Paper Hangings, a covering for interior walls of buildings, made of paper and usually printed with figures and devices, as a substitute for hangings of tapestry or cloth. They came into use in Europe about 200 years ago, but have been used by the Chinese for many centuries. Since the invention of the Fourdrinier paper machine, by means of which strips of paper of indefinite length may be made cheaply, they have been common in Europe and the United States. Previous to this time squares of hand-made paper were pasted together. For most of the period during which paper hangings have been used they have been printed with blocks by hand, after the manner of calico printing or the printing of oil cloth by hand. The colors are opaque and mixed with size. In the better kinds of hangings the whole of the paper is covered and the figures are then applied. In the cheaper kinds a colored paper is used to print on. As many blocks are used as there are colors in the pattern, each block having the part of the pattern upon it which is of one color. One block is printed the whole length of the paper by a succession of impressions; the piece is then dried, and the next color applied. Cylinder printing machines are now in use, which facilitate and cheapen the process.

The pattern is engraved in parts on a series of copper cylinders, to each one of which a particular color is applied as the cylinder revolves. As the paper reaches each cylinder in succession, it receives an impression of one part of the pattern in one color, the figure being completed by the last cylinder. The paper is dried after passing each printing cylinder by the back surface passing over plain heated cylinders. Copper, silver, and gold leaf are often applied, making some of the hangings very expensive. Powdered steatite or French chalk is used as the ground for satin papers, the gloss being produced by polishing. A kind called flock papers are made by coating the surface with a composition called encaustic, made of linseed oil boiled with litharge and ground up with white lead. The flock, made by cutting and grinding woollen colored fabrics, is sifted over the paper as it passes along covered with the encaustic, and is dried by warmed cylinders. Some of the finest French papers have the colors applied by hand. - Many of the colors used upon paper hangings are prepared from mineral substances, some of which are of highly poisonous character.

This is especially the case with the rich greens of the flock papers, which are chiefly what is called Schweinfurt green, a very dangerous compound of arsenic and copper. Costly and elegant paper hangings of this character are now in use, the noxious influence of which seriously affects ' the workmen who put them up, and occasionally so vitiates the atmosphere of the apartments as to impair the health of the inmates of the house.