serted: there are about a hundred large dwelling-houses quite entire, of a very singular construction. Each edifice stands separate, and is constructed of several central arches supporting a pointed dome; while smaller divisions project from the body of the building, also arched, and the whole finished with the greatest neatness, having remains of stucco-painted walls within.

It is probable that the arch and vault and dome were not unknown to the nations in the East, beyond the Indies, in a very remote age; but in Greece and in Asia Minor there are no traces of them before their introduction by the Romans. To the Romans they were familiar at a very early period of their history; a knowledge of which they borrowed perhaps from the Etrus

cans, or from the supposed extinct people who possessed a city on the site of Rome itself, before the Romans.

Domestic Architecture in England. At the termination of the York and Lancaster wars, the fortified style of architecture was gradually abandoned in England; and as we had no other model of domestic architecture than the gable and the cottage, by the duplication of this simple form, in various positions, was constructed what has been called the Old English Manorhouse style. If we take a common two-floored English gable and cottage, add to it one, two, or three cottages side by side, of the same size; and in order to gain rooms out of the roof on the sides of this double or triple cottage, raise gable ends either projecting from the

ground to the top of the roof, or merely raised from the eaves-drop; if we insert broad low windows, divided by simple wooden or stone mullions, in these projecting gable ends, and similar windows at the ends of this double or triple cottage; ornament the inclined sides of the gable ends above the eavesdrop by steps or small pinnacles, or both; then add a parapet, plain or embattled, we have a manor-house in the most florid style. Many such houses came afterwards to be adorned by a centre of architectural decoration, in which Roman, Grecian, and Gothic were strangely mixed. There is, however, a certain degree of antique-like grandeur in such houses, which produces a very striking impression. This step towards a better style took place before the time of Inigo Jones.

"The mansion at South Elmham (represented on the preceding page), when entire, formed a quadrangle, as usual, of which stables and offices made up a part. The domestic and ecclesiastical styles are singularly combined in this building, though the latter seems to predominate; and the occasional discovery of old floor-stones, of a sepulchral character, intimates that the projecting porch led to the chapel of the dwelling, not into the hall; and yet the ceilings of the chambers where the two wings and upper windows are observed, on the right hand of the porch, are flat, divided into small squares by the girders above, and covered with plastered mouldings, in the manner usually seen in dwellings of an early period."

Domestic buildings and castles. The towns and ordinary houses of the Normans were entirely built of wood, and, for the most part, are so to this day. Their castles, having but one destination, that of defence, aimed at nothing but strength in their plan or construction. A site was also selected

which was already fortified by

nature.

The plan of the Norman castles was as nearly the same as the diversity of ground would allow. The principal feature was always the keep, which contained the apartments of the lord of the castle, and was also meant to be the last refuge of the garrison, if the outer works were forced. The keep was usually raised on an artificial mound, or placed on the edge of a precipice. The walls, strengthened in every way that art could devise, were of immense thickness, and composed of grouting poured in between two solid walls of stone. The facing consisted sometimes of irregular courses, and sometimes of small squared stones, after the Roman manner. Ashler was usually introduced at the angles of the building. The windows were few, and little more than chinks, unless very high up, or turned to the court. The door of entrance could only be reached by a staircase.

Under the keep were usually vaults, or dungeons, for the reception of prisoners.

The keep was enclosed in two courts surrounded by walls flanked with towers. The tower at the entrance was called the barbican, and served at once for an outwork and post of observation. The whole fortress was defended by a moat.

The remains of the Norman castles which exist scarcely afford any specimens of early Norman construction, almost all these castles having been besieged, destroyed, and rebuilt, over and over again.

The keep of Falaise is perhaps the only castellated remnant of early Norman times.

The castle of Gizors, which was built by William Rufus, retains nothing of its original construction. Domus, a private house occupied by a single proprietor and his family Doors (Antique). The Greeks in the temple of Minerva Polias, at

Athens, and also the Romans in the temple of Vesta, or the Sibyl, at Tivoli, made the doors and windows smaller at top than at bottom the architrave or dressing always constituted an agreeable decoration when in character with the building. Those of the windows in the Grecian temple have a projection, or what is sometimes termed a knee, at their upper angle; while those of the temple of Vesta, whose apertures have the same form, continue without interruption, and are surmounted by a cornice; but the cornice above the door is separated from the architrave by a frieze, while the cornice of the windows joins the architrave. In the temple of Minerva, the architrave of the windows rests only on a plain socle; those of the temple of Vesta rest also on a socle or support, the face of which is sunk.

Doors (Modern). There are two doors, designs of Vignola, which offer in their profiles and proportions a happy medium between the antique and modern compositions ; and all other designs of this kind are either derived from them, or possess a vague character which renders them unworthy of imitation.

There are breaks in the architrave, as in those of the temple of Minerva Polias; and the termination or lower extremity of these breaks determines the length of the consoles, which gives harmony to the arrangement. These consoles are also placed against a second architrave, beyond which the first projects. The design of the door of the church of St. Lorenzo is more regular. Doorway (Anglo-Norman). The Anglo-Norman builders bestowed

much pains and evinced considerable artistic skill in very elaborately ornamenting the portal entrances

W to churches in their style of arTchitecture, by a profusion of ornamental mouldings and of sculpture. Very many examples are to be met with in great variety in several of the counties of England, particularly in the counties of Norfolk and Suffolk. The example represented in the annexed engraving is a beautiful specimen taken from Todaro the church of St.

Botolph, at Cove, in the county of Suffolk.

Doorways. In the Gothic, and the architecture of the middle ages, doorways are striking and important features, affording in the character of the mouldings and ornaments the style and period of the edifice.

Doric Order. The Doric order, says Palladio, was invented by the Dorians and named from them, being a Grecian people which dwelt in Asia. If Doric columns are made alone without pilasters, they ought to be seven and a half or eight diameters high. The intercolumns are to be little less than three diameters of the columns; and this manner of spacing the columns is by Vitruvius called Diastylos.

The ancients employed the Doric in temples dedicated to Minerva, to Mars, and to Hercules, whose grave and manly dispositions suited well with the character of this order. Serlio says it is proper for churches dedicated to Jesus Christ, to St. Paul, St. Peter, or any other saints remarkable for their fortitude in exposing their lives and suffering for the Christian faith. Le Clerc recommends the use of it in all kinds of military buildings; as arsenals, gates of fortified places, guard-rooms, and similar structures. It may likewise be employed in the houses of generals or other martial men,-in mausoleums erected to their memory, or in triumphal bridges and arches built to celebrate their victories.

Vitruvius himself makes the Doric column in porticoes higher by half a diameter than in temples; and most modern architects have, on some occasions, followed his example. In private houses, therefore, it may be 16, 16, or 16 modules high; in interior decorations, even seventeen modules, and sometimes perhaps a trifle more; which increase in the height may be added entirely to the shaft, as in the Tuscan order, without changing either the base

or capital. The entablature, too, may remain unaltered in all the aforesaid cases; for it will be sufficiently bold without alteration. Doric Order. The height of the Doric column, including its capital and base, is sixteen modules; and the height of the entablature, four modules; the latter of which being divided into eight parts, two of them are given to the architrave, three to the frieze, and the remaining three to the cornice.

In most of the antiques, the Doric column is executed without a base. Vitruvius likewise makes it without one; the base, according to that author, having been first employed in the Ionic order, to imitate the sandal or covering of a woman's foot. Scamozzi blames this practice; and most of the moderns have been of his opinion, the greatest part of them having employed the Attic base in this order. Dorman tree,

a large beam lying across a room; a joist, or sleeper Dormer window, a window pierced through a sloping roof, and placed in a small gable which rises on the side of the roof

Dormitory, a sleeping apartment; a term formerly applied to the sleeping-room of the inmates of monasteries and other religious houses

Dormond, a large beam lying across a room; a joist, or sleeper: same as Dorman

Doron, a hand-breadth, or palm : among the Greeks, their bricks or tiles were termed tetradoron, four hands' breadth, or pentadoron, five hands broad: the word also implies a gift: hence, probably, the origin of the English word dowry Dosel, hangings round the walls of a

hall, or at the east end, and sometimes the sides, of the chancel of a church, made of tapestry or carpet-work; used also in churches, and frequently richly embroidered with silks, and gold and silver

Dosel, ornamental and rich stuff for the back of a chair, a throne, or a screen of ornamental wood-work Double-acting pump, a pump which

lifts and forces water at the same time, by means of a solid piston, and an entrance and exit-valve communicating with each side Double-beat valve, a valve used in Cornish engines and water-works. It has two beats, or seatings, one above the other: the bottom one is similar to an ordinary circular valve seating; the top one is somewhat less in diameter than the bottom one, and is supported from it by ribs, and forms a cover nearly the size of the inner passage. A shell with two beats to correspond with the seatings shuts the sides: when raised, (which requires but little power, as the fixed cover before mentioned bears nearly all the pressure, its diameter being nearly equal to that of the shell,) the steam or water escapes at the sides both of the top and bottom beat.

Double cylinder engine, a marine engine with two cylinders placed at right angles to the crank-shaft, and at a small distance apart, to give space for the vibration of the rod connecting the crank to the long end of a shaped cross-head, which slides in grooves between the cylinders the upper ends of the cross-head are connected to the piston-rods. This form of engine is patented by Messrs. Maudsley. Dove-tail, in carpentry, a method of joining two boards together by letting one piece into another in the form of the tail of a dove, when that which is inserted has the appearance of a wedge reversed Dove-tailing, a method of fastening together two pieces of metal or wood, by projecting bits cut in the form of dove-tails in one piece, to fit into corresponding hollows in

the other

Dowel. A round dowel or coak is the piece of timber to which the

felloes of a carriage-wheel are united Dowsing cheeks, in ship-building, pieces fayed across the apron, and lapped on the knightheads or inside stuff above the upper deck Draft-engine, an engine used for pumping

Drag-bar, a strong iron rod with eye-holes at each end, connecting a locomotive engine and tender by means of the drag-bolt and spring Drag-bolt, the strong bolt coupling the drag-bar of a locomotive engine and tender together, and removeable at pleasure Drag-hook and chain, the strong chain and hook attached to the front of the engine buffer-bar, to connect it on to any other locomotive engine or tender: also attached to the drag-bars of goods waggons Drag-link, a link for connecting the cranks of two shafts: it is used in marine engines for connecting the crank on the main-shaft to that on the inner paddle-shaft Drag-spring, a strong spring placed near the back of the tender. It is attached by the ends to the dragbar which connects the engine and tender, and by the centre to the drag-bar which connects the train to the tender.

Dragon's blood (colour), a resinous

substance brought from the East Indies. It is of a warm semi-transparent, rather dull-red colour, which is deepened by impure air, and darkened by light. There are two or three sorts, but that in drops is the best. White lead soon destroys it, and it dries with extreme difficulty in oil. It is sometimes used to colour varnishes and lacquers, being soluble in oils and alcohol; but notwithstanding it has been recommended as a pigment, it does not merit the attention of the artist.

Drainage of marshes and fen lands. The steam engine is used to raise the water above the level of those lands which lie too low to be drained