CONTENTS

PAGE
INTRODUCTION[ 1]

[CHAPTER I.]
The bases of modern astronomy. Their late formation[ 18]
Instruments and measures used by ancient astronomers[ 19]
Weights and measures sought out by modern astronomers[ 20]
Means employed to discover the density of the earth.
  Measuring by means of plummets not sufficiently exact[ 20]
Measurements with torsion and chemical balances more accurate[ 21]
Sir George B. Airy's theory, and experiments at the Harton colliery[ 22]
Results of experiments not reliable. Theory contrary to the Law of Attraction[ 23]
Proof by arithmetical calculation of its error[ 24]
Difficulties in comparing beats of pendulums at top and bottom of a mine[ 26]
The theory upheld by text-books without proper examination[ 27]
Of a particle of matter within the shell of a hollow sphere.
  Not exempt from the law of Attraction[ 28]
A particle so situated confronted with the law of the
  inverse square ofdistance from an attracting body. Remarks thereon[ 29]
It is not true that the attraction of a spherical shell
  is "zero" for a particle of matter within it[ 31]

[CHAPTER II.]
The moon cannot have even an imaginary rotation on its axis,
  but is generally believed to have. Quotations to prove this[ 33]
Proofs that there can be no rotation. The most confused
  assertion that there is rotation shown to be without foundations[ 35]
A gin horse does not rotate on its axis in its revolution[ 37]
A gin horse, or a substitute, driven instead of being a driver[ 38]
Results of the wooden horse being driven by the mill[ 38]
The same results produced by the revolution of the moon.
  Centrifugal force sufficient to drive air and water away from our side of the moon[ 39]
That force not sufficient to drive them away from its other side[ 40]
No one seems ever to have thought of centrifugal force in connection with air and water on the moon[ 41]
Near approach made by Hansen to this notion[ 41]
Far-fetched reasons given for the non-appearance of air and water[ 42]
The moon must have both on the far-off hemisphere[ 44]
Proofs of this deduced from its appearance at change[ 44]
Where the evidences of this may be seen if looked for at the right place.
  The centrifugal force shown to be insufficient to drive off even air,
  and less water, altogether from the moon[ 45]
The moon must have rotated on its axis at one period of its existence[ 47]
The want of polar compression no proof to the contrary[ 48]
Want of proper study gives rise to extravagant conceptions,
  jumping at conclusions, and formation of "curious theories"[ 48]

[CHAPTER III.]
Remarks on some of the principal cosmogonies. Ancient notions[ 49]
The Nebular hypothesis of Laplace. Early opinions on it.
  Received into favour. Again condemned as erroneous[ 50]
Defects attributed to it as fatal. New cosmogonies advanced[ 51]
Dr. Croll's collision, or impact, theory discussed[ 53]
Dr. Braun's cosmogony examined[ 59]
M. Faye's "Origine du Monde" defined[ 61]
Shown to be without proper foundation, confused, and in some parts contradictory[ 65]
Reference to other hypotheses not noticed. All more or less
  only variations on the nebular hypothesis[ 70]
Necessity for more particular examination into it[ 71]

[CHAPTER IV.]
Preliminaries to analysis of the Nebular hypothesis[ 72]
Definition of the hypothesis[ 73]
Elements of solar system. Tables of dimensions and masses[ 75]
Explanation of tables and density of Saturn[ 78]
Volume, density and mass of Saturn's rings, general remarks
  about them, and satellites to be made from them[ 79]
Future of Saturn's rings[ 79]
Notions about Saturn's satellites and their masses[ 80]
Nature of rings seemingly not well understood[ 81]
Masses given to the satellites of Uranus and Neptune. Explanations of[ 81]
Volumes of the members of the solar system at density of water[ 82]

[CHAPTER V.]
Analysis of the Nebular Hypothesis. Separation from the nebula
  of the rings for the separate planets, etc.[ 83]
Excessive heat attributed to the nebula erroneous and impossible[ 84]
Centigrade thermometer to be used for temperatures[ 85]
Temperature of the nebula not far from absolute zero[ 86]
Erroneous ideas about glowing gases produced by collisions of their atoms,
  or particles of cosmic matter in the form of vapours[ 86]
Separation of ring for Neptune. It could not have been
  thrown off in one mass, but in a sheet of cosmic matter[ 87]
Thickness and dimensions of the ring[ 88]
Uranian ring abandoned, and its dimensions[ 89]
Saturnian ring abandoned, and its dimensions[ 90]
Jovian ring abandoned, and its dimensions[ 91]
Asteroidal ring abandoned, and its dimensions[ 93]
Martian ring abandoned, and its dimensions[ 94]
Earth ring abandoned, and its dimensions[ 95]
Venus ring abandoned, and its dimensions[ 96]
Mercurian ring abandoned, and its dimensions[ 97]
Residual mass. Condensation of Solar Nebula to various
  diameters, and relative temperatures and densities[ 98]
Unaccountable confusion in the mode of counting absolute temperature examined and explained.
  Negative 274 degrees of heat only equal 2 degrees of absolute temperature[ 100]
The Centigrade thermometric scale no better than any other, and cannot be made decimal[103]
The sun's account current with the Nebula drawn up and represented by Table III.[104]

[CHAPTER VI.]
Analysis continued. Excessive heat of nebula involved condensation only at
  the surface. Proof that this was Laplace's idea[108]
Noteworthy that some astronomers still believe in excessive heat[109]
Interdependence of temperature and pressure in gases and vapours.
  Collisions of atoms the source of heat[110]
Conditions on which a nebula can be incandescent. Sir Robert Ball[110]
No proper explanation yet given of incandescent or glowing gas[112]
How matter was thrown off, or abandoned by the Jovian nebula[115]
Division into rings of matter thrown off determined during contraction[116]
How direct rotary motion was determined by friction and collisions of particles[117]
Saturn's rings going through the same process. Left to show process[118]
Form gradually assumed by nebulæ. Cause of Saturn's square-shouldered appearance[120]
A lens-shaped nebula could not be formed by surface condensation[120]
Retrograde rotary motion of Neptune and Uranus, and revolution of their satellites
  recognised by Laplace as possible[121]
Satellites of Mars. Rapid revolution of inner one may be accounted for[123]
Laplace's proportion of 4000 millions not reduced but enormously
  increased by discoveries of this century[124]

[CHAPTER VII.]
Analysis continued. No contingent of heat could be imparted to any planet by the parent nebula[126]
Only one degree of heat added to the nebula from the beginning till it had
  contracted to the density of 1/274th of an atmosphere[127]
Increase in temperature from 0° to possible average of 274°
  when condensed to 4,150,000 miles in diameter[127]
Time when the sun could begin to act as sustainer of life and light anywhere.
  Temperature of space[128]
The ether devised as carrier of light, heat, etc. What effect it might have on the nebula[129]
First measure of its density, as far as we know[130]
The estimate too high. May be many times less[133]
Return to the solar nebula at 63,232,000 miles in diameter[134]
Plausible reason for the position of Neptune not conforming to Bode's Law.
  The ring being very wide had separated into two rings[134]
Bode's law reversed. Ideas suggested by it[135]
Rates of acceleration of revolution from one planet to another[137]
Little possibility of there being a planet in the position assigned to Vulcan[138]
Densities of planets compared. Seem to point to differences
  in the mass of matter abandoned by the nebula at different periods[138]
Giving rise to the continuous sheet of matter separating into different masses.
  Probably the rings had to arrive at a certain stage of density before contracting circumferentially[139]
Possible average temperature of the sun at the present day.
  Central heat probably very much greater[140]
Churning of matter going on in the interior of the sun, caused by unequal
  rotation between the equator and the poles[140]

[CHAPTER VIII.]
Inquiry into the Interior Construction of the Earth.
  What is really known of the exterior or surface[142]
What is known of the interior[143]
Little to be learned from Geology, which reaches very few miles down[144]
Various notions of the interior[145]
What is learnt from earthquake and volcanoes. Igno-aqueous fusion, liquid magma.[146]
Generally believed that the earth consists of solid matter to the centre.
  Mean density. Surface density[147]
More detailed estimate of densities near the surface[148]
Causes of increased surface density after the crust was formed[148]
Calculations of densities for 9 miles deep, and from there to the centre forming Table IV.[150]
Reflections on the results of the calculations[151]
Notion that the centre is composed of the heaviest metals.
  "Sorting-out" theory absurd[151]
Considerations as to how solid matter got to the centre[152]
Gravitation might carry it there, but attraction could not[153]
How the earth could be made out of cosmic matter, meteorites or meteors[154]

[CHAPTER IX.]
Inquiry into the Interior Construction of the Earth—continued[165]
The earth gasiform at one period. Density including the moon may have been 1/10,000th
  that of air. Must have been a hollow body. Proofs given[166]
Division of the mass of the earth alone into two parts[169]
Division of the two masses at 817 miles from surface[171]
Reasons why the earth cannot be solid to the centre[172]
Gasiform matter condensing in a cone leaves apex empty[172]
Proportions of the matter in a cone[173]
Calculations of the densities of the outer half of the hollow
  shell of the earth. Remarks upon the condensation[174]
Calculations of inner half of the hollow shell[175]
Remarks upon position of inner surface of the shell[177]
Calculations of the same[179]

[CHAPTER X.]
Inquiry into the interior construction of the Earth—continued[184]
Density of 8·8 times that of water still too high for the
  possible compression of the component matter of the earth as known to us[185]
Reasons for this conclusion drawn from crushing strains of materials[186]
A limit to density shown thereby[187]
The greatest density need not exceed 6·24 of water[188]
Gases shut up in the hollow centre. Their weight must so
  far diminish the conceded maximum of 6·24[189]
Density of inner half of earth at 3000 miles diameter.
  Greatest density may be less than 5·833 of water[190]
Supposed pressure of inclosed gases very moderate[191]
Meaning of heat limit to density. Temperature of interior
  half of shell and inclosed gases must be equal[193]
State of the hollow interior[194]
Results of the whole inquiry[195]

[CHAPTER XI.]
The Earth. The idea entertained by some celebrated men, and others[197]
Difficulties of forming a sphere out of a lens-shaped nebula[199]
Various studies of the earth's interior made for specialy purposes. Difficulty some
  people find in conceiving how the average density of little over 5·66 can be
  possible, the earth being a hollow sphere[200]
What is gained by its being a hollow shell[201]
Geological theories of the interior discussed.
  Volcanoes and earthquakes in relation to the interior[202]
Liquid matter on the interior surface of the shell, and gases in the hollow,
  better means for eruptions than magma layers[206]
Focal depths of earthquakes within reach of water, but not of lavas[207]
Minute vesicles in granite filled with gases, oxygen and hydrogen, but not water[209]
The Moon. A small edition of the earth[211]
Rotation stopped. Convulsions and cataclysms caused thereby. Air, water,
  vapour driven off thereby to far-off hemisphere. Liquid matter in hollow
  interior would gravitate to the inside of the nearest hemisphere[212]
Form and dimensions during rotation. Altered form after it stopped[213]
Agreeing very closely with Hansen's "curious theory"[214]

[CHAPTER XII.]
Some of the results arising from the sun's being a hollow sphere[215]
Repetition of the effects of condensation on the temperature of the nebula[216]
Ideas called up by the apparently anomalous increase of temperature[217]
How heat is carried from the sun to the earth[218]
The sun supposed to radiate heat only to bodies that can receive and hold it,
  and not to all space. The heat of the sun accumulated in a
  hot box to considerably beyond the boiling point of water[219]
The heat accumulated in this way supposed to be due to a peculiar function of the ether,
  as it is a fact that heat can be radiated from a cold to a hot body[220]
The sun must be gaseous, or rather gasiform, throughout. No matter in it solid
  or even liquid. Divisions and densities of shell[221]
The hollow centre filled with gases, whose mass naturally
  diminishes the mean density of the whole body[222]
The amount of this reduction so far defined. The presence of gases or vapours
  in the hollow a natural result of condensation[223]
The hollow centre filled with gases not incompatible with the sun's being
  a hollow sphere. The temperature at the centre may be anything,
  not depending on any law of gases[223]
Further exposition of hollow-sphere theory put off till after
  further development of the construction of the sun[224]

[CHAPTER XIII.]
The ether. Its nature considered. Behaves like a gas[226]
Can be pumped out of a receive[227]
Light and heat do not pass through a tube in vacuo.
  Laboratory experiments examined[228]
Light and darkness in a partial vacuum, though high[229]
Electricity not a carrying agent[230]
Why there are light and dark strata in a high vacuum[232]
The real carrying agent through a high vacuum is the residue
  of ether left in it. Digression to consider the aurora[233]
How air may be carried to extraordinary heights. Zones of
  air carried up are made luminous by electricity[234]
Comparison of this method with experiments quoted[236]
Experiment suggested to prove whether light passes freely through a vacuum tube[237]
The ether does not pervade all bodies freely[238]
It must be renounced altogether or acknowledged to be a material body,
  subject to expansion, condensation, heating or cooling[239]
How light and heat pass through glass[239]
Temperature of the ether variable. Zodiacal light, cause of[240]

[CHAPTER XIV.]
The ether considered and its nature explained. Further proofs
  given by Dr. Crookes's work, of its material substance[244]
Highest vacuum yet produced. Absorbents cannot absorb the ether[246]
Dr. Crookes's definition of a gas. Not satisfactory. Why[247]
A fluid required to pump matter out of a vessel[248]
Gas as described by Dr. Crookes would not suit[249]
The ether the only elastic fluid we have. The only real gas,if it is a gas[250]
A possible measure of the density of the ether[250]
Causes of dark and light zones in high vacua[251]
The real conductor of light in a high vacuum[252]
How a vacuum tube glows, when electricity passes through it[254]
Conclusions arrived at through foregoing discussions[255]
Some exhibitions of light explained[256]
Gases can be put in motion, but cannot move even themselves[257]
The ether shown to be attraction. And primitive matter also[258]
All chemical elements evolved from it. Its nature stated[259]
Action at a distance explained by the ether and attraction
  being one and the same[259]

[CHAPTER XV.]
Construction of the solar system. Matter out of which it was formed[261]
Domains of the sun out of which the matter was collected[262]
Stars nearest to the sun. Table VII. showing distances[263]
Remarks on Binary Stars. Table VIII. showing spheres of
  attraction between the sun and a very few[265]
Sirius actually our nearest neighbour. Form of the sun's domains of a very jagged nature[266]
Creation of matter for the nebulæ, out of which the whole universe was
  elaborated. Beginning of construction[267]
The law of attraction begins to operate through the agency of evolution[267]
Form of the primitive solar nebula. The jagged peaks
  probably soon left behind in contraction[268]
How the nebula contracted. Two views of the form it might take.
  Comparison of the two forms, solid or hollow[269]
The hollow centre form adopted. The jagged peaks left behind[272]
The nebula assuming a spherical form. Shreds, masses,
  crescents separated from one side[273]
Probable form of interior of nebula. Compared with envelopes in heads of some comets[274]
Reflections on the nebula being hollow. Opinions of others quoted[275]
The matter of a sphere solid to the centre must be inert there[276]
Further proofs of the nebula being hollow[277]
How rotary motion was instituted[278]
Such a nebula might take one of two forms[279]
The form depending on the class of nebula. Planetary in the case of the solar system.
  A similar conception of how rotary motion could be instituted[280]

[CHAPTER XVI.]
The sun's neighbours still exercise their attraction over him[282]
Regions of greatest density in the 9 nebulæ dealt with; compared with the
  orbits of the planets made from them[283]
Results of comparison favourable to the theory[287]
Differences of size in the planets have arisen from variations in the quantity
  of matter accumulating on the nebulæ[289]
Causes of the retrograde motions in Neptune, Uranus, and their satellites[290]
Probable causes of the anomalous position of Neptune[292]
Rises and falls in the densities and dimensions of the planets explained[293]
The form of the nebulæ must have resembled a dumb-bell[295]
More about rises and falls in densities[296]
Reason why the Asteroid nebula was the least dense of the system;[297]
Not necessary to revise the dimensions given to the 9 nebulæ[298]
Causes of the anomalies in the dimensions, densities, etc., of the Earth and Venus[299]
The strictly spherical form of the sun accounted for. But it may yet be varied[299]
Repetition that a spherical body could not be made from a lens-shaped
  nebula by attraction and condensation[300]

[CHAPTER XVII.]
Former compromises taken up and begun to be fulfilled[301]
Estimates of the heat-power of the sun made only from gravitation hitherto[302]
Contraction and condensation of a nebula solid to the centre.
  Heat produced from attraction as well as by gravitation[303]
What quantity of heat is produced by a stone falling upon the earth[304]
Showing again that there is a difference between attraction and gravitation[305]
Contraction and condensation of a hollow-sphere nebula, in the same manner as the solid one[305]
Differences of rotation would be greater in a hollow nebula; because a great deal of
  the matter would be almost motionless in a solid sphere;[306]
In neither case could matter be brought to rest, but only retarded in motion.
  Different periods of rotation accounted for[307]
Table of different rates explained[309]
Heat produced by gravitation, attraction and churning, not all
  constituents of the heat-power of the sun[310]
There can be no matter in the sun so dense as water[311]
The hollow part of the sun acting as a reservoir of
  gases, heat and pressure[312]
The behaviour of heat produced in the nebula, and its power[313]
How sun-spots are produced[314]
Cyclonic motions observed in sun-spots. Why not all in
  certain directions, and why only observed in a very few[315]
Cyclonic motions in prominences treated of[316]
Many other things might be explained, on some of which we
  do not dare to venture. Concluding observations[317]

[CHAPTER XVIII.]
Return to the peaks abandoned by the original nebula. An idea of their number[319]
Example of their dimensions. What was made out of them[320]
What could be made from one of them[321]
How it could be divided into comets and meteor swarms[322]
An example given. How a comet may rotate on its axis. And what might be
  explained thereby. Orbits and periods of revolution[323]
Not ejected from planets. Their true origin[324]
Study of the velocities in orbit of comets, and results thereof[326]
How far comets may wander from the sun and return again[327]
No reason why comets should wander from one sun to another. Confirmatory
  of the description, in Chapter XV. of the sun's domains[328]
Of the eternal evolution and involution of matter.
  The atmosphere and corona of the sun[329]
Partial analogy between it and the earth's atmosphere[331]
The density of it near the sun's surface cannot be normally less than 28 atmospheres,
  but might be so partially and accidentally[332]
Probable causes of the enormous height of its atmosphere[332]
The mass taken into account, but cannot be valued[334]
Most probably no matter in the sun exceeds half the density of water.
  The unknown line in the spectrum of the corona belongs to the ether[335]

NEW
Theories in Astronomy.