s of foreign ecclesiastics, ii. 55.
Makes a speaking head, ii. 116.

Grotius, his opinion of the Reformation, ii. 225.

Guericke, Otto invented the air-pump ii. 286.

Guido, a Benedictine monk, the inventor of the scale of music, i. 437.

Gulf Stream, its influence on the western countries of Europe,
i. 24; ii. 371.

Gunpowder, its composition given by Marcus Graecus, i. 408.

Hades, i. 39. Origin of the Greek, i. 92.

Hadrian IV., Nicholas Breakspear, ii. 25.

Hallam, his opinion of Leonardo da Vinci quoted, ii. 268.

Halley's comet, how described and regarded, ii. 253.

Hallucination, fasting a frequent cause of, i. 428.

Hannina, the earliest Jewish physician, i. 400.

Haroun, a physician of Alexandria, the first to describe the
small-pox, i. 401.

Haroun al Raschid, Khalif, sends Charlemagne the keys of our
Saviour's sepulchre, i. 374.
Places all his public schools under John Masue, i. 392.
Patronizes a medical college and founds a university, i. 402.
Causes Homer to be translated into Syriac, ii. 34.

Harpalus, employed by Alexander in his scientific undertakings, i. 173.

Harvey discovers the circulation of the blood, ii. 285.

Hassan takes Carthage by storm, i. 334.

Heart constructed upon the principles of hydraulics, i. 5.

Heat, control of, over life, i. 8.
Distribution of, in Europe, i. 26.
Sources of, i. 103.
Boundary of organisms by, ii. 309.
Decline of, in the earth, ii. 318.
Properties of, ii. 383.

Helena, the mother of Constantine the Great, superintends the
building of monumental churches, i. 309.
The influence she exercised in the religion of the world, i. 366.
Her benevolence in founding hospitals, i. 386.
Adopts image-worship, i. 414.

Heliocentric theory, its meaning, ii. 254.
Resistless spread of, ii. 274.

Heming introduced street-lamps in England, ii. 241.

Henry V., Emperor of Germany, his resistance to the Popes, ii. 24.

Henry VIII., King of England, had personal reasons for
discontent, ii. 216.
The instrument, not the author, of the revolution, ii. 238.

Henry the Fowler asserts the power of the monarchical principle, i. 376.

Heraclitus, his philosophical system, i. 104.

Heraclius, Emperor, resists the second Persian attack, i. 326.
His contemplated abandonment of Constantinople, i. 329.
Defeated at the battl