PREPARATION OF HYDROGEN. 



85 



water which enable other bodies to burn), we 

 will now consider the other constituent of water, 

 and without embarrassing you too much with 

 the way in which these things are made, I will 

 proceed now to show you our common way of 

 making hydrogen. (I called it hydrogen yes- 

 terday it is so called because it helps to gene- 

 rate water.)* I put into this retort some zinc, 

 water, and oil of vitriol, and immediately an 

 action takes place, which produces an abundant 

 evolution of gas, now coming over into this jar, 

 and bubbling up in appearance exactly like the 

 oxygen we obtained yesterday. 



Fig. 27. 



The processes you see are very different, 



5o>p, " water,'* and 7ewaw, " I generate." 

 G 3 



