CHEMICAL AFFINITY 53 



Whenever oxygen and hydrogen unite together they pro- 

 duce water, and you have seen the extraordinary difference 

 between the bulk and appearance of the water so produced 

 and the particles of which it consists chemically. Now we 

 have never yet been able to reduce either oxygen or hydro- 

 gen to the liquid state; and yet their first impulse, when 

 chemically combined, is to take up first this liquid condition 

 and then the solid condition. We never combine these dif- 

 ferent particles together without producing water; and it is 

 curious to think how often you must have made the experi- 

 ment of combining oxygen and hydrogen to form water 

 without knowing it. Take a candle, for instance, and a clean 

 silver spoon (or a piece of clean tin will do), and, if you 

 hold it over the flame, you immediately cover it with dew 

 not a smoke which presently evaporates. This, perhaps, 

 will serve to show it better. Mr. Anderson will put a candle 

 under that jar, and you will see how soon the water is pro- 

 duced (Fie. 30). Look at that dimness on the sides of the 

 glass, which will soon produce drops, 

 and trickle down into the plate. 

 Well, that dimness and these drops 

 are water, formed by the union of 

 the oxygen of the air with the hydro- 

 gen existing in the wax of which 

 that candle is formed. 



And now, having brought you, in 

 the first place, to the consideration of 

 chemical attraction, I must enlarge 

 your ideas so as to include all sub- FlG * 3 



stances which have this attraction for each other; for 

 it changes the character of bodies, and alters them in 

 this way and that way in the most extraordinary man- 

 ner, and produces other phenomena wonderful to think 

 about. Here is some chlorate of potash, and there 

 some sulphuret of antimony ( w ). We will mix these two 

 different sets of particles together and I want to show 

 you, in a general sort of way, some of the phenomena which 



ie Chlorate of potash and sulphuret of antimony. Great care must be 

 taken in mixing these substances, as the mixture is dangerously explosive. 

 They must be powdered separately and mixed together with a feather on a 

 beet of paper, or by passing them several times through a small sieve. 



