VI CONTENTS. 



CHAPTER Y. 



CRYSTALLOGENIC FORCES. 



Crystallisation and Molecular Force distinguished Experimental 

 Proof Polarity of Particles forming a Crystal Difference 

 between Organic and Inorganic Forms Decomposition of 

 Crystals in Nature Substitution of Particles in Crystals 

 Pseudomorphism Crystalline Form not dependent on Che- 

 mical Nature Isomorphism Dimorphism Theories of 

 Crystallogenic Attraction Influence of Electricity and Mag- 

 netism Phenomena during Crystallisation Can a change of 

 Form take place in Primitive Atoms ? Illustrative Example 

 of Crystallisation .... .50 



CHAPTEE VI. 



HEAT SOLAR AND TERRESTRIAL. 



Solar and Terrestrial Heat Position of the Earth in the Solar 

 System Heat and Light associated in the Sunbeam 

 Transparency of Bodies to Heat Heating Powers of the 

 Coloured Eays of the Spectrum Undulatory Theory 

 Conducting Property of the Earth's Crust Convection 

 Radiation Action of the Atmosphere on Heat Rays 

 Peculiar Heat Rays Absorption and Radiation of Heat by 

 dissimilar Bodies Changes in the Constitution of Solar 

 Beam Differences between Transmitted and Reflected Solar 

 Heat Phenomena of Dew Action of Solar Heat of the 

 Ocean Circulation of Heat by the Atmosphere and the 

 Ocean Heat of the Earth Mean Temperature Central 

 Heat Constant Radiation of Heat Rays from all Bodies 

 Thermography Action of Heat on Molecular Arrangements 

 Sources of Terrestrial Heat Latent Heat of Bodies 

 Animal Heat Eremacausis Spheroidal State Cold Con- 

 densation Freezing Theories of Heat Natural Phe- 

 nomena and Philosophical Conclusion . . .62 



CHAPTER VII. 



LIGHT. 



Theories of the Nature of Light Hypotheses of Newton and 

 Huygens Sources of Light The Sun Velocity of Light 

 Transparency Dark Lines of the Spectrum Absorption of 

 Light Colour Prismatic Analysis Rays of the Spectrum 

 Rainbow Diffraction Interference Goethe's Theory 

 Polarisation Magnetisation of Light Vision The Eye 

 Analogy Sound and Light Influence of Light on Animals 

 and Vegetables Phosphorescence arising from several Causes 

 Artificial Light Its Colour dependent on Matter . 118 



CHAPTER VIII. 



ACTINISM CHEMICAL RADIATIONS. 



The Sun-ray and its Powers Darkening of Horn Silver Niepce's 

 Discovery Prismatic Spectrum Refrangibility of Light, 

 Heat, and Actinism Daguerre's Discovery Photography 

 Chemical Effects produced by Solar Radiations Absorption 



