Abbildungen der Seite
PDF

countries infected by the plague, or suspected of being so. An account of the principal lazarettos of Europe was published by the celebrated Howard. LEAD. (Sax. Leb.) The heaviest metal next to gold, platina, and mercury, being eleven times heavier than its own bulk of water. See Book II. Chap. II. Sect. 6. ": A building whose rafters pitch against or lean on to another building or against * *ail. Leaves. (Sax. Lear.) Ornaments imitated from natural leaves, whereof the ancients used two sorts, natural and imaginary. The former were those of the laurel, palm, acanthus, and olive; but they took great liberties in the representations of all of them. LEDGE. A surface serving to support a body either in motion or at rest. Ledges of doors are the narrow surfaces wrought upon the jambs and sofites parallel to the wall to stop the door, so that when it is shut the ledges coincide with the surface of the door. A ledge, therefore, is one of the sides of a rebate, each rebate being formed of two sides. In temporary work the ledges of doors are formed by fillets. LEDGEMENT. The development of a surface, or the surface of a body stretched out on a plane, so that the dimensions of the different sides may be easily ascertained. LEDGEas. In scaffolding for brick buildings are horizontal pieces of timber parallel to the walls. They are fastened to the standards, or upright poles, by cords, to support the put-logs, which lie at right angles to and on the walls as they are brought up, and receive the boards for working on. LeDoux. See ARchrrects, list of 306. LEGRAND. See ARchitects, list of 309. LEGs or AN HYPER Bol.A. The two parts on each side the vertex. LEGs of A TRIANGLE. The sides which inclose the base. LENGTH. (Sax. Lens.) The greatest extension of a body. In a right prism the length is the distance between the ends; in a right pyramid or cone, the length is the distance between the vertex and the base. LENGTHENING of TIMBER is the method of joining several beams, so as to form a long beam of any given length. LEoNI. See ARCHITECTs, list of 230. LEscor. See ARchirrors, list of 237. Level. (Sax. Loerel.) A line or surface which inclines to neither side. The term is used substantively to denote an instrument which shows the direction of a straight line parallel to the plane of the horizon. The plane of the sensible horizon is indicated in two ways: by the direction of the plummet, or plumb line, to which it is perpendicular; and by the surface of a fluid at rest. Accordingly, levels are formed either by means of the plumb line, or by the agency of a fluid applied in some particular manner. They all depend, however, upon the same principle, namely, the action of terrestrial gravity. The carpenter's level consists of a long rule, straight on its lower edge, about ten or twelve feet in length, with an upright fixed to its upper edge, perpendicular to and in the middle of the length, having its sides in the same plane with those of the rule, and a straight line drawn on one of its sides perpendicular to the straight edge of the rule. This standing piece is generally mortised into the other, and finally braced on each side, to secure it from accident, and has its upper end kerfed in three places, viz. through the perpendicular line, and on each side. The straight edge of the transverse piece has a hole, or notch, cut out on the other side equal on each side the perpendicular line. A plummet is suspended by a string from the middle kerf, at the top of the standing piece, to vibrate freely in the hole or notch when hanging at full length. When the straight edge of the level is applied to two distant points, with its two sides placed vertically, if the plummet hangs freely, and the string coincides with the straight line on the standing piece, the two points are level. If not, suppose one of the points to be at the given height, the other must be lowered or raised, as the case may require, till the string is brought to a coincidence with the perpendicular line. By two points is meant two surfaces of contact, as two blocks of wood, or the upper edges of two distant beams. The uses of the level in carpentry are various, and need not be here detailed. The mason's level is formed of three pieces of wood, joined in the form of an isosceles triangle, having a plummet suspended from the vertex over a mark in the centre of the base. LEvELLING. The art or act of finding a line parallel to the horizon, or at one or more stations, in order to determine the height of one place with respect to another, for laying grounds even, regulating descents, draining morasses, conducting waters for the irrigation of land, &c. LEveR. In mechanics an inflexible rod, moveable about a fulcrum, or prop, and having forces applied to two or more points in it. The lever is one of the mechanical powers, and being the simplest of them all, was the first attempted to be explained. For its properties see Book II. Chap. I. Sect. 8. Levra BoARDs. A set of boards so fastened that they may be turned at any angle to admit more or less light, or to lap upon each other so as to exclude all air or light through apertures. LEw1s or LEwisson. An instrument said to have been used in England by the builders of the middle ages to raise stones of more than ordinary weight to the upper part of a building. It was revived by a French artisan in the reign of Lewis XIV., and is now generally employed. It operates by the pieces forming its dove-tail end being kept in their correspondent places in the stone by a middle straight piece, kept in its situation by a pin passing through it and the dovetail pieces at top, and the combination of the whole, is with a large ring. LIAs. A provincial name adopted by geologists for an argillaceous limestone, which, together with its associated bed, is characterised by peculiar fossils. LIBoN. See ARchitects, list of 11. LIBRARY. An edifice or apartment for the reception of a collection of books. For remarks on the construction of public libraries see Book III. Chap. III. Sect. 9. LIGHTs. A term sometimes used to denote the openings of doors, gates, and windows, and other places through which air and light have passage. Ligh rhouse. A lofty building, on the top whereof artificial lights are placed to guide ships at sea. For general observations on lighthouses see Book III. Chap. III. Sect. 12. LIKE ARcs. In the projection of the sphere, the parts of lesser circles containing an equal number of degrees with the corresponding arcs of greater circles. LIKE FIGUREs. In geometry, such as have their angles equal, and the sides about the equal angles proportional. LIKE SoLIDs. Those which are contained under like planes. LIME. (Germ. Leim, glue.) A most useful earth, obtained by exposing chalk, and other kinds of limestones or carbonates of lime, to a red heat, an operation generally conducted in kilns constructed for the purpose, by which the carbonic acid is expelled, and lime, more or less pure, according to the original quality of the limestone, remains, in which state it is called quicklime. See Book II. Chap. II. Sect. 10. LIMEKILN. One for the purpose of burning lime. They are constructed in a variety of ways, to save expense, or to answer to the particular nature of the fuel. LIMEstone. A generic term for those varieties of carbonate of lime which are neither crystallised or earthy, the former being calcareous spar, the latter chalk. When burned they yield quicklime. LINE. (Lat. Linea.) In geometry, a magnitude having only one dimension, and defined by Euclid to be that which has length without breadth. The term is also used to denote a measure of length used formerly in France, namely, the twelfth part of an inch, or 1's of a foot. LINE of DIRECTion. In mechanics, the line in which motion is communicated. LINE, GEOMETRICAL. In perspective, any straight line in the geometrical or primary line. LINE, HoR1zoNTAL. A line parallel to the horizon. In perspective, it is the vanishing line of horizontal planes. LINE of STATIoN. The intersection of a plane passing through the eye, perpendicular to the picture, and to the geometrical or primary plane with the plane itself. LINE, verticAL. The intersection of a vertical plane with the picture passing along the station line. LINE, visuAL. A ray of light reflected from the object to the eye. LINEs of LIGHT AND SHADE. Those in which the light and shade of a body are separated. Thus, on a curved surface, it is the line determined by a tangent to the surface in the direction of the rays of light. LINEAR PERspEcrive. See Book II. Chap. IV. Seet. 2. LINING. The covering of the surface of any body with another thin substance. Thus the lining of a wall is a wooden boarding, whose edges are either rebated or grooved and tongued. Lining is distinguished from casing, the first being a covering in the interior of a building, whilst the latter is the covering of the exterior part of a building. LINING out STUFF. (Participle.) The drawing lines on a piece of board or plank so as to cut it into thinner pieces. LININGs of BoxINGs for window shutters, are the pieces of framework into which the window shutters are folded back. LININGs or A Door. Those of the sides of apertures of doors called the jambs or jamblinings, that which covers the top or head being the sofite. LINTEL. (Span.) A horizontal piece of timber or stone over a door, window, or other opening to discharge the superincumbent weight. If a wall be very thick, more that one lintel piece will be required, unless scanting of sufficient width be found. In some old books on carpentry lintels are classed under wall plates, but the word is now never used in this sense, unless the joisting or tie-beams rest upon it, in which ease it is both a lintel and a wall plate. List or Lisret. The same as FILLEr, which see.

LIsten BoARDs. See BoARns. ListING. (Participle.) Cutting the sap wood out from both edges of a board. LoAM. A soil in which clay prevails. It is called heavy or light as the clay may be more or less abundant. LoBBY. (Germ. Laube.) An inclosed space surrounding or communicating with one or more apartments, such as the boxes of a theatre, for instance. By it also is understood a small hall or waiting room, or the entrance into a principal apartment where there is a considerable space between it and a portico or vestibule; but the dimensions, especially as regards the width, will not allow of its being called a vestibule or anti-room. Lock. (Sax. Loc.) A well-known instrument, consisting of springs and bolts, for fastening doors, drawers, chests, &c. A good lock is a masterpiece in smithery, requiring much art and delicacy to contrive and vary the wards, springs, bolts, and other parts whereof it is composed, so as to adjust them to the places where they are serviceable, and to the various purposes of their use. The structure of locks is so varied, and the number of inventions of their different sorts so extended, that we cannot attempt to enumerate them. Those placed on outer doors are called stock locks, those on chamber doors spring locks, and such as are hidden in the thickness of the doors to which they are applied, mortise locks. The padlock is too well known to need description here. The conditions which seem indispensable in a perfect lock are, 1. that certain parts of the lock should be variable in position through a great number of combinations, one only whereof shall allow the lock to be opened or shut; 2. that this last-mentioned combination should be variable at the pleasure of the possessor; 3. that it should not be possible, after the lock is closed and the combination disturbed, for any one, not even the maker of the lock, to discover, by any examination, what may be the proper situations of the parts required to open the lock; 4. that trials of this kind shall not be capable of injuring the works; 5. that it shall require no key; 6. and be as easily opened in the dark as in the light; 7. that the opening and shutting shall be done by a process as simple as that of a common lock; 8. that it should open without a key or with one, at pleasure; 9. that the keyhole be concealed, defended, or inaccessible; 10. that the key may be used by a stranger without his knowing or being able to discover the adopted combination; 11. that the key be capable of adjustment to all the variations of the lock, and yet be simple; 12. that the lock should not be liable to be taken off and examined, whether the receptacle be open or shut, except by one who knows the method of combination. The above considerations involve a problem of great mechanical difficulty, which has not yet been solved, though much has been done towards it. For the locks in common use in buildings, see p. 592. Longe. A small house, situate in a park or domain, subordinate to the mansion. Also the cottage placed at the gate of the road leading to the mansion. Loq ARITHMs. See p. 246, et seq. Lochouse. A hut constructed of the trunks of trees. Logistic SriRAL. One whose radii are in continued proportion, and in which the radii are at equal angles; or, in other words, a spiral line whose radii every where make equal angles with the tangents. LoMBARDo, M. See ARchitects, list of 174. LoMBARDo, P. See ARchitects, list of 173. LoMBARDo, SANTE. See ARchitects, list of 216. LoNGIMETRY. A term used to denote the operation of trigonometry for measuring lengths, whether accessible or inaccessible. Loor. (Fr.) A small narrow window. A loophole is a term applied to the vertical series of doors in a warehouse, from which the goods, in craning, are delivered into a warehouse. LoRME, PHILIP DE. See ARchitects, list of 214. Lores. A plant of the water-lily species much used in the architectural ornaments of the early nations, and especially in the capitals of Egyptian columns. Louis. See ARchitects, list of 304. LozENGE. A quadrilateral figure of four equal sides, with oblique angles. LUFFER BoARDINGs. (Fr. Louvre.) See BoARDING LUFFER. LUNE or LUNULA. The space between two equal arcs of a circle. . LUNETTE. (Fr.) A cylindric, cylindrical, or spherical aperture in a ceiling. As an example of the term, we may refer to the upper lights in the nave of St. Paul's Cathedral. LUsARCHE. See ARchitects, list of 110. LUTHERN. The same as DoRMER, which see. LYING PANELs. Those wherein the fibres of the wood, or the grain of it, lie in an horizontal direction. - - Lysis. (Gr.) A plinth or step above the cornice of the podium of ancient temples, which surrounded or embraced the stylobate, whereof an example may be seen in the temple

of Fortuna Virilis at Rome.

[ocr errors]

M Roof. A roof formed by the junction of two common roofs with a vallum between them. The letter A inverted represents this species of covering. MAchicoLATIONs. (Fr. Machicoulis.) In castellated architecture are, according to Grose, the projections, supported by brackets or corbels, through which melted lead and stones were dropped on the heads of assailants. They were not probably, however, projecting works, but sometimes were considered as the series of square holes in the vaultings of the portals used for the same purpose. MACHINE. (Gr. Maxawn.) In a general sense, any thing which serves to increase or regulate the effect of a given force. Machines are simple or compound. The former are the simple mechanical powers, six in number; viz. the lever, the wheel and axle, the pulley, the wedge, the screw, and the funicular machine. The latter are formed by the combination of two or more simple machines, and are classed according to the forces by which they are put in motion, as hydraulic machines, pneumatic machines, electrical machines, &c., or the purposes they are intended to serve, as military machines, architectural machines, &c. MACHUCA. See ARchitects, list of 227. MADER No. See ARchitects, list of 249. MAGLIoNE. See ARCHITECTs, list of 123. MAGNESIAN LIMEston E. An extensive series of beds lying in geological position immediately above the coal measures; so called because the limestone, which is the principal member of the series, contains magnesia. MAGNITUDE. (Lat.) A term by which size, extent, or quantity is designated. It was originally applied to the space occupied by any figure; or, in other words, it was applied to objects strictly termed geometrical, and of three dimensions, length, breadth, and thickness, but it has gradually become enlarged in its signification, so as to be given to every kind of quantity that admits of mensuration, or of which greater or less can be predicated; in which sense it was used by Euclid. MAHoo ANY. A wood often used for doors and window-sashes. See p. 487. The Jamaica mahogany is the hardest and most beautiful, and is distinguished from that of Honduras by the chalky appearance of its fibres. Those from Honduras appear quite dark. After oiling, this distinction is not so clearly observable. MA IN Couple. See Couple. MAJANo. See ARchitects, list of 149. MALLEABILITY. (Lat. Malleus, a hammer.) The property of being susceptible of extension under the blows of a hammer. It is a characteristic of some of the metals, most particularly in gold. Common gold-leaf is not more a two-hundred-thousandth part of an inch in thickness. Five grains may be beaten out so as to cover a surface of more than two hundred and seventy square inches. MALLET. (Lat.) A large kind of wooden hammer much used by artificers who work with a chisel, as masons, stonecutters, carpenters, joiners, &c. MALTHA. (Gr.) A native bitumen used by the ancients for plastering the walls of their dwellings, &c. An artificial kind was made of pitch, wax, plaster, and grease; another sort was composed of lime slaked with wine, and incorporated with melted pitch and fresh figs. MANDREL. (Fr. Mandrin.) In machinery, a revolving shank, to which turners affix their work in the lathe. MAND RocLEs. See ARCHITECTs, list of 6. MANGER. The trough in the stall of a stable wherein is placed the corn or other short food given to live stock, and more especially to horses. MANLIo. See ARchitects, list of 203. MANSARD. See ARCHITECTs, list of 258. MANsARD, JULEs HARDouiN. See ARCHITECTs, list of 267. MANs ARD Roor. (So called from the name of its inventor, François Mansard.) The same as CURB Roof, which see. MANsion. A large house; a term more usually applied to one in the country. The origin of the word and its application is supposed to be derived from the mansiones, or stationary camps of the Roman soldiers. MANTLE TREE. See CHIMNEY. MARBLE (Fr. Marbre.) A term limited by mineralogists and geologists to the several varieties of carbonate of lime, having more or less of a granular and crystalline texture. Among sculptors, the word is used to denote several compact or granular kinds of stone susceptible of a very fine polish; the varieties of it are extremely numerous. The most valuable sorts used by the ancients were the Pentelican, which was white, and was obtained from Mount Penteles in Attica. It was used in the Parthenon and other Athenian buildings, and was also in great repute among the sculptors. The Parian narû. was as its name imports, from the island of Paros, in which Mount Marpessus yielded "best, which was called Marpessian. The marble of Paros was also sometimes termed

Lychneus, because of its use in making candelabra, and Lygdinum, from the promontory of Lygdos. Another of the white marbles of antiquity was that of Mount Hymettus in Attica. The marbles of Thasus and Lesbos were white, and in great repute. The latter island produced also a black marble. At Luna, in Etruria, there was found a marble even whiter than that of Paros. Amongst the white marbles may, moreover, be mentioned the marmor Phellense from Mount Phellens; the marmor Coraliticum, found near the river Coralios in Phrygia, and termed also Sangarium, from another name of the same river. The marmor Cyzicum was taken from the quarries of Cyzicus in Asia Minor; the Synnadicum, or marmor Phrygium, was obtained from the environs of the city of Synnas in Phrygia, and was of a black ground with small circles. Another sort of marble, which resembled ivory in its colour, was called chernites. The marble of Taenarus was highly esteemed as a black marble. The marmor Lybicum, or Numidian marble, called also marmor Luculleum, was what the French term noir antique. The celebrated marmor Chium was excavated from the Mount Pelineus in the island of Chio, and was of a transparent chequered black colour. The marmor obsidianum was from Ethiopia, and of the black species, as was the Proconnesian, or Cyzican marble, from the island of Proconnesus. That from Mount Taygetes, called marmor Laconicum, was the wellknown verd antique of antiquaries. The marble of Carystus was a mingled green; that called the Atracium, from Mount Atrax in Thessaly, was a mixture of white, green, blue, and black. The green Tiberian and Augustan marbles were obtained from Egypt. The marmor Aphites, or Memphites, which took its first name from its resemblance to the skin of a serpent, and its second from the city of Memphis, where it was found, is the Serpentino antico of the Italians. The marble of Corinth was yellow, and the marmor Phengites of Cappadocia was white, with yellow spots. The Rhodian marble was marked with spots resembling gold; that of Melos was yellow, and excavated in Mount Acynthus. The varieties of marble used in modern times are exceedingly numerous, and a classification of them would occupy a larger space than can be here given. Except the finest specimens of white marble, they are mostly opaque. Some extremely fine specimens of white marble are to be seen in the Borghese Palace at Rome, which, on being suspended by the centre on a hard body, bend very considerably. It is found that statuary marble exposed to the sun acquires, in time, this property, thus indicating a less degree of adhesion of its parts than it naturally possessed. Almost every mountainous district of the world produces this mineral, but the finest and most valuable is from Italy. See Book II. Chap. II. Sect. 3. MARBLE, PolishING or. The material is brought to an even face by rubbing with freestone, afterwards with pumice-stone, and lastly with emery of several colours; but white marble is finished with calcined tin. The Italians polish with lead and emery. The sawing of marble, preparatory to polishing, is by a saw of soft iron, with a continued supply of the sharpest sand and water. MARGIN or A Course. That part of the upper side of a course of slates which appears uncovered by the next superior course. MARIGoLD WINDow. See Rose WINDow. MARMoRATUM. (Lat.) A cement used by the ancients, formed of pounded marble and lime well beaten together. MARQUETRY or PARQUETRY. (Fr. Marquetrie.) Inlaid work, consisting of different pieces of various coloured woods, of small thickness, glued on to a ground, usually of oak or fir well dried and seasoned, which, to prevent casting and warping, is composed of several thicknesses. It was used by the early Italian builders in cabinetwork; and John of Vienna, and others of his period, represented by its means figures and landscapes; but in the present day it is chiefly confined to floors, in which the divers pieces of wood are usually disposed in regular geometrical figures, and are rarely of more than three or four species. MAscAL or MARsHALL. See ARchitects, list of 220. MAsoNRY. (Fr.) The science of combining and joining stones for the formation of walls and other parts in constructing buildings. When applied in the construction of domes, groins, and circular arches, it is difficult and complicated, and is dependent on a thorough knowledge of descriptive geometry. The subject is treated in the body of this work, Book II. Chap. III. Sect. 3. Among the ancients, several sorts of masonry were in use, which are described by Vitruvius as follows, in the eighth chapter of his second book:– “The different species of walls," he observes, “are the reticulatum (net-like) (fig. 1045. A), a method now in general use, and the incertum (B), which is the ancient mode. The reticulatum is very beautiful, but liable to split, from the beds of the stones being unstable, and its deficiency in respect of bond. The incertum, on the contrary, course over course, and the whole bonded together, does not present so beautiful an appearance, though stronger than the reticulatum. Both species should be built of the smallest sized stones, that the walls, by sucking up and attaching themselves to the mortar, may last the longer: for as the stones are of a soft and porous nature, they absorb, in dry

« ZurückWeiter »