Word: tubes
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Dates: during 1880-1889
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...optical parts of the telescope are three-the eye-piece, the object glass, which is twelve inches in diameter and a plain mirror of eighteen inches in diameter, set in front of the object glass. Focal length is sixteen and a half feet. The telescope tube is rested permanently upon two stone piers, one near each end, and twelve feet apart. About five feet of the length of the tube projects into the observatory building and the remainder is out of doors...
...glass of the two telescopes is of the finest French make. The mirror is four inches thick, for any plate would probably change its shape from expansion or flexure. The telescopic tube is jointed so as to be air-tight throughout and at the eye-piece. Its material is steel plate one thirty-second inch thick. The temperature of the room does not effect its interior and no fogging of the object glass has occurred during cold nights...
Ralph Ensign, a Yale senior, was generating gas from hydrofluoric acid in the Kent Laboratory recently, when the tube burst and its contents flew in his face and over his clothing. His eyes escaped, but his face was badly burnt...
...short time and by a small pressure for a long time. This is the principle which enables dynamite bombs to be fired. If shot from a cannon the sudden shock explodes the bomb immediately, and the connon is destroyed. But by the use of compressed air in a long tube, thus imparting the velocity gradually, a 1000-pound bomb can be fired two miles without danger to the cannoneer, but with most disastrous effects on the object aimed at. The common notion that force is needed to maintain motion is erroneous; force is only needed to overcome resistance. Without opposition...
...last stage of the making. Finally, last month he telegraphed that he had actually molded a glass without its being broken; and so at last the disk, the one vital organ of a telescope, is completed. The construction of the delicate yet powerful machinery, by which the tube sixty feet long is to be pointed toward any part of the heavens, and kept in motion by clock work, has not yet been commenced. However, the completion of this machinery is only a question of time, and when every thing is finished Lick Observatory will have the largest and most powerful...