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๐ SIMILAR VOLUMES
Didymium Goggles.--( Ceramic Industry, Feb. I932.) Didymium, a chemical element, classed among the rare earth metals, can, in the form of its oxide, be used as a constituent of glass. Its presence in the glass, gives the latter the particular ability of filtering out the yellow light rays at the tim
CURRENT TOPICS. 637 ipated for them in the building of safes. Not only are the plates so extremely hard that they cannot be drilled, but they have a remarkable resistance to the flame of an oxyacetylene lamp. It is estimated that to burn a hole three inches in diameter and 3~ inch thick would requir
After ten years of living on an isolated, tech-free ranch with her mother, sixteen-year-old Hedda is going back to the world of the Glare-her word for cell phones, computers, and tablets. Hedda was taught to be afraid of technology, afraid that it would get inside her mind and hurt her. But now she'