CHLORINE. 149 



ved of this essential constituent, without obtaining any 

 new supply. As a consequence, it soon becomes unfit 

 to breathe. The case is similar to that of a taper 

 burned in a bottle. The oxygen of the air in the bot- 

 tle, is gradually consumed, and the flame grows grad- 

 ually more and more dim, till it goes out. So life grows 

 fainter and fainter, in a close, unventilated room. 

 What is said 350. Oxygen has been used, with great 

 of oxygen as success, as a means of resuscitation, in cases 



a means of ' 



resuscitation ? of suffocatio.ii and drowning, when similar 

 use of air was without effect. In such cases, it is forced 

 into the lungs through a tube, from a jar or bladder. 



CHLORINE. 



What is chlo- 351. DESCRIPTION. Chlorine is a yel- 

 T wLreisit lowish green gas, of peculiar odor, about 

 found"! %\ times as heavy as the air. More than 



one half of common salt is chlorine. Salt mines and 

 the ocean, therefore, contain it in immense quantities. 

 352. PREPARATION. Chlo- 



How is chlo- 



rineprepar- nne is prepared from muriat- 

 ic acid, which is composed of, 

 chlorine and hydrogen, by using some 

 agent to retain the latter, and liberate the 

 former. Black oxide of manganese is 1 

 such a substance. 



Give the com- 353. The oxide is well covered with mu- 

 picte proceeds. r j a ti c acid, and kept warm, as the evolution 

 of the gas proceeds. This is best effected by a cup of 

 hot water, as represented in the figure. Chlorine gas 

 soon displaces the air in the second vial. It should be 

 corked as soon as filled. 



