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Page:Popular Science Monthly Volume 18.djvu/148

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frequently fail at the critical moment, causing loss of life or damage to property. Recently a system of protection has been perfected and is now being introduced, which, the promoters claim, secures perfect safety, and the trials made in this and other cities seem to amply confirm the claim. It consists in making the descending carriage act as a plunger to compress the air in the shaft below it, so as to form a cushion which retards and gradually overcomes its motion. The change in the ordinary construction of the elevator to secure this action is very slight, and can readily be applied to one already put up. The shaft is made to fit the elevator carriage closely, through the first three or four feet of the lower portion, and then gradually widens to the full size. This funnel-shaped portion extends from fifteen to twenty feet above the contracted base, depending upon the size and height of the elevator. A stiff rubber flange around the lower edge of the carriage leaves a space for the escape of the air in the contracted portion of not more than one fourth of an inch wide. The straight part of the shaft above the funnel is of a size to leave a space of six to eight inches all around the carriage. With such a constructed shaft, the carriage, when it begins to fall, readily presses the air from beneath it up the sides of the shaft. As it gains in velocity, greater resistance is offered by the air, and, as it descends through the funnel portion, this is rapidly increased by the narrowing of the air outlet. When the contracted base portion is reached, the confined air has only a narrow outlet, and the resistance it offers is consequently very great. The air arrests the motion of the carriage so gradually that there is very little shock. In one of the trials in this city where the fall was seventy-five feet, eggs and delicate glassware placed on the floor of the car were unbroken. A great number of trials have been made, and many persons have gone down in the falling cars without injury. With the shaft properly and strongly built in the lower portion where the strain comes, this apparatus seems to offer no chance of failure.


Types of Pottery.—Professor E. S. Morse read an interesting paper on this subject at the last meeting of the American Association. The earlier types belonging to the shell-heaps of Japan were described and illustrated by specimens from each of the deposits examined by Mr. Morse and his special students. The pottery of Yezo was nearly all cord-marked, while the shell-heap pottery of the middle of Japan had a much less proportion cord-marked. In the southern portions of Japan, at Higo, cord-marked pottery was extremely rare. He remarked on the extreme diversity in the shape and ornamentation of the pottery in different places in Japan—the pottery of Yezo resembling the pottery of the northern United States, and the pottery from the central portions of Japan resembling that found in Porto Rico and Jamaica. He also spoke of the hard, blue pottery supposed to be Corean, and associated with it a red pottery which might have been made by the same people. This was lathe-turned. Other forms were mentioned and illustrated by examples.


The Fiftieth Meeting of the British Association.—No remarkable discoveries were brought forward at the recent meeting of the British Association for the Advancement of Science, but the addresses and papers in the various sections showed a steady advance in scientific work. Professor A. C. Ramsay, the new President, chose for the subject of his inaugural address the doctrine of uniformity, under the title of "The Recurrence of Certain Phenomena in Geological Time." There has recently been a disposition in certain quarters to question the truth of the doctrine in the extended application made by most geologists. The questioners admit that geologic changes in times past were produced by the same forces now in operation, but deny that they were of the same degree. The uniformity and cataclysmic theories seem to them to both contain truth. Professor Ramsay reaffirms the uniformity doctrine in the broadest and most general manner, and very ably defends his position. One of the most valuable if not the most important address of the meeting was that of Professor W. G. Adams, before the Section of Mathematics and Physics, reviewing recent work in the domain of molecular physics. His statement of the molecular condition of the three forms of matter—solid, liquid, and gaseous—was the clear-