Lime, a white, soft, friable substance prepared of marble, chalk, or other calcareous earth, by burning them in a kiln. The chief uses of lime aire,

1. As an ingredient in mortar to cement brick or stone-buildings j for which purpose, being divested of its humidity, and its pores being at the same time opened by the action of the fire, it is so eminently calculated, that it may be easily reduced to powder, and mixed with sand or other matters.—See Mortar.

2. As a manure, it is of the most extensive utility : we shall, therefore, concisely state the properties of the best limestone, as well as the proportionate quantities in which it is to be spread on lands ; and at the same time point out those soils that are really ameliorated, and likewise such as receive no benefit from its application.

Formerly an opinion generally prevailed, that the most efficacious lime for manuring lands, was produced from the hardest calcareous stones, which most intimate ly approached the nature of marble : modern experience, however, has amply refuted this supposition.-It appears, indeed, that there are two sorts; namely, magnesian and calcareous limestone ; the latter of which is attended with the most beneficial consequences, while the former is highly injurious to land. This remarkable fact was first published by S. Tennant, Esq. in the " Philosophical Transactions of the Royal Society" for 1799 ; who, being informed of the opposite nature of the two species, made various experiments, in which their respective properties were clearly ascertained.

The barren, or magnesian lime, is found in various parts of England, but especially in the county of Nottingham, where a quarry of it is worked to the extent of 30 or 40 miles ; also in the counties of Derby and Northumberland, in the latter of which it is known by the characteristic name of hot, in contradistinction to the mild, or calcareous lime, that abounds in all parts of Britain. We regret that we cannot enter into a detail respecting Mr, Tennant's important discovery ; the particulars of which are recorded in the volume above mentioned.—The magnesian lime may be farther distinguished from that made of pure calcareous stone, by its slow and difficult solution in acids.

The hardness or softness of limestone, however, is of no importance, provided it be pure, that is, free from sand, clay, or other substances, which render the mass less fertilizing.—When the stone is dug out of the earth, it should be conveyed to a kiln, into which coals or turf must be put in alternate layers with the lime-stone, and the latter thoroughly calcined.—With respect to the length of time the materials should be exposed to the fire, it has been found by experiment, that lime burnt in four hours, has a much greater disposition to recover its fixed air from the atmosphere, than that which has been burning for the space of twenty-four hours ; and, as the excellence of this manure is supposed to depend on its re-attra6tion of fixed air, the process of calcination ought to be regulated accordingly.

In this state, it is called quick-lime, and should be spread as speedily as possible, immediately before the plough ; so that the greater part may be slacked in the soil. The proportion used, depends much on the custom of the country ; but should more properly be adapted to the nature of the land. In the county of York, thirty-six bushels only are carted on an acre ; in Wales, a quantity somewhat larger ; in Ireland, from five to six hundred bushels are spread on every English statute acre; and in various parts of England, very small portions are injudiciously scattered ; for it is the opinion of the most experienced agriculturists, that three or Jour hundred bushels at the least (if the price be not too high) should be allowed to each acre; especially when the soil has long been in an uncultivated state. One good liming is, in such cases, decidedly preferable to small quantities frequently repeated.

In common situations, however, where the land does not abound in putrescible matters, and is not vitiated by acids, Mr. Young is of opinion, that 160 bushels per acre, will produce a considerable effect ; but, on stiff strong clays, he thinks at least double, or triple, that quantity ought to be allowed.

If lime be applied without any other manure, it is said to exhaust the most fertile particles of the soil. Some agriculturists, therefore, suggest the propriety of forming small heaps, and covering them with earth : as soon as the soil has, by its moisture, slacked the lime, the heaps are to be opened, and as much dung buried in each as the earth will cover. A more economical and judicious method, is that stated by Mr. Andrews, in the 4th vol. of Annals of Agriculture. He directs about 140 loads (each containing 40 bushels), of moist dung to be heaped up in the month of December, when 200 bushels of lime are to be well incorporated. The whole is then suffered to lie for three months, after which the heap is to be well stirred : when the harvest is completed, the com-post is to be spread on a pea-stubble, and ploughed in for barley; but, if the season should not favour the purpose, he directs these labours to be performed after the first frost that occurs. Mr. Andrews farther observes that, in consequence of such management, his barley-crops have, upon an average of twelve years, amounted annually to four quarters and six bushels per acre.

The advantages arising from this treatment, are, 1. The total destruction of the seeds of weeds, so that the land on which this mixture had been spread, was uniformly the clearest: and, 2. The increased fermentation of the dung, by which its fertilizing properties are more speedily excited. Lastly, the ex-pence of the lime was to him 10s. per acre; and its beneficial effects continued for four years.

The soils peculiarly susceptible of improvement, by means of lime, are :

1. Rich black or brown friable crumbling loams, which abound with vegetable matter : its general putrescency being accelerated by the lime, such land is so greatly meliorated as to yield crops, which they could never have produced by the application of any other manure.

2. On low, rich, drained meadows, that have formerly been bogs, and the black soil of which abounds with vegetable fibres.

3. On old sheep-walks, heaths, and commons, which have been under grass for time immemorial, and are first to be converted into arable land ; but lime will not be of any advantage, after they have been cultivated for several years. And, though such manure will produce favourable effects upon old lay soils, abounding in vegetable particles, yet when the latter are putrefied by liming, and exhausted by repeated cropping, it will be of no service.

4. On moory, boggy, mountainous land j and, according to Dr. Hunter, on black peat-earth. In his opinion, lime prevents the spontaneous growth of heath, and produces a new family of vegetables, especially white clover. He farther remarks, that the greatest improvements ever made on moors, in any country, have probably been effected by means of lime.- There prevails, however, a diversity of opinion on this subject:, which we are unable to reconcile. - In the l6th vol. of the Transact tions of the Society for the Encou ragement of Arts, etc. Thomas Davis, Esq. (steward to the Marquis of Bath), states that, though lime is the only proper manure for such soil, which is thus qualified to produce crops of corn for thefirst 3 or 4 years, after converting it into arable or meadow land ; yet this manure loses its ameliorating properties in the course of ten years and he never found a second liming to be productive of any beneficial effect.

5. On all other waste soils that have been over-run for ages with furze, heath, broom, fern, bushes, or wood ; and which, though richly stored with vegetable food, have contracted an acidity, in consequence of their long rest, and the spontaneous growth of roots.

On the contrary, lime is of little service on poor, light, and thin soils; or such as are on a quarry of lime or other stone, especially after they have borne crops for a considerable number of years. Nor is it productive of any advantage on strong, stony land ; on wet, cold Joams, which have not been sufficiently drained; or similar clays that are tenacious of moisture; but Mr. Arthur Young is of opinion, that large quantities of well drained lime, laid on very stiff clay, would be attended with a favourable effect.; though he candidly adds, that it never has been tried to his satisfaction.

With respect to the expence of procuring lime, the usual cost is from 2 1/2d. to 3d. per bushel, where coals can be easily conveyed to the kiln. But, where fuel is expensive, and at a distance, the price rises to 4d. and sometimes even to 6d. : in this case, however, it is too valuable to be employed as a manure, unless it be ascertained by experience, that a small proportion will answer the purpose. Mr. Young observes, that " a man may venture large quantities at 3d. per bushel;" though even at that price, he would employ it only on those soils which might, in all probability, be thus greatly and permanently improved.

Few manures contribute to promote vegetation in a more conspicuous manner than lime. By its union with the carbonic acid, it renders the latter soluble in water, instead of expanding it into a gas; and thus a great quantity of carbon will be absorbed by the vessels of plants. Dr. Darwin conjectures, that calcareous matter forwards vegetation, by the phosphorus it contains ; and which, being united with the lime, is converted into a hepar, without becoming acid by the addition of oxygen. Although lime be an improper manure for clay-soils, Dr. D. is inclined to believe, that if it were properly mixed with them, such lands would be rendered less cohesive, and consequently admit of being more easily penetrated by vegetable fibres. It destroys worms, snails, and all other insects, which may be touched by it, and with which almost every soil abounds. Lastly, such are its ameliorating effects on grass-land in particular, that if a spadeful of lime be thrown on a tussock, which horses or cattle have refused to eatfor several years, they will for many succeeding seasons eat it close to the ground: this change, Dr. Darwin supposes to arise from a larger portion of saccharine matter being now contained in the joints of the grass, and a smaller degree of acidity in its circulating juices.

Quick-lime is also of great utility in rending rocks and stones, when mixed with gunpowder, in the proportion of one pound of the former, well dried and pulverized, to two pounds of the latter. This singular property of lime was discovered, and is related, by H.D.Griffith, Esq. in the 8th vol. of the Transactions of the Bath and West of England Society ; where he states, that the mixture above specified, caused an explosion with a force equal to three pounds of gunpow der : hence, in those operations, one-third of the expence may be saved,.

As a medicine, lime is of considerable use ; and has lately been employed with success in the fevers of America. It is, however, chiefly prescribed in a state of solution, when it is called lime-water. This fluid is prepared by gradually mixing half a pound of new quick-lime with twelve pints of boiling distilled water. The whole is suffered to stand in a covered vessel for one hour, when it is poured off, and preserved in close bottles.—Lime-water was formerly in great repute as a solvent of the stone, and a remedy in scro-phulous affections. It has likewise been used both externally and internally for cutaneous eruptions ; though we by no means approve of its indiscriminate use, which may be attended with dangerous effects.- On account of its astringent properties, this preparation has also been successfully prescribed in cases of diabetes, or immoderate flow of urine ; and other disorders proceeding from laxity or weakness of the solids. At present, it is chiefly used for washing foul or ill-conditioned ulcers.

Notwithstanding these useful qualities of lime, it is, if accidentally swallowed, or inhaled in any quantity, one of the most fatal poisons. Hence, persons employed in lime-works become subject: to blood - spitting, asthma, painful constipations of the bowels, and consumption : their countenance turns unnaturally pale ; and, after languishing for years, these unhappy victims die in a sleepless state. — Bread adulterated with lime, absorbs all those juices of the stomach, which ought to promote digestion ; obstructs the alimentary canal; occasions almost constant thirst; and at length produces the most violent colics, fevers and death. As soon, there-fore, as it may be discovered, that a person has taken into the stomach either lime or gypsum, the first step will be to administer an emetic, consisting of 1 1/2 or 2 ounces of vinegar of squills, and 20 or 30 grains of ipecacuanha in powder: large draughts of sour whey should next be given, to facilitate the operation of the medicine. In order to counteract: the causticity of lime in the stomach and intestines, it will be advisable to drink, alternately, a mixture of vinegar and water, lemonade, or similar acidulated beverage, for one day; and, on the other, to make use of mucilaginous decoctions, such as barley or rice-water, gruel, fat broths, oils, or sweet whey in which a small quantity of white soap has been dissolved ; to eat salads with a large proportion of oil and vinegar, and ripe sub-acid fruit. To complete the cure, it will perhaps be requisite to administer, according to circumstances, emollient or laxative clysters.