The process, which comes to us from Germany, consists in spreading very smoothly a piece of lace or tulle, and covering it with some fatty substance by means of a printer's roller. The glass being carefully cleaned, the cloth is laid upon it so as to leave in fat a print on the surface of all the threads of the fabric. The glass is then exposed about five minutes to the vapors of hydrofluoric acid, which roughens the spaces between the lines, and leaves the polish on the surface under the fat. A glass thus prepared becomes like a veil, protecting from exterior indiscretion persons who, from their apartment, desire to look commodiously outside. We recall here that the manipulation of hydrofluoric acid requires great prudence. This acid is so corrosive that a drop of its vapor condensed produces upon the hand a lively inflammation, and may even lead to graver accidents. Breathing the emanations should therefore be avoided with the greatest care. No art has been characterized, in the course of its progress, by so much of wonder and undefined belief in the supernatural, as that of the manufacture of glass in its various modes and articles. The old glass-works in Wellsburg, Va., were pulled down a few years since with a tremendous crash. They were erected in 1816, and, with the exception of the establishments at Pittsburg, were the oldest west of the mountains. The beginning of their career was prosperous, but the last owners have invariably sunk money in carrying on the works, and to prevent further losses they have now been finally destroyed, and the ground turned into a potato-patch. [From the "Scientific American."] ETCHING AND ORNAMENTING GLASS.