Volume I Part 12 (1/2)

The follooodcut shows the arrangeements constitute a co exclusively to Egypt, has had results upon which we cannot too strongly insist Both roof and architraves being horizontal, all the pressure upon the walls is vertical There is no force tending to thrust the walls outwards nor to affect the imyptian construction, epitomized by Ch

Chipiez]

Consequently, if the proportions of the vertical and horizontal ele, that is to say, its sections, have been skilfully deter itself no latent cause of disruption; its equilibrium is perfect, and can only be destroyed by external physical causes, by long exposure to the weather, by earthquakes, or by the hand of man[104]

[104] The vertical support and the architrave for, which is therefore enabled to dispense with those buttresses and other lateral supports which are necessary to give stability to the edifices of many other nations

We see then that the first impression caused by the external lines of the architectural ypt is confirmed and explained by further study They are built, as said the Pharaohs thehest andcharacteristic, the true originality, of Egyptian architecture

This character is s, but it is by no means absent from those built of materials created by human industry Works in brick form the transition between the construction that we have described and that which we call compact A stone roof is not often found, and the terenerally a terrace in which wood is the chief element In some cases the secondary parts of such edifices, and sometimes the whole of them, are covered in by brick vaults, and h the use of ypt, it ht that the architects of that country were ignorant of the art of covering voids withvaults There are nureat antiquity, and, yptian builders constructed their vaults after a method of their own In spite of the facilities which they afforded, they played, however, but a secondary _role_ in the developreater importance was attached; they are introduced chiefly in out-of-the-way corners of the building, and in the substructures of greatconfined within such narrow liypt in an architectural systeive birth to any of those accessory for from its use

[105] We yptian fellah are often covered by vaults of pise, that is to say, of coypt possess such vaults, which are of much less durability than those of stone or brick We are, however, disposed to believe that they were used in antique tiories, according to the method of their construction

1 _Off-set vaults_ These vaults are composed of courses off-set one fro 74)

[Illustration: FIG 74--Element of an off-set arch]

[Illustration: FIG 75--Arrangement of the courses in an off-set arch]

[Illustration: FIG 76--Off-set semicircular arch]

If the face of those stones which, in the form of inverted steps, are turned to the void which has to be covered, be cut into the line of a continuous curve, the superficial appearance of a segmental arch or barrel vault will be obtained; but this appearance will be no more than superficial, the vault will be in fact a false one, because, in such a construction, all the stones which enframe the void and offer to the eye the form of a vault, are really laid horizontally one upon another, and their lateral joints are vertical (Fig 76) When the units of such vaults are properly proportioned they are stable in themselves, and they have no lateral thrust

2 _Centred vaults_ These are true vaults They are composed of voussoirs, whose lateral joints are oblique, and radiate towards one centre or s 77, 78, and 79)

[Illustration: FIG 77--Voussoir]

[Illustration: FIG 78--Arrangement of voussoirs]

[Illustration: FIG 79--Semicircular vault]

This method of construction is very convenient because it enables the builder to utilize constructive units of very se has a corresponding drawback These voussoirs thrust one against another and tend towards disintegration

They are not stable in theive the the forces which will effectually prevent their setting up any movement in the structure of which they foryptian architecture, which is consequently very thick, but the radiating arch never arrived at such a developypt as to lead to the adoption of any contrivance specially charged with the yptians not only employed the semicircular arch; they made use, in a few instances, of the pointed fors have roofs cut out of the rock in the formental vault The fact that these sepulchral chambers affected the aspect of vaulted halls, can only be explained by the supposition that a si[106]

[106] Another explanation has been given of the employment of the vault in subterranean work Mariette believed the arch to be synify the canopy of heaven, the heaven of Amen

One objection to this is the fact that the vault was not universal in tos, others have coves