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Page:Popular Science Monthly Volume 19.djvu/733

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POPULAR MISCELLANY.

quite as malignantly. Lockjaw appears in every fatal case. Some men pretend to be acquainted with antidotes, but their first care on being called to a patient is to remove everything that might excite him to convulsions. The father of the native who furnishes the description of the poison assured him that he had been often wounded, and had averted the evil effects by cutting himself in different parts, so as to draw away the poisoned blood.

 

The Secular Changes of Level in the Earth's Crust.—Professor Suesz, author of a work on the "Origin of the Alps," recently delivered an important address before the Geological Institute at Vienna, on the fundamental causes of the repeated changes which have taken place in the distribution of land and water on the globe. He assumed that, as viewed in the light of more recent observations, the question did not concern apparent elevations or depressions of land within particular spaces, but dealt with an increasing prominence of the whole northern polar cap of the earth, far down into the temperate zone, effecting a real change in the form of the planet. Howorth, who thought he had detected an elevation of the land toward both poles, and a depression near the equator, concluded that the solid part of the earth was steadily suffering a contraction in the equatorial regions, and becoming projected toward the magnetic poles. Robert Chambers, in England, forty years ago, and Domeyko, in Chili, inferred from the repeated occurrence of terraces, apparently showing that the land had risen, that a force was at work changing levels which embraced the whole planet; and, in later times, many who have studied the subject most thoroughly, as Pettersen, have not repressed their doubts of the sufficiency of the common theory of elevations to account for the phenomena which they have observed. Many have been led, from the force of these facts, to embrace the theory of Adhemars and his followers, Croll and Schmick, that accumulations of great masses of water take place alternately around one and the other pole; but the presumption of alternation is contradicted by the fact that terrace-formations occur along the coasts of South America, South Africa, and Southern Australia, which seem to be as remarkable and as regular in their distribution as those which have been observed in the northern hemisphere. In order to be accurate in expression. Professor Suesz does not speak of elevations or depressions either of the land or the sea, but of displacements of the coastlines; of negative movements when the result is an apparent elevation, positive movements when it is an apparent depression of the land. Using these forms of expression, the height of the upper level of a series of terraces does not represent a measure of the rising of the land, but the amount by which the sum of the negative movements of the shore-line since the time when it was at its highest level is greater than the sum of the positive movements. That repeated changes from one movement to the other are the rule is shown by the step-like form of the coasts at points where many traces of them have been left, as at Van Rensselaer Harbor, Port Ffoulke, and Cape York, in the Arctic regions. Sometimes they so balance each other that the coast-line is substantially stationary for a long time, when a steep cleft in the rocks is formed, as above Montreal and at the Island of Tromsoe. We know nothing of the laws that govern these oscillations. Many of the comparisons of level hitherto made have been liable to error, arising from regarding the partly compensated sum of the several movements in one place and the latest observed movements in another place as of equivalent value. Many examples show that a positive movement has taken place on the coast of Europe within historical times, reaching at Naples to the holes in the pillars of the temple of Serapis at Puzzuoli; at a later period, perhaps between the fifth and ninth centuries, a negative movement began, of which we can not definitely say whether it still continues or not. The oscillatory character of the changes can hardly be comprehended from the point of view of a movement of the solid part of the earth's crust; it might rather be compared to the breath of a living body. Some investigators, as Charles Darwin and Kjerulf, have adopted the theory of interrupted or rhapsodical elevations, instead of the old one of symmetrical oscillations; but