various sciences, by means of which questions can be framed, either upon the discoveries of any given period, or on the progressive advance, through several centuries, of any of the five main divisions of science which are dealt with in this volume.

In conclusion, I wish to acknowledge my obligations to many kind friends, and especially to Mr. A. R. Wallace and Mr. J. C. Moore, F.R.S., who have rendered me very material and valuable assistance. I am also much indebted to the Rev. R. M. Luckock, of the Godolphin Grammar School, who read the whole work in manuscript, with a view to pointing out any portions which might be unintelligible to schoolboys.

LONDON: December 1875.

Ignorance of the Greeks concerning Nature-Ionian School of

Learning-Thales discovers the Solstices and Equinoxes, and

knows that the Moon Reflects the Light of the Sun-Anaxi-

mander invents a Sun-dial-Discovers the Phases of the Moon-

Makes a Map of the Ancient World-Pythagoras teaches that

the Earth moves, and that the Morning and Evening Star are

the same-He studies Geology, and knows that Land has in

some places become Sea-True sayings of Pythagoras and his

Followers about Geology

CHAPTER II.

499 TO 322 B.C.

· 7

Anaxagoras studies the Moon-Describes Eclipses of the Sun and

Moon-Is Tried and Condemned for Denying that the Sun is a

God-Hippocrates the Father of Medicine-Separates the

office of Priest and Doctor-Studies the Human Body -

Eudoxus has an Observatory-Makes a Map of the Stars-

Explains the Movements of the Planets-Democritus studies

the Milky Way-Aristotle an Astronomer and Zoologist--

Divides Animals into Classes-Teaches that there is a Gradual

Succession of Animal Life-Studies the Difference of the Life in

Plants and Animals-Theophrastus the first Botanist

. 13

CHAPTER III.

320 TO 212 B.C.

School of Science at Alexandria-The Ecliptic and the Zodiac-

Greeks believed that the Sun moved round the Earth-Aristar-

chus knew that it was the Earth which moved-He also knew

of the Obliquity of the Ecliptic, and that the Seasons are caused

by it-He knew that the Earth turns daily on its Axis-Euclid

discovers that Light travels in straight lines-Archimedes dis-

covers the Lever-Principle of the Lever-Hiero's Crown, and

how Archimedes discovered the principle of Specific Gravity-

Screw of Archimedes

PAGE

• 18

CHAPTER IV.

280 TO 120 B.C.

Erasistratus and Herophilus study the Human Body-Eratosthenes

the Geographer lays down the First Parallel of Latitude and the

First Meridian of Longitude-He measures the Circumference of

the Earth-Hipparchus writes on Astronomy-Catalogues 1,080

Stars-Calculates when Eclipses will take place-Discovers the

Precession of the Equinoxes

25

CHAPTER V.

FROM A.D. 70 TO 200.

Ptolemy founds the Ptolemaic System-He writes on Geography

-Strabo, a great traveller, writes on Geography - Studies

Earthquakes and Volcanoes-Galen the greatest Physician of

Antiquity Describes the Two Sets of Nerves-Proves that

Arteries contain Blood-Lays down a theory of Medicine-

Greece and her Colonies conquered by Rome-Decay of Science

in Greece-Concluding remarks on Greek Science

32

Dark Ages of Europe-Taking of Alexandria by the Arabs, and

burning of the Library-The Arabs, checked in their conquests

by Charles Martel, settle down to Science-The Nestorians

and Jews translate Greek Works on Science-Universities of the

Arabs-Chemistry first studied by the Arabs-Alchemy, or the

attempt to make Gold-Hermes the first Alchemist-Hermeti-

cally-sealed Tubes-Gases and Vapours called 'Spirits' by the

Arabs—The use of this Word retained by us

CHAPTER VII.

SCIENCE OF THE ARABS (CONTINUED).

Geber, or Djafer, the founder of Chemistry-His Explanation of

Distillation-Of Sublimation-Discovers that some Metals in-

crease in weight when heated-Discovers strong Acids-Nitric

Acid-Sulphuric Acid-Discovery of Sal-Ammoniac by the

Arabs-Arabs mix up Astronomy with Astrology-Albateg-

nuis calculates the Length of the Year-Mohammed Ben Musa,

first writer on Algebra-Uses the Indian Numerals-Gerbert

introduces them into Europe-Alhazen's discoveries in Optics—

His Explanation why only one image of each object reaches the

Brain-His discovery of Refraction, and of its effect on the light

of the Sun, Moon, and Stars-His discovery of the magnifying

power of rounded glasses

CHAPTER VIII.

SCIENCE OF THE MIDDLE AGES IN EUROPE.

Roger Bacon-His 'Opus Majus'-His Explanation of the Rain-

bow- He makes Gunpowder-Studies Gases-Proves a Candle

will not burn without Air-His Description of a Telescope-

Speaks of Ships going without Sails-Flavio Gioja invents the

PAGE

39

43

Mariner's Compass-Greeks knew of the Power of the Load-

stone to attract Iron-Use of the Compass in discovering new

lands-Invention of Printing-Columbus discovers America-

Vasco de Gama sees the Stars of the Southern Hemisphere-

Magellan's ship sails round the World-Inventions of Leonardo

da Vinci.

PAGE

51

PART III.

RISE AND PROGRESS OF MODERN SCIENCE.

CHAPTER IX.

SCIENCE OF THE SIXTEENTH CENTURY.

Rise of Modern Science-Dogmatism of the Middle Ages-

Reasons for studying Discoveries in the order of their dates-

Copernican theory of the Universe-Copernicus goes back to

the System of Aristarchus-Is afraid to publish his Work till

quite the end of his Life-Work of Vesalius on Anatomy-He

shows that Galen made many mistakes in describing Man's

Structure-His Banishment and Death-The value of his Work

to Science-Fallopius and Eustachius Anatomists-Gesner's

Works on Animals and Plants-He forms a Zoological Cabinet

and makes a Botanical Garden-His Natural History of Animals

-His classification of Plants according to their Seeds-His

work on Mineralogy—Cæsalpinus makes the First System of

Plants on Gesner's plan-Explains Dioecious Plants-Chemistry

of Paracelsus and Van Helmont

63

CHAPTER X.

SCIENCE OF THE SIXTEENTH CENTURY (CONTINUED).

Baptiste Porta discovers the Camera Obscura-Shows that our

Eye is like a Camera Obscura-Makes a kind of Magic Lantern

by Sunlight-Kircher afterwards makes a Magic Lantern by

Lamplight-Dr. Gilbert's discoveries in Electricity—Tycho

Brahe, the Danish Astronomer-Builds an Observatory on the

Island of Huen-Makes a great number of Observations, and