202 METALLOIDS. 



drogen, as it would be in water. Re-charge the gas 

 bottle, if necessary, and hang a second large-mouthed 

 vial above it, as represented in the figure. Af- 

 ter a few minutes, it may be presumed that 

 the tipper vial is filled with hydrogen. Apply 

 a lighted match to its mouth, and the gas will 

 inflame, and continue to burn with a faint 

 light. Introduce a second taper, as represent- 

 ed in the figure. It will be kindled at the 

 mouth of the bottle, and again extinguished 

 above. The match is extinguished, because, a little 

 abo've the mouth of the vial, there is no oxygen to sup- 

 port the combustion of the carbon and hydrogen, of 

 which it is composed. 



500. HYDROGEN MADE BY THE METAL 



Describe the ./*,-, 



preparation SODIUM. Another very beautiful, but more 

 expensive method of making hydrogen 



gas, is as follows. Fasten a piece of me- 

 tallic sodium, of the size of a pep- 

 per-corn, upon the end of a wire, and 

 thrust it suddenly under the end of 

 a test-tube filled with water, and held 

 very near the surface, as represented 

 in the figure. The metal melts as soon as it touches 

 the water, and rises to the top of the tube. Hydrogen 

 is immediately formed, and displaces the water, fill- 

 ing the tube rapidly with the liberated gas. 

 Explain the 501. EXPLANATION. Sufficient heat is 

 process. evolved by the action of sodium on water 



to fuse it at once. The metal is lighter than water, 

 and therefore rises to the top of the tuba. At this 



