CONTENTS 



Vll 



As water is next to 

 air in importance in 

 our environment, its 

 treatment naturally fol- 

 lows the chapter on air. 



The chapter on water 

 in general is followed 

 by a chapter on running 

 water, showing its geo- 

 graphic and economic 

 importance. 



The study of the 

 chapters on the earth 1 s 

 relation to the sun, and 

 on heat, air, and water, 

 has paved the way for 

 the introduction of this 

 chapter on weather and 

 climate. 



CHAPTER VI. THE WATERS OF THE EARTH 



Composition of Water Effects of Varying 

 Temperatures on Water Ability of Water to 

 Absorb Heat Water as a Solvent Freezing 

 Mixtures Suspension and Solution Emul- 

 sions Pressure in Water Buoyancy, of 

 Water Water Reservoirs of the Earth 

 Animal Life in Water Waves Currents 



Tides .135 



Water, ice, and steam in everyday life. Hot- 

 water bags. Irrigation to prevent freezing. A 

 " sticky " salt cellar. Salt on ice in a freezer, or 

 on steps, sidewalks, or car track switches in 

 freezing weather. Settling basins, filtration. 

 Emulsifying action of soap. Pressure in water 

 mains and reservoirs, hydraulic press. Sub- 

 marines. 



CHAPTER VII. THE WORK OF RUNNING 

 WATER 



Power of Running Water River Develop- 

 ment Inland Waterways and History Sup- 

 plying Water to Populous Communities 

 Pure Water and Health . . . .170 

 Fertility of "bottom-lands." Natural and arti- 

 ficial levees. Harbors. Beginnings of great 

 cities. Canals, extension of inland navigation. 

 Ancient and modern city water supplies, reser- 

 voirs, pumping stations, water intakes. Water 

 purification, the St. Louis water system. 



CHAPTER VIII. WEATHER AND CLIMATE 

 The Atmosphere as both Blanket and Sun- 

 Shield Circulation of Air Winds Cy- 

 clones and Anti-cyclones Storm-paths 

 Sudden Weather Changes Thunderstorms 

 Tornadoes Rainfall Climate Mountain, 

 Seaside, and Island Climates Summer and 

 Winter Resorts . . . . .209 

 Cold-frame. Blizzards and "hot winds." Fore- 

 casting the weather. Absorption of heat. Fruit- 

 raising districts. 



