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maining in the vessel, when I hold it upside down, that I 

 produced during the experiment with the iron barrel. This 

 is what we get from water, the same substance which is 

 contained in the candle. 



Let us now trace distinctly the connection between these 

 two points. This is hydrogen a body classed among those 



FIG. 70 



things which in chemistry we call elements, because we can 

 get nothing else out of them. A candle is not an elementary 

 body, because we can get carbon out of it; we can get this 

 hydrogen out of it, or at least out of the water which it sup- 

 plies. And this gas has been so named hydrogen, because it 

 is that element which, in association with another, generates 

 water.* Mr. Anderson having now been able to get two or 

 three jars of gas, we shall have a few experiments to make, 

 and I want to show you the best way of making these 

 experiments. I am not afraid to show you, for I wish you to 

 make experiments, if you will only make them with care and 

 attention, and the assent of those around you. As we advance 

 in chemistry we are obliged to deal with substances which 

 are rather injurious if in their wrong places; the acids, and 

 heat, and combustible things we use might do harm if care- 

 lessly employed. If you want to make hydrogen, you can 

 make it easily from bits of zinc, and sulphuric or muriatic 

 acid. Here is what in former times was called the " philoso- 

 pher's candle." It is a little phial with a cork and a tube or 

 pipe passing through it. And I am now putting a few little 

 pieces of zinc into it. This little instrument I am going to 

 apply to a useful purpose in our demonstrations, for I want 

 to show you that you can prepare hydrogen, and make some 



* 'Yfiwp, " water." and yewow, " I generate." 



