92 CHEMICAL AFFINITY. 



would follow. [A lighted match was brought 

 to the mixture, which immediately exploded 

 with a sudden flash, evolving a dense white 

 smoke.] There you see the result of the action 

 of chemical affinity, overcoming the attraction of 

 cohesion of the particles. Again, here is a little 

 sugar ( 18 ), quite a different substance from the 

 black sulphuret of antimony, and you shall see 

 what takes place when we put the two together. 

 [The mixture was touched with sulphuric acid, 

 when it took fire and burnt gradually and with 

 a brighter flame than in the former instance.] 

 Observe this chemical affinity travelling about 

 the mass, and setting it on fire, and throwing 

 it into such wonderful agitation! 



I must now come to a few circumstances 

 which require careful consideration. We have 

 already examined one of the effects of this 

 chemical affinity but to make the matter 

 more clear we must point out some others. 

 And here are two salts dissolved in water. ( l9 ) 

 They are both colourless solutions, and in these 

 glasses you cannot see any difference between 

 them. But if I mix them, I shall have chemical 

 attraction take place. I will pour the two 

 together into this glass, and you will at once 



