There is combination of Hine with an organic acid, viz., oxalate of lime, which is of great importance in pathology as a frequent constituent of urinary calculi and sedi ments; for a description of it see OXALIC ACID.
The soluble salts of Hine (or, more accurately speaking, of calcium) give no precipi tate with amtnonia, but yield a white precipitate (of carbonate of lime) with carbonate of potash or of soda. These reactions are, however, common to the salts of barium, strontium, and calcium. Solution of sulphate of lime produces no marked effect when added to a salt of calcium, but throws down a white sulphate with the Other salts. The most delicate test for lime is oxalate of ammo-ilia, which, even in very dilute neutral or alkaline solutions, throws down a white precipitate of oxalate of lime.
There are several compounds of phosphoric acid and lime, of which the most impor tant is the baffic phosphate of lime, sometimes termed bone phosphate, from its being the chief ingredient of bones. The basic phosphate is represented by the formula 3CaO,ro„ and not only occurs in bones,' but also in the minerals apatite and phosphorite. and in the rounded nodules termed coprolites, which are found in the Norfolk crag. It forms four-fifths of the ash of well-burned bone, the remaining one-fifth being carbonate of lime. This ash is known as &me-earth, and is employed as a manure and in the prepa ration of phosphorus, etc.
The substance commonly designated as chloride of lime has been already described in the article BLEACHING POWDElt.
Lime a..9 Manure. —This mineral substance has been used for many centuries as a means of increasing the fertility of land. All crops require a certain amount, as is found by analyzing the ash which remains after combustion. It is sometimes supplied, with out previous preparation, in the form of marl and chalk, but in most cases is first cal cined and reduced to a fine powder by slaking with water. The quantity of calcined hme applied varies from three to eight tobs to ate acre. The smaller quantity rnay be
sufficient for light land containing little legetubl&matter, while the larger may be required for strong land, or for land holding much organic matter in an inert state. The large quantity of lime applied shows that its manurial effect is due more to its producing a certain chemical effect on the land than to its affording nutriment to the crops. Lime promotes the decomposition of all kinds of vegetable matter in the soil, and, further, it corrects any acidity in the organic matter, and thus destroys those weeds which are favored by such a condition of the soil. It assists in the decomposition of certain salts whose bases form the food of plants, and in this way it may be said to digest or preparo their food. On certain kinds of land, the finer grasses do not thrive until the land has been limed, and in these cases its use becomes all-important. Lime is the only cure, too, that can be relied on for " finger-and-toe " in turnips, and its use is, from this cause, becoming more general.
Lime-Compounds in Nateria Medica.—Quicklime, in association with potash, either as the potassa cum calce, or as Vienna paste, is occasionally used as a caustic. Lime-water, mixed with an equal quantity or an excess of milk, is one of our best remedies for the vomiting dependent on irritability of the stomach. From half an ounce to two or three ounces may be thus taken three or four times a day. Its use as a constituent of carron oil in burns is noticed in the article LINIMENTS. Chalk, or carbonate of lime, when freed from the impurities with which it is often associated, is used as a dusting-powder in moist excoriations, ulcers, etc.; and in the form of chalk mizture and compound powder of chalk, is a popular remedy in various forms of diarrhea. A mixture of an ounce of precipitated carbonate of lime and a quarter of an ounce of finely powdered camphor, is sold as camphorated cretace,aus tooth-powder.