FREEZ′ING MIXTURES. See Ice and Refrigeration.
FRENCH BER′RIES. Syn. Persian berries,
Avignon b.; Graines d’Avignon, Fr. The unripe berries or fruit of the Rhamnus infectorius. They are imported from France and Persia; those from the latter country being esteemed the best. Some writers state that the Persian berries are the product of a distinct species, namely, R. amygdalinus. They are chiefly used for dyeing morocco leather yellow. Their decoction dyes cloth, previously mordanted with alum, tartar, or protochloride of tin, of a yellow colour; with sulphate of copper, an olive; and with red sulphate of iron, an olive-green colour.
FRENCH POL′ISH. Several varnishes are used under this name. That most generally employed is a simple solution of pale shell-lac in either methylated spirit or wood naphtha. Sometimes a little mastic, sandarac, or elemi, or copal varnish, is added to render the polish tougher.
Prep. 1. From pale shell-lac, 51⁄2 oz.; finest wood naphtha, 1 pint; dissolve.
2. Pale shell-lac, 3 lbs.; wood naphtha, 1 gall. Methylated spirit (68 o. p.) may be substituted for the naphtha in each of the above formulæ.
3. Pale shell-lac, 5 oz.; gum sandarac, 1 oz.; spirit (68 o. p.), 1 pint.
4. Pale shell-lac, 51⁄2 oz.; gum elemi, 3⁄4 oz.; spirit, 1 pint.
5. Pale shell-lac, 11⁄4 lbs.; mastic, 1⁄4 lb.; spirit, 2 quarts.
6. Pale shell-lac, 21⁄4 lbs.; mastic and sandarac, of each 3 oz.; spirit, 1 gall.; dissolve, add copal varnish, 1 pint, and mix by roughly agitating the vessel. All the above are used in the manner described below.