VANILLA. The succulent fruit of a plant of the Orchidaceous order, climbing over trees in the tropical parts of this con tinent after the manner of ivy. Its fra grance is owing to the presence of ben zoic acid, crystals of which form upon the pod if allowed to be undisturbed. It is au aromatic, employed in confectionary and the preparation of liqueurs, and in flavoring of chocolate, ice-cream, &c. VARNISH. A fluid which when spread thin upon a solid surface becomes dry, and forms a coating impervious to air and moisture. There are two kinds of varnish, namely, spirit and oil var nishes: rectified alcohol is used for the former ; and for the latter fixed and vo latile oils, or mixtures of the two. The solid substances dissolved in the above menstrua, and which constitute what is termed the body of the varnish, are al most exclusively resinous, and are chiefly the following: 1. Turpentine, all the va rieties of which are employed by the varnisher : they form an excellent body, and give strength and glossiness at a small expense ; but they do not dry with out other additions. 2. Copal, a peculiar resin, very difficult to but form ing a hard and durable ingredient. It is generally melted over a gentle fire pre vious to use. 3. Lac, which gives great toughness and hardness ; but is often in on account of its reddishbrown color. 4. Mastic, which yields a I tough, bard, brilliant, and colorless var- I nish. 5. Elemi, a resin of a pale yellow I green tint, and a valuable ingredient on account of its toughness and durability. 6. Sandarach, a resin which imparts splendor, but which alone is not dura ble. 7. Amber ,a valuable ingredient, on account of its hardness and durability ; but difficult of transparent solution, and hence chiefly used in opaque varnishes. 8. Benzoin, added on account of its fra grancy. 9. Anime, which gives brillian cy and some scent. 10. Gamboge, for yellow varnishes. 11. Dragon's blood, for red varnish. These, together with tur meric, saffron, and annotta, are chiefly used on account of their color, and to cover brass and copper under the name of lacquers. 12. Caoutch,ouc. This extra ordinary vegetable product has of late been much employed in a variety of pre parations used as varnishes. It is invalu able where materials are to be rendered air-tight, as balloons, for example, and where at the same time flexibility, and even elasticity, are required ; but its principal application in this way is in the manufficture of various water-proof arti cles. 13. Asphaltum, the varieties of which are indispensable in black oil var nishes. In making spirit varnishes, the strongest alcohol of commerce should be used (of a specific gravity not ex ceeding 820), and its solvent power over some of the more intractable resins is sometimes improved by the addition of a little camphor ; in order to prevent the agglutination of the resin, it is often re quisite to mix it with sand or pounded glass, by which the surface is much in creased, and the solvent energy of the spirit facilitated. The proportions in
which the several ingredients are used, and the selections for particular purposes, are infinitely various. The following are a few good varnishes, in illustration of their varieties : 1. Spirit varnish. San darach 4 oz., seed lac 2 oz., elemi 1 oz., digest the whole in a quart of moderately warm alcohol, and when dissolved add Venice turpentine, 2 ozs. 2. Lac varnish. Seed lac 8 oz.; digest for four days in a warm place with a quart of alcohol, and then strain through flannel. 3. Turpen tine varnish. Mastic 12 oz., mixed with 5 oz. of pounded glass, and digested in a quart of oil of turpentine, adding at in tervals about half an ounce of camphor in small pieces. When the mastic is dissolved, add to the warm fluid an ounce and a half of previously liquefied Venice turpentine, and stir the whole together. 4. Copal varnish. Copal which has been previously melted by a gentle heat 3 oz., oil of turpentine 20 oz. (measure) : put the oil into a flask placed in boiling water, and add the powdered copal in small portions at a time, an that it may be gradually dissolved ; let it stand a few days to clear, and then pour it off, and if too thick for use, add to it a little warm oil of turpentine. This varnish dries slowly, but is very durable. 5. Linseed varnish. Melt 16 oz. of copal in an iron pot with as gentle a fire as possible, and when fused pour in 3 oz. of hot linseed oil ; stir the mixture, remove it from the fire, and while yet warm gradually add a pint of warm oil of turpentine ; when the whole is incorporated, strain it through a pica of linen into phials. This is a hard and durable, but also a colored varnish. 6. Amber varnish. Melt 16 oz. of amber in an iron pot, then add two oz. of melted lee, and 10 oz. of hot, dry ing linseed oil ; incorporate the whole by stirring ; remove it from the fire, and be fore it cools add a pint of warm oil of turpentine. 7. Black varnish. Melt 16 oz. of amber in an iron pot, and add half a pint of hot, drying linseed oil, 3 oz. of powdered rosin, and 3 oz. of powdered asphaltnm • stir all together, and when removed from the fire and sufficiently cool, add a pint of warm oil of turpentine. 8. Lacquer. Digest 3 oz. of seed lac, 1 oz, of turmeric, and 2 drs. of' dragon's blood for six days in a pint of alcohol, frequently shaking the bottle, which should be kept in a warm place; strain the lacquer through linen. The above are samples of each of the principal varnish es ; but every maker varies the propor tions, and often the nature of the ingre dients. In the preparation of varnisTes, in consequence of the highly combusti ble nature of all the materials, the utmost care is requisite to avoid accidents by fire.