X CONTENTS 



CHAPTER V. 



Water 76 



How Water Occurs in Nature. Substances Dissolved in Natural 

 Water. Drinking Water. Hardness of Water. Purifying Water. 

 Filtering. Filtering City Water. Exercises. Why Ice Forms 

 Only at the Surface. Artificial Ice. Steam. The Boiling Point 

 Changes with Pressure. Solutions. Properties of Solutions. 

 Freezing Mixtures. Solubility. Crystals. Summary. Exercises. 



CHAPTER VI. 



Elements and Compounds 94 



Physical and Chemical Changes. Composition of Water. 

 Electrolysis of Water. Elements and Compounds. Mixtures. 

 Preparation of Hydrogen. Properties of Hydrogen. Burning of 

 Hydrogen. Diffusion of Gases and Liquids. Exercises. Salt. 

 Sodium. Chlorine. Hydrochloric Acid. Ammonia. Sulphur. 

 Number of Elements and Compounds. Summary. Exercises. 



CHAPTER VII. 



Carbon and its Compounds 110 



Carbon as an Element. Coal. Uses of the Forms of Carbon. 

 Hydrocarbons. Petroleum. Flashing Point. Other Compounds 

 of Carbon. Dry Distillation of Coal and Wood. Exercises. 

 Carbon Dioxide. Carbon Dioxide in the Air. To Prepare Carbon 

 Dioxide. Carbon Dioxide in Fermentation. Baking Powders. 

 Carbon Dioxide as a Fire Extinguisher. Limestone. Summary. 

 Exercises. 



CHAPTER VIII. 

 Magnets and Electricity 125 



Magnets. Poles of a Magnet. Magnetic Substances. The 

 Magnetic Field. The Earth a Magnet. Exercises. Electric 

 Charges from Friction. Conductors and Insulators. Attraction 

 and Repulsion. Induction of Charges. Electric Discharge. Stor- 

 ing a Charge; Leyden Jar. Electricity of the Atmosphere. Light- 

 ning Rods. Exercises. Electric Currents. Kinds of Cells. Sal 

 Ammoniac Cell. Currents and Magnetism. Electro-Magnets. 

 The Telegraph. Electric Bell. Changing the Current into Light. 

 Electric Furnaces. Electroplating. The Dynamo. Electric Mo- 

 tor. Electric Power. Summary. Exercises. 



