ILLUSTRATIONS.

PART I.
FIG.PAGE

Dante Studying.From a fresco by Luca Signorelli at Orvieto

[Frontispiece]
1.The Sun’s Path in the Sky at different Seasons[11]
2.The Moon at Sunset, soon after New, and three days old[14]
3.Path of Mars among the Stars, 1909[16]
4.The Star Sphere[19]
5.Synodic and Sidereal Periods[21]

Star Map

[34]

The Moon-God of Ur. From a Cylinder-seal in the British Museum, date about b.c. 2400. By permission of the Trustees of the British Museum

[36]
6.The triple Star-sign of the Babylonians[37]
7, 8, 9.The young Moon and the Pleiades after sunset, as seen in Babylon, b.c. 1000[42]
10.

The Scorpion. From a Babylonian boundary stone of aboutb.c. 1120, set up in the reign of Nebuchadnezzar I. Now in the British Museum

[43]
11.

The Goat with Fishes’ Scales. From a Babylonian boundary stone

[43]

The Boat of the Sun travelling over the Sky.From an ancient Egyptian papyrus. Reproduced from Flammarion’s Astronomical Myths

[46]
12.The Universe according to Anaximander[59]
13.The Universe of Leucippus[63]
14.The Universe of Democritus[64]
15.The Universe of Pythagoras[71]
16.The System of Philolaus: night on Earth[73]
17.do.twelve hours later: day on Earth[73]
18.Earth and Sun according to Heraclides[74]
19.The Spheres of the Sun in the system of Eudoxus[90]
20.Method of Aristarchus for finding the Distance of the Sun[108]
21.Pekin Observatory[114]
22.

A Pekin Astrolabe of the thirteenth century a.d.From photographs taken in 1888 and published in the Bulletin de la Société belge d’Astronomie

[116]
23.The Moveable Eccentric[119]
24.The Movement of Spica[124]
25.The Sun and the Equinox[128]
26.

The Movement of the Earth’s Axis which is the true cause of Precession. From Young’s Manual of Astronomy, 1902

[131]
27.Precession of the Equinoxes[133]
28.Path of Mars, 1909[139]
29.The Epicycle[139]
30.A Planet “retrograding” and “in opposition”[140]
31.Venus, Mercury, and the Sun[142]
32.The Sun’s Deferent[145]
33.

Apparent Variation in the size of the Sun. Photographs taken at Kodaikanal Observatory, with the spectroheliograph, July 1, 1911, and Jan. 3, 1912. Actual size of the negative

[146]
34.The Moon’s Epicycle and Deferent[148]
35.The Ptolemaic System[151]
36.

Method (erroneous) of estimating Planetary Distances, described by Alfraganus

[188]
37.Earth’s Shadow[192]
PART II.
FIG.PAGE

A Mediæval Astronomer.From a painting by Gerard Dow

[200]

Astronomy.From a fresco in the Spanish Chapel of Santa Maria Novella, Florence

[217]
38.The Half-Moon shape of the Habitable Earth (Ristoro)[247]

Climate Map of about a.d. 1110. Reproduced from Beazley’s Dawn of Modern Geography

[248]
39.Sun, Moon, and zenith. To illustrate Par. xxix 1-6[267]
40.The Zodiac and the Months[276]
41.

The Ram on the Ecliptic. From the Cosmi Historia of Robert Flud, a.d. 1612. Reproduced from Brown’s Aratos.

[279]

Map of Stars visible before Dawn in Purgatory

[295]
42.Ursa Minor as a Horn. Par. xiii. 10[299]
43.The Sun at the Equinox, seen from the poles and the equator. Conv. III. v.[327]
44.Lunar and Solar Eclipses[339]

Map of the World by Heinrich of Mainz, about a.d. 1110. Reproduced from Beazley’s Dawn of Modern Geography

[344]
45.The Universe of Dante[355]
46.The Signs of the Zodiac at sunrise from the Mountain of Purgatory[375]
47.Northern Slope of the Mountain of Purgatory[377]
48.Dante’s View of Earth from the stars. Par. xxii.[395]
49.do. Six hours later. Par. xxvii.[396]
50.An impossible interpretation of Par. xxvii.[399]
51.The Rising Sun at the spring equinox. Par. i. 39[403]
52.The Moon’s Epicycle and Deferent[449]
53.Comparative sizes of the Sun and his satellites[490]

ABBREVIATED TITLES OF
BOOKS USED IN THE TEXT.

Dante’s Works:—
Inf.Inferno.
Purg.Purgatorio.
Par.Paradiso.
Canz.Canzone.
Son.Sonetto.
Ball.Ballata.
Ecl.Eclogue.
V. N.Vita Nuova.
Conv.Convivio.
De Mon.De Monarchia.
V. E.De Vulgari Eloquentia.
Ep.Epistola.
Qu.Quæstio de Aqua et Terra.
El. Ast.Elementa Astronomica (Alfraganus).
Comp. del Mond.Della Composizione del Mondo (Ristoro).