-Agassiz
and the glacial theory--Perraudin the chamois-hunter, and his
explanation of perched bowlders--De Charpentier's acceptance of
Perraudin's explanation--Agassiz's paper on his Alpine studies--His
conclusion that the Alps were once covered with an ice-sheet--Final
acceptance of the glacial theory--The geological ages--The work of
Murchison and Sedgwick--Formation of the American continents--Past,
present, and future.

CHAPTER V. THE NEW SCIENCE OF METEOROLOGY

Biot's investigations of meteors--The observations of Brandes and
Benzenberg on the velocity of falling stars--Professor Olmstead's
observations on the meteoric shower of 1833--Confirmation of Chladni's
hypothesis of 1794--The aurora borealis--Franklin's suggestion that
it is of electrical origin--Its close association with terrestrial
magnetism--Evaporation, cloud-formation, and dew--Dalton's demonstration
that water exists in the air as an independent gas--Hutton's theory of
rain--Luke Howard's paper on clouds--Observations on dew, by Professor
Wilson and Mr. Six--Dr. Wells's essay on dew--His observations
on several appearances connected with dew--Isotherms and ocean
currents--Humboldt and the-science of comparative climatology--His
studies of ocean currents--Maury's theory that gravity is the cause
of ocean currents--Dr. Croll on Climate and Time--Cyclones and
anti-cyclones,--Dove's studies in climatology--Professor Ferrel's
mathematical law of the deflection of winds--Tyndall's estimate of
the amount of heat given off by the liberation of a pound of
vapor--Meteorological observations and weather predictions.

CHAPTER VI. MODERN THEORIES OF HEAT AND LIGHT

Josiah Wedgwood and the clay pyrometer--Count Rumford and the vibratory
theory of heat--His experiments with boring cannon to determine the
nature of heat--Causing water to boil by the friction of the borer--His
final determination that heat is a form of motion--Thomas Young and the
wave theory of light--His paper on the theory of light and colors--His
exposition of the colors of thin plates--Of the colors of thick
plates, and of striated surfaces,--Arago and Fresnel champion the wave
theory--opposition to the theory by Biot--The French Academy's tacit
acceptance of the correctness of the theory by its admission of Fresnel
as a member.

CHAPTER VII. THE MODERN DEVELOPMENT OF ELECTRICITY AND MAGNETISM

Galvani and the beg