, founded by Arcesilaus, i. 169.
New, founded by Carneades, i. 169.
Fourth, founded by Philo of Larissa, i. 170.
Fifth, founded by Antiochus of Ascalon, i. 170.

Acherusian Cave, superstitiously believed to lead to hell, i. 36.

Achilles, spear of, preserved as a relic, i. 51.
Puzzle, advanced by Zeno the Eleatic as one of four arguments
against the possibility of motion, i. 122.

Acoustics, discoveries in, and phenomena of, ii. 370.

Adrian, Pope, incurs the displeasure of Charlemagne in
consequence of selling his vassals as slaves, i. 373.

Adriatic Sea, North, change of depth in, i. 30.

Aeneas Sylvius becomes Pope Pius II., i. 299.
His remark on the Council of Basle, ii. 100.
On the state of faith, ii. 103.
On Christendom, ii. 109.

Aerial martyrs, account of, i. 426.

Aeschylus condemned to death for blasphemy, but saved by his
brother Aminias, i. 50.

Aesculapius, the father of Greek medicine, i. 393.

Affinity, first employed in its modern acceptation by Albertus
Magnus, ii. 153.

Africa, circumnavigation of, by the ships of Pharaoh Necho, i. 78.
Conquered by the Arabs, i. 333.
Effects of the loss of, on Italy, i. 350.
Circumnavigation of, by Vasco de Gama, ii. 168.

Age of the earth, problem of, ii. 294.
Proofs of, ii. 334.

Age of Faith, Greek, i. 143.
Its problems, i. 217.
European, i. 308.
In the East, end of, i. 326.
In the West, i. 349; ii. 1, 27, 77, 105.
Its literary condition, ii. 128.
Results of, in England, ii. 229.
Contrast of, and age of Reason, ii. 389.

Age of Greek decrepitude, i. 207.

Age of Inquiry, Greek, its solutions, i. 217.
History of, European, i. 239, 265.

Age of Reason, Greek, i. 171.
Greek, its problems, i. 221.
Approach of, ii. 151, 190.
History of, ii. 252, 294.

Ages, duration of Greek, i. 222.

Ages of life of man, i. 14.
Of intellectual progress of Europe, i. 19.
Algazzali's, of life of man, ii. 52.
Each has its own logic, ii. 192.
Agriculture in a rainless country, i. 85.

Air, modern discoveries of the relations of, i. 102.

Aix-la-Chapelle, adorned by Charlemagne, i. 373.

Aiznadin, battle of, i. 335.

Al Abbas, a Moorish writer on botany, ii. 39.

Alaric, capture of Rome by, i. 300.

Albategnius discovers the motion of the sun's apogee, i. 325.
Determines th