. Popular electricity magazine in plain English. es by the simple expe-dient of surrounding the tube with aglobe of ordinary glass, which is almostopaque to rays of this kind. The ultraviolet rays are invisible themselves, ormore accurately speaking, do not havethe power of rendering ordinary objectsvisible. Under certain conditions, theyproduce an effect called fluorescence, bywhich some substances are caused toglow when exposed to the rays and arethus made visible. This fact has been put to practicalaccount in the assortment of zinc of the principle ores of zinc is thesilicate, whic
. Popular electricity magazine in plain English. es by the simple expe-dient of surrounding the tube with aglobe of ordinary glass, which is almostopaque to rays of this kind. The ultraviolet rays are invisible themselves, ormore accurately speaking, do not havethe power of rendering ordinary objectsvisible. Under certain conditions, theyproduce an effect called fluorescence, bywhich some substances are caused toglow when exposed to the rays and arethus made visible. This fact has been put to practicalaccount in the assortment of zinc of the principle ores of zinc is thesilicate, which is of a grayish colorexactly similar in tint to the rock in whichit is found, which is known as far as the eye can delect by daylighlthe two minerals look exactly the same;but when the ultra violet rays from thequartz mercury vapor lamp are thrownupon them the zinc ore assumes a btiful, deep, turquoise blue color, whilethe calcite remains gray. The separa-tion can thus he made by any unskilledworkman possessed o( ordinary LAUKLK .5T00T. 1308
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectelectri, bookyear1912
