Flame. 195 



set free.another portion, and so on until the stock 

 of hydrogen is exhausted. A common lamp or can- 

 dle is a gas-manufacturing apparatus where the burn- 

 in-- of one portion of the gas, while it gives light 

 and heat, as though that were its only office, is set- 

 ting free another portion to renew the flame. The 

 flame is constantly consumed, and yet never grow- 

 ing less. A third property of hydrogen that fits it 

 for illuminating purposes is, that its product with 

 oxygen is water, which, intensely heated at the in- 

 stant of its formation, passes off in an invisible form, 

 neither obscuring the light nor doing injury to the 

 air. But hydrogen alone is not sufficient to produce 

 light. It gives thine and heat, but there is a want 

 of brilliancy. Even the compound blow-pipe flame, 

 giving the most intense heat produced by combus- 

 tion, would be almost useless of itself for illumina- 

 tion. And here we have another remarkable pro- 

 perty of hydrogen, that fits it for giving light. 

 Whenever it is produced by heat, from organic sub- 

 stances, it brings off in combination with it a por- 

 tion of carbon. This carbon is set free as minute 

 particles of charcoal in the hydrogen flame, and for 

 a moment these thousand points of white hot car- 

 bon glow with intense heat, and give us the light of 

 the common flame. The next moment they are 

 burned to invisible gas, while another series takes 

 their place. How nicely all these affinities must be 

 balanced. Suppose the affinities were changed so 

 that the carbon should burn first, we should have 

 heat, but no sufficient light. Or if the affinity of 



