Chapter 9

James Clerk-Maxwell's conception of ether--Thomas Young 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