158 METTALLOIDS. 



BROMIDE. 



379. Bromine is a dense reddish-brown 

 of bromine? fluid, exhaling at ordinary temperatures, a 

 deep orange-colored vapor. It is similar, in 

 its chemical properties, to chlorine, but the latter is 

 the stronger of the two, and expels bromine from its 

 compounds. Thus, if chlorine be passed into one end 

 of a heated tube containing bromide of silver, the va- 

 pors of bromine will be seen to pass out at the other 

 end, and escape, while the chlorine remains, and takes 

 possession of the metal. Bromine, like chlorine, is 

 found in sea- water, and in the water of mineral springs, 

 combined with sodium, or some other metal. The 

 power of chlorine to expel it from its compounds, is 

 made use of in manufacturing bromine. This sub- 

 stance is used in photography, but is otherwise of little 

 general interest. Although widely distributed, it ex- 

 ists in nature, in comparatively small quantities. Bro- 

 mine vapors have the effect of imparting to starch a 

 beautiful orange color. 



FLUORINE. 



'^What is said 380. Fluorine is yellowish-brown gas, 

 of fluorine? O f stron g odor, somewhat similar to that of 

 chlorine. It is one of the elements of the beautiful 

 mineral, fluor spar. It is prepared from the fluoride of 

 potassium, by means of the galvanic current. Its isola- 

 tion has been attended with great difficulties, and the 



