18. _To take Stains out of Marble._--Mix unslaked lime in finest powder with stringent soap-ley, pretty thick, and instantly with a painter's brush lay it on the whole of the marble. In two months' time wash it off perfectly clean; then have ready a fine thick lather of soft soap, boiled in soft water; dip a brush in it, and scour the marble. This will, with very good rubbing, give a beautiful polish. 19. _To take Iron-stains out of Marble._--An equal quantity of fresh spirit of vitriol and lemon-juice being mixed in a bottle, shake it well; wet the spots, and in a few minutes rub with soft linen till they disappear. 20. _Mixture for cleaning Stone Stairs, Hall Pavements, &c._--Boil together half a pint each of size and stone-blue water, with two table-spoonfuls of whiting, and two cakes of pipe-makers' clay, in about two quarts of water. Wash the stones over with a flannel slightly wetted in this mixture; and when dry, rub them with flannel and a brush. Some persons recommend beer, but water is much better for the purpose. 21. _To Color or Paper the Walls of Rooms._--If a ceiling or wall is to be whitewashed or colored, the first thing to be done is, to wash off the dirt and stains with a brush and clean water, being careful to move the brush in one direction, up and down, and not all sorts of ways, or the work will look smeary afterwards. When dry, the ceiling is ready for whitewash, which is to be made by mixing whiting and water together, till quite smooth, and as thick as cream. Dissolve half-an-ounce of glue in a teacupful of water, stir it into the whitewash. This _size_, as it is called, prevents the white or color rubbing off the wall, and a teacupful is enough for a gallon of wash. Stone color is made by mixing a little yellow ochre and blue black with the size, and then stirring it into the whitewash; yellow or red ochre are also good colors, and, with vermilion or indigo, any shade may be prepared, according to taste.