[21] ‘Journal de Pharmacie et de Chimie,’ xii 6-11.
LISBON DIET DRINK. 1. (Foy.) Prep. Guaiacum wood, rasped, 1 oz.; sarsaparilla, bruised, 3 oz.; mezereon, sliced, 1⁄2 oz.; crude
antimony (in a rag), 2 oz.; water, 12 pints. Boil down to 8 pints, and add—red sanders, rasped, white sandal, rasped, of each 3 oz.; rosewood, rasped sassafras bark, sliced, of each 1 oz.; liquorice root, sliced, 1⁄2 oz. Infuse for four hours, strain, and add syrup according to taste.—Dose, 1 to 2 pints a day.
2. (Pearson.) Sarsaparilla, bruised, 4 oz.; dried walnut peel, 4 oz.; guaiacum, rasped, 11⁄2 oz.; crude antimony (in a rag), 1⁄2 oz.; water, 4 pints. Boil down to 3 pints.
LIST. The border or selvage torn off a piece of cloth. It is used by the French polishers and law stationers to form their rubbers, and for numerous other purposes.
LITH′ARGE. Syn. Semi-vitrified oxide of lead; Plumbi oxydum (Ph. L.), Plumbi oxydum semi-vitreum (Ph. D.), Lithargyrum (Ph. E.), L. The litharge of commerce is semi-vitrified protoxide of lead, obtained chiefly by scraping off the drops that form on the surface of melted lead exposed to a current of air (dross of lead; plumbum ustum), and heating it to a full red, to melt out any undecomposed metal. The fused oxide, in cooling, forms a yellow or reddish semi-crystalline mass, which readily separates into scales; these, when ground, constitute the ‘powdered litharge’ of the shops. Litharge is also prepared by exposing red lead to a heat sufficiently high to fuse it, and ‘English litharge’ is obtained as a secondary product, by liquefaction, from argentiferous lead ore, when it is often called ‘silver stone.’
Pur. “Entirely, or almost entirely, soluble in dilute nitric acid. This solution is blackened by sulphuretted hydrogen. Potassa throws down a white precipitate, which is redissolved by adding the same in excess. If sulphate of soda be added to 100 gr. of this oxide dissolved in nitric acid, 135 gr. of sulphate of lead is precipitated.” (Ph. L.) “50 gr. dissolve entirely, and without effervescence, in 11⁄2 fl. oz. of pyroligneous acid, and the solution precipitated by 53 gr. of phosphate of soda remains precipitable by more of the test.” (Ph. E.) The solution in both acetic and nitric acid should be colourless. It is of great importance to the pharmaceutist to obtain pure litharge, as the slightest impurity will often colour and spoil his lead plaster (EMP. PLUMBI), and solution of diacetate of lead (LIQ. PLUMBI DIACETATIS).
Uses. Litharge is employed in pharmacy, to make plasters and several other preparations of lead; by painters as a ‘drier’ for oils; and for various other purposes in the arts.
Obs. The litharge of commerce is distinguished by its colour as LITHARGE OF GOLD (LITHARGYRUM AURI, L. AURIUM, L. CHRYSITIS), which is dark coloured and impure, and LITHARGE OF SILVER (SILVER STONE; LITHARGYRUM ARGENTI, L. ARGENTUM, L. ARGYRITIS), which is purer, and paler coloured. The dark colour of the former is generally said to be owing to the presence of red lead.
Foreign litharge generally contains copper and iron; and, not infrequently, a little silver and silica. These are readily detected by the usual tests. In grinding litharge, about 1 lb. of olive oil is usually added to each 1 cwt. to prevent dust. The best solvents of litharge are nitric acid and acetic acid. As it slowly absorbs the carbonic acid of the air, it generally effervesces slightly when treated with acids, and this effervescence is stronger in proportion to its age. See Lead.