began his medical training at Edinburgh University in 1845; held a Lectureship on Botany at King's College, Aberdeen, in 1850; and has occupied professorial chairs in science at King's College, Cork, Belfast, and Edinburgh, where he succeeded Professor Allman as Professor of Natural History in 1870. He has contributed many papers of merit to scientific societies and periodicals, beginning with ono on the application of photography to the compound microscope, which was read before the British Association in 1850. His most distinguished service, and one by which he won an enduring fame, was as Director of the Civilian Scientific Staff of the Challenger Expedition, where he gave unremitting personal attention to the dredging operations, and the examination of specimens. He had been for some time in feeble health, and his death followed his becoming severely chilled on a visit to Edinburgh. "Sir Wy-