e, 25.

Myus, 103.

Nemean games, 251.

Neptune, spring of, 237.

Nexaris, 199.

Nile, 36, 231;
temples on, should face the river, 117.

Nonacris, "Water of the Styx," 238.

Notes, names of, 141 _f._

Number, perfect, 73 _f._

Nymphodorus, 199.

Nymphs, temple of Corinthian order, 15.

Oak, 60;
in floors, 202.

Obols, 74.

Ochre ([Greek: ochra]), 214.

Oeci, distinction between Corinthian and Egyptian, 179;
Cyzicene, 180.

Oil room, 184.

Olympian games, 251.

[Greek: Opai], 108.

Opus incertum, 51;
reticulatum, 51;
Signinum, 247 _f._

Orchestra, reserved for senators, 146;
of Greek theatre, 151.

Order appropriate to temples, 15;
origin of different orders, 102 _ff._

Organ, water, 299 _f._

[Greek: Organon], 283.

Orientation of streets, 24 _ff._;
of temples, 116 _f._

Orion (constellation), 268.

Ornaments of the orders, 107 _ff._

Orpiment ([Greek: arsenikon]), 214.

Ostrum, source of purple dye, 220.

Paconius, 289.

Paeonius of Ephesus, 200.

Palaestra, 159 _ff._

Palla, stone quarries at, 49.

Panels of doors, 118.

Paphlagonia, intoxicating springs of, 239.

[Greek: Paradromides], 188.

Paraetonium, 235;
white, 214.

Parapet of theatre, dimensions of, 148.

Parmenio, 273.

Paros, 289.

Pastas, 186.

Patras, cellae of temple built of brick, 53.

Patrocles, 273.

Pausanias, son of Agesipolis, 7.

Peiraeus, 234;
naval arsenal at, 198.

Peisistratus, 199.

Pelecinum (sun dial), 273.

Penne, 234.

Pentaspast (hoisting machine), 285.

Pergamus, 196.

Peripteral temple, 75 _f._

Peristyle, 186;
decorations of, 210 _f._;
proportions of, 179;
Rhodian, 186.

Peritreti, 303 _f._

Perseus (constellation), 266.

Persian Porch, 7.

Persians, statues of, 8 _f._

Perspective, commentaries on by Agatharcus, Anaxagoras, and Democritus, 198.

Pesaro, 63.

Pharax of Ephesus, 70.

Phasis, 231.

Phidias, 69.

Philippus (physicist), 269.

Philip son of Amyntas, 310.

Philo, 198, 200;
of Byzantium, 199.

Philolaus of Tarentum, 12.

Philosophy, why useful to architect, 8.

Phocaea, 103.

Phrygia, 236.

Phthia, 102.

Picenum, 49.

Picture galleries, 179, 186.

Piles, of alder, 61;
olive, or oak, 88.

[Greek: Pinax] of water organ, 299.

Pine, 61.

Pixodorus discovers marble near Ephesus, 289;
his name changed to Evangelus, 290.

Planets, 257 _ff._;
their retrograde movemen