Book contents
- Frontmatter
- EDITOR'S PREFACE
- PREFACE
- Contents
- LIST OF ILLUSTRATIONS
- CHAPTER I BELIEFS AND SUPERSTITIONS RELATIVE TO COMETS
- CHAPTER II COMETARY ASTRONOMY UP TO THE TIME OF NEWTON
- CHAPTER III THE MOTIONS AND ORBITS OF COMETS
- CHAPTER IV PERIODICAL COMETS
- CHAPTER V PERIODICAL COMETS
- CHAPTER VI THE WORLD OF COMETS AND COMETARY SYSTEMS
- CHAPTER VII PHYSICAL AND CHEMICAL CONSTITUTION OF COMETS
- SECTION I COMETS PHYSICALLY CONSIDERED
- SECTION II COMETARY NUCLEI, TAILS, AND COMÆ
- SECTION III COMETS DEVOID OF NUCLEUS AND TAIL
- SECTION IV DIRECTION OF THE TAILS OF COMETS
- SECTION V NUMBER OF TAILS
- SECTION VI DIFFERENT FORMS OF TAILS
- SECTION VII LENGTH OF TAILS
- SECTION VIII FORMATION AND DEVELOPMENT OF TAILS
- SECTION IX BRILLIANCY OF COMETS
- SECTION X DIMENSIONS OF NUCLEI AND TAILS
- CHAPTER VIII PHYSICAL TRANSFORMATIONS OF COMETS
- CHAPTER IX MASS AND DENSITY OF COMETS
- CHAPTER X THE LIGHT OF COMETS
- CHAPTER XI THEORY OF COMETARY PHENOMENA
- CHAPTER XII COMETS AND SHOOTING STARS
- CHAPTER XIII COMETS AND THE EARTH
- CHAPTER XIV PHYSICAL INFLUENCES OF COMETS
- CHAPTER XV SOME QUESTIONS ABOUT COMETS
- I ELLIPTIC ELEMENTS OF THE RECOGNISED PERIODICAL COMETS OF THE SOLAR SYSTEM
- II GENERAL CATALOGUE OF THE ORBITS OF COMETS
- Plate section
SECTION I - COMETS PHYSICALLY CONSIDERED
Published online by Cambridge University Press: 05 March 2012
- Frontmatter
- EDITOR'S PREFACE
- PREFACE
- Contents
- LIST OF ILLUSTRATIONS
- CHAPTER I BELIEFS AND SUPERSTITIONS RELATIVE TO COMETS
- CHAPTER II COMETARY ASTRONOMY UP TO THE TIME OF NEWTON
- CHAPTER III THE MOTIONS AND ORBITS OF COMETS
- CHAPTER IV PERIODICAL COMETS
- CHAPTER V PERIODICAL COMETS
- CHAPTER VI THE WORLD OF COMETS AND COMETARY SYSTEMS
- CHAPTER VII PHYSICAL AND CHEMICAL CONSTITUTION OF COMETS
- SECTION I COMETS PHYSICALLY CONSIDERED
- SECTION II COMETARY NUCLEI, TAILS, AND COMÆ
- SECTION III COMETS DEVOID OF NUCLEUS AND TAIL
- SECTION IV DIRECTION OF THE TAILS OF COMETS
- SECTION V NUMBER OF TAILS
- SECTION VI DIFFERENT FORMS OF TAILS
- SECTION VII LENGTH OF TAILS
- SECTION VIII FORMATION AND DEVELOPMENT OF TAILS
- SECTION IX BRILLIANCY OF COMETS
- SECTION X DIMENSIONS OF NUCLEI AND TAILS
- CHAPTER VIII PHYSICAL TRANSFORMATIONS OF COMETS
- CHAPTER IX MASS AND DENSITY OF COMETS
- CHAPTER X THE LIGHT OF COMETS
- CHAPTER XI THEORY OF COMETARY PHENOMENA
- CHAPTER XII COMETS AND SHOOTING STARS
- CHAPTER XIII COMETS AND THE EARTH
- CHAPTER XIV PHYSICAL INFLUENCES OF COMETS
- CHAPTER XV SOME QUESTIONS ABOUT COMETS
- I ELLIPTIC ELEMENTS OF THE RECOGNISED PERIODICAL COMETS OF THE SOLAR SYSTEM
- II GENERAL CATALOGUE OF THE ORBITS OF COMETS
- Plate section
Summary
WHAT is meant by the physical or chemical constitution of a celestial body, or of any luminary whatever, whether star or sun, planet or moon; or, as we are treating of comets only, what is meant by the physical or chemical constitution of a comet?
We have presented for our consideration a question the nature of which is easily explained and not less easily understood; but it is one that the best-informed of astronomers would find it difficult to answer in its full integrity.
By comparison with the bodies that we see on the surface of the earth and with the terrestrial globe itself, considered as a whole, we shall proceed to explain what is meant by the physico-chemical constitution of a comet.
The earth is a globe, more accurately, a spheroid, whose form and dimensions are perfectly defined and well known, at all events as far as concerns its solid crust, the atmosphere that surrounds it, and the rocks and strata near its surface.
———Facies non omnibus una
Nec diversa tamen qualem decet esse sororum.
Comets are, from all these points of view, their movements alone excepted, conspicuously different from the earth and the rest of the planets.
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- The World of Comets , pp. 193 - 195Publisher: Cambridge University PressPrint publication year: 2010First published in: 1877