PART III.

Earths and Earthy Salts.

629

first to slack the lime with a small portion of water, before thewhole quantity be added; as by this it is prevented from run-ning into a paste, which confines the action of the water. Thedirection of the Dublin College to use the. water for slackingthe lime in a boiling state,'is superfluous. Cold water actsmore powerfully on lime than hot water: in Mr. Phillips's ex-periments 10000 grains of water at 212° dissolve 7'8 grains oflime, whereas 10000 grains of water at 32° dissolve 15*2grains ; and by heating cold saturated lime water a crystallinedeposition of hydrate of lime was thrown down. Water at60° retains in solution rather less than 0*002 parts, or one sixhundredth part of lime.

Qualities. —Lime water is inodorous; has a strong, styptic,acrid taste; is limpid and colourless; and changes to green, thevegetable blue and red colours. It unites with oil, forming animperfect soap. When exposed to the air, it attracts carbonicacid, which, combining with part of the lime held in solution,forms on its surface a pellicle of carbonate of lime, whichthickens, cracks, and sinks to the bottom of the vessel, leavingits place to be supplied by another pellicle; and thus, by suc-cessive formations, the whole of the lime is abstracted fromthe water. Hence the necessity of preserving the solution inwell closed bottles. It is decomposed by the acids and sul-phur, die alkaline carbonates, phosphates, borates, tartrates,and citrates; the infusions of orange-peel, columba, cinchona,rhubarb, and senna, which are consequently incompatible informulae with it.

Medical properties and uses. — Lime-water is tonic, antacid,anthelmintic, and externally detergent. It proves very usefulin dyspepsia attended with much acidity of the stomach, byneutralizing the acid, and dissolving the sordid mucus withwhich it is often loaded in this disease; and has also beenfound efficacious in diarrhoea, diabetes, and leucorrhcea. Itdestroys intestinal worms, and dissolves the mucus whichforms their nidus; and for the same reason proves serviceablein slimy bowels. Its internal use, however, should be occa-sionally suspended for a few days, as its long continued actionon the stomach is apt to prove hurtful. Externally it is ap-plied as a lotion to foul and cancerous ulcers, tinea capitis,and scabies, but with little advantage.

The dose is from fj ij to Oss, alone, or diluted with milk.

Officinal preparations. Oleum Lini cum Calce, E. D. Aqua Calciscomposita, D.

LIQUOR ALUMINIS COMPOSITUS, Lond. Com-pound Solution of Alum.

" Take of alum, sulphate of zinc, each half an ounce; boil-ing water, two pints. Dissolve the alum and the sulphate ofzinc together in the water; then filter the solution."

s s 3