150 METALLOIDS. 



Explain the 354. It will be remembered that black 



process. oxide of manganese, is a substance con- 



taining a double portion of oxygen, part of which 

 is feebly held, and very willing to go. Its use in 

 making chlorine, depends on this fact. The loosely 

 held oxygen, seizes upon the hydrogen of the muri- 

 atic acid, remaining with it as water, and at the same 

 time setting its chlorine at liberty. 



355. A SIMPLER METHOD. Acids expel 



Describe an- . - , , . , , 



other method chlorine from many bases which have 

 of preparing prev iously been made to absorb it. 



chlorine f 



Lime is one of these bases. Bring 

 into a wide-mouthed, half-pint vial, a table 

 spoonful of dilute sulphuric acid, and add 

 rather more than the same bulk of chlo- 

 ride of lime, or bleaching powder. It is best 

 to add it in small portions, covering the vial 

 with a cork or bit of glass, after each addition. 

 The vial will soon be filled with faintly green chlorine 

 gas. More of the materials will be required, if the 

 chloride of lime is deteriorated by exposure to the air, 

 as is often the case. The gas thus produced, may be 

 used for most of the experiments which follow, with- 

 out transferring it to another vessel. 



356. CHLORINE, HEAVIER THAN 

 that chlorine AIR. This is already imperfectly 

 lhan *af P roved ; in the first method of col- 

 lecting chlorine, but the follow- 

 ing proof is more satisfactory. The gas pro- 

 duced in the last experiment, may be slowly 

 poured 'from the vessel containing it, into 



