CHAPTER XVI 

 WATER 



89. The composition of water can be determined by 

 decomposing it with an electric current after a few drops 



of acid have been added so that 

 it will conduct electricity. Two 

 tubes filled with water, each 

 one containing a platinum elec- 

 trode, are connected with an 

 electric battery or other cur- 

 rent-producing apparatus with 

 an electro-motive force of two 

 or more volts. As the water is 

 decomposed, one gas will col- 

 lect in one of the tubes and .the 

 other gas in the other tube. 

 When these gases are tested it 

 will be found that one is hydro- 

 gen and the other oxygen. The 

 tube containing hydrogen will 

 have twice as much gas by vol- 

 ume as the one containing oxy- 

 gen. This shows that water is 

 composed of two parts hydrogen 

 and one part oxygen, by volume. 



gases is as follows: The tube 

 which has the greater amount of gas is supposed to con- 



