An Ellustrated Glossary of Technical
Terms used in Architectural and
Interior Decoration.

(Continued from page 162.) CONICAL, of the shape of a cone.

effects of the weather. Its construction may be explained as follows:-In the extremity of the arm, F Q, that extends from the side of a small square box, B L, is placed a double convex lens, whose axis is inclined in an angle of forty-five degrees, to a plane mirror, в 0; the focal length of the lens is equal to its distance from the side of the box, o T, therefore, when the lens is turned towards the illuminated prospect, it would project the image on the side or if the mirror were removed, but this CHAMBRAULE, an ornamental bordering, will reflect the image to the side M L, which is generally taken from the architrave of the as far distant from the middle of the mirror as order of the building, placed on the sides and this is from the side o r. It is then received tops of doors, windows, and fireplaces. In on a piece of glass rough at the upper side and window-frames, the sill is also ornamented, smooth at the lower, and appears in its proper forming a fourth side. The top of a three-colours on the upper side of the plate. It is sided chambraule is called the transverse, and evident that in this instrument the image is the sides ascendants. inverted with respect to the object. мs is a lid delineation of the picture, and others for the to prevent the admission of light during the same purpose are applied to the sides м R and

CAMERA LUCIDA (in painting), an optical instrument, which, by means of lenses, a stile, &c., gives the outline of external objects on the paper or canvas with much clearness and accuracy, so that the artist can sketch the subject without his hand moving in a dark box like the camera obscura. This instrument was the invention of the celebrated Dr. Wollaston.

N L.

CONTRARY FLEXURE, POINT or, the meeting of two curves, which bear the convexity of one

Sculpture.

THE origin of this art is veiled to the researches of man; but there can be no doubt of its extreme antiquity. In the earliest period of sacred writ, we find proofs that images were made; and of the value placed upon them we may judge, by Laban's pursuit of Rachael when she fled with Jacob and with Leah. Fifteen hundred years at least before the Christian æra, we find the names of sculptors occurring in the sacred volume,-Bezaleel the son of Uri, of the tribe of Judah, and Aholiab the son of Ahisamach of the tribe of Dan. The golden calf, the brazen serpent, the graven images, the names of the gods of mythology, before whose images the children of Israel bent the knee, when they left the worship of the true God, so frequently occur in the Bible, that although there is not the slightest trace of that they had acquired much of the mechanical the remains of art, we arrive at the conclusion processes, upon which the higher branches of the fine arts are dependent. Babylon must have had workmen of superior talent, if we may judge from the testimony of Herodotus, who, from personal inspection, describes the temple of Belus, in which there was a large COPING, the upper tier of masonry which golden statue of the god seated, and by it a covers a wall. When it is of an equal thick-golden table, the step of the chair and the chair were of gold. ness, which is done only on inclined surfaces, or on a wall that is intended to be covered by a roof, it is called parallel coping. (1) When

and the concavity of the other on the same

side of the line.

CONDUIT or CONDUICT, an underground walled passage; a canal or pipe formed or laid down for the conveyance of water.

CO-ORDINATE PILLARS, pillars standing in equal order.

2

1

3

art of sculpture; but they never arrived at any The Egyptians without doubt cultivated the degree of perfection except that of ugliness.

The materials employed by the early sculp-| tors, must have been clay or wood, on account of the ease with which they could be wrought. The woods, mentioned by the Count de Clarac in his list of the different materials employed by the ancients for statues, are as follows:

Box.-Statues were made of this, and the living tree also was cut into the figures of men and animals. We see instances of this appropriation of the box and the yew in the ancient paintings of the Museum of Portici, now at Naples, where these trees are represented cut and disposed in compartments, serving as ornaments, in the Roman gardens, in the same way as they are used in modern times. Tablets of box, and also those covered with wax, were used for drawing in the time of Apelles.* thinner on one edge than the other, it is called Cedar, was regarded as incorruptible. A resin feather-edged coping. (2) When thick in the mid- was also extracted from this tree, which was dle and thin at each edge it is called saddle-applied to wood and other objects wished to be backed coping. (3) The soffit of a projecture is said to cope over when it slants downwards from the wall.

preserved. It was often used as a kernel or core of statues of gold and ivory-according to some authors the Diana of Ephesus was of this wood.-Citron. This was a kind of cedar, CORBEILS, Sculptured baskets of flowers o and was used in making valuable tables of fruit, sometimes placed on the heads of carya-large dimensions. Mr. Monges read at the tides.

Institute, some years ago, an interesting paper on this wood and on the tables.-Cork. The bark of this tree was one of the first substances used for small figures.-Cypress. Ebony was much esteemed. Dipones and Scyllis, of Egina made many statues of it, and as a reli

by Albert Durer; and bamboo is used by the Chinese in their plates for printing.

Box is used by the wood engravers; pear-tree was used

gious idea was attached to the colour of certain The information conveyed in the volume is objects, it was probably used as a substitute for concise, clear, and well arranged. The folblack marble.-Fig-tree, being white and easily lowing account of the safety valve may prove worked, was also used for certain divinities.-interesting to many of our non-professional Fir was used for the wood-work of the horse readers :of Troy.-Limetree, Lotus, Maple, Myrtle. At Lemnos, there was, according to Pausanias, a statue of Venus erected by Pelops in female myrtle. This was probably a kind of log or rude idol, covered with real drapery. -Oak, Olive, Palm replaced the cork, although, from its fibres and knots, it could not have been favourable to sculpture.-- Wild Peartree. Of this wood there was a Juno at Samos. -Peach, Pine, Poplar Vine. The wild vine, and that of Cyprus, were particularly used. The Diana of Ephesus was, according to some authors, of this wood. Although there are vine stocks of large dimensions, it is not easily to be conceived how statues could be made of them, on account of the number of knots; the wood also is stringy, and not easily worked. Yew, Willow, Osier, and Sallow. An Esculapius of Sparta, and a Juno of Samos, are mentioned as being made of wicker, but they must have been as rude as scarecrows. The colossal figures called Arga, thrown yearly into the Tiber, were made of these trees; as also the immense Colossus in which the Germans and Druids burned their prisoners in honour of Teutates.

(To be continued.)

Review.

The Steam-Engine, from the earliest to the present time. Atmospheric Railways, the Electric Printing Telegraph, and the Screw Propeller. By EDWARD PORTWINE. Second Edition. London: E. Appleyard, Farrington-street.

FIRST NOTICE.

This valuable treatise is evidently the production of a practical man, and one deeply versed in the subject of which he treats. Already it has become celebrated, in connexion with the disastrous accident which happened to the "Cricket," the danger having been pointed out in the following words :

"The object of this valve is to permit the escape of steam, should it possess more force than the boiler can support; thus preventing an explosion of the boiler. It is loaded, and will open with a pressure of steam, a little more than is necessary to work the engine, and much less than the utmost the boiler can bear. The steel-yard safety valve consists of a lever, the point or fulcrum of which is set on a support at the side of a short tube or pipe, communicating with the boiler. From the lever over the aperture of the tube, a rod descends, having a plug attached, which closes the tube. At the other extremity of the lever, weights may be attached at different distances from the fulcrum, which will possess the power of keeping down the valve or plug, in proportion to their distance from the fulcrum. The force of the steam will tend to push up the plug or valve, and permit the of the steam. The atmospheric pressure, and the weight attached to the lever, will tend to press down the plug, and prevent the exit of steam. The valve will open and shut according to the relative strength of these forces, acting on it in opposite directions. Sometimes the valve becomes impaired, and accidents may occur by the sudden formation of steam which cannot escape with sufficient, rapidity when the water is shallow in the boiler, or the decomposition of the steam, or water, by the heated sides of the boiler. This valve opens outward to the air.

escape

"The internal safety valve opens inward: its use is to admit air should the steam be condensed suddenly. Were there no such valve, the atmospheric pressure on the surface of the boiler would crush it, or cause it to force of the steam should take place. This collapse, if any sudden diminution of the internal valve yields, and admits the air, when the internal pressure is greatly diminished, and thus produces furnace, above which the boiler is placed, is an equilibrium. The entirely excluded from air, excepting at two parts, at the grating, on which rests the fuel, "Three vessels on the Thames, called the and between which the air enters and induces Ant, Bee, and Cricket-boats which profess to combustion, and at the throat at the bottom of work with low-pressure condensing engines. the chimney, where the smoke, and products The public are not aware that they are of combustion, leave the furnace. Thus no working at 36lbs. on the square inch. The cold air is admitted to the chimney, and the engines are by Joyce, two of fifteen horse draught is rendered more powerful, air suppower; the fuel consumed is only about 2 cwt.plied more quickly to the fuel, and the heat 1 qr. per hour. These are the halfpenny produced more intense. There are a great boats, plying from Hungerford to London many contrivances to prevent smoke. Watt, Bridge; and, working at high pressure, they and a host of others, have taken out patents may, when out of order, blow up their decks for this purpose. Papin was the first who and the myriads of passengers they are attempted to prevent it. The usual method burthened with." is, by constructing the furnace so that the new coal is introduced below the live coal, by which the smoke, arising from the fresh fuel, is consumed as it rises. This is Witty's invention Sometimes, to retain heat, the furnace is placed inside the boiler, and the flue also conducted through the same: this is thought the best contrivance."

Sculptures of this material, are often to be found as ornaments in English architecture, and most frequently occur in the Elizabethan style. It is not difficult to account for their frequency, as the circumstance of the oak being the emblematical tree, as it were, of England, added greatly to the estimation in which it was held in former times; and even now our long-cherished veneration, for it has not. departed. [Note by the EDITOR.]