214 CHEMISTRY. 



yellow flame. Compounds of sodium are most abundant in 

 nature. 



295. Experiment. A very neat experiment can be tried 

 showing the decomposition of water by sodium. Boil some 

 water for about fifteen minutes in order to expel the air from 

 it, and after it is cool fill a bowl and a test-tube with it. 



Close the test-tube with the finger, and invert 

 it under the water in the bowl, as seen in 

 Fig. 88. Throw a bit of sodium on the wa- 

 ter, catch it witli a spoon of wire gauze, and 

 thrust it quickly to the opening of the test- 

 tube, and disengage it from the spoon by 

 turning it over. As it is lighter than water, 

 it will rise at once to the top of the tube, and there will 

 busy itself in decomposing the water. By taking the oxy- 

 gen of the water and half the hydrogen the sodium becomes 

 sodium hydrate, and the rest of the hydrogen, being thus 

 set free, accumulates in the tube, forcing down the water 

 that is in it. When the sodium has all disappeared, close 

 the tube with the finger, and remove it from the vessel. If 

 now, holding the tube with its, opening upward, you apply 

 a light to it, the hydrogen will burst into a flame. 



296. Common Salt. The chloride of sodium, NaCl, is the 

 most abundant and important of the compounds of this 

 metal. This salt is composed of two elements that are en- 

 tirely different from the compound which they form. One 

 of them is a gas, which is so suffocating that no one can 

 breathe it undiluted and live. The other is a metal, which 

 has such an affinity for oxygen that if it were introduced 

 into your mouth it would set the moisture there on fire in 

 seizing its oxygen. And yet the compound which these two 

 elements make is a very mild substance, which we take into 

 our mouths every day in our food. It is most widely dif- 

 fused in the animal and vegetable as well as the mineral 



