104 ELEMENTS AND COMPOUNDS 



Owing to the danger that sodium may be spattered into our eyes, we 

 never put more than a very small piece at a time upon water, and 

 we add it at arm's length, holding a piece of glass between our eyes and 

 the dish. An excellent way is to use a small wide-mouth bottle 3 / 4 

 full of water (Fig. 85). The bottle is provided with a glass cover, 

 which is drawn aside when the sodium is added, and replaced during 

 the action. Several pieces of sodium may be added, one at a time. 

 The hands and tongs used must be dry. If, after each piece of sodium 

 has disappeared, we apply a match to the mouth of the bottle, the hy- 

 drogen will burn. All sodium compounds make a colorless flame yellow. 



110. Chlorine. While the element sodium is a solid 

 at the ordinary temperature, chlorine, the other element 

 present in salt, is a gas. The gases we have studied up 

 to this time are colorless, odorless, and tasteless; but 

 chlorine has a green color, a suffocating odor, and a dis- 

 agreeable action on the lining of the nose and throat. It 

 produces the effects of a bad cold. Its name comes from 

 chloros, the Greek word for " green." We have the same 

 word in "chlorophyll," the green coloring matter of 

 plants (cf. 309). 



Chlorine has the power of bleaching ; that is, of removing 

 the color of grass, straw, and other plant products. It also 

 bleaches cloth or paper dyed with indigo, litmus, cochineal, 



etc. Large quantities of 

 chlorine are used in mak- 



ing bleaching powder 



FIG. 86. ("chloride of lime") and 



bleaching solutions. These 



are used for the whitening of cotton goods (Fig. 86) 

 and, as "disinfectants," for destroying disease germs. 

 Bleaching solutions are also used to remove ink and 

 other stains from fabrics (cf. 230) . 



