The Romance of Modern Chemistry

. ____ _________________ CONTENTS CHAPTER Vil METALS, COMMON AND UNCOMMON An aristocracy among the metals—Gold and platinum—Iron in modern life—Cast-iron, wrought-iron, and steel—How razors and watch-springs are hardened—Aluminium and its affec- tion for oxygen—Thermit—A metal that does not tarnish__ Platinum in electric lamps—Why we want tantalum now- adays . __................................_ CHAPTER VII WHERE TWO METALS ABE BETTER THAN ONE Metals not always what they seem—Tinplate, galvanised iron, and the common pin—Why a sovereign is not made of pure gold—Common solder — Fire-alarms and sprinklers — The melting-point of alloys ... .... 72 CHAPTER VIII ACIDS AND ALKALIS What an acid is, and how it may be “ killed’’—Engraving on metals—An ink which marks glass—Oil of vitriol and its love for water—The chemical fire-engine—Alkalis as antidotes— How one may safely enter a poisonous atmosphere—Ammonia and lime—Energy manifested in the slaking of lime—Mortar the scene of unceasing chemical activity • ... 82 CHAPTER IX NATUBAL WATERS, AND WHAT THEY MAY CONTAIN How two gases make one liquid—Some physical peculiarities of water—Hard and soft water—The making of a lather__ Carbonate of lime and the “furring” of a kettle—Stalac- tites, stalagmites, and petrifying springs—How fresh water is obtained from sea water—Germs in water and their removal—Seltzer water, Epsom salts, and sulphur springs . 95 CHAPTER X CHEMICAL CHANGES WHICH PRODUCE LIGHT AND HEAT The “ Red Flower”—Chemistry of a Candle—The use of a lamp chimney—Can smoke be abolished ?—Gas stove versus coal fire—The Bunsen burner—The wonderful changes that ac- company combustion—Slow burning in the human body__ How two men are equivalent to one gas burner—Rusting a kind of slow combustion_____________________ 106 10