| 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.
public@vhost@g@html@files@45356@45356-h@45356-h-6.htm.html#Page_172" class="pginternal">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
ss="tdr">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 |
