COLUMNS are variously named, according to their mate rials, construction, formation, decoration, disposition, and destination.
I. Columns, according to their materials, are, moulded, fusilde,..transparent, scagliola, masonic, or wooden.
When a column is made by cementing gravel and flints of different colours, it is called a moulded column.
Tlw art of moulding (Anions was known to the ancients, as would appear by some lately discovered near Algiers, in the ruins of the ancient city of Cesarea ; where the same inscriptions in antique characters, and even the same defects, are to be found repeated on every shaft, which is certainly a proof of their being moulded: the cement employed in the emplastation of columns, grows perfectly hard, and receives a polish like marble.
Columns of fusible matter, as metals, glass, &c., are called fusible columns ; the secret of making them is said to have been known to the ancients, who are also said to have thsed and cast columns of stone. Columns of this description may also he called moulded columns.
When the material of which a column is made is transpa rent, the column is called a transparent column. The columns of the theatre of Scanrus, mentioned by Pliny, were of crystal, and those in the church of St. Mark, at Venice, arc of transparent alabaster.
When columns are constructed with a kind of plaster, so as to imitate marble in polish and colour, they are called scout iola columns.
Columns built of rough stone, or compass bricks, and cased with stucco, are called masonic columns, or columns of masonry ; as are likewise those made in courses of stone, jointed, and cemented in the best manner, with a rubbed or smoothed surface. See STONE COLUMN.
When the shaft of a column is constructed of wooden staves, glued together, and the interior angles strengthened with bloekings, the column is said to be a joinery column. See the articles BASE, CAPITAL, :Ind WOODEN COLUMN.
2. Columns, according to their construction, are columns in bands or tambours, columns in trenchcons, or banded columns.
When the shafts of columns are formed of courses of stone of a less height than the diameter of the column, they are called columns in bands or tambours. This method is only practised in large columns.
When shafts of columns are formed in courses of greater height than the diameter of the column, they are said to con sist of trencheons ; this is practised in small columns, when the fewer the pieces, the more beautiful will the column be but the difliculty of raising them from the quarry is greater, and the carriage more expensive.
When the shafts of columns consist of plain or ornamented cinctures, beyond the general line of the shaft the column is said to he banded, and is therefore called a banded column. Columns of this description were first introduced by De Lortne, in the chapel de Villers-Coherets, and at the 'Tuileries, who by this means supposed the joints would be concealed.
3. according to their formation, are attic, conical, colloidal, cylindrical, cylindroidul, or polygonal.
The attic column is an insulated pilaster, having four equal titces, of the highest proportion. Though this is commonly inserted among the number of columns, it should not be so deemed, but rather what we have already denominated it, an insulated pilaster. To prevent confusion, the use of the term coboun, in architecture, should be restrained to a body of circular horizontal sections.
it conical column has the superior diameter of its shaft less than the inferior, with its sides straight in every plane passing through the axis.
conoida/ column also has the superior diameter of the shaft less than the inferior, hut its exterior sides are convex in any plane passing through the axis. This practice of making the shaft swell •is ancient, being mentioned obscurely by Vitruvius, and has been generally followed by modern architects.
Cylindrical columns have the extreme diameters of the shafts of equal circles.