Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/417

Rh which has previously been ground in oil, to this mixture add sufficient common oak varnish to bind the color. Two, or if required, three coats of this varnish are now to be applied, and as it dries very rapidly the whole may be finished in a few hours.

Varnish, To remove, from Pictures or Fine Work. By friction, if it be a soft varnish such as that of mastic, the simple rubbing of the finger ends, with or without water, may be found sufficient, a portion of the resin attaches itself to the fingers, and by continuous rubbing removes the varnish. If it be hard varnish such as that of copal which is to be removed, friction with sea or river sand, the particles of which have a rotundity that prevents their scratching, will accomplish the purpose. The solvents commonly employed for removing varnish are the several alkalies, alcohol and essential oils used simply or combined. Of the alkalies, the volatile in its mildest state, or carbonate of ammonia, is the only one which can be safely used in removing dust, oil, and varnish from a picture, which it does powerfully, it must, therefore, be much diluted with water, according to the power required, and employed with judgment and caution, stopping its action at the proper time by the use of pure water and a sponge. A thick coat of wet fuller's earth may be employed with safety, and, after remaining on the paint a sufficient time to soften the extraneous surface, may be removed by washing. Both pictures and gilding have been restored to their original beauty by the application of wet clay.

Worm in Wood-work, Prevention of. The ravages of worms and insects are among the principal causes of the destruction of timber. Some woods are more subject than others to be destroyed by them, such as alder, beech, birch, and in general all soft woods of which the juices are of a saccharine nature. Against the common worm, oil of spike is said to be an excellent remedy; and oil of juniper, or of turpentine, will prevent them in some degree. A free