CHEMICAL AFFINITY 55 



into a solid body a wonderful manifestation of chemical 

 affinity? 



There is another remarkable circumstance in chemical 

 affinity, which is, that it is capable of either waiting or acting 

 at once. And this is very singular, because we know of noth- 

 ing of the kind in the forces either of gravitation or co- 

 hesion. For instance: here are some oxygen particles, and 

 here is a lump of carbon particles. I am going to put the 

 carbon particles into the oxygen ; they can act, but they do 

 not they are just like this unlighted candle. It stands here 

 quietly on the table, waiting until we want to light it. But it 

 is not so in this other case: here is a substance, gaseous like 

 the oxygen, and if I put these particles of metal into it thf 

 two combine at once. The copper and the chlorine unite by 

 their power of chemical affinity, and produce a body entirely 

 unlike either of the substances used. And in this other case, 

 it is not that there is any deficiency of affinity between the 

 carbon and oxygen, for the moment I choose to put them in 

 a condition to exert their affinity, you will see the difference. 

 [The piece of charcoal was ignited, and introduced into the 

 jar of oxygen, when the combustion proceeded with vivid 

 scintillations.] 



Now this cheniical action is set going exactly as it would 

 be if I had lighted the candle, or as it is when the servant 

 puts coals on and lights the fire : the substances wait until we 

 do something which is able to start the action. Can any 

 thing be more beautiful than this combustion of charcoal in 

 oxygen? You must understand that each of these little 

 sparks is a portion of the charcoal, or the bark of the char- 

 coal thrown off white hot into the oxygen, 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 



