THE ARCH
It has been truly said that the arch was first invented by people whose building materials were of a small size, and however open to objection this generalization may be, it is certainly true in the case of Babylonian architecture, and also in a somewhat lesser degree in that of the later Assyrian architecture. Strabo informs us that “all the houses in Babylonia were vaulted”—διὰ τήν ἀξυλιαν—“because of the dearth of wood,” XVI, 1, 5—but however reliable or unreliable his statement may be, the dearth of wood and stone in the alluvial plain of Lower Mesopotamia of necessity taxed the inventive powers of the Babylonian architect to the utmost, when he was confronted with the problem of roofing the buildings he had erected, and the various rooms which they were destined to contain. But his genius seems to have arisen to the occasion, and evolved the principle of the arch as the best, and indeed the only means of coping with an otherwise insurmountable difficulty, for the construction of flat roofs depended on the existence of slabs of stones or timber-beams, alike large in size and durable, but both stone and wood of the kind wanted were not to be found in Babylonia, and the architect would clearly be unable to fetch wood or stone from the distant mountains for the purpose of roofing the chambers of an ordinary house. His inventive faculties were thus stimulated by the urgency of the case, and the result produced by these combined factors is to be seen in the early appearance of the arch, crude indeed as regards its structure, but none the less involving the same principles upon which all arches are built.
The early arches in the tomb-passages in Egypt are supposed to owe their origin to the removal of the lower part of the buttress-walls erected to keep the side walls of the passages from collapsing: such buttress-walls would of course fulfil their function in preventing the side walls from falling in, but they would frustrate their own ends by completely blocking the passage, thus rendering it perfectly useless. Accordingly the lower portion of the buttress-wall was removed, the upper part being allowed to remain, and forming in fact a rudimentary arch, and it is possible that the Babylonian arch owes its origin to like fortuitous circumstances. It is perhaps more probable, however, that the origin of the arch-shaped structure, if not the discovery of the principle of the arch, is to be traced to the peculiar form assumed by the native reed-huts, which doubtless bore a close resemblance to those commonly used in the Euphrates valley to-day. This view is advocated by Heuzey, and is the one which Hilprecht is disposed to favour.
| Fig. 15.—Early T-shaped Arch
at Nippur. (Cf. Hilprecht, Explorations, p. 399.) | Fig. 16.—Arch at Tellô. (Cf. Déc. en Chald., Pl. 57 (bis), 1.) |
Most of the ancient buildings of Babylonia have succumbed to the concurrent ravages of time and climate, and have consequently bequeathed to us very little material for the study of Babylonian architecture; the roofs of buildings, and of the chambers comprised therein, have long since ceased to be, and we can thus only theorize as to the general mode of roofing adopted, but the drains and aqueducts constructed beneath the buildings have luckily survived to tell their tale, and we owe our knowledge of the early existence of the arch in Babylonia chiefly to these comparatively insignificant remains.
One of the most ancient arches as yet discovered is that which was brought to light during the course of the excavations carried on by Peters, Harper, Haynes and Hilprecht at the ancient city of Nippur (cf. Fig. [15]). It was found at a great depth below the surface of the mound, being more than twenty-two and a half feet below the pavement of Ur-Engur (circ. 2400 B.C.), and fourteen feet below that of Narâm-Sin (circ. 2700 B.C.); it is a true keystone arch pointed in shape, made of well-burnt plano-convex bricks, and measuring a little over two feet in height and having a span of about one foot eight inches, while its length is about three feet, but it seems probable that originally the tunnel was vaulted throughout. The irregularity of its construction somewhat diminishes the significance that it would otherwise have, but it is of supreme interest as testifying to the fact that the principle of the arch was known at this very remote period, however crude the embodiment of that principle may happen to be. The plano-convex bricks composing this arch measure 12 × 6 × 2-1/2 inches and bear the impress of finger-marks on their convex side, a characteristic feature of pre-Sargonic bricks at Nippur, Tellô and elsewhere, while the clay from which the bricks are made is of a light yellow colour. The tunnel itself seems to have been “a protecting structure for a drain,”[83] rather than a drain itself, for below the pavement two terra-cotta pipes were discovered, the existence of which can only be explained on this hypothesis. At the top of the arch were found the remains of another terra-cotta pipe, the object of which must have been to drain off the percolating rain-water, and thus prevent it penetrating through and disintegrating the vaulted structure below. The T-shaped centre-piece, which was similarly made of plano-convex bricks, doubtless served the purpose of keeping the sides of the arch from falling in. Haynes further informs us that in one of the private houses at Nippur which had been occupied at least three times, the earliest of the three doorways traceable in the ruins, consisted in a segmental arch.
Another very early arch was discovered by M. De Sarzec at Tellô, close to the building of Ur-Ninâ (cf. Fig. [16]), having much the same shape as the Nippur arch illustrated in Fig. [15] and doubtless used for a similar purpose, while vaulted passages of which the arch was semicircular, were discovered by Taylor[84] in his excavations at Muḳeyyer (Ur), as early as 1855.
Again the German excavations at Fâra (Shuruppak) in 1902 and 1903 revealed a number of circular rooms, each of which was roofed by means of an arch formed by overlapping bricks placed horizontally, somewhat after the fashion of the later corbelled arch at Nippur seen in Fig. [17], to which Hilprecht assigns a provisional date of 2500 B.C. We know that the dome was invented in Babylonia at a very early date, thanks to Dr. Banks’ discovery at Bismâya of an oval-shaped room in the vicinity of the temple, the lower parts of the domed roof of which were found still in place. Its antiquity is attested by the date of the temple itself which would appear to have belonged to the pre-Sargonic period, as the ziggurat was faced with the plano-convex bricks characteristic of that period, and the pottery furnace, not far distant, was composed of bricks of the same kind.
In later times the arch was doubtless used more frequently in Babylonia. A good example of a late Babylonian arch was discovered by the German excavators on the Ḳasr at Babylon; the arch in question (cf. Fig. [18]) which is Roman in character, forms the roofing of a lofty gate cut in the fortification wall. Koldewey[85] is of opinion that the wall in which this arched gate occurs, is a good deal older than the Nebuchadnezzar period.
But Assyria, the more or less faithful imitator of Babylonia in all matters great or small, is also known to have employed the arch as an architectural device, though, as in Babylonia, most of the Assyrian arches which the excavations have brought to light are connected with the drainage system with which all the principal buildings were provided. The best examples of an Assyrian arch of ordinary dimensions are those found at Khorsabad, the gateways of which town were roofed with semicircular vaults. One of these gateways was pulled down by Place in order to make a close examination of its construction. The height from the pavement to the top of the arch was found to be twenty-four and a half feet, the width being a little over fourteen feet. The arch was made of crude bricks, all of which were of the same size, and had the same shape, the bricks being cemented together with soft clay. The vault itself had long since become disintegrated, but the materials of which it was made were discovered in the ruins. Of the brilliantly painted friezes which adorned these rounded openings (cf. Pl. [XXX]), something will be said in the chapter on Painting.
| Fig. 17.—Corbelled Arch at Nippur. (Cf. Hilprecht, Explorations, p. 420.) | Fig. 18.—Arch at Babylon. (Cf. Mitteil., 8, Abb. 1.) |
But in regard to the study of what may be called the arch-principle, the subterranean channels which formed part of the system of drainage employed by the Assyrians are of greater importance. These aqueducts are found in all the palaces, both at Nimrûd and Kouyunjik, but Khorsabad furnished the best preserved examples, and therefore afforded the most valuable material for the careful examination of this architectural contrivance. At Khorsabad, Place discovered several arched drains of different shapes, some of them being round, others elliptical, while others again were pointed, but apparently in every case the stones or bricks were set at an angle, so that each course had the support of the course preceding it, and thus the pressure on the centre of the arch was reduced to the minimum. In the case of the pointed arched aqueducts found by Place, the arches in question are no true keystone arches, indeed they have no keystones of any kind as will be seen in Figs. [19], [20]; this arched drain measures four feet eight inches from the ground to the centre of the vault, its width is about three feet nine inches, while its original length is unfortunately not known, though Place succeeded in tracing it for some two hundred and twenty feet. The floor was made of large slabs of limestone set in asphalt, while the ends of the stone-slabs extended beyond the walls of the vault on either side. The rounded type of arch is seen in Fig. [21]; it is semicircular in shape and is formed of three voussoirs on each side, which together with the key, thus make seven in all, but owing to some miscalculation, the keystone appears to have been too small, in consequence of which there was a gap between it and the top voussoir on the right, which was filled in by means of a stone wedge which can be seen in the figure. Its width and height vary at different points, in some places it is said to be wide enough for two men to walk abreast in it.[86] The floor was composed of slabs of limestone which were laid in asphalt just like the floor of the pointed arch described above. An elliptical-shaped arch, also found at Khorsabad, is illustrated in Fig. [22]: it is formed of eight voussoirs and a keystone, the gap on either side of which is filled in by means of two stone wedges. The failure to make the keystones sufficiently large, and the consequent necessity for these supplementary wedges may be due to the architects not having allowed for the shrinkage of the bricks.
| Fig. 19. (Place, Nineveh, Pl. 38.) | Fig. 20. (Place, Nineveh, Pl. 38.) |
| Fig. 21. (Place, Nineveh, Pl. 39.) | Fig. 22. (Place, Nineveh, Pl. 39.) |
In regard to the arched structures at Nimrûd (Calah) Layard says he found a vaulted room and more than one arch. He tells us that “the arch was constructed upon the well-known principle of vaulted roofs, the bricks being placed sideways, one against the other, and having been probably sustained by a framework until the vault was completed.” Knowledge of the principle of dome-shaped roofs in Assyria as well as in the mother-country, is evidenced both by the discovery of rooms whose dimensions would have rendered any other mode of roofing impossible, and also by the representations on Assyrian bas-reliefs, as we have already seen.[87]
| Fig. 23. (After Andrae.) | Fig. 24. (After Taylor.) |
The arch-principle is further embodied in some of the Babylonian and Assyrian graves, and as there is no other opportunity of discussing the burial-places of the Babylonians and Assyrians in this volume, it may be permissible to give here a brief and general description of one or two of the best preserved of these burial-vaults. At Muḳeyyer (Ur) Taylor found a number of arched vaults (cf. Fig. [24]) which in most cases measured about 5 feet in height, and 3 feet 7 inches in breadth, while they were about 7 feet long at the bottom and 5 feet long at the top. The arch is formed by successive layers of overlapping bricks. It is interesting to compare the burial vaults discovered by Andrae at Ḳalat Sherḳat (Ashur), one of the best preserved of which is seen in Fig. [23].[88] This vault was discovered about 16 feet below the level of the floor of a Parthian door in the neighbourhood, and over 13 feet below a later Assyrian pavement. At the time of its construction the vault would appear to have been about 9 feet beneath the surface of the soil. The perpendicular walls forming the sides of the lower part of the tomb are set upon a brick pavement, the bricks being about 10-1/2 inches square and nearly 2-1/2 inches thick. The height of these perpendicular walls is approximately 30-1/2 inches and the layers of bricks which each contains number 13. The vault itself, which of course commences where the perpendicular walls cease, is more or less oval in shape, has a span of 5 feet 2 inches, and is 2 feet 11 inches high, the total height of the tomb from the floor to the top of the arch thus being nearly 5-1/2 feet. The arch, upon the construction of which much care had evidently been bestowed, was formed of forty-six courses of quasi-wedge-shaped bricks, each resembling a truncated segment of a circle. The interstices between the courses were filled in with stones, broken pieces of clay and clay mortar. The outside of the vault was coated with clay, but the inside was left plain. The walls at either end incline inwards, while they are built separately from the arch and are also rather higher. Access to the tomb from outside is gained by a slanting and somewhat winding entrance-shaft built close to the western wall, in which there is a small arched opening. The threshold of this opening, which was filled in with loosely laid bricks, lies 23-1/2 inches above the floor of the tomb. In the eastern wall the usual recess was found, the floor of which was some 35 inches above the floor of the burial chamber. This recess was about 19 inches in height and 13 inches in breadth, while the depth of the recess was greater than that of the wall, and it was therefore necessary to build another wall on the outside to close it up. In the recess of another double grave found by Andrae on the same site, a clay lamp was found, but this was not the case here; possibly there was at one time a lamp in the recess of this tomb, its disappearance being due to the disintegration to which the long infiltration of damp subjects all articles of unburnt clay. The entrance-shaft was 39 inches square, while its bottom was level with the threshold of the small opening in the western wall; 4 feet 2 inches above this floor was a second floor made of gypsum blocks which were supported by the walls of the shaft. The interstices between these blocks were filled in with stones and pieces of clay, while the upper part of the shaft (i.e. the part above these blocks), the walls of which had only half the thickness of the walls below, was similarly filled in right up to the surface level. The uppermost part of the shaft had been disturbed by a later building. In the vault, Andrae found three skeletons, one of which apparently belonged to a man, and the other two to women. The arms of these skeletons were at right angles to the bodies, and the legs were contracted and apart, while the man lies on his right side and the two women on their left. Traces of a decayed whitish material were found in the tomb, which Andrae believes to be the remains of grave-clothes. Bone needles and pottery had also been deposited with the corpses. The most interesting articles of pottery were three wide-necked bottles, two of which were decorated with dark horizontal lines, while the neck of the third was adorned with white painting on a dark ground, a technique well known in early Assyrian times. What were the contents of the vessels we do not know; rams’ bones were found near the door as well as elsewhere, and without doubt these vessels once contained meat offerings and drink offerings for the dead. There was evidence for at least three different periods of occupation in the strata above the grave, two of which belonged to the Assyrian era and one to the Parthian times.
The vaulted graves at Ashur do not however all belong to the same time; some of them may be assigned to the early Assyrian period, while others were built at a later date. One of these later brick burial-vaults was excavated and carefully examined by Andrae in the spring of 1909.[89] The construction of this vault apparently involved the demolishment of an earlier Assyrian building. The bricks of which the vault was composed in some cases bore the inscription of Tukulti-Ninib I, but in spite of this fact, the grave itself was not built till a later date. Access to the vault was gained by means of an entrance-shaft the lower end of which was connected by means of a passage with the door of the burial-chamber. A few inches above the ruined débris of the entrance-shaft the remains of a Parthian building were discovered. The passage was entirely destroyed, though the shape of the displaced bricks led to the conclusion that it was roofed by a barrel-vault. The arched door into the grave-room which measures nearly 4 feet in height and has a span of about 22-1/2 inches is composed of very small bricks 6-1/2 × 2-1/8 inches. It is built into one of the small walls of the grave-room, and the threshold is made of bricks like its other parts.
The bricks composing the barrel-vaulted roof of the grave-room are 11-3/4 inches square and 2-3/8 inches thick. At the other end of the burial-chamber is a small arched door leading into another room, also barrel-vaulted. This latter room which measures nearly 5 feet in length, and 35-1/2 inches in breadth, is built with less care and regularity than the main burial-chamber. The side-walls of the annexed room are 5-1/8 inches thick, but the thickness of the back wall is only 2 inches. The threshold of the entrance-door to the main burial-chamber is 20-3/4 inches lower than the pavement of the entrance-shaft, and nearly 19 inches above the floor of the burial-chamber. Asphalt and plaster were both used extensively in the interior.
North-east of the entrance-door, there was a lamp-niche, 3 feet 11-1/4 inches above the floor, and measuring 12-1/2 × 13-3/4 inches in size, and 12-1/2 inches in depth. In this niche, three terra-cotta pots were discovered, and Andrae thinks that these pots were probably used as lamps. The burial-chamber contained two bath-shaped sarcophagi, one of which measured 6 feet 7-1/2 inches in length, 28 inches in breadth and 18-1/8 inches in height, while the other was just over 6 feet 6 inches long, 31 inches wide, and 17 inches deep. The lids of both these sarcophagi were slightly arched and were tightly cemented. The top end of one of the covers bore the rough outline of two flowers.
Upon the brick floor of the annex was the extended skeleton of a man, while in one of the sarcophagi four skulls and three skeletons were found. Two of the skeletons belonged to men, but the third and best-preserved was that of a woman, while the skeleton to which the fourth skull belonged was not found. The funeral furniture was of the ordinary type and consisted chiefly in terra-cotta dishes and vases, copper bangles and glass beads.
| Fig. 24 A.—Ziggurat on an Assyrian Bas-relief. | Fig. 24 B.—Actual remains of Ziggurat at Khorsabad. (After Place.) |