OUTLINE OE THE PHYSICAL AGENCIES WHICH LEAD TO SECULAR
CHANGES OF CLIMATE.
Eccentricity of the Earth’s Orbit; its Effect on
Climate.—Glacial Epoch not the direct Result of an
Increase of Eccentricity.—An important Consideration
overlooked.—Change of Eccentricity affects Climate only
indirectly.—Agencies which are brought into Operation
by an Increase of Eccentricity.—How an Accumulation
of Snow is produced.—The Effect of Snow on the Summer
Temperature.—Reason of the Low Summer Temperature of Polar
Regions.—Deflection of Ocean-currents the chief Cause of
Secular Changes of Climate.—How the foregoing Causes deflect
Ocean-currents.—Nearness of the Sun in Perigee a Cause of
the Accumulation of Ice.—A remarkable Circumstance regarding
the Causes which lead to Secular Changes of Climate.—The
primary Cause an Increase of Eccentricity.—Mean Temperature
of whole Earth should be greater in Aphelion than in
Perihelion.—Professor Tyndall on the Glacial Epoch.—A
general Reduction of Temperature will not produce a Glacial
Epoch.—Objection from the present Condition of the Planet
Mars 54