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their needle on a cork, It is without any just foundation. The Loadstone is known by the names of the Herculean stone, from its commanding iron, Lapis Heracleus, from Heraclea, where it is said to have been first discovered, and Lapis Nauticus, from its utility to mariners.
When from the bosom of the mine,
LINSEED (See Flax).
An imperfect metal, of a dull grey colour, the least ductile, elastic, and sonorous of all others, and the heaviest excepting mercury, gold, and platina. It is found in many parts of Europe, in North and South America, and in the East Indies.
The ores of this metal are various and numerous ; they occur in almost every rock formation, but principally in limestone; they generally contain a portion of silver, particularly those of Devonshire and Cornwall, where the most abundant is the grey variety, from which the common lead is chiefly produced. Other ores of lead are white, green, yellow, red, &c. which may generally be discovered by their weight. Lead, after it has been raised, is crushed in a mill and smelted. It is used in the construction of cisterns, boilers for chemical purposes, pipes, the covering of buildings, &c. but utensils made of this metal for domestic purposes are highly pernicious. Lead is also used in casting shot. The fumes, when inhaled into the human body, are productive of various disorders, to which the miners are particularly subject.-Red Lead, or Minium, is sometimes made from Litharge, (49) but the best is made from the metal in its pure state, which when properly melted produces the finest fint glass. The greater the proportion of Red Lead, the heavier is the glass, and the greater its power of refraction; it is, therefore, employed for the lenses of telescopic instruments, and is much used in glazing pottery.-White Lead, or Ceruse, is a Calx of Lead, made by exposing plates of that metal to the vapour arising from vinegar. It is used by painters, and in surgery. That from Venetia is esteemed the best.
Black Lead, or Plumbago, is a genus of inflammable substances, found in great abundance in Cumberland, and in many parts of Spain. The best sort for making pencils (its principal use) is met with at Borrowdale. It is also useful in cleaning stoves, grates, &c.—Yellow Lead, or Masticot, is the ashes of Lead obtained by slow calcination, used in oil painting, medicinally, and in glazing pottery.
LOGWOOD, OR CAMPEACHY WOOD.
A wood very much used by dyers. The tree, which generally grows to the height of about twenty feet, is found in many parts of the Spanish West Indies, particularly in the bay of Campeachy. The colours extracted from it are more or less inclined to red, from lilac to violet, according to the different ingredients employed, and among the colours prepared from Logwood the black is the most durable, but they are all of a fading nature. Logwood is cut in the spring, when the bark and white sap are chipped off, and the red part or heart is reserved for sale. Logwood is so heavy as to sink in water and is capable of bearing a very fine polish. Lately it has been used in medicine.
A white, soft, friable substance, procured from chalk, limestone, marble, and other calcareous
earths, by burning in a kiln. It is principally used as an ingredient in mortar, also as a manure for the land. There are two sorts, the magnesian and calcareous, the former of which is injurious to land, whilst the latter is highly beneficial,—the former may be easily distinguished by its slow and difficult solution in acids. It has also been successfully employed, when mixed with other things, as a medicine, but taken or inhaled in any quantity alone it has proved poisonous. Lime combined with Fluoric Acid, forms the fossil called Fluor Spar.—(See Spar.)
LIMES (See Citron).
A leather made of the skins of goats, tanned and dyed in a particular way by the Turks.
The name is derived from its being invented in the kingdom of Morocco. That prepared in England is inferior, and generally made from sheep skins. Morocco leather is often counterfeited for Shagreen, but may easily be detected by the surface peeling off, whilst the genuine article remains bard.
A dark coloured mineral, frequently attendant upon iron ores and ochreous substances. Its general
appearance is earthy, brown, or black; it soils the fingers when touched, and frequently contains delicate fibres of a bright iron-like lustre. It also occurs with earthy substances, and gives the colour to amethysts, calcareous spar, quartz, and other gems. It is found in Devonshire, and in the lead and iron mines in Somersetshire, in America, and various parts of Europe. When reduced to powder Manganese becomes magnetical, which is not the case in large pieces. It melts quickly with other metals, mercury excepted, and renders copper extremely malleable when united with it. It is employed in glass works, for purifying glass from the effects of colouring substances, as it renders vitrified matters perfectly clear, and it also imparts red tinge to glass in a state of fusion. It is employed in bleaching, and in glazing earthenware, wbich thus acquires a black colour.
MAHOGANY, OR SWIETENIA.
A tree growing wild in South America, and in some of the West Indian Islands. It grows very tall and straight, and is generally about four feet in diameter. The foliage is a deep green—the flowers are rather red-the fruit oval and about the size of a turkey's egg. The wood is very hard, takes a fine polish, and is used for cabinet ware of every