and "Luminiferous ether,"--Young's and Fresnel's conception
of transverse luminiferous undulations--Faraday's experiments
pointing to the existence of ether--Professor
Lodge's suggestion of two ethers--Lord Kelvin's calculation
of the probable density of ether--The vortex theory of
atoms--Helmholtz's calculations in vortex motions
--Professor Tait's apparatus for creating vortex rings in the
air---The ultimate constitution of matter as conceived by
Boscovich--Davy's speculations as to the changes that occur in
the substance of matter at different temperatures--Clausius's
and Maxwell's investigations of the kinetic theory of gases--Lord
Kelvin's estimate of the size of the molecule--
Studies of the potential energy of molecules--Action of
gases at low temperatures.

APPENDIX




A HISTORY OF SCIENCE

BOOK III

MODERN DEVELOPMENT OF THE PHYSICAL
SCIENCES

With the present book we enter the field of the
distinctively modern. There is no precise date
at which we take up each of the successive stories,