It is maintained that there are brick arches at Thebes in Egypt, which belong to a very remote epoch, and one long prior to the occu pation of that country by Alexander the Great. Etruria seems to have been the first European country in which the arch was used. The great sewer of Rome, com monly called the Cloaca Maxima, is an arched construction, which probably belongs to the age of the Tarquins.
The application of the arched structure is one of the most useful mechanical contrivances. By means of it small masses of burnt clay, and conveniently sized pieces of soft and fria ble sandstone, are made more extensively use ful for the economic purposes of building, than the most costly and promising materials were in the hands of the Greeks and Egyptians. By means of it cellars are vaulted ; subways, or sewers, are made to pass under heavy structures and along streets with certainty and safety; and secure and permanent roadways for every purpose of communication are formed across wide, deep, and rapid rivers.
The Romans did not deviate much from the semicircular form. Arches of smaller seg ments were certainly used by them, as well as elliptical arches, but in these eases they were Fortified with enormous abutments, which proves that the architects knew very well the weak points of such a construction. The
architects of the twelfth, thirteenth, and four teenth centuries, showed what could be done by varying the form and construction of the arch.
The pointed arch, upon its invention or first introduction into Europe, seems to have exercised the ingenuity of architects in vary ing its form and application. This we ob serve in the numerous ecclesiastical structures in this country, in our beautiful pointed styles, and most particularly in some of the greater churches and cathedrals.
The origin of the pointed arch has been almost as much disputed as the discovery. of the principle of the arch itself. It became general in most parts of Europe at nearly the same time, and about the period of the re turn of the warrior-priests and pilgrim-sol diers of the first crusade. This, and other circumstances which might be adduced, added to the fact of the pointed arch being used in Asia before that period, and that an arch of the pointed form cannot be satisfactorily shown to have been used in the northern and western parts of Europe anterior to it, give a reasonable degree of certainty to the suppo sition that the notion was brought from the east by the crusaders.
The most notable of the departures from the principle of the arch in building are de.. scribed under BRITANNIA BRIDGE ; SUSPEN SION BRIDGE.