t should be
enlarged somewhat and published in a form more convenient for the
public. The enlargement consists in the addition of a chapter on the
"_Contrasted Properties of Matter and the Ether_," a chapter containing
something which the author believes to be of philosophical importance in
these days when electricity is so generally described as a phenomenon of
the ether.

A. E. DOLBEAR.

TABLE OF CONTENTS

CHAPTER I

Ideas of phenomena ancient and modern, metaphysical and
mechanical--Imponderables--Forces, invented and
discarded--Explanations--Energy, its factors, Kinetic
and Potential--Motions, kinds and transformations
of--Mechanical, molecular, and atomic--Invention of
Ethers, Faraday's conceptions p. 7

CHAPTER II

Properties of Matter and Ether compared--Discontinuity
_versus_ Continuity--Size of atoms--Astronomical
distances--Number of atoms in the universe--Ether
unlimited--Kinds of Matter, permanent qualities
of--Atomic structure; vortex-rings, their
properties--Ether structureless--Matter
gravitative, Ether not--Friction in Matter, Ether
frictionless--Chemical properties--Energy in
Matter and in Ether--Matter as a transformer
of Energy--Elasticity--Vibratory rates and
waves--Density--Heat--Indestructibility of
Matter--Inertia in Matter and in Ether--Matter
not inert--Magnetism and Ether waves--States
of Matter--Cohesion and chemism affected by
temperature--Shearing stress in Solids and in
Ether--Ether pressure--Sensation dependent upon
Matter--Nervous system not affected by Ether
states--Other stresses in Ether--Transformations
of Motion--Terminology p. 24

CHAPTER III

Antecedents of Electricity--Nature of what is
transformed--Series of transformations for the
production of light--Positive and negative
Electricity--Positive and negative twists--Rotations
about a wire--Rotation of an arc--Ether a
non-conductor--Electro-magnetic waves--Induction
and inductive action--Ether stress and atomic
position--Nature of an electric current--Electricity
a condition, not an entity p. 94

CHAPTER I

Ideas of phenomena ancient and modern, metaphysical and
mechanical--Imponderables--Forces, invented and
discarded--Explanations--Energy, its factors, Kinetic
and Pot