669. _Method of preparing the Composition used for Colored Drawings and Prints, so as to make them resemble Paint in Oil._--Take of Canada Balsam, one ounce; spirit of turpentine, two ounces; mix them together. Before this composition is applied, the drawing or print should be sized with a solution of isinglass in water, and when dry, apply the varnish with a camel-hair brush. 670. _Oil and Water Gilding._--In oil gilding, the frame is first covered with a composition of whiting and parchment size, then with a coating of "_oil gold size_," (a kind of varnish,) upon which when nearly dry, gold leaf is applied. 671. _In Water Gilding_, a size mixed with _water_ is used. Parts of the frame are burnished, other parts left _dead_. This is the most beautiful and expensive style of gilding, but it does not bear washing as oil gilding does. ["The Carver and Gilder," published by Knight, furnishes much useful information on this subject.] 672. _To mount Prints or Maps._--Upon a table, floor, or board, stretch a piece of calico or smooth canvas, by first fixing it with tacks along one side, then straining it tightly with one hand, and driving the tacks with the other: nail the remaining edges, leaving no wrinkles on the surface. Paste the back of the print or map, fold it together, and let it remain until the paper is _soaked_, then open it, and place it evenly on the canvas, cover it with a sheet of clean paper, and beginning in the middle, rub it down carefully with the hand, going from the centre all round to the edges, until all the air is excluded, and the paper adheres closely to the canvas. When quite dry, with a large camel-hair brush lay on a coating of parchment size, repeating this when dry: then varnish with mastic varnish. Parchment size is made by boiling parchment cuttings in water, until it forms a jelly when cold. Mastic varnish may be procured at oil and color-shops. 673. _New Camera Lucida._--Sir John Robinson devised, a few years since, a cheap and easily-used camera lucida, applicable to the delineation of flowers and other small objects. A piece of plate glass is made to stand in a vertical position by means of a support. It rests on a table covered with white paper, and the object is placed on the paper on one side of the glass. On looking down from that side of the glass diagonally, an image of the object is seen on the paper on the other side, and a drawing of it can be readily taken. 674. _Varnish for Oil Pictures._--According to the number of your pictures, take the whites of the same number of eggs, and an equal number of pieces of sugar-candy, the size of a hazel-nut, dissolved, and mix it with a tea-spoonful of brandy; beat the whites of your eggs to a froth, and let it settle; take the clear, put it to your brandy and sugar, mix them well together, and varnish over your pictures with it. This is much better than any other varnish, as it is easily washed off when your pictures want cleaning again.