STAIR, a series of steps arranged one above the other, occa sionally varied by platforms known as "landings." The total height of a stair is the "rise," the total horizontal distance between the top and bottom steps is the "run." A series of steps without a landing is called a "flight." The horizontal surface of a step is called its tread, and the vertical front its riser. The projection of the tread beyond the face of the riser is termed a nosing.
Long use has demonstrated that certain proportions of riser and tread are safe and easy. For interior stairs twice the height of the riser, plus the length of the tread, should be 23, all dimen sions being in inches. A variant is that the sum of rise and tread should be between 17 and 171 in. ; a third rule specifies that the product of rise and tread, in inches, should be not less than 7o nor more than 75. In general, English usage advocates a slightly lower rise for a given tread than American usage, while in Europe the rise is frequently greater. For exterior stairs, the general usage is to keep the riser below 6 in., and the tread above It is uncertain what is the oldest stair in existence. On the sacred road up the mountain of Tai Shan, in Shantung, China, there are many great flights of ancient granite steps. In Egypt stairs in pylons exist which date from the second millennium B.C. Assyria has left massive stairs on the ziggurats (q.v.), which date from the 9th and 8th centuries, B.C. and the palace terrace at Persepolis has a double flight of steps, of great beauty, which shows the skill of the Persians in the 6th century B.C.
Further west, stairs play an important part in the Cretan pal 'Sir Walter Scott took the plot of his Bride of Lammermoor from this incident, but he disclaimed any intention of making Sir William Ashton a portrait of Lord Stair.
aces, as in the palaces at Knossos and Phaistos (both c. 150o B.c.). In Hellenic Greece the monumental stair was of less importance, due to the Greek love of informal and picturesque approaches. Thus in Athens the propylaea of the Acropolis was probably en tered by a winding path and the present great flight of stairs, dat ing from the Roman period, is not part of the original design. In the post Alexandrian period there developed a new love of monu mental grandeur, largely Asiatic in origin, which produced such magnificent stairs as those of the altar of Zeus at Pergamon (18o B.c.). A similar monumental sense distinguished Roman stairs. Those of the propylaea at Baalbek (time of Hadrian), over loo ft. wide, are typical, and again and again stairs are made essen tial parts of great architectural conceptions, as in the temple of the Sun on the Quirinal hill at Rome, built by, Aurelian (A.D. 273), some of the steps of which were taken, in 1348, to build the f a mous stairs of the Aracoeli on the Capitoline hill at Rome.
Although during the middle ages stairs were used more for utili tarian than aesthetic purposes, where they were necessary they received adequate treatment, usually more direct and informal and more picturesque than those of the Roman tradition. Thus at Le
Puy en Velay, in France, the i i th century cathedral, which was built on a hilltop, is approached by a magnificent stair that pro vides a superb foreground to the polychrome facade. The steps that mount up to and past the apse of the i4th century cathedral at Erfurt, in Germany, show the direct and beautiful relationship between the building itself and the stairs which is characteristic of the best Gothic usage.
The Renaissance produced a recrudescence of the tradition of Roman formality in stair design. Particularly magnificent are the stairs of the Baroque period, such as the so-called Spanish stairs at Rome in the Piazza di Spagna (1723-26), by F. de Sanctis, those of the Campidoglio, at Rome (begun 1547), by Michelangelo and the infinitely varied terrace stairs of the Italian villas. The inspiration of these Italian Baroque stairs was felt throughout Europe and is largely the foundation of stair design in modern city and garden planning. Thus the enormous stairs of the gardens of Versailles (1667-88), by A. Le Notre, owe much to the Italian precedent, and were themselves imitated widely all over Europe. Among modern stairs may be noted the extremely lavish stairs of the monument to Victor Emmanuel II., in Rome (begun 1885), by Giuseppe Sacconi, with the altar of the Patria; the broad flights leading up to the library of Columbia university, New York (1896), by McKim, Mead and White; Waterloo steps in London by Benjamin Wyatt and those of the Lincoln memorial at Washington, D.C. (1924), by Henry Bacon.
In the Orient, the stairs leading down to the river at Benares, in India, of various dates, combine monumentality and pic turesqueness; a similar skill is shown in the design of large num bers of temple and palace steps throughout the peninsula. Further east the ruins of Angkor use wide flights of steps with magnificent effect in connecting the various levels of the terraced group. The Chinese have always been superb stair designers and builders, and there is hardly a temple or large house or palace which does not owe some of its effect to its stairs, either monumental and formal, like those of the Forbidden City or the Temple of Heaven, both in Peking, or winding and informal, as in Chinese garden design. Many of the temple stairs have, in the centre, an inclined plane running the entire height of the rise, richly carved with the symbolic dragon—the so-called spirit stairs by which the beneficent powers are supposed to enter. In Japan the tradition is much more informal, but the hilly nature of the country makes stairs an important feature of almost every temple layout. (T. F. H.)