Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/432

424 twenty-four hours at least, then wash off, and polish with a coarse flannel. The above quantity is quite enough for an ordinary mantelpiece.

Restoring Antique Furniture. To restore to their original appearance antique pieces of furniture which have become unsightly on account of too frequent varnishing or besmearing by unskilled hands, the following method should be employed: Take equal parts of strong alcohol and good oil of turpentine, and heat this mixture in a bottle by placing it in hot water. With this warm liquid paint the article, whereupon the old varnish will dissolve at once. The varnish is then removed by scraping and wiping, and the spreading, scraping, and cleaning is repeated as often as necessary until the surface has become entirely clean again, so that the object may be rendered glossy, or dull, as required. This process is especially recommended, since it does not change or attack the color of the wood, as is often the case if lye is used.

Rotten Stone. This is sometimes harsh and gritty, and the best way of trying it is to take a little between the teeth, when the least portion of grit may be detected. Careful workmen will always wash it before they use it. This is effected by stirring the fine powder in a considerable quantity of water, then allowing it to remain at rest for a few seconds, and pouring the water into a glazed earthen vessel, the powder which precipitates will be very fine and smooth, by washing the remainder, the whole of the finer parts may be separated from the grit.

Rust on Marble. To remove rust from marble, an operation which depends upon the solubility of iron sulphide in a solution of potassium cyanide, is thus effected: Clay is made into a thin paste with ammonium sulphide, and the rust spot smeared with the mixture, care being taken that the spot is only just covered. After a lapse of ten minutes, this paste is washed off and replaced by one consisting of white bole mixed with a solution of potassium cyanide,