FORMATION OF WATER FROM ITS ELEMENTS. 75 



I will now fill this large bell-jar (F) with 

 water ; and I propose letting the gas ascend 

 into it, and I will then show you that we can 

 reproduce the water back again from the 

 vapour or air that is there. Here is a strong 

 glass vessel (G), and into it we will let the gas 

 (from F) pass. We will there fire it by the 

 electric spark, and then after the explosion you 

 will find that we have got the water back again ; 

 it will not be much, however, for you will 

 recollect that I showed you how small a portion 

 of water produced a very large volume of 

 vapour. Mr. Anderson will now pump all the 

 air out of this vessel (a), and when I have 

 screwed it on to the top of our jar of gas (F), 

 you will see upon opening the stopcocks (H' H H) 

 the water will jump up, showing that some of 

 the gas has passed into the glass vessel. I will 

 now shut these stopcocks, and we shall be able 

 to send the electric spark through the gas by 

 means of the wires (i, K) in the upper part of 

 the vessel, and you will see it burn with a most 

 intense flash. [Mr. Anderson here brought a 

 Leyden jar, which he discharged through the 

 confined gas by means of the wires i, K.] You 

 saw the flash, and now that you may see that 



