538.  Varnish for coloured drawings

Mix together 1 oz. of Canada balsam and 2 ozs. of spirits of turpentine.  Before applying the composition, size the drawing or print with a solution of isinglass in water; when this is dry, apply the varnish with a camel’s-hair brush.  The use of this varnish gives to coloured drawings and prints an appearance resembling that of oil paintings.

539.  Varnish for glass

Reduce a quantity of gum tragacanth to powder, and let it dissolve for twenty-four hours in the white of eggs well beat up; then rub it gently on the glass with a brush.

540.  To clean pictures

Having taken the picture out of its frame, take a clean towel, and making it quite wet, lay it on the face of your picture, sprinkling it from time to time with clear soft water; let it remain wet for two or three days; take the cloth off, and renew it with a fresh one; after wiping your picture with a clean wet sponge, repeat the process till you find all the dirt soaked out of your picture; then wash it well with a soft sponge, and let it get quite dry; rub it with some clear nut or linseed oil, and it will look as well as when freshly done.

541.  Another method

Put into two quarts of strong lye a quarter of a pound of Genoa soap rasped very fine, with about a pint of spirits of wine; let them simmer on the fire for half an hour, then strain them through a cloth; apply it with a brush to the picture, wipe it off with a sponge, and apply it a second time, which will effectually remove all dirt; then, with a little nut oil warmed, rub the picture, and let it dry; this will make it look as bright as when it came out of the artist’s hands.

542.  Varnish for Clock faces, &c.

Take of spirits of wine, 1 pint; divide it into four parts; mix one part with half an ounce of gum mastic, in a bottle by itself; one part of spirits and half an ounce of gum sandrac in another bottle; and one part of spirits and half an ounce of the whitest part of gum benjamin; mix and temper them to your mind; if too thick, add spirits; if too thin, some mastic; if too soft, some sandrac or benjamin.  When you use it, warm the silvered plate before the fire, and with a flat camel-hair pencil stroke it over till no white streaks appear; which will preserve the silvering for many years.

543.  Varnish for balloons

Take some linseed oil, rendered drying by boiling it with 2 ozs. of sugar of lead and 3 ozs. of litharge for every pint of oil till they are dissolved, which may be in half an hour.  Then put 1 lb. of birdlime and half a pint of the drying oil into an iron or copper vessel, whose capacity should equal about a gallon, and let it boil very gently over a slow charcoal fire, till the birdlime ceases to crackle, which will be