COMBUSTION IN OXYGEN. 95 



and burning in it most brilliantly, as you see. 

 And now let me tell you another thing, or you 

 will go away with a very imperfect notion of 

 the powers and effects of this affinity. There 

 you see some charcoal burning in oxygen. 

 Well, a piece of lead will burn in oxygen just 

 as well as the charcoal does, or indeed better, 

 for absolutely that piece of lead will act at once 

 upon the oxygen as the copper did in the other 

 vessel with regard to the chlorine. And here 

 also a piece of iron ; if I light it and put it into 

 the oxygen, it will burn away just as the carbon 

 did. And I will take some lead and show you 

 that it will burn in the common atmospheric 

 oxygen at the ordinary temperature. These 

 are the lumps of lead which you remember we 

 had the other day the two pieces which 

 clung together. Now these pieces, if I take 

 them to day and press them together, will not 

 stick, and the reason is that they have attracted 

 from the atmosphere a part of the oxygen there 

 present, and have become coated as with a 

 varnish by the oxide of lead, which is formed 

 on the surface, by a real process of combustion 

 or combination. There you see the iron burn- 

 ing very well in oxygen, and I will tell you the 



