Lithium, Citrate of, Effervescing. (Paris Pharm. Society.) Citric acid, 40 grams; sodium bicarbonate, 50 grams; lithium bicarbonate, 10 grams. Mix the powders and place them in a flat-bottomed vessel having a large surface; heat to about 100° C., stirring the powder continually until it takes the granular form, then by means of appropriate sieves obtain granules of suitable and uniform size, and preserve the preparation in well-closed bottles.
Lithium, Oxide of. Li2O. Syn. Lithia. An alkaline earth found in petalite, &c., and in small quantities in most mineral waters.
Prep. Petalite (a silicate of aluminum
and lithium) in powder mixed with twice its weight of fluor spar is heated with strong sulphuric acid as long as acid vapours are given off. The residue is treated with ammonia, boiled, and filtered, evaporated to dryness, and heated to redness. The residue consists of sulphate of lithium, from which the oxide is obtained by decomposing it with acetate of barium, filtering and heating after having evaporated the solution to dryness.
This yields the so-called oxide, which is in reality the hydrate, LiHO, and is a white, non-volatile, soluble, caustic solid. The true oxide is a white powder decomposed by water forming the hydrate, and obtainable by igniting the metal in oxygen.
Lithia, Effervescing Solution of. Syn. Liquor lithiæ effervescens. Comp. Water charged with carbonic acid and holding in solution carbonate of lithium. 10 fl. oz. contain 5 grains of the carbonate.—Props. Colourless liquid, possessing powerful diuretic properties.—Use. Antilithic, for dissolving calculi of uric acid.—Dose, 5 to 10 fl. oz.
LITHOFRACTEUR. See Blasting powders.
LITHOG′RAPHY. The art of tracing letters, figures, and other designs, on stone, and transferring them to paper by impression. Our notice of this beautiful and useful art must necessarily be brief.
There are two methods of lithography in general use. In the one, a drawing is made on the stone with a lithographic crayon, or with lithographic ink; in the other method the design is made on lithographic paper, which, on being moistened and passed through the press, leaves its design on the surface of the stone, reversed. In either method, water acidulated with nitrous acid, oil of vitriol, or hydrochloric acid, is poured over the stone, and this, by removing the alkali from the chalk or ink, leaves the design on it in a permanent form, at the same time that it ‘etches’ away a portion of the lights, and renders the surface more absorbent of water.
The process of lithographic printing is as follows:—Water is thrown over the stone, the roller charged with printing ink is passed over the surface, the paper is applied, and a copy is obtained by the action of the lithographic press. The same process must be had recourse to for each copy. The nature of the stone is such that it retains with great tenacity the resinous and oily substances contained in the ink or crayon employed to form the design and also absorbs water freely; this, combined with the peculiar affinity between resinous and oily substances, and their mutual power of repelling water, occasions the ink on the printing roller to adhere to the design, and to leave untouched the lights.