The _Revue Industrielle_ gives the following method of drilling holes in glass: First, prepare a saturated solution of gum camphor in oil of turpentine. Then take a lance-shaped drill, heat it to a white heat, and dip it into a bath of mercury, which will render it extremely hard. When sharpened and dipped into the above-named camphor solution, the tool will enter the glass as if the latter were as soft as wood. If care be taken to keep the spot being drilled constantly wet with the solution, the operation will proceed rapidly, and there will rarely be any need of sharpening the tool.
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