xii CONTENTS. 



PACK 



modify the Intensity of Action and Reaction between all other 

 kinds of Elementary Molecules. Its Relations to our Atmos- 

 phere Reverse the Proportions of Nitrogen aud Oxygen in 

 the Air, and Nitric Acid would be produced. Relations of 

 Nitrogen to Explosive Substances. Isomeric Bodies. Dif- 

 ferent Results from similar Groupings. Attempts to convert 

 Resin into Butter. Different Kinds of Molecules reflect Vibra- 

 tions *of Light with different Intensity, corresponding to a 

 Chromatic Scale of Colors. On these and the " Frauenhoffer 

 lines," the Spectrum Analysis is based. Formation of Mol- 

 ecules into Crystals. The Symmetrical Electro-magnetic 

 Union of Molecules in Inorganic Formations of Crystals is 

 the Basis of Crystallography. Cause of Angular Shapes. 

 P'orms of Molecules. 



CHAPTER XXI. 



PECULIAR QUALITIES OF COMPOUND SUBSTANCES DEVEL- 

 OPED BY VARIOUS RELATIVE PROPORTIONS OF THE 



SAME KINDS OF MOLECULES 1 86 



Vinegar, Butter, Vegetable Oils, and Fat produced by combining 

 various Proportions of Carbon and Hydrogen with a constant 

 Quantity of Oxygen. The Properties of Drugs and Medicines 

 developed by varied Molecular Groupings. Table of Com- 

 parative Quantities of Elementary Molecules, grouped in the 

 Organisms of Plants and Animals, forming Albumen, Fibrine, 

 and Caseine. Albumen the starting point of Animal Tissues. 

 Table showing the relative Proportion of the four Kinds 

 of Fluid Atmospheric Molecules which enter into the organic 

 Formations of Food and Fuel. 



CHAPTER XXII. 

 PLANTS AS ELECTRIC MACHINES 191 



Matter Organic and Inorganic. Plants and Animals composed 

 of Congeries of Tubes. The Leaves of Plants cover the Sur- 

 face of the Earth, and are adapted to decompose Water and 

 Carbonic- Acid Gas : thus they are really Electric Machines. 

 Thermo-electric Circuits between Leaves exposed to the Sun 

 and the Roots buried in the cool, mo'st Earth. Plants as 

 Current-changers. The Organs of living Plants Galvanic 

 Batteries. Equilibrium restored by Chemical Decomposition. 

 - Elementary Molecules of Plants are the same as those com- 

 posing the Atmosphere and Water. The two great Processes 

 in the Growth of Plants. Leaves are Current-changers. 



