APPENZELL, Canton of, the birthplace of Ulric and Jean Grubenmann, 141. AQUEDUCTS, ROMAN, the Pont du Gard, 83, 167-75, 321; at Lyon, 176, 213; at Luynes and Fréjus, 176; the Marcian Aqueduct, 189 _footnote_; Nero’s Aqueduct, 189; the Alexandrine, 190; Anio Vetus, 190; at Minturnæ, 190; Tarragona, 189; Segóvia, 183-4, 189, 190; see also the illustration facing page 184; Smyrna, 165; number of aqueducts at Rome in the sixth century A.D., 189 _footnote_; Sextus Julius Frontinus, Superintendent of the Aqueducts at Rome, wrote, in the first century of our Era, a treatise on Roman aqueducts, 189 _footnote_. AQUITAINE, DUKE OF, William the Great, his attitude to the collection of tolls on bridges, 240. ARABIAN ARCHES, their shapes are of three sorts, the horseshoe, the semicircular, and the pointed. Often they are enriched by a sort of feathering or foliation around the arch, and this ornament is closely akin to Gothic work, which it preceded by a considerable time. The Arabian style, known also as Saracenic and Moorish, is a fanciful composition in which details from Egypt and Greece and Rome are alembicated with “the light fantastic lattice-work of the Persians.” To-day we find its graceful influence in the greatest bridges at Isfahan, 213, and also in much Spanish work, 28-9, 285-6, 288. Some writers believe that pointed arches were invented by the Arabs, yet they were built in Egypt during the Fourth Dynasty, 155-6, and also by the Babylonians, 275 _footnote_. The Saracenic pointed arch was a forerunner of the Gothic pointed style, and it became familiar to the Crusaders, 86-93; but we must draw a wide distinction between the pointed arch and the pointed Gothic style. Arabian architects did not achieve an upward flight and rhythm akin to the vertical principle of inspired Gothic; their buildings preserved the horizontal line which gave and gives character to classical traditions, 152, 153, 336. If, then, the pointed arch in Europe was borrowed from Arabian architects, as many antiquaries believe, 88, it passed through a great transformation in technical sentiment, and became an original inspiration. ARAGON, 275. ARCADES cut transversely through the piers of the ruined Roman aqueduct at Lyon, 213; and also in the two greatest bridges at Isfahan, 214, 215, 270. ARCADES, COVERED, in the best bridges at Isfahan, pierced through the outer walls from one end to the other, 214, 215, 269. ARC DE ST. BÉNÉZET, in the Bridge of Avignon, 81; its elliptical shape had a forerunner in the vault of Chosroes’ great hall at Selucia-Ctesiphon, which may have been derived from Babylonian tradition, 275 _footnote_; there is even a Roman starting-point for Bénézet’s arch, 196.