CHAPTER XIX. 



DISTILLATION. 



54. DISTILLATION OF WATER AND ALCOHOL. 



i. How to obtain water from the air. Put some pieces of ice into a 

 test-tube, or other glass vessel, which is clean and dry on the outside. In 

 a few minutes the outer surface of the vessel will become covered with 

 moisture. 



If ice is not available, put a little ether in a test- tube and make it evaporate 

 quickly by blowing vigorously down a narrow tube on to the surface of the 

 ether. As the air is cooled by the evaporation of the ether, the moisture 

 in the outside air is deposited on the outside of the test-tube in the form 

 of minute drops ; in other words, the water vapour in the air is changed to a 

 liquid. 



FIG. 86. As the water boils it is converted into steam, and this steam 

 is condensed again into water in the cooled flask. 



ii. The distillation of water. Obtain a glass retort containing some 

 ordinary tap-water coloured with ink and in which some sand has been 



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