TER I.

EARLY OBSERVERS OF MARS,
--Mars the only planet the surface of which is
distinctly visible
--Early observation of the snow-caps and seas
--The 'canals' seen by Schiaparelli in 1877
--Double canals first seen in 1881
--Round spots at intersection of canals seen
by Pickering in 1892
--Confirmed by Lowell in 1894
--Changes of colour seen in 1892 and 1894
--Existence of seas doubted by Pickering and
Barnard in 1894.

CHAPTER II.

MR. LOWELL'S DISCOVERIES AND THEORIES,
--Observatory at Flagstaff, Arizona
--Illustrated book on his observations of
Mars
--Volume on Mars and its canals, 1906
--Non-natural features
--The canals as irrigation works of an intelligent
race
--A challenge to the thinking world
--The canals as described and mapped by Mr. Lowell
--The double canals
--Dimensions of the canals
--They cross the supposed seas
--Circular black spots termed oases
--An interesting volume.

CHAPTER III.

THE CLIMATE AND PHYSIOGRAPHY OF MARS,
--No permanent water on Mars
--Rarely any clouds and no rain
--Snow-caps the only source of water
--No mountains, hills, or valleys on Mars
--Two-thirds of the surface a desert
--Water from the snow-caps too scanty to supply
the canals
--Miss Clerke's views as to the water-supply
--Description of some of the chief canals
--Mr. Lowell on the purpose of the canals
--Remarks on the same
--Mr. Lowell on relation of canals to oases and
snow-caps
--Critical remarks on the same.

CHAPTER IV.

IS ANIMAL LIFE POSSIBLE ON MARS?
--Water and air essential for animal life
--Atmosphere of Mars assumed to be like ours
--Blue tint near melting snow the only evidence
of water
--Fallacy of this argument
--Dr. Johnstone Stoney's proof that water-vapour
cannot exist on Mars
--Spectroscope gives no evidence of water.

CHAPTER V.

TEMPERATURE OF MARS--MR. LOWELL'S ESTIMATE,
--Problem of terrestrial temperature
--Ice under recent lava
--Tropical oceans ice-cold at bottom
--Earth's surface-heat all from the sun
--Absolute zero of temperature
--Complex problem of planetary temperatures
--Mr. Lowell's investigation of the problem
--Abstract of Mr. Lowell's paper
--Critical remarks on Mr. Lowell's paper.

CHAPTER VI.

A NEW ESTIMATE OF THE TEMPERATURE OF MARS,
--Langley's determination of lunar heat
--Rapid loss of heat by radiation on the
earth
--Rapid loss of heat on moon during eclipse
--Sir George Darwin's theory of the moon's ori